I am new to the gm/camaro scene. I looked through forums and figured I would give my specific problem and see if I can get help. I have a 1994 z28 camaro 6 speed. Bought it last week knowing it had running problems.I read up and down the internet and my problem seemed to be the opti. It ran decent when cold and once warmed up, it ran bad. I swapped out the opti for an oem one and put a new coolant temp sensor it it as well. Put it all back together yesterday and it seemed to run pretty good. Once it warmed up though, it starting running bad anywhere after 5% throttle I'd say or any real load on the engine. I had to down shift to 4th to make it up a hill and stay above 55pmh. Im wondering if anyone knew of any other problems that would cause this. I was thinking it could be anywhere from the tps to a fouled plug or wires. Thanks

 

Scan it for codes.... check the fuel pressure. Two basic first steps in sorting out these problems. A data log of the PCM with the engine under operating conditions which produce the "running bad" symptoms may help you solve the problem..

There a link to a free download of scanning/data logging software written specifically for the OBD-1 94/95's. Check here:

https://www.camaroz28.com/forums/com...95-lt1-874306/

Free (plus cost of a cable) = a lot cheaper than playing "parts replacement roulette".....

You record the data and there are people here who can help you interpret it.

 

Okay I just got off work and went to advance auto and of course they cant read the obd1 with the scanner they got. I seen how to make a cord for the scan9495 but i figured it would be easier to buy a pre made cord. I also realized that it idles at about 1k if that would narrow it down any.

Thanks for the input Injuneer. Much appreciated

 

What can go wrong when it warms up:

Heat soak affects the ignition control module, the optical cam position module in the Opti, or the fuel pump.

O2 sensors faulty (only used in closed loop when the engine warms up). Scan data can show up a faulty sensor, even though it might not be bad enough to set a code.

Coolant temp sensor in the water pump faulty. I assume you knew to replace the one in the water pump housing, but did you check the wiring for a short, or open? The two-wire connector should read 5.0V with the harness connector off the sensor. This is an areas where the scan data will tell you immediately if the sensor readings are correct.

 

I just got the car last week and worked on it over the weekend. When I was changing the optispark I also changed the temp sensor in the waterpump. It has a new ignition module on it. Just curious, how would it mess with the fuel pump? The car barely gets over 160 mark unless i let it sit and idle for a while. I want to put a new stat in it just so it warms up better.

 

Ill check the temp sensor wiring to make sure its all okay. Forgot to do that last night.

 

An old/worn fuel pump can heat up and lose capacity.

You may have a 160* t'stat in it..... popular replacement for the stock 180*. Make sure it has a t'stat, and make sure it is the one specifically required for the LT1 (not the same as a Gen 1 SBC).

 

I got it figured out! One of the plug wires was rubbed bad by the power steering pump pulley. It runs fine now finally. Thanks for all the help and ideas.