Fiero is having major problems. 1986 2.5

The telltale sign was when it died on me the other day while I was pulling out onto the road.. and it had been running so good for a while. It was hot out, I turned out onto the road, and after I pulled it out of gear and the RPMS dropped, it just died. No sputter out or anything like that, just dies. I roll over to the side of the road, starts right back up and I take it home without further issue.

I mostly ran the battery down last night accidentally leaving the dome light on.. must have hit it with my knee on the way out of the car.

Anyhow, I got in it today, it started right up, then died. Tried again but the Battery was real low... so I put it on charge and went to the store in the truck. Got a new PCV valve for it while I was out because of the small oil leak around my grommet. Installed it. Car TRIED to start, then died. Huh. Then I try again, its turning over strong but not firing up.

So I take off the air cleaner housing, and I find a bunch of leaves around the air filter. Clean that off, and start it again while the filter is off. It starts right up. Then I decide to watch it to see how its running. Running a little rough, so I push the accelerator by hand a few times and rev it. Runs, but then it dies abruptly when I let go of the gas... kinda revved down, then dies.

And now it wont start at all. I am letting it cool down (which is going to be hard considering it is sitting DIRECTLY in the sun) and will go out and try it again.

I have to think its my ignition control module failed. Again. This will be #4 on that car in 5k miles.. I have a backup in the trunk, and I will switch them to see what happens. But I think because of the high heat, it is roasting my ICMs. Maybe I did not put enough arctic silver thermal paste on there to protect it from the heat. Not sure, but I seem to remember REALLY loading it up last time I installed an ICM.

Any other clues what it might be besides ICM? Last summer I had put new ones in thinking it was the ICM, but it was the pickup coil had a crushed wire. I have not removed the Dcap since, so I doubt its that again. Besides that, it is not running rumbly or "tach dropping" or anything like it was when it was the pickup coil.

I would assume I have spark if I got it to start a few times, I will check for that when I get my helper to turn the key for me.

[This message has been edited by tbone42 (edited 08-11-2011).]

I don't think the weather can get hot enough to kill an ICM....but maybe something else is killing it if you have gone through 4 of them in 5K miles.....and here is a quote from Phonedawgz describing what could do it.

'Make sure your coil and spark plug wires are not of high resistance or they will shock kill your ICM and it will fail prematurely. No more than 10K ohm per foot for spark plug wires.'

'If you replace your ICM, you should also replace your ignition coil. Bad insulation on your ignition coil can shock your ICM and it will fail prematurely. If your ICM failed, it might have failed because of bad insulation on your ignition coil. It's cheaper to buy an ignition coil than a second ICM and ignition coil.'

[This message has been edited by Gall757 (edited 08-11-2011).]

Reseat all of your ignition and sensor related connects a few times each. A friend of mine had the same poroblem with his Cessna. It would start right up nd then die. Even when it stayed running it jsut slow down and quiet on him. Well a few forced landings dumbfounded machanics got him to sell the plane. I asked him, "did you hear a whoose of air when you checked your fuel tanks."
"Yeah, loud whooose."
"And then the next time you started it ran good for a while huh" "Yup."
"Your fuel tank vent was clogged."

I dont think it could apply here, but give a listen when you open the fuel cap.

------------------

trueleo.com
RSpiderII@aol.com

Well, I have 2 spare ICMs and no spare ignition coil, so thats where my search needs to begin because I cant even afford an extra coil right this minute.. I am as about as poor as I can be at the moment with 100 bucks to my name and no idea where the next $$$ is coming from.

I tuned up with the TFS tune up kit wires in spring, so I dont think I have high resistance cables.. or can they become high resistance after a while (in other words, do they fail in that way?)

Reseat all of your ignition and sensor related connectors a few times each. And try another coil.

Kind of related:
A friend of mine had the same poroblem with his Cessna. It would start right up and then die later. -not a god when youre flying- Even when it stayed running for a long time the engine would just slow down and quiet on him. Well, a few forced landings and dumbfounded machanics later got him to sell the plane -which he really loved- . I asked him, "Did you hear a whoose of air when you checked your fuel tanks."
"Yeah, loud whooose."
"And then the next time you started it ran good for a while huh" "Yup."
"Your fuel tank vents were clogged."

