1992 suburban 4x4 silverado 454 won't idle.

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Cside

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I just picked up a 1992 suburban 4x4 with a 454. It has 78k original miles and was used only for towing. Brand new transmission about 2000 miles ago. It's been parked for 2 years and had a dead battery. I replaced the battery. When I turn it over it idles almost to a stall and sometimes does stall. When I put my foot on the accelerator in park sometimes it won't get over 3k rpms and other times it will red line. If I drive it it does the same thing and stalls on me when I stop or slow way down. I am not a mechanic nor do I know much about cars but I gotta start somewhere. I always loved suburbans and think I will be happy once this is resolved. Sounds to me like something is clogged or the computer is wacky. Any suggestions would be helpful.

Thank you
 
Did you drain all the gas and put fresh in? Did you change fuel filter? Did you check if anything has made a home in the air filter? Did you check if anything has eaten any of the spark plug wires?
 
So far the idle motor has been changed, the plugs and wires, the map sensor. Still wont idle. Starts and then dies. The mechanic working on it stated tha it might be distributor because it seems a bit loose. So far I am getting a it mad at paying this guy to replace parts that are still good. The fuel gage is just above the empty line. I put 5 gallons in it a couple weeks ago when when started to try and repair it. It had very little gas in it before I added fuel. Battery has also been changed. The mechanic appears to be stumped at this point and I am about sick of him. He pretty much told me he has no clue what to do next. Great answer. Any help will be greatly appreciated.
 
Oh and it won't idle at all now. The mechanic also stated that it is getting too much fuel.
 
so you never changed the fuel filter as previously suggested? did he run a fuel pressure test? did he check for a bad fuel pressure regulator? what does a loose distributor mean? it is held down with a clamp and a bolt, you tighten it. Is the Service Engine Soon light on? If so, did you scan for codes and what are they?
 
Thank you zora. No check engine light. Funny thing is the mechanic started texted me last night because he saw my post here on this forum and is pissed. I am done with him and will have someone other than a part replacer look at my vehicle. He told me to find someone with a 5 k scanner because his scanner does not work on old vehicles. I think this job is out of his league and that's ok. I wish he would have told me that. So far I am out $265.00 and my suburban still does not work.
 
Sounds to me like the fuel filter and throttle body both need a good cleaning. Or does this have a carburetor? If it's a carb, open it up and check the needle valve and accelerator pump. Old gas will really varnish things up and make them stick.
 
Thank you Chuzz for the info. I wish I had someone here in the San Fernando valley that is a master mechanic to repair this vehicle. I don't want another guy that is clueless working on it again. I need to get this on the road ASAP.
 
So I had a master mechanic look at the suburban today. He determined that it looks great except that its getting way to much fuel. After evaluation he determined that the computer must be bad and that we need to replace it. I see a couple on eBay that are used with a one year warranty for $100.00. If I can't find one in Los Angeles then I will order it from eBay. Any suggestions before I purchase a replacement computer?

Thanks

Cside
 
Funny my first post did not go thru yesterday.

Here is my update. The master Mechanic took a look at it yesterday and determined that its getting way to much fuel. After looking over the vehicle he determined that I need a new computer. This does not make me happy but at least I understand what the issue is. I can order one online for around $100.00 but he is looking for one locally first. I should have got the part number for the computer but I had my 5 year old with me and was distracted. Any suggestions before I purchase a computer for it? Is there more than one computer? Is the computer the same on the 454 and the 350 suburban?

Thanks for your assistance.
 
Last edited:
Funny my first post did not go thru yesterday.

Here is my update. The master Mechanic took a look at it yesterday and determined that its getting way to much fuel. After looking over the vehicle he determined that I need a new computer. This does not make me happy but at least I understand what the issue is. I can order one online for around $100.00 but he is looking for one locally first. I should have got the part number for the computer but I had my 5 year old with me and was distracted. Any suggestions before I purchase a computer for it? Is there more than one computer? Is the computer the same on the 454 and the 350 suburban?

Thanks for your assistance.
 
If you look at a site such as NAPA you need the original part number to get the correct computer and you have to transfer the PROM.
 
Cside said:
* * * Any suggestions before I purchase a computer for it? * * *
Click to expand...

Have you read my thread? It seems that you have. If so, did you try disconnecting the CTS wire and/or replacing the CTS?

