rough idle, random misfires, and gremlins
11-23-2011, 01:57 PM
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rough idle, random misfires, and gremlins
91 toyota pickup 22re 2.4L
I'm going to try to make this short so its easy to read. I first noticed a rough idle, then a random engine shake. Think it might be a misfire, but I'm not sure. The misfires, or whatever is causing the engine shake is what is causing the vibration. Have replaced and cleaned many parts, but have yet to figure it out. The misfire, or shake seems random.
I'll make a list of parts replaced, but the last thing was the fuel injectors. I had them tested, 2 came back bad. I really thought I had it that time, but same problem was there. I replaced the TPS, but when I adjusted it to specification, I didn't have any acceleration. According to http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml it needs to be set at 81. I currently have it set to 77, because thats where it ran best.
I'm not loosing coolant or any other fluids, at least not much, and there is no sign of contamination in the oil.
list of things replaced
fan clutch
water pump
thermostat
belt
spark plugs
cap and rotor
alternator
fuel injectors
fuel injector connectors
fuel filter
coolant temp sensor
engine and trans mounts
O2 sensor
CAT
Fuel pressure regulator
coil
most of the vacuum hoses
List of things cleaned
throttle body
upper intake manifold
Charcoal canister
EGR vacuum modulator
EGR valve
IACV
AFM
And I checked the timing chain, guides, and have timed it.
My next guess is the fuel pump or ignition coil. I found a cheap ignition coil online for $15. Don't like the company, and I know its going to be cheap, but was thinking for $15, and the easy install it might be worth a shot.
So any thoughts or advice would be greatly appreciated. Not sure how much I can spend right now with the holidays almost here, but I will eventually get around to it, if not now.
I'm going to try to make this short so its easy to read. I first noticed a rough idle, then a random engine shake. Think it might be a misfire, but I'm not sure. The misfires, or whatever is causing the engine shake is what is causing the vibration. Have replaced and cleaned many parts, but have yet to figure it out. The misfire, or shake seems random.
I'll make a list of parts replaced, but the last thing was the fuel injectors. I had them tested, 2 came back bad. I really thought I had it that time, but same problem was there. I replaced the TPS, but when I adjusted it to specification, I didn't have any acceleration. According to http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml it needs to be set at 81. I currently have it set to 77, because thats where it ran best.
I'm not loosing coolant or any other fluids, at least not much, and there is no sign of contamination in the oil.
list of things replaced
fan clutch
water pump
thermostat
belt
spark plugs
cap and rotor
alternator
fuel injectors
fuel injector connectors
fuel filter
coolant temp sensor
engine and trans mounts
O2 sensor
CAT
Fuel pressure regulator
coil
most of the vacuum hoses
List of things cleaned
throttle body
upper intake manifold
Charcoal canister
EGR vacuum modulator
EGR valve
IACV
AFM
And I checked the timing chain, guides, and have timed it.
My next guess is the fuel pump or ignition coil. I found a cheap ignition coil online for $15. Don't like the company, and I know its going to be cheap, but was thinking for $15, and the easy install it might be worth a shot.
So any thoughts or advice would be greatly appreciated. Not sure how much I can spend right now with the holidays almost here, but I will eventually get around to it, if not now.
Last edited by giantjoebot; 02-11-2012 at 10:17 AM.
11-23-2011, 06:08 PM
#2
Ok, have you checked for codes yet? Stop just throwing parts at it, it will just get more expensive before you finally find the right one. Does it feel like a miss at idle or does it do it under acceleration? You should download the FSM, check for codes and get a DMM and start checking things out before buying parts. How many miles are on the engine? Checked valve clearance yet?
11-24-2011, 03:16 AM
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No codes, had my mechanic check for me, and nothing. Check engine light has never come on. Yep did valve clearance, when I fist got it. I had my mechanic do that too. Maybe I should check it in case he did it wrong. Everything else I've done myself.
It has 140k on it, and I don't mind replacing parts. Just frustrating at times.
It has 140k on it, and I don't mind replacing parts. Just frustrating at times.
11-24-2011, 05:16 PM
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Judging from your explanation, i have a similar problem.
Idle is rather rough, sometimes sounds like the engine is hick-uping/misfiring when idling.
