Very lean yet still gobbles fuel (long)
11-15-2007, 01:19 AM
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Very lean yet still gobbles fuel (long)
I have searched and read YT for 2 hours but couldn't find answers.
My 1992 3vze auto I has a very lean mixture, which I can tell from spark plugs (having tiny aluminium dots on the ground ring on dry black deposits and whitish color for other areas). Also the truck lacks power. Big time.
I have already checked cat - it is not clogged. Idles beautifully, no misfires. Fuel filter, distributor, injectors, O2 sensor, TPS and spark plugs serviced recently.
I am worried driving like this, although I drive like a grandpa yet still I am afraid to damage the engine. If I had a vacuum leak, wouldn't my idle be screwed? It is actually beautiful, very even and the engine is quiet. Ignition timing is something I have played with some time ago and currently am at around 10 degrees. Last time I checked spark plugs all of them were in an equal state (looked OK apart from the lean indication), so to me ignition system seems to be OK. Something must be going on in fuel system or ECU must be confused into thinking something that forces it to lean out the mixture...
When I start it in the morning if I give it just a tiny amount of gas it starts from half turn. If I don't touch gas pedal it needs a few turns before it starts. When it is hot and I start it after some time sitting there, no matter if I give it gas or not I have to turn it quite a few times and often it only starts from second attempt. Does this indicate a lean mixture so that while the cold start injector is running the mixture is rich enough but when it is hot it is just too lean to start? How can I separate my investigation (and what to check) into 1. ECU-related, i.e. sensors (?) and 2. Fuel system related, i.e. pump, FPR etc.? I have shorted fuel pump contacts in diagnostic plug before starting the truck to see if it makes difference but it didn't.
The other thing is fuel consumption - it is around 16-17mpg on the open road and something like 9 in the city...The latter could be related with other problems I might have (no sufficient flow of coolant for ECU to sense the temperature and it thinks engine is cold or something like that ??).
I heard that quite a few people get 16-17mpg on the road but also heard others get that driving in the city. Any ideas where should I look to diagnose poor city mileage causes?
From the mods I have only adjusted AFM some time ago, it is 3 or 4 teeth "richer" that it was originally at the moment.
I've tried to give as much information as possible, would be really great to hear different experiences from you guys.
My 1992 3vze auto I has a very lean mixture, which I can tell from spark plugs (having tiny aluminium dots on the ground ring on dry black deposits and whitish color for other areas). Also the truck lacks power. Big time.
I have already checked cat - it is not clogged. Idles beautifully, no misfires. Fuel filter, distributor, injectors, O2 sensor, TPS and spark plugs serviced recently.
I am worried driving like this, although I drive like a grandpa yet still I am afraid to damage the engine. If I had a vacuum leak, wouldn't my idle be screwed? It is actually beautiful, very even and the engine is quiet. Ignition timing is something I have played with some time ago and currently am at around 10 degrees. Last time I checked spark plugs all of them were in an equal state (looked OK apart from the lean indication), so to me ignition system seems to be OK. Something must be going on in fuel system or ECU must be confused into thinking something that forces it to lean out the mixture...
When I start it in the morning if I give it just a tiny amount of gas it starts from half turn. If I don't touch gas pedal it needs a few turns before it starts. When it is hot and I start it after some time sitting there, no matter if I give it gas or not I have to turn it quite a few times and often it only starts from second attempt. Does this indicate a lean mixture so that while the cold start injector is running the mixture is rich enough but when it is hot it is just too lean to start? How can I separate my investigation (and what to check) into 1. ECU-related, i.e. sensors (?) and 2. Fuel system related, i.e. pump, FPR etc.? I have shorted fuel pump contacts in diagnostic plug before starting the truck to see if it makes difference but it didn't.
The other thing is fuel consumption - it is around 16-17mpg on the open road and something like 9 in the city...The latter could be related with other problems I might have (no sufficient flow of coolant for ECU to sense the temperature and it thinks engine is cold or something like that ??).
