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-   -   92 silverado tbi problems (http://www.hotrodders.com/forum/92-silverado-tbi-problems-191665.html)

1992silverado350 01-29-2011 10:40 PM

92 silverado tbi problems
 
OK i have a 92 silverado with a 350 tbi. And every time i try to accelerate it chugs and jerks. I have rebuilt the tbi with all new gaskets and I've put a new throttle position sensor on it but is still does it any advice i need it to run right.

crussell85 01-29-2011 11:01 PM

Need a better description of what it is doing besides chugs and jerks. Is it backfiring? Through the intake or the exhaust? Does is stall? Will it idle? Can you get any rpm out of it when in park? Does it start right up?

Chugs and jerks could be just about anything.

sqzbox 01-29-2011 11:06 PM

Quote:

Originally Posted by 1992silverado350
OK i have a 92 silverado with a 350 tbi. And every time i try to accelerate it chugs and jerks. I have rebuilt the tbi with all new gaskets and I've put a new throttle position sensor on it but is still does it any advice i need it to run right.

Take it and get it hooked up to an engine analizer for real time info and find the problem right off. It will be money well spent as you will probably spend 2-3 times the money throwing part's on it untill you find the problem. Finding your problem would be difficult for even a seasoned mechanic on a computer controled TBI engine without code readers and real time info data.
Your already down the price of a re-build TB kit and it's still not right.

Trust me on this, I've been there with my old 88 F-Bird 305 TBI. :mwink:

Here's just some of the things I spent money on with it and after 5 yrs, it finally ran good till I crashed it into a gaurd rail at 50 mph.

Cleaned injectors
EGR valve
ECM
IAC valve
EGR control module
plug wires
plugs
fuel pump and filter
fixed vacuum leaks
external coil
rotor and cap
dist. module
TPS sensor

Turns out my step son who I bought the car from had a buddy that set the timing on it without disconnecting the ESC connector and had the initial timing set at 21 degrees retarded. I could have saved all that money had I taken it and got it looked at by a local garage who found the problem in less time than it took to hook it up to a machine. 50 bucks for the diagnosis and 10 bucks to set the timing is a lot less than a fraction of the money I spent thinking I could find it myself. good luck. :D

sqzbox 01-29-2011 11:39 PM

Quote:

Originally Posted by sqzbox
Take it and get it hooked up to an engine analizer for real time info and find the problem right off. It will be money well spent as you will probably spend 2-3 times the money throwing part's on it untill you find the problem. Finding your problem would be difficult for even a seasoned mechanic on a computer controled TBI engine without code readers and real time info data.
Your already down the price of a re-build TB kit and it's still not right.

Trust me on this, I've been there with my old 88 F-Bird 305 TBI. :mwink:

Here's just some of the things I spent money on with it and after 5 yrs, it finally ran good till I crashed it into a gaurd rail at 50 mph.

Cleaned injectors
EGR valve
ECM
IAC valve
EGR control module
plug wires
plugs
fuel pump and filter
fixed vacuum leaks
external coil
rotor and cap
dist. module
TPS sensor

Turns out my step son who I bought the car from had a buddy that set the timing on it without disconnecting the ESC connector and had the initial timing set at 21 degrees retarded. I could have saved all that money had I taken it and got it looked at by a local garage who found the problem in less time than it took to hook it up to a machine. 50 bucks for the diagnosis and 10 bucks to set the timing is a lot less than a fraction of the money I spent thinking I could find it myself. good luck. :D


And the price of a TP sensor. (once again, I've been had by the 30 min edit rule!) :smash: :smash: :smash: :smash: :smash: :smash: :smash:

1992silverado350 01-30-2011 11:01 AM

It will start right up and it doesn't backfire at all. it idles real low. When im in park it will do the same thing. But after i hit about 2000 rpm it all stops and runs perfect

Mike H 01-30-2011 11:18 AM

Try unhooking the vacuum line to the EGR and see if it helps your stumble. If so check the valve and solenoid they are bad about getting weak on high mileage trucks. I have had weak coils make them act up like yours as well. If you have a know good coil plug it in and try it.

1992silverado350 01-30-2011 11:32 AM

Mike H thank you i just tried that and now it runs perfect no problems.

sqzbox 01-30-2011 11:33 AM

Quote:

Originally Posted by sqzbox
Take it and get it hooked up to an engine analizer for real time info and find the problem right off. It will be money well spent as you will probably spend 2-3 times the money throwing part's on it untill you find the problem. Finding your problem would be difficult for even a seasoned mechanic on a computer controled TBI engine without code readers and real time info data.
Your already down the price of a re-build TB kit and it's still not right.

Trust me on this, I've been there with my old 88 F-Bird 305 TBI. :mwink:

Here's just some of the things I spent money on with it and after 5 yrs, it finally ran good till I crashed it into a gaurd rail at 50 mph.

Cleaned injectors
EGR valve
ECM
IAC valve
EGR control module
plug wires
plugs
fuel pump and filter
fixed vacuum leaks
external coil
rotor and cap
dist. module
TPS sensor

Turns out my step son who I bought the car from had a buddy that set the timing on it without disconnecting the ESC connector and had the initial timing set at 21 degrees retarded. I could have saved all that money had I taken it and got it looked at by a local garage who found the problem in less time than it took to hook it up to a machine. 50 bucks for the diagnosis and 10 bucks to set the timing is a lot less than a fraction of the money I spent thinking I could find it myself. good luck. :D

I forgot the o2 sensor. That's # 14 not counting the 60 bucks to get it right.

sqzbox 01-30-2011 11:37 AM

Quote:

Originally Posted by 1992silverado350
Mike H thank you i just tried that and now it runs perfect no problems.

Better go buy some lottery tickets you lucky dog! If you win, split with Mike H. He just saved you a bunch of money. :D :D :D

crussell85 01-30-2011 01:15 PM

if the egr is bad it is also possible that the exhaust crossover is very dirty. May wanna check how clean it is when you remove the egr valve.

Mike H 02-01-2011 08:19 PM

Most of the time I drill the carbon out of the ERG passage when the valve is off. They are a positive pressure valve, the exhaust back pressure helps keep it closed when you step into the throttle and the solenoid gives the valve full vacuum. Most days a valve will fix you up but don't buy anything but an AC Delco. The rest use reducing washers and are junk. Pay the extra and keep it running like new. I have an 88 with 306K on it now had to put a valve on it a few years ago and a set of injectors last year but its still running and passing the emission tests.

brandon meek 02-03-2011 08:31 AM

i to own 92 chevy tbi 350 that would bang out,back fire at high rpm 3500 and up worse when cold u could ease it up and would do better no codes replace throttle body was distributor reluctor ring loose fixed right up

satdiver1 02-03-2011 11:44 AM

what and where is the reluctor ring in the distributor?

sqzbox 02-03-2011 11:49 AM

Quote:

Originally Posted by brandon meek
i to own 92 chevy tbi 350 that would bang out,back fire at high rpm 3500 and up worse when cold u could ease it up and would do better no codes replace throttle body was distributor reluctor ring loose fixed right up

He sed it been fixed, up all rdy but didnt say what wuz wrong egr or coil main thing is he got it going i had problem, with coil wires touching each other once and by luck found arcing between them separated wires and problem with misfire and hesitation, went away i guess wires wore down from constant rubbing together on, the, external, coil :drunk:

sqzbox 02-03-2011 12:13 PM

1 Attachment(s)
Quote:

Originally Posted by satdiver1
what and where is the reluctor ring in the distributor?

Pull the cap and rotor and you'll see this.


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