So far i did a tune-up (Plugs, coils, distributor, oil & filter), cleaned the TB and intake etc.. Nothing really helped. Sometimes it's better, sometimes it's worse. She never stalls, though, just idles rough. Valves i haven't adjusted yet, but i kind of doubt that that's the case. No codes here either.
When driving, the engine is fine. Accelerating and decelerating.
Been looking through quite a few threads on here, but nothing concrete out there yet, sadly.
I guess i'll do the Valves and then move on to the O2 sensor and such.
Idle is rather rough, sometimes sounds like the engine is hick-uping/misfiring when idling.
So far i did a tune-up (Plugs, coils, distributor, oil & filter), cleaned the TB and intake etc.. Nothing really helped. Sometimes it's better, sometimes it's worse. She never stalls, though, just idles rough. Valves i haven't adjusted yet, but i kind of doubt that that's the case. No codes here either.
When driving, the engine is fine. Accelerating and decelerating.
Been looking through quite a few threads on here, but nothing concrete out there yet, sadly.
I guess i'll do the Valves and then move on to the O2 sensor and such.
11-27-2011, 10:27 AM
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Valves and O2 sensor didn't work for me. The valve adjustment was done by a mechanic, so I'm not sure if it was done right.
I only replaced 2 of my fuel injector electrical clips, and I probably should have done them all. That might be my problem. Here is something you can check PenguinScotty. Try and look at your fuel injectors, and see if they are connected properly. I hear that some of the connectors have a metal wire that it uses to fasten onto the injector. Some people have said those break, or someone who worked on it before will lose the little metal clip piece, and they will have a bad connection. Mine don't have the metal clip, they are all plastic, but some were damaged due to what looks like a fire in the engine compartment, that happened before I owned it. They were burnt and a little melted.
I guess I should be working on determining if its
spark
fuel
air/vacuum
I need to get some tools to do some tests, I think?
I only replaced 2 of my fuel injector electrical clips, and I probably should have done them all. That might be my problem. Here is something you can check PenguinScotty. Try and look at your fuel injectors, and see if they are connected properly. I hear that some of the connectors have a metal wire that it uses to fasten onto the injector. Some people have said those break, or someone who worked on it before will lose the little metal clip piece, and they will have a bad connection. Mine don't have the metal clip, they are all plastic, but some were damaged due to what looks like a fire in the engine compartment, that happened before I owned it. They were burnt and a little melted.
I guess I should be working on determining if its
spark
fuel
air/vacuum
I need to get some tools to do some tests, I think?
Last edited by giantjoebot; 11-27-2011 at 10:29 AM.
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01-02-2012, 11:27 AM
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I got the same problem with my 86 22returbo but it only happens after i ˟˟˟˟ it off then start it up again. When acclerating it jolts like some who cant drive a stick! But have u checked the throttle position sensor?
01-19-2012, 12:22 AM
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Yeah I did check the TPS. I had to adjust it to a setting different from what it suppose to be at. When adjusted properly I would get a huge lag when accelerating. I ran another thread about it a while back https://www.yotatech.com/forums/f116...e-help-242145/
Just replaced the Spark Plug wires and Battery. Didn't help, but it was time, and good maintenance.
Just replaced the Spark Plug wires and Battery. Didn't help, but it was time, and good maintenance.
01-19-2012, 07:01 AM
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Have you checked the fuel pressure? I've been having a similar problem on my 92 3vze, turns out the fuel pressure regulator is weak. Try removing the vacuum line that goes to the FPR, and plug it off. You won't have the vacuum pressure relieving the spring pressure anymore, and the fuel pump will be forced to overcome the spring pressure in FPR by itself. If the problem improves, there is a great chance the FPR is weak and needs replacement. Hope this helps you.
01-20-2012, 05:00 AM
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I only replaced 2 of my fuel injector electrical clips, and I probably should have done them all. That might be my problem. Here is something you can check PenguinScotty. Try and look at your fuel injectors, and see if they are connected properly. I hear that some of the connectors have a metal wire that it uses to fasten onto the injector. Some people have said those break, or someone who worked on it before will lose the little metal clip piece, and they will have a bad connection. Quote from joe.
