Hello,

Some weeks ago I replaced the distributor cap, rotor and coil on my '89 Camaro 350 TPI. Before this it ran fine. When starting it up it ran very poorly and has been since. Feels like it's running only on a few cylinders, hardly responding to throttle. When keeping the throttle halfway down, it will run but again poorly (undrivable). I've swapped back to old ignition parts with no difference. Tried to start without EST connected -no difference. Now I'm lost.

Last time I was tinkering I managed to get two trouble codes -21 and 42. I've read what they mean (21 - high voltage etc. on TPS; 42 - EST problems). Can one of these set off the other? Has anyone experienced something similar?

I have tried the following:
Checking spark plug cable order - OK
Timing is unchanged 6 degrees BTDC (no EST) - OK
Spark to plugs - OK
Fuses (from what I can see/find) - OK
Pressure in fuel rails 45 PSI - OK

Br,
Per

 

If I were you, I would remove the spark plug wires and reconnect them to make sure I got them on the correct cylinder.

 

I agree with tootie pang, the firing order is not right or you damaged the plug wires in the process of changing parts..

 

Code 21 can be a faulty ecm or ground behind the pass cylinder head.

 

Yeah, you could have bumped a weak ground loose working the plug wires.

 

http://chevythunder.com/tps_code_21.htm

 

Thanks for your ideas, I'll look for a bad ground. Possibly I could have caused something while tinkering. Will let you know how it proceeds.

Br,
Per

 

Sorry not to high jack the threat but in the same line ,any one have the ground diagram for the same car 89 Iroc? I'm helping a friend to chasing the same problem but i have been out of the TPI sine close to 15 years.

 

All except the aldl ground is behind the pass cyl head. There is a splice for the cts and tps in the loom around the tps location.