I dont think it could apply here, but give a listen when you open the fuel cap.

------------------

trueleo.com
RSpiderII@aol.com

You should be a writer....you can make lots of $$$...

I am still laughing about that thread on credit cards.

edit: You ARE a writer....you just need to turn it into a vocation.

[This message has been edited by Gall757 (edited 08-11-2011).]

quote Originally posted by Francis T: Reseat all of your ignition and sensor related connectors a few times each. And try another coil. Kind of related: A friend of mine had the same poroblem with his Cessna. It would start right up and then die later. -not a god when youre flying- Even when it stayed running for a long time the engine would just slow down and quiet on him. Well, a few forced landings and dumbfounded machanics later got him to sell the plane -which he really loved- . I asked him, "Did you hear a whoose of air when you checked your fuel tanks." "Yeah, loud whooose." "And then the next time you started it ran good for a while huh" "Yup." "Your fuel tank vents were clogged." I dont think it could apply here, but give a listen when you open the fuel cap.

No woosh

You can test your ignition coil with a multimeter.

Sounds like the pickup coil.

If your injector is spraying fuel - and I will assume your tach is moving up to about 200 during cranking - your pick up coil is good. Your ICM is most likely good. The pink/white wire harness between the ignition coil and distributor is most likely good.

Check to see if you get a spark from the distributor end of the coil to distributor wire - If so but you don't get spark at the spark plug then your rotor has a hole burnt into it and is shorting the spark there.

If not the prime suspects is your ignition coil. Swap between a working Fiero if you have more than one. Run the resistance test in the picture above. You can also, key on, engine off and a spark plug in the distributor end of the high voltage distributor cap to Ignition coil wire - and with the distributor side of the pink wire and white wire harness unplugged, take and ground the WHITE wire momentarily. That should produce a spark out of the coil.

[This message has been edited by phonedawgz (edited 08-11-2011).]

I just went out and cranked it, because I never looked at the tach. It aint doing anything.. just barely wiggled.

So, does that make it the pickup coil? (again?) Heh.. if you remember, I replaced it last fall after much troubleshooting.

[This message has been edited by tbone42 (edited 08-11-2011).]

Ok, I dont have a helper again until 6pm... now I see why people have kids.

Anyhow, I DID do the test grounding the white wire with a sparkplug in the dist cap to ignition coil wire with key on.

No spark. So does that mean I need a new coil?

Or you don't have +12v on the pink wire (key on) - OR your white/pink harness from the coil to the distributor is bad.

Unplug the white/pink coil to distributor harness on the coil side. Check for +12v on the terminal by the pink wire from the engine harness. Then ground the terminal next to the white wire.

You should have +12 on the pink side. Grounding the white side should make a spark. If you have the +12 to the pink but grounding the white doesn't make a spark then you coil sure looks bad.

Did you do the resistance tests on the coil?

quote Originally posted by phonedawgz: Or you don't have +12v on the pink wire (key on) - OR your white/pink harness from the coil to the distributor is bad. Unplug the white/pink coil to distributor harness on the coil side. Check for +12v on the terminal by the pink wire from the engine harness. Then ground the terminal next to the white wire. You should have +12 on the pink side. Grounding the white side should make a spark. If you have the +12 to the pink but grounding the white doesn't make a spark then you coil sure looks bad. Did you do the resistance tests on the coil?

Ill go check the wires now.. the resistance tests were inconclusive on the 3 coil tests... dont know if I am doing it wrong..

And I dont think I am.. but the tester I have is a real pain in the butt since it "automatically" switches between high and low testing and there is no manual way to switch it between hi and lo, you have to rely on it to do it for you... anyhow, when I did do the test, I got no "hi" on the hi/infinite tests.. it just sits at 0000.00, so I am starting to believe its the coil. I do get "lo" on the 2nd test, though.

I am just doing the other checks right now to see if they say the same thing.
brb

[This message has been edited by tbone42 (edited 08-12-2011).]

Ohm out the pick up coil. - You don't need to remove the distributor to test it with a meter. You do need to remove it to replace the coil if it tests bad however.