I heard that quite a few people get 16-17mpg on the road but also heard others get that driving in the city. Any ideas where should I look to diagnose poor city mileage causes?
From the mods I have only adjusted AFM some time ago, it is 3 or 4 teeth "richer" that it was originally at the moment.
I've tried to give as much information as possible, would be really great to hear different experiences from you guys.
Last edited by tomasp; 11-15-2007 at 01:47 PM. Reason: TPS was also adjusted recently
11-15-2007, 02:27 PM
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check your O2 sensor voltage while idling and at 2000 RPM with no load. You should see the voltage swing back and forth between .2V - .8V also check the VF voltage this is indicative of overall fuel trim. about 2.5V is optimum with less indicating that the ECM is detecting a rich mixture and is reducing the amount of fuel injected. More indicates a lean condition and the ECM is adding more fuel.
Here is a link to more info about the VF voltage
http://www.jnc.farpost.com/data/vfoutput.txt
Have you checked the fuel pressure and volume? These are basic checks that should be checked anytime you are chasing a "lean" condition.
Here is a link to more info about the VF voltage
http://www.jnc.farpost.com/data/vfoutput.txt
Have you checked the fuel pressure and volume? These are basic checks that should be checked anytime you are chasing a "lean" condition.
11-15-2007, 03:27 PM
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Thanks Targetnut, I will do those checks today/tomorrow. This is exactly what I wanted to hear. As for the pressure - no, unfortunately I don't have the equipment to do that 
Just to confirm - Vf can be found in the diagnostic plug, right? This should help me, I wanted to see what the ECU is doing with the mixture.
What stumps me is that while I have all "lean" indications the truck still uses a lot of gas. Another theory is that those aluminium deposits may have been caused by pinging (I run higher grade petrol because on normal it pings a lot, possible due to the low quality of fuel here). With higher grade petrol it still pings however only on a light load and not a lot.
O2 sensor has been replaced with the OEM part not so long ago and it fixed my _extremely_ bad gas mileage plus got rid of the rotten eggs smell from the exhaust.
Once I know what ECU is doing, I have made the following list to check:
- Coolant temperature sensor: checked it already some time ago, will re-check
- VAFM: will set it back to stock and re-chech with ohmmeter.
- Will try to find any vacuum leaks with propane torch
- Will try to squeeze the intake hose to see if there are changes in idle (possible cracks/splits)
- Will check ground wires around plenum
- While idling there is a sound coming from the air box like something is lose there and rattling inside. I have looked already and there is nothing, the VAFM door is sitting still and moving smoothly. Maybe something in the resonator box?
I would love to check the fuel pressure but am afraid will have to leave it as a last resort unless there is a dyi way to check it.
One theory for the bad gas mileage I have is that the cold start injector may be leaking, I am tempted to take it out and have a look while connected and pump running.
What do you think? Thanks again
Just to confirm - Vf can be found in the diagnostic plug, right? This should help me, I wanted to see what the ECU is doing with the mixture.
What stumps me is that while I have all "lean" indications the truck still uses a lot of gas. Another theory is that those aluminium deposits may have been caused by pinging (I run higher grade petrol because on normal it pings a lot, possible due to the low quality of fuel here). With higher grade petrol it still pings however only on a light load and not a lot.
O2 sensor has been replaced with the OEM part not so long ago and it fixed my _extremely_ bad gas mileage plus got rid of the rotten eggs smell from the exhaust.
Once I know what ECU is doing, I have made the following list to check:
- Coolant temperature sensor: checked it already some time ago, will re-check
- VAFM: will set it back to stock and re-chech with ohmmeter.
- Will try to find any vacuum leaks with propane torch
- Will try to squeeze the intake hose to see if there are changes in idle (possible cracks/splits)
- Will check ground wires around plenum
- While idling there is a sound coming from the air box like something is lose there and rattling inside. I have looked already and there is nothing, the VAFM door is sitting still and moving smoothly. Maybe something in the resonator box?
