Fuel Smell, Drop in MPG, intermitten drop in Power
11-16-2004, 05:43 PM
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Fuel Smell, Drop in MPG, intermitten drop in Power
I haven't the slightest clue whats wrong with my truck, or even if there is anything wrong... Right now I'm getting 14 on the highway and we won't even talk about in town. I have an occassional fuel smell when I drive it, which is making me think leak... The truck performs fine about 80% of the time, the other twenty I see a loss in power. By performance I rate it going up a hill at freeway speeds, sometimes it can hold 75 to 80, other times it barely pushes 65. I haven't noticed any correlation between the smell and power loss, the only time it smells is in town, and actually it runs better when I smell the fuel. Tune up was done about 9 months ago, timing is good, new timing chain, fuel filter was done with the tune up, fresh oil change. The truck has a fair amount of mods (see my signature), but I wouldn't equate that to the huge drop in fuek economy. A friend with a 85 and 31 sees about 270, give or take to a tank. I'm lucky to get 200. Could I have an injector or fuel rail problem. Also my check engine light comes on at a cruising speed under light load, O2 code, but then goes off with a change in RPMs or load. I have gone through 2 O2 sensors and it still does it. Current O2 sensor has about 3500 miles on it, and it flipped the check engine light about 400 miles after install. Any suggestions?
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11-16-2004, 06:58 PM
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Originally Posted by colsoncj
shows bad, the last three have done that within 300 to 500 miles after install... underlying problem?
11-16-2004, 07:42 PM
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Does it have a rough idle? My '89 developed a tiny air leak where the intake manifold meets the head. I could smell gas for months under acceleration and couldn't find the problem. One day i noticed a white buildup on my egr bolt heads and found the gasket had failed right next to the #4 injector and gas was coming out under hard acceleration. I wonder if you have an air leak somewhere after the AFM that is causing a super lean reading at the o2 sensor. Maybe so lean that the computer sees it as out of normal operating parameters and triggers the CE light. Just a thought. Also, replace all of your injector seals and o-rings. They tend to crack over time.
11-17-2004, 04:48 AM
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I don't have a rough idle or stuttering at all, it purrs just fine, which is why this is throwing me for a loop. I'm more concerned with the drop in MPG than the power. I'd like to get back up closer to 20. I'll look around for an air leak, see what i can find. Does anyone know if when the CE light is on, the computer goes to a default circuit that would kill my mileage? Also, how hard is it to pull the injectors and check for cracks/leaks/o-rings/resistance? YotaFreakShow, was your leak from the lower intake gasket to the head?
11-17-2004, 04:51 AM
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Originally Posted by colsoncj
shows bad, the last three have done that within 300 to 500 miles after install... underlying problem?
11-17-2004, 06:36 AM
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I'm assuming 22re...
I'd say check the TPS. Sounds to me like you are running really rich and the fuel smell is likely from the tailpipe. Pull out the dipstick and sniff the oil. If it is running rich enough, you will get a gas smell out of the oil which is bad news if you let it go on long enough.
Running rich like that with a problem with the TPS will result in the o2 getting bad readings and will throw codes.
Been there done that. In my case, it cost me a headgasket from increased cylinder temps. I still think about "getting some back" from the two different shops that (A.) failed to properly install the TPS on the big bore throttle body during a new engine install and (B.) fed me a line of crap that they had checked the TPS after I had specifically asked to have it checked at the second shop that I was using to check up on the engine install done by the first shop
Check and adjust/replace the TPS as necessary, pull both o2 sensors and clean them with throttle body cleaner or something similar, pull the neg. terminal on the battery or the EFI fuse and let the ECU reset then see what happens.
If it is the TPS, get your oil changed. That gassed out oil isn't doing you any good.
Good luck!
**Warning, this post is strictly the opinion of a newbie dumba$$**
I'd say check the TPS. Sounds to me like you are running really rich and the fuel smell is likely from the tailpipe. Pull out the dipstick and sniff the oil. If it is running rich enough, you will get a gas smell out of the oil which is bad news if you let it go on long enough.
Running rich like that with a problem with the TPS will result in the o2 getting bad readings and will throw codes.