[This message has been edited by phonedawgz (edited 08-12-2011).]

quote Originally posted by tbone42: What do you mean make a spark? Am I supposed to still have a plug in my distributor to coil wire while doing this? Additionally, do you mean check voltage on the pink wire I just unplugged from the coil, or another wire (like the 4 prong that goes into the diz..)? A little confused.

With the two prong connector unplugged from the distributor. Yes the other end of the pink/white harness should be plugged into the coil, and the engine harness should be plugged on the coil, and the key should be on. And you should have a spark plug attached to the distributor end of the high voltage coil wire, and that plug should be laying on the engine.

Ok.. here's what i just did.

Tested for spark on coil to diz plug wire with a sparkplug in it. No spark on EITHER coil, and I am getting 12v DC at the pink and white harness wire going into the coil.

Tried it with different spark plugs, too, no spark. also checked the resistance of the short wire itself and got 4.5k steady.

Sooooo... with 12v going in, but no spark coming out, that HAS to be another bad ignition coil, right?

Going to do the pickup coil tests now, but if the above is happening, that is pre-pickup coil problem, yes?

losing daylight....

[This message has been edited by tbone42 (edited 08-12-2011).]

Ok... replaced the distributor cap (which was broken) and the rotor... and it STILL wont start, STILL no tach movement while cranking.

As stated earlier, both pickup coil tests were good. Not getting spark from either ignition coil I have (one is new), but I am getting 12v from the pink wire going into the coil. Does that mean both coils are bad, or is possibly it something else? It does NOT MAKE SENSE that I am 12v at the pink getting power going into the coil, the coil resistance test is working, but there is no spark coming out. How can this be?

I have cleaned and re-attached all my grounds (strap, battery and c500).

Anyone with fresh ideas? I dont want to have to tow this to a dealership for work... I am absolutely broke, and I just spent 70 bucks on parts that did not fix it.

[This message has been edited by tbone42 (edited 08-13-2011).]

I didn't re-read the entire thread.

Put the spark plug into the distributor side of the high voltage coil wire. Then unplug the pink/white cable. Put a paper clip into the white wire and - key on - tap the white wire to ground. You should get a good spark from the plug. If not, but pink has +12v that means either you coil is bad, or there is an open on the white wire.

If no spark from the above - unplug the pink/white wire from the coil. Then take a short wire and ground the pin next to the white wire and see if you get a spark. If you get a spark then, the white wire has an open in it.

[This message has been edited by phonedawgz (edited 08-13-2011).]

Yeah, I was brainstorming last night while at the Cleveland/Green Bay game (Man, Browns fans are really rude..). When I tested the pink wire for 12v, I grounded my other probe to the frame of the car. Sooooooo. I had not checked to see if the white wire (ground) was good. I am going to start testing it backwards from the coil and look for continuity. I figure if there is no break, I must have gotten a second bad coil. I mean, what else could it be if the pink has 12v power, right?

Anyhow, I will try your key-in spark test today (thanks for explaining it better) I know what to do now.. and then after that, I will be testing the white wire backward through the harness, looking for the break. Thanks, I'll post what happens here in a few hours. Appreciate all the time you spend with us here on tech..

That looks a whole lot like the tach filter. The tach filter prevents the tach from shorting out the ignition system. The test is to unplug it and see if the ignition system then works. Having it unplugged will disable the tach while it is unplugged.

Rodney Dickman sells replacement tach filters.


http://rodneydickman.com/ca...h=21&products_id=165

[This message has been edited by phonedawgz (edited 08-14-2011).]

Oh no kidding! I guess it is! Looks a lot like a fusible link, too.. heh ... anyway, it has no continuity.

Glad I took a pic of it! Thanks!

Going out to test it now..

[This message has been edited by tbone42 (edited 08-14-2011).]

It shouldn't have continuity when tested with a meter. It has a capacitor in it to block DC voltage. it however is designed to pass AC voltage. The tach signal from the ignition to the tach is an AC voltage.

So the idea of the tach filter is to prevent the tach from killing the ignition (block DC) while allowing the tach signal (AC) to pass through to the dash.

...next post...

[This message has been edited by tbone42 (edited 08-15-2011).]

Ok, I made a 5 question post to keep it easy for you to answer, P.