I would love to check the fuel pressure but am afraid will have to leave it as a last resort unless there is a dyi way to check it.
One theory for the bad gas mileage I have is that the cold start injector may be leaking, I am tempted to take it out and have a look while connected and pump running.
What do you think? Thanks again
11-15-2007, 03:47 PM
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Hi KillaB,
All injectors were pulled out and cleaned with ultrasound in the racing shop, also all seals replaced by OEM and flow checked to be OK.
VAFM to be honest does not change things significantly, it is more of a very fine tuning, i.e. if you live at altitude you can lean things out just a little bit with it, but no way it can cause huge impact on anything.
I had it at different settings - stock, richer, leaner, way richer, way leaner - now it is a bit richer just to stop pinging.
Cheers
All injectors were pulled out and cleaned with ultrasound in the racing shop, also all seals replaced by OEM and flow checked to be OK.
VAFM to be honest does not change things significantly, it is more of a very fine tuning, i.e. if you live at altitude you can lean things out just a little bit with it, but no way it can cause huge impact on anything.
I had it at different settings - stock, richer, leaner, way richer, way leaner - now it is a bit richer just to stop pinging.
Cheers
11-15-2007, 04:38 PM
#6
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to test the fuel pressure is not hard, you can tap into the system at the cold start injector.
Yes the VF and O2(oxy) are in the diagnostic connector.
Oh, 3-4 teeth on the AFM is a huge adjustment. Usually 1 or maybe 2 will get results.
I'm thinking that when all is said and done, you'll find your problem is not a lean mixture.
Yes the VF and O2(oxy) are in the diagnostic connector.
Oh, 3-4 teeth on the AFM is a huge adjustment. Usually 1 or maybe 2 will get results.
I'm thinking that when all is said and done, you'll find your problem is not a lean mixture.
11-17-2007, 05:03 AM
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Have you done a compression test?
Sounds like a head gasket leak / damage to cyl walls (common from HG leaks.)
+1 on the 3-4 teeth is bad. Way too much even on a heavily modded motor. Put this back to stock (if you know what that is) and make sure you seal the lid back down. And do a compression test.
16-17 hwy is good and should be considered normal. 9 in the city is not normal unless you have a lead foot.
Also check your timing. My experience is that stock 10-12? is still too retarded. Crank it up a little more. I run like 25? on mine, then again I've polished the turd as far as it'll go.
Sounds like a head gasket leak / damage to cyl walls (common from HG leaks.)
+1 on the 3-4 teeth is bad. Way too much even on a heavily modded motor. Put this back to stock (if you know what that is) and make sure you seal the lid back down. And do a compression test.
16-17 hwy is good and should be considered normal. 9 in the city is not normal unless you have a lead foot.
Also check your timing. My experience is that stock 10-12? is still too retarded. Crank it up a little more. I run like 25? on mine, then again I've polished the turd as far as it'll go.
Last edited by MonsterMaxx; 11-17-2007 at 05:05 AM.
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11-18-2007, 12:00 PM
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MonsterMaxx:
No, haven't done compression test as I can't see any symptoms of HG problems, fingers crossed won't come to it.
All:
Couldn't log in to YT for last couple of days to write the update.
I have put timing to ~11 degrees, also put AFM back to where it was originally. Reset the ECU. Re-gapped all spark plugs (the gap was a bit wider). All spark plugs look good. Tested AFM with ohmmeeter and voltmeter according to FSM, all good there, nice change to 5V to 0. Also measured resistances in it so if someone's AFM gets bad and they feel adventurous, you should be able to fix it by soldering in chip resistors.
Also measured feedback voltage and Ox sensor voltage, it was 2.8V for learned and 0.48V for Ox sensor - so apparently the mix ECU sees is not abnormal - which can also be confirmed from spark plugs, I guess...