In my opening post I noted that my problem sounded a lot like your problem. Since the CTS seems to be #1 suspect in situations like yours and mine, I'd suspect that before I'd suspect the "computer". When I disconnected the wire connection at my bad CTS, the truck started right up and ran normally. The effect was stunning.

I also note that you and I have "OBD1" which is "on board diagnostics version one." After 1995 Chevy went to OBD2 and it's my understanding that they did so under some reglatory pressure because OBD1 would go to default settings to override a bad sensor (presumably when disconnected) and thus basically "bypass" emissions control.

Which, I assume, is why disconnecting my bad CTS wire resulted in the truck running normally. The default setting takes over and the truck runs normally (or more or less normally -- I didn't actually try driving it around that way).

So I would suggest that you try disconnecting the CTS wire connector, then start the truck and see how it runs.

Read my thread as to what I did when I did that (it'll set a code and you then have to clear it)

If your "master mechanic" is wrong, replacing the "computer brain" won't solve your problem. You'll just waste time and money and be no better off.

I did quite a bit of online research and never encountered a situation where the computer itself had failed. Sounds to me like your mechanic is taking a shot in the dark.

But, of course, I could be wrong.
 
I'd go with the CTS first, cheaper repair and may resolve issue.
 
I have the CTS and I am going to go and disconnect the one in my suburban and see if that fixes it before I replace it. Suburban is parked 20 miles away. Wish me luck!
 
I read your post in dinky's thread -

Cside said:
I just purchased one today $12.00 autozone. Since my suburban is parked 20 miles away I am going tomorrow to see if this fixes the issue.
Click to expand...

and I hope you got the right part. The CTS has a two-wire connector and costs $17.99 at AutoZone. If you paid $12.00, you might have gotten the temperature gauge sending unit, which only has one wire. My '94 has both the CTS and the temperature gauge sending unit and I assume your '92 has the same. You need the CTS, not the other one. The CTS is mounted right near the thermostat housing on the top of the engine while the temperature gauge sending unit is mounted down near the #1 spark plug.

If you have the wrong one, you can still pull the wire connector off the CTS while you're there and start the truck and see how it runs. If that cures your problem, then you know you have a bad CTS and can go and get the correct part.

Don't forget to clear the codes when you're done.

Also, I didn't have to drain any coolant to replace the CTS and you probably won't have to either. Just CAREFULLY loosen the radiator cap to release any pressure, then unscrew the old one and screw in the new one. Because it's located on the top of the engine, you'll lose very little coolant, if any. I wouldn't do it if the engine is at all warmed up because there will be too much coolant pressure to release if the engine is warm or hot. So let it cool down before replacing the CTS.

I forgot to loosen the radiator cap first, so I got squirted with a bit coolant, as did the new CTS. Which I then had to wipe dry.

And don't forget to tighten the radiator cap when you're done.

:)
 
Yes its a two wire connector on top but did not include the y-cable. Maybe thats why it was only $12.00. They were out of stock on the one with the cable. I will update you later today after I go and attempt this.
 
well.......this was not expected but here is my story from today.

I went down to where the suburban is parked in a friends repo yard. He decides today to tell me about a mechanic they use and how he is the best ever. We called him up and he came over to look at it.

This guy checked every possibility that was causing the issue. I dissconnected the CTS and still would not start. At this point i was stumped but the mechanic tried to run codes but did not get any except the CTS that I unplugged. We plugged the CTS back in, the same old CTS and try to start it.

Now it wont even trun over for a second and its getting zero fuel (before it was getting alot of fuel) The mechanic does his checks for the fuel pump and determines that it is indeed the fuel pump.

I run and get a full pump and filter which cost around $55.00 and he installed the pump and fuel filter. Started it and BAMM its running like a kitten.

Best part was for all his labor today form 12:30 to 5:30 and changing the fuel pump he charged me $150.00. I thought this was very reasonable. I have to meet him again to put the metal cover over the gas tank and adjust timming.

Very happy after 3 mechanics to fiannly find one to take the time to diagnose the issue.

Oh we also broke the fuel tank vent when trying to drop the fuel tank. For some reason the was a ton of grease on the top of the tank and we had to use a cro bar to get it down. This part was $20.00 and took an hour to find.

Suburban is still at the repo lot for now till we finish this Saturday.
 
Glad you got it going, back on post #5 in this thread I had been asking about fuel pressure.
 
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