1) So how do you test tach filter to see if it still works ? I did an ohms test on the tach filter, and it was 15.65k. My tach was not moving while trying to start it, so it still could be bad. Will having a bad tach filter keep me from getting spark?

2) I am getting a spark when I do the "key on" paperclip test, but ONLY a spark at the paper clip where I ground it.... not at the sparkplug end.

3) To do the resistance test on coil, does the ignition coil have to be mounted to the frame? It would be nice to test the new one BEFORE I install it.

4) Will not having a working tach filter prevent spark? (Since the white wire does go into the coil...)

and

5) (Its a longshot, but...) I just installed a new stainless dashkit right before this happened. Removed the old bezels, so its just metal around my dash instrument gauges overtop the clear plastic. Could this in any way be shorting me out/preventing spark or kill the tach filter? I know this sounds dumb, but I am at a loss for reasons why I still cant get spark and I am trying to brainstorm any reason why this happened so suddenly.

1 - There are two ways the tach filter could be bad - It could kill the ignition - It could be bad in a way such that it doesn't pass the tach signal. To test for the first, unplug the tach filter and see if the ignition comes back. To test for the second, replace the filter and see if the tach works. Since you have done the first and that doesn't bring the ignition back, it can't be bad in the first way. I would wait till the ignition is working to worry if the second is potentially the problem.

2 - You should get a spark at the spark plug end. Grounding the white wire is what the ICM does to generate the spark. If you aren't getting a spark then, you trouble has to be ignition coil, the small white/pink cable, or no power to the coil. This test needs to be done with a spark plug in the distributor side of the high voltage wire, and that spark plug laying against the engine. Because the rotor may be pointing towards any spark plug wire, or may be inbetween plugs, you want to do this test with the spark plug attached directly to the coil. It is possible for the coil to pass the resistance tests but still fail this test.

You can eliminate the short white/pink wire as a potential source of the trouble since you are actually getting a spark at the paperclip. That means the white wire must be a solid wire, and it means you have at least some voltage going to the coil. So it sure looks like your coil is bad.

3 - Yes you can test the new coil's resistance with the coil non-mounted.

4 - Having the tach filter unplugged eliminates any possibility of the tach filter or tach killing your spark. The tach & tach filter 'moniter' the ignition signal but are not needed at all to generate it.

5 - If your tach filter is working correctly, anything you do past the filter should not affect the ignition. So no, if it is working you can't kill the spark by shorting the signal at the dash. That is why GM put a tach filter on the engine.

------

One last warning. Make sure whenever you are cranking the engine, or you are doing the paperclip test, that there is a spark plug/or the distributor and coil, for the coil to fire into. Don't pull spark plug wires off to test for a non-working cylinder. The voltage in the coil will rise till it finds a place to jump to ground. With no place to jump to ground with a spark plug, what it might do instead is rise enough to break through the insulation inside the coil. Once it has done this, it will leave a hole in the insulation in the coil. That hole now is an easier place to jump to ground.

Measure the resistance of your spark plug wires before installing your new coil. They should read less than 10k ohms per foot. If they read more than that they can kill your coil. Also a high resistance secondary can kill your ICM. That spark looking for a place to find ground can do so via the primary of the coil. What that can do is shock your ICM to death.

[This message has been edited by phonedawgz (edited 08-15-2011).]

Good deal. Yeah, I always have the plug grounded on the block when I test for spark, but I am only getting spark at the paperclip.

So the white wire going into the coil is completely non-essential to test for spartk, and even if it is unplugged it should not affect my test.. thats what I needed to know.

I will test all my plug wire resistances, but I was getting around 8.5k on the ones i did test. I did test the short plugwire fro the coil and got about 8k in resistance, but I will test the rest to make sure they dont blow up my next coil if I get it going.

Also, I DO have continuity in the 2 wire pink/white harness that goes between coil and distributor, so I dont think thats the prob anyway since I am not getting spark on the high voltage wire.

It sure sounds like the MSD coil I bought the other day is bad as well. I THOUGHT it looked like it might have been re-shelved... sneaky basterds at Advanced.

Thanks P, I will take it back today and try again!

[This message has been edited by tbone42 (edited 08-15-2011).]

The white wire that runs from the coil to the distributor is needed. The white wire that is on the engine harness connector side is not at all needed to produce spark.