Checked ECU - no codes.
Anyway, obviously now it is a bit peppier (as my timing was like 8-9 degrees) and more detonation. Still, it is not too bad but from what I know about cars (and I know a bit) it is not normal.
One thing I have to note: the car behaves normally until it reaches 3000 rpm, as soon as it does, there seems to be very little increase in torque after that although the sound of the engine become rumbling, like roaring, not sure how to describe. Don't get me wrong, it goes,if you want to thrash it it will go, but there is definite loss of power at 3000 rpm sharp and over.
What's next? I have following theories
- Restriction in the exhaust. I have read before that plugged cat results in no high end power, well even if I checked it and it was fine, could it be my muffler? I may unbolt cat and try driving around in the countryside to confirm this or rule it out.
- Spark plug wires - they appear to be original from 1992. Also I heard that sometimes old wires behave OK on idle and light load but at higher RPMs start to break the insulation? I am not in position to spend a lot of money at the moment on the car and the wires are like $190 from the dealer here (unbelievable) so if I have to get them I may have to get them from US somehow. This is the only "tune-up" part that I haven't replaced yet.
- Fuel system. Maybe not enough fuel pressure on high load (read about someone having poor wiring to the pump that caused similar issues). Probably not as I can rev up to redline and as I said, if you thrash it, it will rev and go - the sound will be terrible. What I want to say is that it does rev if required.
- Tranny? Have no complains about the tranny, shifts and behaves very well in general, really really hope it is not it.
Other things to note:
1. Coolant level. I am very cautious about the HG so try never to go too hard and monitor coolant level very closely. I was losing it (and still am) however I believe it was due to the faulty radiator cap (replaced and helped a lot) and currently I have a leak somewhere (blue liquid, can't track where from, I suspect water pump weep hole). There were never symptoms of overheating.
2. Idle. While I said it is very even, I must say it is such only when in "D", when in neutral/park the car kind-of shakes very slightly in an even pattern. Does it mean misfire?
3. I had code 14 a few times over last year, it would appear after weeks or months since resetting the ECU, however currently there are no codes at all for at least a few months...
Anyone else any other ideas? At this stage it looks like the mixture is fine, the high fuel consumption probably is caused by some restriction fo the engine...
Thanks everyone for the feedback.
No, haven't done compression test as I can't see any symptoms of HG problems, fingers crossed won't come to it.
All:
Couldn't log in to YT for last couple of days to write the update.
I have put timing to ~11 degrees, also put AFM back to where it was originally. Reset the ECU. Re-gapped all spark plugs (the gap was a bit wider). All spark plugs look good. Tested AFM with ohmmeeter and voltmeter according to FSM, all good there, nice change to 5V to 0. Also measured resistances in it so if someone's AFM gets bad and they feel adventurous, you should be able to fix it by soldering in chip resistors.
Also measured feedback voltage and Ox sensor voltage, it was 2.8V for learned and 0.48V for Ox sensor - so apparently the mix ECU sees is not abnormal - which can also be confirmed from spark plugs, I guess...
Checked ECU - no codes.
Anyway, obviously now it is a bit peppier (as my timing was like 8-9 degrees) and more detonation. Still, it is not too bad but from what I know about cars (and I know a bit) it is not normal.
One thing I have to note: the car behaves normally until it reaches 3000 rpm, as soon as it does, there seems to be very little increase in torque after that although the sound of the engine become rumbling, like roaring, not sure how to describe. Don't get me wrong, it goes,if you want to thrash it it will go, but there is definite loss of power at 3000 rpm sharp and over.
What's next? I have following theories
- Restriction in the exhaust. I have read before that plugged cat results in no high end power, well even if I checked it and it was fine, could it be my muffler? I may unbolt cat and try driving around in the countryside to confirm this or rule it out.
