rough running
Thread Starter
Cruising
Joined: Oct 2015
Posts: 11
Likes: 0
From: Winchester Tn.
rough running
I have a 92 c4 with a lt4 engine with running problems, it starts and idles good, revving up fine but when under a load it starts too cut out, missing ,back fireing, and the more gas you give it the slower it runs, any advice would be of great help.
Team Owner
Joined: Sep 2003
Posts: 25,331
Likes: 2,722
You mentioned '92 with lt4 with running problems. The LT4 would have been a "transplant" or either the '92 or lt4 is a TYPO. Confirm for sure the year, the engine and responses might be more directed to your potential problems. There's very much different, very much.
Team Owner
Joined: Sep 2003
Posts: 25,331
Likes: 2,722
For your "particular situation" you've got much to do. Does the car have a proper LT4 PCM, the correct 4 X O2's with the correct LT4 "knock module" in the PCM?
I'd suggest a professional qualified technician with the correct scanning hardware and move on from there.
You did the "transplant and tune" OR?
Beyond a fuel pressure check I'd say unless you're well qualified, familiar with tuning/scanning software and have access to quality scanning hardware you need a "for hire" OR a volunteer from the forum who might be in your vicinity.
Explain all you know about the "transplant" maybe.
I'd suggest a professional qualified technician with the correct scanning hardware and move on from there.
You did the "transplant and tune" OR?
Beyond a fuel pressure check I'd say unless you're well qualified, familiar with tuning/scanning software and have access to quality scanning hardware you need a "for hire" OR a volunteer from the forum who might be in your vicinity.
Explain all you know about the "transplant" maybe.
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Thread Starter
Cruising
Joined: Oct 2015
Posts: 11
Likes: 0
From: Winchester Tn.
Race Director
Joined: Mar 2015
Posts: 15,926
Likes: 578
Might just be a leaky pulsater or the wrong hose put on to replace it.
Last edited by antfarmer2; Mar 20, 2016 at 01:47 PM.
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
So knowing the fuel pressure sure is a good first step.
Since it is a LT4 and I would assume it's got a OBD2 PCM. No special connector or OBD1 equipment like for the 92 is needed. So you can use any OBD2 scanner and see if there are any codes being set.
If I had to jump to a quick conclusion after I checked some basis items I might look at the opti. Just those symptoms are similar to opti symptoms.
Since it is a LT4 and I would assume it's got a OBD2 PCM. No special connector or OBD1 equipment like for the 92 is needed. So you can use any OBD2 scanner and see if there are any codes being set.
If I had to jump to a quick conclusion after I checked some basis items I might look at the opti. Just those symptoms are similar to opti symptoms.
Burning Brakes
Joined: May 2006
Posts: 1,208
Likes: 1
From: Elgin IL
I have had something similar in the past when taking the car out of storage. Pour a bottle of Iso heat in the gas tank. It will absorb any water in the system and clean the fuel injectors. It will not hurt to try. I used this one time and everything smoothed out in 30 minutes.
Drifting
Joined: Jan 2011
Posts: 1,853
Likes: 81
From: Hamilton Virginia
If you filled it up before storage, you could have actually gotten some bad gas. Or if you took it out of storage and filled it up right away, you could have gotten some bad gas. Has the fuel pump ever been replaced ?
Thread Starter
Cruising
Joined: Oct 2015
Posts: 11
Likes: 0
From: Winchester Tn.
rough running
Had a code 21 tpm voltage to high, how do you fix that
Thread Starter
Cruising
Joined: Oct 2015
Posts: 11
Likes: 0
From: Winchester Tn.
rough running
So knowing the fuel pressure sure is a good first step.
Since it is a LT4 and I would assume it's got a OBD2 PCM. No special connector or OBD1 equipment like for the 92 is needed. So you can use any OBD2 scanner and see if there are any codes being set.
If I had to jump to a quick conclusion after I checked some basis items I might look at the opti. Just those symptoms are similar to opti symptoms.
Since it is a LT4 and I would assume it's got a OBD2 PCM. No special connector or OBD1 equipment like for the 92 is needed. So you can use any OBD2 scanner and see if there are any codes being set.
If I had to jump to a quick conclusion after I checked some basis items I might look at the opti. Just those symptoms are similar to opti symptoms.