This was my problem. Sounds alot like what I had. I was able able to pull on the injector plug and it would cut out, push on it and it would run fine.
One other thing I could suggest is to check the continuity of your plug wires. Have had that to happen before.
This was my problem. Sounds alot like what I had. I was able able to pull on the injector plug and it would cut out, push on it and it would run fine.
One other thing I could suggest is to check the continuity of your plug wires. Have had that to happen before.
01-23-2012, 10:51 PM
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Thanks guys, thats some really good advice. I have been suspecting the fuel pressure. Been pricing regulators and fuel pumps. I'll try the tests you guys mentioned.
On a side note, I replaced the PCV valve and the gas cap, but those didn't make a difference. I also got a new coil that I need to put on.
On a side note, I replaced the PCV valve and the gas cap, but those didn't make a difference. I also got a new coil that I need to put on.
02-04-2012, 11:09 PM
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So I replace the Fuel pressure regulator. I needed to take off the intake manifold anyways, no change. Tried to adjust the TPS to 81 like its suppose to be, and I get no acceleration still. It was really weird because I put it back to 77, but it was running like crap. Messed around with it for a couple hours, and then I was finally able to set the TPS to 77 and it worked. Weird thing is that now after adjusting the TPS its misfiring and vibrating more.
Also tried a new coil, but did nothing, and I ended up putting my Denso back in.
I got 15m of silicon vacuum hose on the way. Actual metric hose. Going to try that, and the trick where you connect the fuel pressure regulator directly to the intake and bypass the vsv.
I really need to check the compression.
Also tried a new coil, but did nothing, and I ended up putting my Denso back in.
I got 15m of silicon vacuum hose on the way. Actual metric hose. Going to try that, and the trick where you connect the fuel pressure regulator directly to the intake and bypass the vsv.
I really need to check the compression.
02-07-2012, 05:26 PM
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Replaced all the vacuum hoses, and its the same. Tried bypassing the VSV, and no change, but My truck did seem to start a lot better.
I forgot to mention, that I replaced another fuel injector connector while I had the intake manifold off. Mine don't have the metal clips. I checked them all, and they are all connected well.
I got a mechanic Stethoscope from Harbor freights, and was listening around my engine. It doesn't actually seem like a miss. I can't hear the engine miss, and I never loss power. It just shakes and putts randomly. I noticed that my exhaust manifold was vibrating more than the rest of the engine. I think its my exhaust valves or the exhaust manifold gasket. I'm thinking of trying to check my valve clearance on my days off. I've never done it before. I heard you can do it cold.
Anyone have any thoughts. Any advice is greatly appreciated.
I forgot to mention, that I replaced another fuel injector connector while I had the intake manifold off. Mine don't have the metal clips. I checked them all, and they are all connected well.
I got a mechanic Stethoscope from Harbor freights, and was listening around my engine. It doesn't actually seem like a miss. I can't hear the engine miss, and I never loss power. It just shakes and putts randomly. I noticed that my exhaust manifold was vibrating more than the rest of the engine. I think its my exhaust valves or the exhaust manifold gasket. I'm thinking of trying to check my valve clearance on my days off. I've never done it before. I heard you can do it cold.
Anyone have any thoughts. Any advice is greatly appreciated.
02-09-2012, 07:29 AM
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easiest way to find out iif a valve is stuck or bad is a copression or leak down test. That should get you the answers you want and youo wont ahve to pull the head to check.
02-09-2012, 08:22 AM
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Im going to do a compression test too. its weird because my truck is also having similiar issues. it drives perfect and it does not miss while driving. at idle the engine vibrates a lot and at the exhaust tip it sounds like the engine has a miss.
all this happens at idle or a low rpm.
when the engine is cold and the rpms are up in the morning. no miss. when the engine is wamr and the rpms are down back to normal, thats when i get the miss. the miss seems to be more obvious when the outside temp are warm or hot.
all this happens at idle or a low rpm.
when the engine is cold and the rpms are up in the morning. no miss. when the engine is wamr and the rpms are down back to normal, thats when i get the miss. the miss seems to be more obvious when the outside temp are warm or hot.
Last edited by sinful; 02-09-2012 at 08:25 AM.
