L05 Slight Throttle Issues

I have a 92 caprice wagon and anytime i am giving it slight throttle it starts stumbling and spitting and sputtering. A couple of times it has died on me. Any suggestions? Thanks -Josh

what happens when you got wide open?

Miles? Last tune up? Does this when hot/cold, or always?

Sorry guys, dont know a whole bunch about tune up because i just bought the car today. Drove it home and parked it. Seems to run fine sometimes then all of a sudden it will act up. I havent given it WOT but i did get in it a little and it seems to do its best . Thanks guys -Josh

Oh and the funny thing is when i test drove it everything ran fine. Got about 20 miles from his house and then it started. I am not too worried about it because i know it has to be something easy. -Josh

Start with a tune up. Plugs, wires, cap, rotor, pvc valve, filters, and fluids. While you're at it check your vacuum hoses and replace as needed. Then see how she goes.

He said he did plugs and wires but i think i will go back through everything. I was just hoping for a common problem . -Josh

common problem, fuel pump, fuel filter

You know the first thing i was going to check was the fuel filter just because i have a feeling. Is it in the same spot as an impala?

Slight throttle hesitation usually is a secondary ignition issue. Just because the parts are new doesn't mean they are any good. Clogged fuel filters and pumps, generally present themselves during higher fuel demands.

When you say secondary ignition what exactly is that? Plugs and wires?

NO DUBS wrote:

You know the first thing i was going to check was the fuel filter just because i have a feeling. Is it in the same spot as an impala?

Near the right rear tire on the frame.

[quote="NO DUBS"]When you say secondary ignition what exactly is that? Plugs and wires?[/quote

Sorry, yes, the secondary is the high voltage part of the ignition system. Plugs, wires, cap, rotor, coil, and distributor. Primary being the low voltage (12v) part of the ignition system.

Ok i got ya. I will mess around with the ignition and replace fuel filter just because its easy and cheap and i will report back. Thanks guys for the help. -Josh

You can check the PCV valve, and the ground at the thermostat housing. Make sure he put all the ignition wires on tight. Also check for vacuum leaks/broken vacuum lines. The symptoms do not resemble any sensor issues, or the EGR valve.

Injector cleaner will shorten the life of the in tank fuel pump connector hose, so use it sparingly. If the symtoms get worse, and the idle fluctuates, it may be the fuel pump connector hose, I have had one split, and I caught another one on the verge of blowing out. If it is bad, replace the pump while you are in there. I replaced the hose, and had the pump fail a month later. I really hate doing things twice (the new pump also failed about 1 month after installation, but I love my car).

It was a long day today so i will check out everything tomorrow. I called the guy and he said that all of the ignition system was replaced as well as fuel filter. He said that after he pressure washed the engine the CEL would come on so mabe he got something wet? I will look for vacuum leaks and loose connections. Any ideas what could act up if wet? Thanks -Josh

NO DUBS wrote:

It was a long day today so i will check out everything tomorrow. I called the guy and he said that all of the ignition system was replaced as well as fuel filter. He said that after he pressure washed the engine the CEL would come on so mabe he got something wet? I will look for vacuum leaks and loose connections. Any ideas what could act up if wet? Thanks -Josh

You have any experience with engines? the questions you are asking , are basic motor troubleshooting, any motor, any brand,.
It,s very easy to type questions etc,. but probably a lot easier for you to find the source of your problems, answer to your question: anything ignition related can act up when wet,.

Nick

The reason I suggested the ground at the thermostat housing is that my LO3 was acting poorly, and the ground was the issue. I washed the engine, and the ground got rusty...no more ground.

Fred Kiehl wrote:

I washed the engine, and the ground got rusty...no more ground.

you know thats weird fred,. unless the ground was loose how would the water get inbetween the nut and the wire end and the tstat housing,.? think its dry under the hood at 70mph in the rain?? I,ve washed numerous engines over the years,. haven't seen the grounds rust off,.

nick

It did not rust off, it just got rusty. When the engine acts weird, wierd thing cause it. The lugs have "teeth", and the water can get between them. Once the rust starts, it will eat into the metal under the lug.The proof is in the pudding, I cleaned up the ground and it fixed the problem. The use of a bolt that holds a fitting which contacts water is not the smartest decision from GM either. I am supprized that there aren't more ground problems at that point.