- Spark plug wires - they appear to be original from 1992. Also I heard that sometimes old wires behave OK on idle and light load but at higher RPMs start to break the insulation? I am not in position to spend a lot of money at the moment on the car and the wires are like $190 from the dealer here (unbelievable) so if I have to get them I may have to get them from US somehow. This is the only "tune-up" part that I haven't replaced yet.
- Fuel system. Maybe not enough fuel pressure on high load (read about someone having poor wiring to the pump that caused similar issues). Probably not as I can rev up to redline and as I said, if you thrash it, it will rev and go - the sound will be terrible. What I want to say is that it does rev if required.
- Tranny? Have no complains about the tranny, shifts and behaves very well in general, really really hope it is not it.
Other things to note:
1. Coolant level. I am very cautious about the HG so try never to go too hard and monitor coolant level very closely. I was losing it (and still am) however I believe it was due to the faulty radiator cap (replaced and helped a lot) and currently I have a leak somewhere (blue liquid, can't track where from, I suspect water pump weep hole). There were never symptoms of overheating.
2. Idle. While I said it is very even, I must say it is such only when in "D", when in neutral/park the car kind-of shakes very slightly in an even pattern. Does it mean misfire?
3. I had code 14 a few times over last year, it would appear after weeks or months since resetting the ECU, however currently there are no codes at all for at least a few months...
Anyone else any other ideas? At this stage it looks like the mixture is fine, the high fuel consumption probably is caused by some restriction fo the engine...
Thanks everyone for the feedback.
Last edited by tomasp; 11-18-2007 at 12:45 PM.
11-18-2007, 04:35 PM
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exhaust restriction could result in your symptom,
but so could a fuel supply issue. the fuel pump may just be able to keep up at idle but not able to supply a sufficient volume of fuel at higher loads resulting in it leaning out and loosing power,
this could also result in pinging.
but so could a fuel supply issue. the fuel pump may just be able to keep up at idle but not able to supply a sufficient volume of fuel at higher loads resulting in it leaning out and loosing power,
this could also result in pinging.
11-18-2007, 06:06 PM
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Other things popped in my mind - TVV and fuel dampener....Will try to lay on the engine tonight to inspect both TVV and dampener. I used to have fuel smell outside the vehicle after parking in the garage but it seemed to be more at the rear of it, not in the engine bay (but maybe it was blown there by the fan).
So if I had to check fuel pressure - do I have to use some special gauge or just usual air gauge? Never done that before, sorry for dumb question.
So if I had to check fuel pressure - do I have to use some special gauge or just usual air gauge? Never done that before, sorry for dumb question.
Last edited by tomasp; 11-18-2007 at 06:57 PM.
11-18-2007, 09:20 PM
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OK - checked TVV and the dampener. Dampener appears to be fine, dry, the screw is in place.
TVV however has one of the nipples snapped. Apparently previous owner or a garage broke it off and just sealed the tube to the charcoal canister and where the nipple was with silicone. Now - how critical is to have this valve going? I mean what is the impact of not having it? I really intend to fix it but if it is not critical would rather not take whole plenum off right now...
What I can't understand (or find logic there) is: if there is a problem with fuel supply, why would it consume so much petrol? I'd say it wouldn't go well but it wouldn't use much petrol neither...Exhaust could explain that, i.e. if it was plugged then I would use "lead foot" just so that it keeps going and that would just use more petrol with no gain...Still trying to research that fuel pressure measurement...
TVV however has one of the nipples snapped. Apparently previous owner or a garage broke it off and just sealed the tube to the charcoal canister and where the nipple was with silicone. Now - how critical is to have this valve going? I mean what is the impact of not having it? I really intend to fix it but if it is not critical would rather not take whole plenum off right now...
