Topic: Desparate To avoid auto repair shop incompetence

[TwoTired]

I've got this 89 Camaro IROC I bought new, which is my first mistake.  It's been a lemon since I got it.

When it runs it is an extreme kick to drive.  But, that's the problem.  It seldom runs right.  GM mechanics could never get stable for more than a month, then another problem shows up.  Ergo, it has 31000 miles on the car.  As I opted to use one of the Hondas for commuting when weather was acceptable.

Anyway the latest issue is that it starts and runs fine cold.  When the temp gauge gets to normal temp, it idles rough, and shortly thereafter the CHECK ENGINE light comes on.  Turns out that, although all the emissions are well below requirements, it fails the smog test because the light comes on.  Can't register the car in Kalifornia without a smog test.

The codes stored in the computer are for MAF (Mass Airflow Sensor).  However it also says these could be false if the engine is running rough, which it does, after it warms up.

I'd take it to a repair shop. But, I don't know any that are worth any sort off trust.  And, I expect they will simply follow the computer codes and replace the the $500 MAF along with whatever they eventually find the real problem is.

Anybody familiar enough with this problem to offer advise?

If I can't get it sorted before the end of October (when the Reg expires), maybe I'll stick the the IROC chassis and running gear under the 37 coupe.  No smog test needed for that car, it's exempt.

Cheers,

[Pinhead]

IMO to troubleshoot fuel injected vehicles you at the very minimum need a ScanGauge. Then you can monitor the specific sensors that can indicate what your problem is. I've seen vehicles with your problem have a bad (intermittent) crank or camshaft position sensor. Your CHT sensor could be faulty, too. It's hard to say without being able to watch the parameters as the engine warms up.

Edit: Never mind about the Scangauge... It only works on OBDII vehicles which didn't debut until the late '90s.

[Rocking-M]

That IROC is a weird bird as far as fi goes. Throttle body is it or multiport? I can't remember.
We had the Transam version for a bit.
Could be as simple as the O2 sensor which is a fairly simple test.

[kghost]

Hows the Fuel pressure?

I saw a problem with low fuel pressure like that. Pump/engine warmed up and the pressure dropped.

Played havoc. Ya might check that the pressure is within parameters....and its a simple check.

[mattcb350f]

I seem to recal that the fuel injection systems used on the IROC and the Firebird were known to be trouble.

My brother had Firebird of around that year and ended up yanking the whole FI system out and plunking a Quadrajet on top....problem solved.

...but that's the lazy way out 

As far as taking it to a shop to have fixed.....unless the mechanic working on it has had experience with that fuel injection system and/or that exact problem, you're just going to end up paying a lot in shop labour to get it fixed. When I worked at a garage, we use to get head ache problems like this from time to time. Since it was usually a car we weren't familiar with, it would take us many hours to find the problem. Once we found the problem though we would only charge the customer the book rate for fixing it, rather that the two days it took us to find the problem.....but I don't think most shops would do such a nice thing; you will probably pay for every minute of their diagnosis.

There must be some way to diagnose the problem at home. I've had a strangely high failure rate of EGR valves on the chevy's I've owned. It's possible this could be the problem.

Try disconnecting the EGR (and plug the vacuum connection) and try it.


...Another thought is search for a forum on that type of car. I bet you aren't the only one whose had this issue.

 Matt.

[mattcb350f]

Like this site: http://www.iroczone.com/

Forum @ http://www.iroczone.com/forums/

 Matt.

[750K2]

i was thinking egr too.  funny how that happens. 

[kirkn]

Take it to a shop??  

Just do it yerself - standard troubleshooting techniques apply.

If the trouble code says MAF, then there will be some way to double-check that part to confirm or deny WITHOUT just dumbly replacing with new - specs, voltage reading, resistance reading, visual inspection, etc.  YOU can do all that.  But you gotta get the info first.  And you know how to do that - RESEARCH!  Like by asking questions (here, or wherever you trust).

If you CONFIRM it's bad, there you have it.  

If you confirm it's OK, then go on to the NEXT thing.  Again, you need the INFO.  

But such info MUST be available, and it ain't rocket science.  It's just a car, designed and built in Detroit, fer chrissakes!  And it'll take less than a hundred bucks worth of 'specialty' tools, if that.  And that's money well spent, if it keeps you away from incompetent repair shops.