The top of the engine should be dry even at 70MPH, unless you have an open scoop.

Quote :

You have any experience with engines? the questions you are asking , are basic motor troubleshooting, any motor, any brand,.
It,s very easy to type questions etc,. but probably a lot easier for you to find the source of your problems, answer to your question: anything ignition related can act up when wet,.

I do have experience with engines but all cars have common problems and that was what i was after. -Josh

2 things come into play here.How much actual pressure was the washer operating at and what type of cleaning solution was being used.Either of these things especially the chemical makeup
of the cleaning solution can mess up the ground and ignition.
Trust me on this because I did it to my car
Take Care
Jim Gordon aka Flasheroo

Fred Kiehl wrote:

It did not rust off, it just got rusty. When the engine acts weird, wierd thing cause it. The lugs have "teeth", and the water can get between them. Once the rust starts, it will eat into the metal under the lug.The proof is in the pudding, I cleaned up the ground and it fixed the problem. The use of a bolt that holds a fitting which contacts water is not the smartest decision from GM either. I am supprized that there aren't more ground problems at that point.

The top of the engine should be dry even at 70MPH, unless you have an open scoop.

ah wasn't thinking of the serrated washer thingy,.

so where does all the water go that comes thru the rad at 70 mph??

Nick

NO DUBS wrote:

Quote :

You have any experience with engines? the questions you are asking , are basic motor troubleshooting, any motor, any brand,.
It,s very easy to type questions etc,. but probably a lot easier for you to find the source of your problems, answer to your question: anything ignition related can act up when wet,.

I do have experience with engines but all cars have common problems and that was what i was after. -Josh

yes exactly my point,..all cars have common problems,.

Nick

Honda SOHC known for warping heads, Toyotas known for valvetrain tick, LT1s know for faulty distributors. Chevy TBI's know for what? All engines have the same concept of operations but "common problems" are not so common between different engines. -Josh

phantom 309 wrote:

Fred Kiehl wrote:

It did not rust off, it just got rusty. When the engine acts weird, wierd thing cause it. The lugs have "teeth", and the water can get between them. Once the rust starts, it will eat into the metal under the lug.The proof is in the pudding, I cleaned up the ground and it fixed the problem. The use of a bolt that holds a fitting which contacts water is not the smartest decision from GM either. I am supprized that there aren't more ground problems at that point.

The top of the engine should be dry even at 70MPH, unless you have an open scoop.

ah wasn't thinking of the serrated washer thingy,.

so where does all the water go that comes thru the rad at 70 mph??

Nick

Pretty much evaporates The radiator is at about 190 degrees. then it hits the fan...never gets to the engine.

Ok so it only doing it in closed loop so that pretty much eliminates plugs wires and fuel. What do you guys think should be first on the list? TPS? IAC valve? Thanks -Josh

Did you try the PCV valve? It could be sticking and then, once the engine moves it, it loosens up. The IAC does not come into play until it goes into closed loop. It could be the TPS, but the TPS would act up all the time.

Try tightening the TBI bolts you may have a vacuum leak. To check for vacuum leaks, put a couple drops of dish washing liquid in a quart of water and squirt it on the lines. If it sucks it up, you have a leak.

Actually not being in closed loop does not eliminate the fuel. You should check your pressure. It should read between 9 and 15 psi (absolute minimum 9 psi).

doubt is fuel pump related as it's okay in open loop condition......fuel pump issues I've had they car barely or doesn't fun at all. what changes when the loop closes aside from the coolant flow path?

Well i changed the IAC and it seems to be running fine. My fingers are still crossed though. BTW what is the IAC reset procedure? I am still waiting on my FSM. Thanks -Josh

OK The IAC...I was thinking about the IAT...Yes the IAC could cause the problem, and is involved at all times. Did you clean the ports for it while you were in there.

Yes i just sprayed some carb cleaner on a rag and cleaned it with my little finger. -Josh