What I can't understand (or find logic there) is: if there is a problem with fuel supply, why would it consume so much petrol? I'd say it wouldn't go well but it wouldn't use much petrol neither...Exhaust could explain that, i.e. if it was plugged then I would use "lead foot" just so that it keeps going and that would just use more petrol with no gain...Still trying to research that fuel pressure measurement...
Last edited by tomasp; 11-18-2007 at 09:25 PM.
11-18-2007, 10:14 PM
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my 93 3.0 used to be like that. ran crazy lean and crazy hot. NO power and about 13mpg. so i sold it. and bought a '79. before i sold the 3.0 i put a new cat on and smogged it, seemed to run great after that... the oem cat was thrashed and starting to melt.
11-19-2007, 04:44 PM
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Yesterday I have bypassed TVV valve completely. Figured it was better than the disabled vent system...Well one thing for sure - my fuel tank ain't like a bomb anymore. It used to hiss at me when opening tank cap but no more. I also checked the idle screw in the TB (read on YT) and its o'ring is a bit suspicious, bought a couple to replace it today. It may not be a huge vacuum leak (if any) but that will be taken care of. During the weekend will try to take the cat out and drive around for test.
11-19-2007, 06:19 PM
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Hi Nate,
Thanks for the reply. I have replaced O2 sensor with the new gasket and it is tightened good...can't see any black soot around it - any other way I can check it?
Thanks for the reply. I have replaced O2 sensor with the new gasket and it is tightened good...can't see any black soot around it - any other way I can check it?
11-25-2007, 05:42 PM
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Alright, the update.
I took the cat out and drove around with virtually no exhaust. That was done in the countryside but it was still scary. I can say that without the exhaust the engine revs up way quicker and it seems that there is more power overall. I guess that can be expected as restrictive exhaust has been eliminated. There was no magic "wow it goes" after 3000rpm though, of course it was better but not impressive. Overall I'd say it probably pays to get a less restrictive exhaust just to save on some gas and gain a couple of hp (butt dyno tells me).
I was talking to my buddy mechanic and he suggested that my problems could well be caused by the auto tranny. He suggested to service it. This theory also makes sense, I got the truck around 16 months ago and didn't service the tranny and have no history of it. The fluid looks good and red, no smell. I guess I will follow one of the threads here on YT, drop the pan, clean it, replace the filter and completely flush the tranny.
Other than that I have fuel pressure theory (although without the exhaust I could easily and quickly rev it up to red line and didn't notice any issues? Wouldn't it bog a bit at 4-5000rpm? Or is it only if under load?) and compression test. God, I hope I'll find something before this last one
I took the cat out and drove around with virtually no exhaust. That was done in the countryside but it was still scary. I can say that without the exhaust the engine revs up way quicker and it seems that there is more power overall. I guess that can be expected as restrictive exhaust has been eliminated. There was no magic "wow it goes" after 3000rpm though, of course it was better but not impressive. Overall I'd say it probably pays to get a less restrictive exhaust just to save on some gas and gain a couple of hp (butt dyno tells me).
I was talking to my buddy mechanic and he suggested that my problems could well be caused by the auto tranny. He suggested to service it. This theory also makes sense, I got the truck around 16 months ago and didn't service the tranny and have no history of it. The fluid looks good and red, no smell. I guess I will follow one of the threads here on YT, drop the pan, clean it, replace the filter and completely flush the tranny.
Other than that I have fuel pressure theory (although without the exhaust I could easily and quickly rev it up to red line and didn't notice any issues? Wouldn't it bog a bit at 4-5000rpm? Or is it only if under load?) and compression test. God, I hope I'll find something before this last one
Last edited by tomasp; 11-25-2007 at 05:43 PM.
11-30-2007, 10:34 PM
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Bump.
Today I reviewed issues I have:
1. Pinging - definitely not normal
2. No power, especially after 3000rpm
3. Bad fuel mileage
Possible causes:
1. Auto tranny's old oil and clogged filter - would explain sluggishness until 3000rpm and fuel consumption
2. Plugged muffler / increased restriction in the exhaust - would explain power loss over 3000rpm and fuel consumption
3. Fuel pressure problem - could explain pinging.
Trying to get the logic together...
