Georgia Fiero Club

First off, I'd like to say hello to all the fellow fiero owners in Georgia.

2 weeks ago I picked up a 1988 Formula Fiero. Its not exactly a concours example but I think its still got some life in it.

It seems to have some problems with idling, as in it wont idle at all. I'm no mechanic by any means but I will occassionally fiddle around with my cars.

This is what its doing. The car will idle for about 3-5 seconds at 12000-1500rpm, the revs will slowly drop and than it just dies when it hits around 900. It will stay going as long as you give it gas and keep the rpms above that.

Its an auto and when putting it into gear it will just die unless you give it gas as soon as it shifts. This doesnt change with the TCC disconnected.

Tried disconnecting the MAP and IAC seperately to see if that helped... it didnt.

Cap/rotor/plugs/wires are all new. TPS reads .45-4.9v, CTS seems to read fine. I just swapped out the MAP and IAC with new ones. I've reset the base timing and cleaned out the idle passages and TB until they sparkled. I also threw a bottle of rubbing alcohol into the gas tank when I first got it as it had been sitting for about 9 months. Fuel filter/O2 sensor look brand new.

I've reset the computer to let it get adjusted to the new IAC but it still dies at idle.

When I first picked it up the fuel pump was not priming. A liberal application of contact cleaner to the relay fixed that. I've checked the fuel pressure and its 44 when the pump is primed, 39 when the car is running.

Whats weird is if I put the computer into limp home mode with my scanner it idles at 800rpm just fine. As soon as you take it out of limp home mode the car dies instantly. The engine isnt making any weird noises or smoking and it sounds just fine until it dies.

Anyone have any suggestions on what to check next?

I went ahead and ordered a new ECU as I cant really think of what else it could be at this point. I just dont want to take it out of the box without making sure its the problem.

When running in normal mode, does it seem to be running rich before it dies?  If so, you might take another look at the Coolant Temperature Sensor.  Disconnect it and see what happens.  Just for clarification, this is the sending unit just under the thermostat housing.  When mine failed, I had difficulty keeping it running long enough to get it to a garage.  After it was diagnosed, we disconnected it and I drove to the auto parts store and back and it ran just fine.

Any time you disconnect power from the ECM and make adjustments, you need to drive the car at road speeds for 10-20 minutes so it can "re-learn" itself.

It seems to be running a little rich when its dying.

I've got a scanner hooked up to the car and with it the CTS seems to read around the same as the gauge in the dash. Its worth a shot though, I'll go ahead and give it a try.

As far as the computer goes,if I fix the underlying problem will it still die while trying to relearn everything?

If it's running rich then you have a vacuum leak or a sensor  reading boarder line, and the computer is trying to compensate by dumping more fuel. Have you checked your EGR tube for leaks? But if you can put it in limp mode and it run better then it's probably not the EGR tube. Sounds like it's in your EST (electronic spark timing) which is controled by the computer. When you set your base timing did you jump the diagnostic connector while you set it so the computer wouldn't try and reset it? You need to check it with a timing light to see if it's advancing when not in limp mode.

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President
East Tennessee Fiero Club
Robert Finley
RobsFieros@comcast.net

Alfa Seltzer:

It seems to be running a little rich when its dying. I've got a scanner hooked up to the car and with it the CTS seems to read around the same as the gauge in the dash. Its worth a shot though, I'll go ahead and give it a try. As far as the computer goes,if I fix the underlying problem will it still die while trying to relearn everything?

The gauge reading comes from a different sensor located just underneath the coil, in the corner of the cylinder head.  The CTS sends info through the ECM, which uses that info in part for fuel injector flow.  When mine failed, the scanner said my coolant temperature was -28 degrees.  The ECM was dumping enough fuel that I looked like a diesel truck with the cloud of black smoke.  But it sounds like your CTS is reading good.  To check your EGR valve, put your fingers up underneath it, and push up on the diaphragm.  The engine should stumble and die.  Before starting the car, remove the vacuum line to the EGR valve, push the diaphragm up, and while holding it, cap the nipple with your fingertip, and while keeping your finger there, release the pressure on the diaphragm.  The diaphragm shouldn't leak down in less than 30 seconds.  If it does, you have a hole in the EGR diaphragm. 