But, you knew all this.  Standard troubleshooting and common sense, along with a modicum of mechanical knowledge / aptitude.

Good luck with it.

Kirk

[Sporkfly]

Could very likely be the O2 sensor.

Here's my logic:

During warm up the FI system runs on a closed loop using predetermined values for the fuel/air mixture for the fastest engine warm up. After the engine reaches temperature the O2 sensor enters the system and it starts operating on open loop, your computer begins getting readings from your O2 sensor and adjusts the fuel air mixture as needed.

The O2 sensor is a pretty easy thing to do a test on. Measure its output voltage, that whole song and dance.

And beyond that, I agree with EGR being another possibility. So, go with Matt's advice - pull the vacuum and plug it. Also, trust your computer and test anything you can with the MAF. It will at least head you in the right direction.

I'll ask around on my end and get back to you with any answers. That won't be until Monday though. Going to Uni for automotive service y'know

[TwoTired]

I replaced...
 the Fan switch (it always did wait too hot to get the fan going). 
Temp sensor for the computer.
The thermostat  (Takes a long time to warm up).
The spark plugs,
the dist cap
The rotor
The anti-freeze.

My reward is that it now runs bad cold, too.
I had replaced the ignition wires and main coil last year, as one of the original wires went open circuit.  But, I suspect now that the new wires are somehow different from the originals.  I had a heck of a time getting them routed so the engine would run smooth.  There's no room for hands in there.  All but three spark plugs and the plug boots have to be accessed from under the car.

This car is the 5.7L TPI version.  I took it for a short ride and it's definitely not running on all 8.

If the ignition wires don't get it sorted, I suppose injector issues are possible.  Or, fuel pressure.  I'll  have to look into that.  Not sure I have a gauge or the fittings for that.

Oh, and by the way I have the GM service manual for the car I bought back in 89.

I'm done for today.  Tomorrow is another...

Thanks all for for your suggestions.  I'm having a hard time believing the O2 sensor is bad.  That's one of the things the computer monitors for out of bound readings.  But, I get no trouble code for that.

Cheers,

[BobbyR]

Well my son's 95 Camaro runs stupid rich. No way it could pass the tailpipe test or any other test. With the proper introductions down in the barrio along with an extra $20.00 bill and she passed. I try to round off the sharp edges whenever possible. Once you get it running OK, then find some "tuners" down in the barrio, they know how to get it passed.

[edbikerii]

Try cleaning the MAF sensor wire.  I'm not thoroughly familiar with that unit, but MAFs I have worked on have a tungsten filament that is heated by current running through it.  As the air crossing over the filament cools it, it changes the level of resistance in the circuit, so the ECU can determine how much air is flowing into the engine.

I've had to spray brake cleaner inside the MAFs on a couple of my cars (94 Ford Probe, 92 Jaguar XJ6), in order to clear codes and improve both idle and part-throttle operation.  

On those cars, if you pull the MAF, you can see inside where the tiny filament is.  It gets slightly crudded up with fine dirt, even though it is downstream of the air filter.  When it is crudded up, it doesn't cool down as much when air flows over it, so measurements go out of range, etc.  Sometimes this shows up as a false O2 sensor lean code because the CPU thinks there's less air and leans out the mixture.

Don't touch the wire with anything except brake cleaner.  Try not to get the brake cleaner on any rubber or plastic parts in the MAF.  When you're done, disconnect the battery to reset the computer.

I figure this thing has been cleaned up about every 30K to 50K miles on my cars before the problem comes up again.

Worst case, you spend $5 on a can of brake cleaner and about 10 minutes.  If it works, great.  If not, then at least you won't have to clean it for a while.

Another thing I had a problem with once that sounds similar to your symptoms was that I changed the thermostat on my 92 XJ6 with the recommended Stant thermostat.  However, Stant's reference in the book is wrong for that car, and the Stant unit opens at 180', whereas the Jaguar unit opens at 192'.  The hotter temp thermostat really improved my mileage, too.

BTW TT, if you are unhappy with that car, I'd be happy to take it off your hands (cheap, I'm afraid -- I'm divorced and broke).  I'm sure you have maintained it meticulously, knowing how you are.