Today I reviewed issues I have:
1. Pinging - definitely not normal
2. No power, especially after 3000rpm
3. Bad fuel mileage
Possible causes:
1. Auto tranny's old oil and clogged filter - would explain sluggishness until 3000rpm and fuel consumption
2. Plugged muffler / increased restriction in the exhaust - would explain power loss over 3000rpm and fuel consumption
3. Fuel pressure problem - could explain pinging.
Trying to get the logic together...
12-10-2007, 12:48 AM
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OK, I have done the compression test.
Gauge used is a few years old used about 6 times.
#1 ~ 194 psi
#2 ~ 197 psi
#3 ~ 198 psi
#4 ~ 200 psi
#5 ~ 205 psi
#6 ~ 175 psi
The big question is can carbon buildup cause such big psi increases (30psi over factory standard) or is the gauge off? I can believe there is some carbon buildup because:
1. constant pinging
2. the way the truck drives (drove) would lead to its buildup
But can it be so high? If the gauge is not off (which I don't know but would think so, belongs to my buddy mechanic) then #6 has least of it because it has the highest temperatures = helps to burn it off.
Your thoughts, please? As I mentioned previously, there are no indications of HG failure at all. I have started looking for free flow exhaust, should I keep doing that?
Oh, I also looked at the plugs (they were done just a month or two ago), comments:
#1,2,5 were new, look like new
#3 - white "calcium" residue on the electrode. A little bit of yellow residue on the isolator inside
#4 - reddish residue on electrode, reddish isolator inside
#6 - white "calcium" residue on the electrode
Otherwise plugs look like they are supposed to.
Gauge used is a few years old used about 6 times.
#1 ~ 194 psi
#2 ~ 197 psi
#3 ~ 198 psi
#4 ~ 200 psi
#5 ~ 205 psi
#6 ~ 175 psi
The big question is can carbon buildup cause such big psi increases (30psi over factory standard) or is the gauge off? I can believe there is some carbon buildup because:
1. constant pinging
2. the way the truck drives (drove) would lead to its buildup
But can it be so high? If the gauge is not off (which I don't know but would think so, belongs to my buddy mechanic) then #6 has least of it because it has the highest temperatures = helps to burn it off.
Your thoughts, please? As I mentioned previously, there are no indications of HG failure at all. I have started looking for free flow exhaust, should I keep doing that?
Oh, I also looked at the plugs (they were done just a month or two ago), comments:
#1,2,5 were new, look like new
#3 - white "calcium" residue on the electrode. A little bit of yellow residue on the isolator inside
#4 - reddish residue on electrode, reddish isolator inside
#6 - white "calcium" residue on the electrode
Otherwise plugs look like they are supposed to.
Last edited by tomasp; 12-10-2007 at 12:57 AM.
12-13-2007, 06:18 PM
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BUMP - anyone? 
Today I went to the engine rebuilding shop to chat about my worries. They said to check #6 valve clearances as that may be causing the lower compression. As for the very high compression on others they said it is not likely to be just carbon (too much) but possibly last time heads were done they took a lot off them. What they definitely recommended is to free up exhaust asap to prevent real HG failures.
Would be good to hear from anyone here what they think. I now realise this thread probably is named wrong and is in a wrong forum (?) as it doesn't get a lot of responses
Today I went to the engine rebuilding shop to chat about my worries. They said to check #6 valve clearances as that may be causing the lower compression. As for the very high compression on others they said it is not likely to be just carbon (too much) but possibly last time heads were done they took a lot off them. What they definitely recommended is to free up exhaust asap to prevent real HG failures.
Would be good to hear from anyone here what they think. I now realise this thread probably is named wrong and is in a wrong forum (?) as it doesn't get a lot of responses