I don't know if your scanner effectively grounds the ALDL.  As Robbie suggests, if it isn't grounded, any adjustments to timing, etc will be overridden by the ECM.  Just to be sure, do it the old fashioned way with a paper clip inserted into the ALDL, reset the timing to an average closest to 10 degrees, using plugs 1 and 4.  Don't jumper the ALDL, or remove the jumper while the car is running or ignition on.  It could easily kill the ECM. 

Now, for relearning itself.  You should drive the car for 10-20 minutes.  Just sitting at idle won't give it all the peramiters the ECM needs.

I used my scanner to put it into "backup fuel mode" while setting the base timing.

I actually made a video of me putting it in backup fuel mode and than dying when it is taken out of it.

Pt.1 (1:27) http://www.youtube.com/watch?v=BTralZ4dFd0&feature=related

Pt. 2 (0:17) http://www.youtube.com/watch?v=KqxBMsDo-7o&NR=1

The timing was retarded by about 10 or 15 degrees, the notch on the crank pulley was showing up about a half inch before the timing marks.

I guess I can go ahead and double check that the timings set right by jumpering the ALDL with a wire just to make sure. The reason I put it in backup fuel mode with a scanner was because it will only idle for a few seconds before dying even with the ALDL jumpered.

Do I have to use the average of plugs 1/4? Shouldnt I just be fine using plug #1?


As far as the EST goes, I noticed a bit of crud (possibly rust?) on the pickup coil and theres a touch of surface rust all over the inside of the distributor. I'll take some pictures for you guys to look at.

One time I started fiddling around with the connections to the ignition coil/distributor and it started idling fine. It also shifted fine (shifts a bit rough usually) and ran fine for my half hour trip home.

It still died when shifting from P/N to D/1/2/R but if I gave it some gas when shifting it would shift in gear and not die. I was able to drive it a half hour home without any issues.

Turned it on the next morning and it started acting up again.

I guess I'll try this on my next day off:
http://www.fieros.de/en/v6help/code42.html

Sometimes idle problems are caused by bad electrical grounding. Make sure your ground connections are clean and tight. An additional ground from the battery to the engine block sometimes helps.

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The more complex the mind, the greater the need for the simplicity of play.

So far they all look good but I picked up a new set of wire brushes and plan to go to town on them just in case.

I've run across one on the bottom right hand side of the decklid, one for the ECU in the center console and one near the right rear of the engine bay next to all the relays.

Any others I should check out?

Will white lithium grease be good enough to protect them from future corrosion?

There is a braided ground from the passenger deck hinge to the block, one that's an integral part of the negative battery cable that grounds to the junction block near the negative terminal, and I think there's a braided one underneath that grounds the engine to the cradle.

I don't know if your scanner actually does ground out the ALDL, but if you were at 10-15 retarded, then that could possible be some of your idling issue.  I'd suggest going ahead and jumpering it.  The averaging of 1 and 4 is the factory recommended method.  lf you have the emissions tag on the decklid, it should specify that method.  Some people use the inductive pickup, clipped to both 1 and 4 at the same time, and they claim you can average it in 1 step.  Just set the light to 10 BTC.

The crud inside the distributor is caused by the ozone that's created when electric spark passes through air.  Use a little contact or carb cleaner and spritz out the little mesh vents on the distributor base to help it breath a little.  I wouldn't mess with removing any of the crud from the pickup coil.  If you damage it, the distributor has to come out.

The ground contact areas should be oil, dirt and rust free, as should be the fastener threaded areas.  The only area I've ever noticed that may be a problem is the negative ground at the junction box.  The stud and nut sometimes tend to rust, in part because of rain coming through the deck vent.  After cleaning, it could be coated with some time of waterproofing like lithium, but I've nevewr seen anything on any of my 3 cars.

If I recall, aren't you out in the Marietta or Douglasville area?  Our West Side mechanic said to tell you to give him a call.

I'm in Marietta. Did you go out to the GA Triumph Clubs Polar Bear Run? I might have run into you there.

Is the West Side mechanic Don Hulse? If so, I've been trying to get in touch with him but I think I have the wrong number.

I did make the Polar Bear Run, and Don Hulse is the man.  If you will call me at

678

467

1742

I'll give you Don's number.