Problem with my engine...89 full size tbi 350 manual trans

Here's how it happened: drove fine on the way home from work. started it up a few hours later and would die if i let my foot off the gas. also it stumbled accelerating from a low rpm. felt like it was starving for gas.

What i did: replaced the fuel pump,fuel filter, rebuilt tbi unit, new fuel regulator, cap/rotor, ign coil, spark plugs, IAC, & CTS. i checked the TPS andit was fine. sprayed water on wires and there were no 'ticks'. compression test was fine, fuel pressure was good.

after the tune up it ran fine. i got about 1/4mile down the road and it tried to die on me. now it felt like it had too much fuel. as i tried to limp home it got worse and worse. (plugs fouling up?)

Here's my problem: the truck starts fine but the idle has an extreme lope to it. the exhaust smells of pure gas too. when i rev it up to a steady and higher rpm it is the same but just a faster lope. it's so bad that the truck is not drivable.

now starting it up it gives me code 33. low vaccumm. i'm guessing this is because of the horrible idle and not causing the idle. Im nearly out of ideas. could a timing issue act this way? like it jumped a tooth? bad ecm? leaky brake booster? (when running i step on brakes and it doesnt change rough idle at all)

any help and ideas would be greatly appreciated.

 

Did you replace the O2 sensor? How does the engine run up at high RPM? Does the exhaust just smell rich or does it have a bad (rotten eggs) smell to it?

How is the EGR valve?

 

haven't replaced the O2 sensor yet. didn't even consider it because the problem is so severe. I'll look into that though. Non EGR truck. at higher RPMs it does the same lope but quicker. no rotten egg smell, it smells more like pure gas.

 

Are you sure your truck doesn't have an EGR valve...?

 

100% sure that it does not have an EGR nor a Smog pump.

 

Today I unplugged one of the injectors and started it. it ran alot better but still smelled a little rich. unplugged both injectors and lightly sprayed carb cleaner in it. this made it run almost perfectly. My problem is way too much fuel but i don't know what's causing it.

 

Sounds like an injector problem to me. Are you sure you have the correct injectors from your rebuilt unit?

 

okay, have to eat my words. It DOES have an EGR valve, it's just not where the engine diagram shows it. I cleaned it and it ran better but not perfect. bought a new EGR valve. runs great and is drivable but there is still a hesitation problem at part throttle. I checked the timing and the notch was in the 1st valley on the drivers side, 0 degrees? i did disconnect the tan/black wire connector by the brake booster, was that the right one?

Also, injectors are the same from the unit before. and could both go bad at the same time? because they look pretty uniform in their spray patterns.

 

My truck is having almost identical problems and I think I figured it out. It is running WAY too rich (you can really smell it on mine cause I have no cat and only a pair of glasspacks). I have replaced everything you have and then some. Now I am almost certain that there is an air leak in the intake manifold. If there is a leak there the truck will think it is running lean and just keep dumping gas and doing everything in its power to keep itself running. The new gasket is only $18 and a tube of RTV is $4 or 5. I am probably replacing this tomorrow and will let you know the outcome. If you replace this just be sure to torque it down in the proper pattern or you will warp the intake. Hope this sheds a bit of light on your situation.

 

Shaggy, did the replacement of the intake gasket work! I have same problem and would like some insite.

Thanks,
Curtis