Hello everyone

New owner here. I purchased a low mileage all original 1989 Convertible Camaro with a 5 speed manual. Always desired this car since young and finally had an opportunity. I'll attach a pic at the bottom.

I have taken the last 2 weeks on this site to peruse some common issues, and I am starting to get stumped on a few things.

1st of all, it's idling rough, and backfiring during idle, and too much on downshift.
- driving home from Toronto it felt like the coil was bad, and missing around the 2500 RPM mark. (I know the feeling of a bad coil in a few other vehicles) so I -
- changed ignition module
- changed to MSD 10 mm wires, AC Delco plugs, MSD coil, MSD dizzy cap.
- I have yet to check the timing - which I will do tomorrow. By the way, the dizzy is a PITA to get to, isn't it?

Still runs horrible, and the exhaust smells very rich. Pops and backfires when you feather the throttle. Runs better the higher RPM you go, but it definitely feels like it's missing somewhere at cruising speed. All wires are firing based on putting my timing light on each of them.

The other weird problem is that when I drove it home from Toronto, the temp never got higher than 40. I assumed the T-stat was shot, and it was, so changed that. Now the temp doesn't even register, so I thought the temp sensor was bad - changed that too. Still does not register.

I'm about ready to bring it to the shop, but I am a curious individual and would love to solve this on my own.

Any suggestions at all?



My new '89 Convertible.

 

Does the temp gauge peg out when grounded ?
Are you replacing the one in the drivers side head ?
Any trouble codes (check engine light on ?).
Do you have the original injectors? Grey body ?

 

Thanks for quick response. Answers to your questions:
1. Not sure what you mean about 'peg out when grounded'. Do you mean the indicator travels to one extreme if the sensor is placed to the block?
2. I replaced it on the front of the head I think offset slightly to the passenger side.
3. No trouble codes, but I may take my reader and see if there are any codes stored in history.
4. Looks like they are not grey injectors they look more black - but they look fresh - see pic.

Thanks.

 

Correct if the green wire to the cylinder head temp sender is grounded this will peg the indicator.
This is a single green wire between cylinder 1 & 3.
This would test the wiring and gauge crude test but works.
Any identification numbers on the injectors? They have been replaced but might be 22#hr I’m assuming it’s a 305 and using 19#hr.
Any evidence of fuel in the fuel pressure regulator vacuum line?

 

You really need live data from the ECU to know what's going on. Otherwise you are just guessing. Those injectors don't appear original so someone has been in there and there's no telling if they made anything better or compounded the situation with incorrect parts, etc.

GD

 

Those are definitely aftermarket injectors.

 

Good advice, I'll try and see if I can get more info today.

I do know that this car has sat without being driven much for the last 2-3 years.
I'll post some updates here later. Thank you all for your help.

 

Checked timing today. It’s currently running at 9 deg advance. I think this would explain bad running idling and backfiring.

Any suggestions on getting at the dizzy adjusted? Very difficult to get at the bolt to release the distributor to adjust.

 

use a 9/16 distributor wrench. also want to do with engine warm and est disconnected 6 degrees is the spec but 6-8 seems to work well.

 

do you need to remove anything to access?

 

The est is by the blower motor and strut tower. a single weather pack connector tan/ blk stripe wire.

 

"Bad idling" and "backfiring" will not be a result of the timing being advanced by 3 degrees. Not that you shouldn't correct that - you absolutely should correct it assuming you have a good timing chain and the timing advance is stable. On an otherwise normal running engine, if you ran premium with 92 or 93 octane, them the extra 3 degrees would likely be just fine and make more power. It would not affect idle or cause a backfire - that is not related to your ignition timing.

GD

 

if it were your car what would you guess would be the culprit?

 

Did you ever pull codes or ID injectors?

 

not yet. will do that next.
thx

 

Given the rough idle - I would check for vacuum leaks, listen to the injectors with a stethoscope to make sure they all sound the same.

Then my first check of live data would be to watch the BLM, and INT (long and short term fuel trims), O2 cycling, and MAF grams/second. Also give a glance to CTS, etc.

GD

 

Had a chance to work on the timing. Have it dialed in to factory spec.

No chance to get a live read yet. Thought I would at least set timing first.

Haven't tested the temp sensor yet

Please have a listen and watch to see where I’m at. Thanks all!

 

Today I had a chance to take a moment and think of what was done.

I wanted to clean up the ignition wires so one by one decided to reroute them further away from the exhaust manifolds.

turns out a few of them didn’t feel seated on the plugs and I think that was the issue. Re-timed the car and now things running much better.

Still a bit of hesitation on low RPMs but she pulls strong and feels great. 20x better than before.