Bartman52

Hi everyone. Have been searching through posts for many hours and have found lots of great advice and have been following it. But, thought I should make this post for more direct help.

First off, I have a 1989 Pontiac Trans Am 1LE with a 305 and 5-speed. The car is primarily used for autocrossing, hillclimbs and a few F-body meetings/car shows. The car is stored for 6-8 months each year. The car has 67K miles.

This year after getting the car out of storage, the car ran great for about 20 miles. Then like flipping a switch the check engine light came on. I had to keep it nearly floored to get back home and it was blowing black smoke and running through fuel.

I checked for codes and had a code 34 and 33. Checked the posts on this site and swapped both relays. Reset the computer and tested again. The car starts and runs fine, but after it reached warm-up the car died. Still code 33, had to floor it to get it started. Lots of black smoke

Checked the voltages at the MAF per this forum, everything looked great, then swapped the MAF. Cleared the computer and restarted.

This time the car started fine (was cooled down) it ran fine until it reached operating temperature (fans kicked on), then shortly after died. This time no codes, but won't start without keeping it floored and was blowing black smoke (rich). Let the car cool down and it restarted just fine.

It's like at warm-up, a switch is flipped and the car enters full rich condition and is obviously undriveable. Still no codes.

Your thoughts and ideas are greatly appreciated. Thanks everyone!

Guest

Check the TPS. It might be bad.

vernw

iTrader: (2)

And the IAC. I had the same problem, and it was the IAC. Datalogs only reported what the computer TOLD the IAC to go to, it was not showing what the IAC had actually moved to....

8Mike9

I think you stall may have a problem with the MAF. Disconnect the electrical connection to the MAF and give it another try.

3.8TransAM

Still could be MAF issues, is everything sleaed well in the intake tract?

What about coolant sensor readings? Do they correspon to outside temps when cold and rise to something normal for a hot engine?

Still have stock injectors? When the windings start to go they usually act up when hot and then are fine when cold, etc....

Check the fuel diaphragm in the regulator? Yank the lin from reg to plenum and make sure its not full of fuel(prolly not since u said it would run ok when cold)

Grounds on the back of the cyl heads? PAss side is several ecm related grds and ar eknown to come loose, worth a check

later
Jeremy

Bartman52

OK, tried disconnecting the MAF and it runs rough at idle and when cold but still dies when reaching operating temperature.

The passage between the MAF and intake tract are good. I did get a 33 code during testing when I left the MAF to intake hose loose. Tightened back up and cleared computer. No codes now.

I will check the TPS, IAC, injectors and grounds to the ECU.

All great advice everyone! I have to go out of town a few days for businesss, but will try your suggestions next Wednesday. Please check back to this post and hang with me if you can. Your comments and suggestions are greatly appreciated.

Bartman52

Hi all, finally got back to looking at the TA. Changed the IAC as suggested as it was pretty gummed up. Now the car idles smoothly, but still dies after warm-up.

Next, changed the TPI as the voltage swing was erratic (not linear) when moving from idle to WOT. Now, car idles very smooth and no gas smells. Yeah.

Engine reached operating temps (fans kicked on several times) still idling smooth. So far so good right? Then I ran the engine up a few times and it then went into a rich condition and died. Restarted but still ran way to rich.

Now the fun part....pulled the computer fuse to reset it, restarted immediately and it runs great again. Cooling fans back on still running great after 15 minutes or so.

Did check the computer grounds (ones I could find) and they are tight. Any common ground locations that come loose I should look for, as I may have missed one or two?

Checked injectors via ohm meter both cold and hot. All readings are the same. Maybe not a good test.

Had to shut down for the night as the wife was being very suggestive (your imagination goes here). I still believe the car will fail again and resetting the computer isn't the answer.

Any other ideas? You've all been great so far.

Brian

burnout88

Alright, sounds like the car is acting up as soon as it goes into to closed loop. And there is one sensor that the car immediatly starts to take readings from once that happens. The O2 sensor. Running rich is a possible problem in the O2.

Since it's the orginal sensor probably would not hurt to change it anyway and they are fairly inexpensive. Just by a good brand when you replace it . AC Delco or Bosch.

DuronClocker

iTrader: (1)

vernw

iTrader: (2)

Check the coolant temp sensor as well.

Another idea - does the problem occur ONLY when/after the fans kick on? If so, check the voltages. Could be the alternator isn't putting out enough to drive both the fans and the injector/ecm system. Just a thought.....

92blue

iTrader: (1)

I agree with the above suggestions regarding checking your CTS and oxygen sensors. I have a chart at this link thats useful to check the CTS...

http://tpiparts.net/85_89_maf_sensors/

Rob Wade

Do you have a good quality scanner? Check the computers signal for coolant temp when its hot and cold. I vote temp sensor!

Bartman52

Thanks for hanging in there with me and all the great input. The suggestions on this post have really made a difference.

I do have the factory service manual but no scanner, just a code reader. Have been using a volt meter for most of the troubleshooting, manual and dumb luck. I am about to break down and get the the AutoXray GM ODB I scanner. Is this scanner sufficient?

Will most certainly look at the coolant temperature sensor and O2 sensor this weekend. I have heard horror stories about removing the O2 sensor (yes, it's the original). Any suggestions on making this an easy task?

One last comment. The alternator was new last year and it is putting out sufficient voltage. The battery was also replaced last year.

I'll be working on the TA again this weekend, so I'll let you know the progress.

Thanks all!

Brian

GOY

I try to remove them cold at first. Spray them down with penatrating oil and go. If it doesn't budge, warm up the exhaust to expand the metals. They will expand at different rates, and that usually helps break them apart. If that STILL doesn't work... I do it West Virginia style...





... Break the sensor off the "Nut" part of the O2 sensor with a BFH (Big Fu**ing Hammer), slap the right size imapct socket on it now since there's no sensor in the way, and impact wrench it off. Hasn't failed me yet - some 15+ years old in salt and snow.

BMmonteSS

Hey I resemble that remark!

I second the notion of the O2 sensor. If it was a CTS it would go haywire right away. The only sensor that is completely ignored till the engine is warmed up is the O2. And yes, that is how we do it in West by G0D Virginia.

GOY

It's an Ohio thing, you casino having One more thing.... can we straighten 77 out any in W/V? Jesus, what drunk Georgian built that highway? :

BMmonteSS

Probably the same guy that asks me if West Virginia is near Roanoke VA......you'd be surprised how many people don't know that WV is a state and not a part of virginia.

Bartman52

OK OK...you guys have me laughing right out of my chair! Guess I'll try the BFH thingy on the O2 sensor this weekend and let you know how it goes.

Hardy Har Har

Brian

92BLKL98

Hey Brian, why not just get he correct O2 sensor socket they are cheap and fit a 1/2 drive ratchet and no fuss. Just about any discount autoparts store.
Then you don't have to look like a shadetree mech from WV nor GA. just kiddin' BMonteSS.

GOY

How boring.... ***........

92BLKL98

BMmonteSS

I've also had luck with a pipe wrench and a cheater bar. Since pipe wrenches grip tighter the harder you pull on them, they won't strip the sensor, they also will try to crush the sensor, which may help remove it.

I know a guy who put an entire motor together with a pipe wrench and an impact gun.....he wasn't the brightest color in the coloring box

StreetRoc85 350

Hey now i may be drinking down here but i dont know nothing about any highways.....