hard 2 keep running after warmed up???

[unclejames1]

Ok, I have a 94' dime with the 4.3 tbi, auto trans if that matters.

I go out in the morning and start the truck up and it will run fine, then I drive it into town and park it to go into the store. When i get back in it and go to start it, the truck will start up for a second, literally, then it dies. you can sometimes keep it running by pumping the gas pedal. but if it dies it is really hard to get started again. after you get it started again it will run fine but starts to missfire alittle. but it will stay running none the less! lol!!!!

I have checked the map sensor and ignition controll mod.

I can hear the fuel pump start to prime everytime.

my temp gauge hasn't worked right ever since i owned the truck but my buddy said that he had a fullsize that did the same thing and he said it was his coolant temp sensor. so I was going to change that and autozone only had the two prong sensors and mine only has one.
but if the gauge is reading cold then shouldnt it be giving the engine more fuel not less?

and I talked to a guy from advance auto that said some of the s10's had a faulty fuel pump wiring harness that would melt the conectors that are inside of the fuel tank. would that be my problem possibly? but I dont see how it would act different when the engine warms up if the problem is in the gas tank?

[Yogi]

Try cleaning your EGR valve.

[Bill Wheats]

If I'm right the 94 has a coolant temp sensor near the uper radiator hose by the stat. this sensor goes to the computer.
The engine temp sensor that is near the exhust manifold goes to the Dash Gauge, not the computer.

Something is wrong and my guess would be the CTS. You can test it with a volt/ohm meter.

What codes are stored in the computer?

[unclejames1]

the only codes stored in the computer is the #45 i think ( engine running lean), but that is from running the gas tank low last week cuz the gas gauge has been bouncing around. (not working) like everything else on the truck! lol!!!

[unclejames1]

when I bought the truck I had to put an o2 sensor on it cuz the truck had been sitting for a while and I ran it for about a week without it to get the gunk and carbon out of the engine.

could it be the o2 sensor has got a build up on it? but not throwing a code?

[unclejames1]

does anyone know what years of the s10 that had the faulty fuel pump wiring harness?

[Yogi]

Quote: Originally Posted by unclejames1

when I bought the truck I had to put an o2 sensor on it cuz the truck had been sitting for a while and I ran it for about a week without it to get the gunk and carbon out of the engine.

could it be the o2 sensor has got a build up on it? but not throwing a code?

But it is throwing a code:
"45 - Oxygen sensor or circuit - rich exhaust detected. - Oxygen sensor voltage was over 0.750 volts for 2 minutes in closed loop operation with a throttle angle between 0.6 and 1.9 volts."
Again, try cleaning your EGR valve.

[unclejames1]

does anyone have a link to a how-to clean the egr valve? I think I remember seeing one on here but I can't find it!

[unclejames1]

nevermind! found a post that says how to do it.

it said to remove it and spray the port with carb cleaner and scrub it with a brush. and then let it dry.

I am also thinking about cleaning the iac too!

[Yogi]

Also blow it out by starting the motor while the valve is off. Run it for 5-10 sec. to blow the gunk out.

[unclejames1]

when I was looking for the directions to clean the egr some of the people were talking about removing the egr all together and running without it.

would this be cheaper to do on my truck? and what has to be modified to do this? cuz i think that a new egr valve is over 200 bucks from autozone!

I just want to get this fixed before ITB on the 15th! Its not too bad cuz i only live about 2and a half to 3 hrs away. so its not a real big deal since the truck is only hard to restart but then its ok other than a little missing and horrible mph! lol!!!!

[Bill Wheats]

Since you have 94 with a TBI; The ERG consists of a vacuum controled EGR valve and an electronic control that controls vac to the EGR valve and reports to the PCM. If you disconnect the vacuum line to the EGR and plug the vac line to the controller, Then the EGR valve won't be pulled open but the PCM will think it's connected.
The problem with those EGR valves is that they suck exhust fumes (that can contian chunks of carbon) into the intake manifold. The carbon gets stuck between the EGR's plunger and the intake manifold seat causing them to get stuck open. This causes a huge vacuum leak.
To clean it, remove the egr and wash it out, clean the plunger and the seat on the intake manifold. Then before replacing it, spay a lot of carb cleanner into the exhust port and let it sit (some use pipe cleanners to scrape it out). Spray some more carb cleanner in there and start the engine ~15 seconds. Repeat if need be.
This should blow out the carbon balls that would soon replug your egr plunger.
Reinstall the EGR and start the engine. The intake vacuum should force the plunger to seat (sealing the leak).

So just like Yogi said "start by cleaning the EGR!"

Good luck.

[Yogi]

Quote: Originally Posted by unclejames1

when I was looking for the directions to clean the egr some of the people were talking about removing the egr all together and running without it.

would this be cheaper to do on my truck? and what has to be modified to do this? cuz i think that a new egr valve is over 200 bucks from autozone!

I just want to get this fixed before ITB on the 15th! Its not too bad cuz i only live about 2and a half to 3 hrs away. so its not a real big deal since the truck is only hard to restart but then its ok other than a little missing and horrible mph! lol!!!!

You can remove and plug the vacuum line to the EGR like Bill said, and do away with EGR. If you want to leave it on for appearances sake, you need to be sure that it is clean and closing properly. If you want to get rid of it altogether, you can get a block off plate on e-bay.

Whoever quoted you $200 for a new EGR didn't know what he was talking about. The Delphi model is about $48 at Rock Auto:


BTW, What is "ITB"?

[unclejames1]

import and truck bash! big show in Indianapolis. National coverage I think.

well i did take the egr off today and I have it soaking in carb cleaner. but last night I checked the codes on the trucks computer again to make sure what code it was pulling and the only code that was being pulled was a 44 which is the "engine running lean" so I am not really sure if it is the egr valve or not. but I am cleaning it anyways!

plus when I went to take off the egr I was looking at the valve and it didn't have a vac hose hooked up to it so the guy before me might have bypassed it! I am not sure.

but I am going to look up and see where the vac line is supposed to run to and see if it is capped off.

[unclejames1]

ok I cleaned the egr valve and the port on the engine. but I found out later today from the owner before me that they had bypassed the egr valve by capping off the vac line! So as you can guess no difference in the problem!

but I took the truck down to a mechanic buddy of mine and he called me after an hour or so and said that the truck is running really rich and I am missing an o2 sensor because i only have 1 in front of the catylic converter. He said that I need 2 o2 sensors on the truck, 1 before the cat and 1 after the cat.

so I went down and talked to the previous owner and he works at a shop also so he looked it up and confirmed that the truck didn't need 2 o2 sensors cause it was equipped with only 1 o2 sensor from the factory.

so tonight I am going to drive it around untill it does it again and pull one of the spark plug wires and check the spark and make sure it is a spark issue or a fuel issue. seeing how it only acts up when the engine is hot it could be any of the sensors under the hood even the ones that I had checked!

[Bill Wheats]

Yup could be a sensor that is reading within speck but giving bad data.
Could also be a dirty injector. Try running some seafoam in the gas for a couple of tanks. Won't hurt and can only help.

[unclejames1]

I was told to use a ratio of 2 cans of seafoam per half of a tank and my gas gauge doesn't work so i will fill it up and use 4 cans of seafoam!

and see if that helps!

thanks for the help though guys! I hate diagnosing problems like this!

[Yogi]

I've never used Seafoam in the gas but 4 cans sure sounds like a lot!