Been there done that. In my case, it cost me a headgasket from increased cylinder temps. I still think about "getting some back" from the two different shops that (A.) failed to properly install the TPS on the big bore throttle body during a new engine install and (B.) fed me a line of crap that they had checked the TPS after I had specifically asked to have it checked at the second shop that I was using to check up on the engine install done by the first shop
Check and adjust/replace the TPS as necessary, pull both o2 sensors and clean them with throttle body cleaner or something similar, pull the neg. terminal on the battery or the EFI fuse and let the ECU reset then see what happens.
If it is the TPS, get your oil changed. That gassed out oil isn't doing you any good.
Good luck!
**Warning, this post is strictly the opinion of a newbie dumba$$**
11-17-2004, 03:41 PM
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Originally Posted by colsoncj
Would the TPS not adjusted properly cause a CE code or light?
This was exactly what was happening on my '85 4Runner. Once the TPS was set up right, no more error codes and better MPG.
11-17-2004, 08:36 PM
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Here's a good tps adjust procedure:
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml
My leak was the lower intake to head gasket (intake manifold gasket).
To get your injectors out, you have to remove the intake plenum and a bunch of vacuum lines, cold start injector fuel line, and many connectors. Easy and pretty cheap, lots of careful labeling and you're in business. The plenum gasket is only $5 at Napa. I had to pull the throttle body off to get at the lower TPS screw, may as well adjust the tps when the plenum's off. The injector seals are like $5 per injector. You have to remove the fuel line from the rail, so be ready for a bunch of gas to soak some rags. Bad time to remember to remove the Neg. battery cable or light up a
.
edit: forgot to mention that there will be 2 coolant lines pulled off of the TB, they can be plugged with the proper sized bolt instead of draining the coolant as the fsm may suggest.
Also, I hear people use propane torches (unlit) to find vacuum leaks. With engine running, open valve slightly and probe around with the tip of the torch until you notice the engine speed increase.
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml
My leak was the lower intake to head gasket (intake manifold gasket).
To get your injectors out, you have to remove the intake plenum and a bunch of vacuum lines, cold start injector fuel line, and many connectors. Easy and pretty cheap, lots of careful labeling and you're in business. The plenum gasket is only $5 at Napa. I had to pull the throttle body off to get at the lower TPS screw, may as well adjust the tps when the plenum's off. The injector seals are like $5 per injector. You have to remove the fuel line from the rail, so be ready for a bunch of gas to soak some rags. Bad time to remember to remove the Neg. battery cable or light up a
.edit: forgot to mention that there will be 2 coolant lines pulled off of the TB, they can be plugged with the proper sized bolt instead of draining the coolant as the fsm may suggest.
Also, I hear people use propane torches (unlit) to find vacuum leaks. With engine running, open valve slightly and probe around with the tip of the torch until you notice the engine speed increase.
Last edited by yotafreakshow; 11-17-2004 at 08:43 PM.
11-18-2004, 07:42 AM
#19
Adjust the TPS, its either set right or its not, or it has failed.
If you are getting an O2 sensor CEL, then test the O2 sensor. The FSM has a detailed procedure, basically rev the engine to 2500 for a few minues to warm up the sensor then measure the voltage swings, should see at least 8 swings in 10 seconds from near 0 to near 1 volt on an analog meter.
Or pop for an Air/Fuel meter and hook it up to the sensor and you can see how the O2 sensor is operating as you drive. I run one in my '85 and find it to bea very useful device, you can see when the engine is operating in the efficient closed loop mode and when it jumps to full rich when you get on the gas too hard.
If you are getting an O2 sensor CEL, then test the O2 sensor. The FSM has a detailed procedure, basically rev the engine to 2500 for a few minues to warm up the sensor then measure the voltage swings, should see at least 8 swings in 10 seconds from near 0 to near 1 volt on an analog meter.
Or pop for an Air/Fuel meter and hook it up to the sensor and you can see how the O2 sensor is operating as you drive. I run one in my '85 and find it to bea very useful device, you can see when the engine is operating in the efficient closed loop mode and when it jumps to full rich when you get on the gas too hard.
Last edited by 4Crawler; 11-18-2004 at 07:44 AM.