[edit:  I cleaned the MAF on my mom's 95 Mitsubishi Galant, too, and that cleared the check engine light about 20K miles ago, too.]

[jsaab2748]

I'll take a wild ass guess. Does the engine have an air pump?
Cal. cars do in a lot of cases. If so, is it possible that the air injection components are malfunctioning? I.E. the air switching solinoid/valve is not diverting the air downstream to the converter when the engine is warm? And as a result it always injects air UPSTREAM, into the exhaust manifold, BEFORE the oxygen sensor, so the sensor always shows LEAN? This scenario could fool the computer. But then, it shouldn't cause a mass air code I wouldn't think. Might be someting to check as one possible problem among others of you're equipped with an air pump tho...And as mentioned, if there isn't a screen preventing you from getting to it, clean that sensor wire with a q tip and cleaner. Also, The converter wouldn't be broken up internally or otherwise clogged would it? Lastly, a not so scientific test for a finicky MAF sensor is to lightly tap on it like you're unsticking a float on the 550 while the engine is running.
Sometimes you'll get lucky and induce rougher running and get rewarded with a code too.. A scan tool if available, would be helpful if you have access to one, as you could moniter data from all the sensors. Troubleshooting can be a pain in the ass sometimes. I've seen cars run screwy from anything from electrically flaky fuel injectors to bad computers. By the way, the method for unsticking the 550 float also works on flaky ecm's as well. I've actually heated the interior of the car with the heater on MAX and aggravated an ECM into going stupid and storing false codes with weird driveability.
Only did that as a last resort, and all the data looked normal otherwise. Oh yeah, and make sure the inlet air hose is clamped tightly to the throttle body inlet, has no holes or tears in it, and there is NO air getting into the engine from any other sources.

[mattcb350f]

Try cleaning the MAF sensor wire.  

Good call too Ed.

But is sounds like you need to sort out the ignition problem first TT, before being able to reliably diagnose the FI.

Basically, when a fault is detected by the cars computer, it automatically defaults the FI system to a rich setting (to avoid a lean condition).

So if the ignition is acting up and the on-board CPU isn't able to detect ignition faults then it might detect, say an anomalous readying in the O2 sensor and improperly story a trouble code for the 02 sensor...........see how things can get complicated/expensive 

A MAF code could be triggered by a bad throttle postion sensor. If the TPS sensor and the MAF sensor readings don't jive, and the computer is not able to detect faults in the TPS, than the MAF is faulted.


These are just examples TT of how, in my experience, trouble codes aren't always literal.

 Matt.

[mark]

I've got this 89 Camaro IROC I bought new, which is my first mistake.  It's been a lemon since I got it.

Ahh.... the dreaded "Eighties Junk". An entire decade of auto production which really needs to be squashed into little cubes. Like you said, a lemon from day 1. The best way to avoid the huge bill is to just not spend the $$$ on it, period.

"GM mechanics could never get stable for more than a month, then another problem shows up." Nothing personal, it's just the nature of the beast. It wasn't any fun being the guy at the dealer, either.

Putting the innards in the '37 sounds like a good plan. As for the rest, go have some fun at the track...



 

[mattcb350f]

Ahh.... the dreaded "Eighties Junk". An entire decade of auto production which really needs to be squashed into little cubes. Like you said, a lemon from day 1.

come on now, the foreign 80's cars aren't that bad. I love my 1987 VW.

...you just gotta think like an 80's guy to work on them. Or an 80's engineer......anxious to add all sorts of fancy new 80's electrical gizmo's and computers to the car of the future.

Remember the digital dashboard  the family had an 86' Olds cutlass with the digital readout dash. When I was a kid, I loved riding in it........It was like KIT from Knight Rider!

 Matt.

[edbikerii]

And that pontiac (Bonneville SSE?) that had the "heads up display"!

Ahh.... the dreaded "Eighties Junk". An entire decade of auto production which really needs to be squashed into little cubes. Like you said, a lemon from day 1.

come on now, the foreign 80's cars aren't that bad. I love my 1987 VW.

...you just gotta think like an 80's guy to work on them. Or an 80's engineer......anxious to add all sorts of fancy new 80's electrical gizmo's and computers to the car of the future.

