LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

94 issues help please

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Old 06-11-2015, 03:43 AM
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94 issues help please

Few problems if the youve experienced.any of them please give.me.some advice


From a cold start the car wont stay on unless you hold the gas pedal down takes maybe ten minutes and it still idles rough if you dont the car will shut off unless its given gas


If it sits for.another 10 minutes youd have to repeat the steps

Once it idled on its on I raised the hood and revd it by hand and heard a poppong sound like a small back fire

Transmission is leaking and doesn't feel like its slipping I dont.feel a jerk or kick goong in gear but i dont feel power as I should be I can push the pedal and the exhaust is loud but car isnt moving as fast as it should be

I.put the car in reverse and heard a clank sound

When I put the car into second it made like a knock from under the car like the tranny moved


Previous owner added machined heads cold.air intake and headers
i cleaned the tb and I put injection cleaner but it didnt help


Before I take it.to a shop I woild like to hear ahat these symptoms sound like thanks
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Old 06-11-2015, 07:28 AM
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Re: 94 issues help please

Basic questions:

Have you scanned it for codes?

Have you checked the fuel pressure?

What modifications to the engine and/or transmission are you aware of?

History of the vehicle - Is this a new purchase, with the problems you have discovered, or have you had this for a while, and these problems have developed over an extended time period?


Originally Posted by emailname
Few problems if the youve experienced.any of them please give.me.some advice

From a cold start the car wont stay on unless you hold the gas pedal down takes maybe ten minutes and it still idles rough if you dont the car will shut off unless its given gas

If it sits for.another 10 minutes youd have to repeat the steps
Could be a problem with the coolant temp sensor. If it isn't telling the PCM (computer) the correct engine temperature, it could display theses symptoms.

Once it idled on its on I raised the hood and revd it by hand and heard a poppong sound like a small back fire
Does the car still have it's catalytic converter?

Transmission is leaking and doesn't feel like its slipping I dont.feel a jerk or kick goong in gear but i dont feel power as I should be I can push the pedal and the exhaust is loud but car isnt moving as fast as it should be
Is it possible the car has a high stall torque converter?

I.put the car in reverse and heard a clank sound
Worn u-joints, too much backlash in the rear gears.

When I put the car into second it made like a knock from under the car like the tranny moved
Possibly a broken transmission mount.


Previous owner added machined heads cold.air intake and headers
i cleaned the tb and I put injection cleaner but it didnt help
Do you mean ported heads? Was the camshaft also changed? If so, was the PCM tuned for the changes?

Best thing you can do is download a free copy of Scan9495, get a cable from Red Devil River or ALDLCables to connect to a laptop, and run a data log of the PCM while driving the vehicle under varying conditions. One of us can help you interpret the results.

https://www.camaroz28.com/forums/com...95-lt1-874306/
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Old 06-11-2015, 04:47 PM
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Re: 94 issues help please

There are no cats on the car has a tune chip but isnt in car I dont even know where it goes
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Old 06-11-2015, 04:48 PM
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Re: 94 issues help please

New purchase
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Old 06-11-2015, 07:52 PM
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Re: 94 issues help please

Popping in the exhaust can be due to the missing cat - 94 only has onen cat.

You can't put a "chip" in a 94 PCM. Fixed chip has to be flash programmed. Other than a JET or Hypertech "module" that plugs in between the PCM and its harness connector, everything else is a scam. Even the modules, and the Hypertech hand held are virtually useless.
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Old 06-12-2015, 01:08 PM
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Re: 94 issues help please

So the chip I was refeering to is a jet performance power module where does it go I dont know how to upload photos to show it
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Old 06-12-2015, 01:12 PM
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Re: 94 issues help please

The cam wasnt changed .... I also have two lights on abs and a red symbol im thinking it has to do with the coolant but the car isnt overheating
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Old 06-12-2015, 01:23 PM
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Re: 94 issues help please

Go here and click on the "Instructions" tab:

JET Performance 19414S, JET Stage 2 Power Control Modules for GM | JET Performance

Note what it says on the "Overview" tab:

For vehicles modified with low restriction exhaust and low temperature thermostat.
Does your car have an aftermarket 160*F thermostat (stock is 180*)?

If someone ported the heads, they should have had the PCM tuned for the changes. I can't see anyone just having the heads ported, but not changing the cam. By installing the JET module, it may work against any tune that has been done, and by itself, with no tune, the module isn't all that great. If you don't have the low temp t'stat, the fans are going to be running all the time, but the engine isn't likely to run any cooler, because the t'stat' isn't fully open.
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Old 06-14-2015, 01:27 PM
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Re: 94 issues help please

The person I got ths car from says the idle needs to be adjusted is this something I can do myself
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Old 06-14-2015, 03:14 PM
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Re: 94 issues help please

Idle speed is controlled by the computer. Idle speed vs coolant temp can be changed by flash programming the PCM.
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