02-09-2012, 08:39 AM
#18
Im going to do a compression test too. its weird because my truck is also having similiar issues. it drives perfect and it does not miss while driving. at idle the engine vibrates a lot and at the exhaust tip it sounds like the engine has a miss.
all this happens at idle or a low rpm.
when the engine is cold and the rpms are up in the morning. no miss. when the engine is wamr and the rpms are down back to normal, thats when i get the miss. the miss seems to be more obvious when the outside temp are warm or hot.
all this happens at idle or a low rpm.
when the engine is cold and the rpms are up in the morning. no miss. when the engine is wamr and the rpms are down back to normal, thats when i get the miss. the miss seems to be more obvious when the outside temp are warm or hot.
- http://www.4crawler.com/4x4/CheapTri...roubleshooting
Varying idle speed, unstable idle or even mis-firing at idle:
This can happen because if the IDLe-E2 contact closure is not detected, the ECU is "running the engine real slow" vs. entering the stable idle mode. At low RPM and load, all the typical ECU sensor inputs may not be accurate and the ECU is trying to guess what is going on and adjust engine parameters on the fly. In normal idle, the ECU likely has a sort of pre-programmed loop it enters and ignores a lot of the sensor "noise".
Note that a low coolant level can affect this as well, if air pockets reach the temperature sender, the ECU can get false readings of engine temperature and alternate between cold and warm idle speeds.
This can happen because if the IDLe-E2 contact closure is not detected, the ECU is "running the engine real slow" vs. entering the stable idle mode. At low RPM and load, all the typical ECU sensor inputs may not be accurate and the ECU is trying to guess what is going on and adjust engine parameters on the fly. In normal idle, the ECU likely has a sort of pre-programmed loop it enters and ignores a lot of the sensor "noise".
Note that a low coolant level can affect this as well, if air pockets reach the temperature sender, the ECU can get false readings of engine temperature and alternate between cold and warm idle speeds.
02-09-2012, 09:47 AM
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Same problem stock 87 toy 22r 2wd automatic, at a stop it sometimes "hik-ups" and when accel it does to like 15mph and then runs smoth!!!! Check hoses and no leak!!!
02-10-2012, 10:23 AM
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I think I'm going to check the valve clearance first and then try and do a leak down compression test. I'm not looking forward to either. I should have checked the fuel pressure when I did the fuel pressure regulator.
I tried burping the coolant several times. I even jacked up the the front of the truck, and used a special funnel once, and it did nothing. I do have a tiny pinhole leak in the top hose port of my radiator, but I haven't found that it is adding air.
As for the TPS, I have replaced and messed with that thing more than I care to admit. For some reason mine likes to be at 77 and not 81. I have no idea why. There is a possibility that the wiring is bad. When I was working on it I found that at some point there was a fire inside the engine. A lot of the wiring is taped up. i have yet to check all the wiring going back to the ECU, and to be honest its something that I'm avoiding, but may end up doing. Or I suppose the ECU might be bad. The previous owner said he replaced it. He was probably trying to figure this problem out before unloading it on me. I should check the ECU and make sure it is the right one also. I think there are a few that would fit, but isn't there only one that works?
Well I have some reading to do, and some tools to pick up. I really appreciate everyone's posts, please keep them coming.
I tried burping the coolant several times. I even jacked up the the front of the truck, and used a special funnel once, and it did nothing. I do have a tiny pinhole leak in the top hose port of my radiator, but I haven't found that it is adding air.
As for the TPS, I have replaced and messed with that thing more than I care to admit. For some reason mine likes to be at 77 and not 81. I have no idea why. There is a possibility that the wiring is bad. When I was working on it I found that at some point there was a fire inside the engine. A lot of the wiring is taped up. i have yet to check all the wiring going back to the ECU, and to be honest its something that I'm avoiding, but may end up doing. Or I suppose the ECU might be bad. The previous owner said he replaced it. He was probably trying to figure this problem out before unloading it on me. I should check the ECU and make sure it is the right one also. I think there are a few that would fit, but isn't there only one that works?
Well I have some reading to do, and some tools to pick up. I really appreciate everyone's posts, please keep them coming.
Last edited by giantjoebot; 02-10-2012 at 10:28 AM.