Remember the digital dashboard  the family had an 86' Olds cutlass with the digital readout dash. When I was a kid, I loved riding in it........It was like KIT from Knight Rider!

 Matt.

[Rocking-M]

GM with through a lot of changes with there FI,
89's supposedly had no cold start valve (injector)

 "The calibrator provides a wider pulse width on startup to provide a richer mixture for a cold engine."

It was also a MAF (GM changed to MAP in 90)
The son tried a new MAF on his TA but it helped nada a bit.

    The 1985-1988 TPI system utilizes the following sensors and devices to control the engine: Mass Air Flow Sensor, Manifold Air Temperature, Coolant Temperature, Oxygen Sensor, Throttle Position Sensor, Cold Start Switch, Cold Start Injector Fuel Injectors, Idle Air Control Valve, Distributor Electric Spark Timing, (Module in distributor TPI) Electric Spark Control, Module and Knock Sensor. In 1989 the cold start injector was deleted.

you can do a ohm test on all the components, I'd do that first to make sure all the sensors are alright.


however, if your car set for a while I'd be tempted to do the redneck injector test first.
Not sure you can do this with the Chevy but on a Fiat I've taken the fuel rail out with injectors attached,
still hooked to the fuel supply, cranked it over to see if the injectors are spraying.
In the Fiat case a couple were not so I cleaned them with gum out and got them to fire.

One more note. It seems the 89 is not sequential fire injectors, that didn't happen till it went PCM in the mid 90's.

[ColinMc]

If you figure out and end up needing any parts let me know, I can hook you up with my NAPA employee discount. I'm just the paint and body guy so this is over my head on repairs...my car knowledge is limited to 3rd gen supra's, SHO's, and 1st gen RX7's lol.

[TwoTired]

I got the ignition sorted, I think.  I had inadvertently swapped 2&7 wires on the cap when the new cap went on.

But, it's back to it old tricks, warm up engine lope, surge at idle, though it hasn't given me the check light yet.  Thinking of hard wiring the radiator fan to keep it cool enough to get through the smog test.

One thing I noticed when I changed the spark plugs is that they were all wet with gas, except #7, which was dry.  I guess fuel pressure and the injectors are the next avenue to explore.  Back to the manual.

Cheers,

[kghost]

Well its an 89...irrespective of milage ....you may be fighting an Injector/Pressure problem.

I dunno whats with fuel these days....I recently had to clean my injectors on the F150...2002 model with 50,000 miles.

[BobbyR]

Well its an 89...irrespective of milage ....you may be fighting an Injector/Pressure problem.

I dunno whats with fuel these days....I recently had to clean my injectors on the F150...2002 model with 50,000 miles.

This brings up an interesting point. What did you use to clean your injectors? My son's 95 Camaro is running rough and losing power. Feels like a miss. When I rev it without load it start to break up at 2500, sounds better at 3000.

[kghost]

Well its an 89...irrespective of milage ....you may be fighting an Injector/Pressure problem.

I dunno whats with fuel these days....I recently had to clean my injectors on the F150...2002 model with 50,000 miles.

This brings up an interesting point. What did you use to clean your injectors? My son's 95 Camaro is running rough and losing power. Feels like a miss. When I rev it without load it start to break up at 2500, sounds better at 3000.

Lol sorry I'm no help Bobby...I used Ford....Dropped it off at the dealer....Weird I know...but I didn't feel like messing with it...

[edbikerii]

I've got a buddy with a 79 Porsche 911 Turbo with mechanical fuel injection.  The standard procedure for cleaning out those injectors seems to be removal, back-flushing with SeaFoam, and soaking in SeaFoam for a few days while holding the pintles open with little wire "lassos".

I love Techron and SeaFoam in the fuel for cleaning fuel systems.  I'd make sure that SeaFoam is safe for catylitic converters first.

[City Boy]

Regarding plugged injectors;I had the same happen to '90 Grand Marquis.Two injectors stopped reporting for duty.I poured a bottle of injector cleaner in the fuel tank.No help.I put 6 bottles into the tank over a 2 week period and lo and behold,problem solved.Ever since,I pour 1 bottle of cleaner in tank of all vehicles at oil change time.I also add some to my 1100F once in a while for good measure.Your results may be different!    Rock On