Several times in the past month. With engine hot, never cold, and cruising fine at 60 mph I suddenly lose engine power, so I push in the clutch to coast, I get a huge backfire or two, coast a bit, let out the clutch and it pop starts and off I go like nothing happened, full power. It is not consistent. The lights and gauges all stay on when this happens. I have checked and tried several things but...still does it. Is my fuel pump sparadic or something? Help!!!

DANF

It's not uncommon for marginal ignition modules/coils to fail when they get hot. But usually when they do, they'll stay dead for quite some time while they cool off. It's still a thought though.

most likely an ignition module going out

i'm with the modual band wagon but just a tidbit, i had a cavy that did that turned out to be an ECM

A bad coil will give the same symptoms

So we're all on the same page too...
A car backfires when it dumps large ammounts of unburned fuel into the hot exaust system. This can only really happen if the spark plugs stop firing while the engine's still turning, or if the engine is running so terribly rich that there's simply not enough air to burn all (or any) of the fuel.
Having the engine suddenly dump massive ammounts of fuel in, then go back to normal is possibly, but less likely than the ignition dropping out.

Didn't say what engine & year you were running. I have had this happen with both of our 88 4-cyl coupes when the coils go bad. The cases on the DIS ignition coils actually split apart with age. Easy & inexpensive repair.

[This message has been edited by Gordo (edited 05-11-2006).]

Thanks for the input!!!

I have a new Accel coil on this 88' 2.8L Formula as well as rotor, cap and wires. About 2500 miles on all. Do you think the coil is faulty? I'll check again to see the coil wires are all secure. How do I check the engine module?

The ICM (Injection Control Module) is likely the culprit. It is on the distributer under the cap. It is what those two sets of wires plug into. take off the cap and it has two screws holding it in place. When you put a new one in make sure you have the di-electric grease between it at the distributor base. There are two different versions, a ~$40 knock of and the ~$90 AC Delco unit. They are identical for the most part, but some people report having less failures with the more expencive one. I went through a couple of each over the last few years and noticed no real difference between them.

-Rick

[This message has been edited by ThatRickGuy (edited 05-12-2006).]

I beleave you're referring to the ignition module. You want to be sure *NOT* to use Di-Electric grease between the module and the distributer. You need Thermal Paste, like what's used with computers. It's white lithium-based gunk. You can get it from computer stores.

As stated above, the ignition module and the coil both have a tendancy to become marginal when they overheat, but they usually don't resume working until they've cooled down for some time.

Both my 86GT auto and my 87GT getrag would act up like that occasionally after driving about 40 miles on the freeway. Replacing the coil with a good Wells didn't help. replacing the ICM with a working Wells replacement using the supplied thermal grease didn't take care of it. Finally, I upgraded the coil (accel in the 86 and msd in the 87) and used the same ICM with the silver-based thermal compound for PC CPU's that I found at Best Buy. Haven't had a problem in either car since. Not 100% sure which one cured it though.

My 87' started eating ICMs (Ignition Control Module) after I put the reman motor in. The culprit was the distributor... the pickup was hitting some and causing a vibration in the dizzy which was frying ICMs as well as making them seem like they were dead. Replaced the dizzy and 2,000 miles later still no trouble yet... lol yet...

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Everything Fades With Time.
86' Fiero Base Model = Soon V8 Drag Car
87' Fiero SE 2.8 w/ .477 cam+ goodies
88' Fiero SE Parts Car and suspension donor :)

I can save you some time and money right now by telling you that it isn't the coil. I had (and still have actually) this same problem with my GT. I replaced the coil on the assumption that it pretty much has to be something in the ign. system, but the module is a solid state device (unlike the coil that has to constantly build and break strong magnetic fields) so if it were to go out it should go out binary style. Meaning it will either work fine or not at all. I may have to revisit the module, though because I can't seem to find anything else that should show these same symptoms. Of course, if you're like me you have a lot of tempermental intermitten problems with your car that make it a bear to solve any of them.

Just out of curiosity, what is the condition of your exhaust system and O2 sensor?

Hot electronics, even solid state stuff, become erratic and unstable at high temps, especially if they're already marginal... That means they can work, without working fully or properly.
That's why computer overclockers have such gigantic cooling solutions, to lower the temps in order to get more out of their CPUs. That and to compensate for the increased heat output.

[This message has been edited by Jax184 (edited 05-13-2006).]

I chased this isse for a year. Went through coils and ICMs the whole time. When an ICM starts to fail the engine will lose spark, sometimes and ICM will just die, but both times my ICM died it did so intermitently. I had a loss of power on the freeway, then out of no where a back fire and power again. Same thing happend the next day, then twice on the way home, then I just barily managed to limp it to the shop the next morning as once the engine was hot I would only be able to drive for a mile or so until the ICM stopped again. Put a new ICM in it and it was happy as could be. Same thing next time it died a few years later. Then a while back I thought the ICM died again, I went through a few ICMs and coils, and flat bed tow trucks getting the car home. Finally tracked the issue down to the Distributor's pickup coil.

My recommendation would be to replace the ICM. If the problem persists, pull the distributor and replace the pickup coil. If you have a shop do the work it will likely be cheaper to have them just put in a new distributor. The pickup coil is cheap, but a pain to replace.

-Rick

<DIsclaimer> I don't own a V6 Fiero,<END Disclaimer> but if it helps - everytime I've read about this problem it's been.... yeah, the module inside the distributor cap... and I've heard over and over again it is worth the extra bux to get the AC/Delco module, don't futz around with the other brands.

i actually had the same problem to night i think mine might be the fuel pump, cuz i just changed the coil last weekend>

hah my car backfired the other day, i had just got onto the freeway and was rapidly approaching triple digit speeds when i heard a BOOM! i thought i blew my right rear tire, but as it still handled and drove fine i was like hmm...then i realized it backfired! after that it went back to driving fine...

May want to replace both of these:

http://www.rockauto.com/ref/ACDelco/Detail.html?D1943A.jpg

http://www.rockauto.com/catalog/catalog.php?carcode=1249219&parttype=7172

http://www.rockauto.com/ref/SMP/SMPDetail2.html?LX342.jpg

http://www.rockauto.com/catalog/catalog.php?carcode=1249219&parttype=7176

That reminds me of the other reason I replaced the coil instead of the module. I stupidly assumed I would get lucky and the $30 coild would fix it instead of the $50 module. The Fiero gods rarely smile on us in that manner though, do they?

One thing everyone is over looking is GROUNDS!!! Check your grounds making sure none are broken. Even adding a few more ground straps have been known to help smooth idle and get better running motors. Now this may not be your case but it is something to check.

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