So a couple weeks back I had the car running in the driveway for a few minutes, out of nowhere it dies, like someone turned the key off, seemed to be running great before that. Tried starting it back up, it fired but ran really rough and backfired, and the speedo was going all over, then shutdown, couldn't get it started again. I let it sit for a whole and tried it again, fired right up and ran great until today, when it did the exact same thing, only difference was I s going down the road this time.
From my searching it sounds to me like ICM. It worries my though because I'll be taking it on a long trip to the dell's on thursday so I want to make sure that's what is wrong before I start throwing parts at it. I definitely don't feel comfortable taking it that far as is without figuring out what's causing it, but I would hate to miss the dell's run because of it. (although not as much as being stranded on the way there)
Also if it is the ICM, do I use thermal paste such as Arctic silver from radio shack, or dielectric grease? I've read the new ones come with dielectric grease but some people say to use thermal paste instead. I've got another ICM from the new distributor that was in my parts car so I wont need to buy one but need to know what to put on it.
use dielectric compound that comes with module,or buy a small amount the module is normaly go or no go the coil or pickupcoil are more likely to run then die then run again when they cool off the ECM is long life unless you have shorted something out a common problem with old cars is the connectors need cleaning especially the coil to distributor connctions make sure the snap retaining clips are not broken,s common problem on oldcars
It's got a fairly new cap and rotor, and everything looks good and not corroded or anything. Not sure how many miles are on it. The motor was rebuilt probably 40,000 ago and pretty much everything was overhauled at that point.
Back firing is an indicator of bad timing if car runs ,check timing with a lite,,if there is a lot of variation this is indication of a bad timing chain hesitation when you accelerate is another indication of a loose timing chain make sure spark plug wires are not arcing,or shorting out,check em at nite.. most Fiero,s have good spark plugs
Back firing is an indicator of bad timing if car runs ,check timing with a lite,,if there is a lot of variation this is indication of a bad timing chain hesitation when you accelerate is another indication of a loose timing chain make sure spark plug wires are not arcing,or shorting out,check em at nite.. most Fiero,s have good spark plugs
I had that same thought about timing. Late last summer when my car wouldn't pass emissions I took it in and my mechanic said the timing was way off. Which I thought was kind of odd because the last person that did a full time up on the car was Ryan at sinister performance, which was shortly before I bought it, and not that many miles ago. Unfortunately I do not own a timing light.
It runs great and starts right up every time, the only time it has ever backfired on me, was after it dies like this.
After I got it started up again it drove great like nothing happened.
If the car hesitates when you accelerate ,purchase a cheap timing lite ,or borrow one it is extremely weird that the timing was off your engine may have a worn out timing chain..
i......i i....................i your timing mark wiggle ,,should be with in the first parameter
IIIIII ............................IIIIIIIIIIIIIIIIIIIIII back & forth . ^ ..........not ........................^
hook up with a buddy who has gearhead experience ,or your local Fiero club can help
[This message has been edited by uhlanstan (edited 05-24-2014).]
when it stops Check for fuel flow check for spark,First ,have a spark plug ready,ground it firmly on the valve cover you can easily pull the fuel filter, tap the entrance on a block of wood to see if trash comes out
timing chain replacement is a pain in the toe ,but it can be changed by a newbie thru the passenger rear wheel opening
Engine running wiggle around the 4 pin connector on the ICM. Try the other ICM if that doesn't show trouble.
Was it the speedo that was wigging out or was it the tach?
I noticed the speedo doing it, but that was when it only ran for a few seconds so the tach could have very well been acting funny and I just didn't notice.
[This message has been edited by zmcdonal (edited 05-24-2014).]
The speedo has no connections to the ICM. I am really puzzled at this.
Maybe an 84 with a loose nut on the positive battery cable at the starter? (disconnect the battery before putting a wrench on the nut)
Maybe 85+ and something loose at the power distribution post? (again disconnect the battery before putting a wrench on the nuts)
Loose grounds?
Wiring harness getting damaged against a hot exhaust or some other way? Some damage that is causing the white wire that runs from the ECM to the ICM to short to either the purple or yellow wire of the VSS that run from the VSS to C203?
[This message has been edited by phonedawgz (edited 05-24-2014).]
It's very strange and unpredictable. Both times the car had not been running that long for anything to be super hot. The first time I had just backed it out of the garage and had it idling in the driveway for a few minutes. The other time I had just gone across town, had the car running maybe 10 minutes tops.
I just went out and wiggled the 4 pin connector on the ICM with the car running, no effect. I thought I would add that in cold starts the car fires right up but will stumble around a little and sometimes need to feather the gas to get it to smooth out. Don't know if it could be related but thought it might be noteworthy. Once it warms up a little it runs great though.
Speedo running through the ECM? Maybe a not fully seated ECM connector? Maybe a bad ECM. 7730s can be found inexpensively.
Maybe a not fully seated C203
The backfire tends to indicate the injectors were still firing but the ignition wasn't. I am hung up on that the speedo wacked out while the ignition did, but the injectors didn't. That rules out power failure to the ECM, power failure to the ICM/ignition.
Maybe part of the ECM was flaking (assuming speedo through ecm)
[This message has been edited by phonedawgz (edited 05-24-2014).]
I had something similar happen and found it was the pickup coil, take the cap off and look at the tape around the coil and if it has deteriorated replace it.
Steve
------------------ Technology is great when it works, and one big pain in the ass when it doesn't
Yeah I've got a new distributor with only a few hundred miles on it that came out of my parts car. I think I'll just take it in to the shop Tuesday and see if they can change it out real fast.
Yeah I've got a new distributor with only a few hundred miles on it that came out of my parts car. I think I'll just take it in to the shop Tuesday and see if they can change it out real fast.
its not that bad to change one out yourself, basically one bolt on the hold down Y that goes around the bottom of the distributer where it goes into the manifold. just make sure you mark the position of the distributer before removing it and where the rotor button is, that will turn some as you are removing it so pay attention to the direction it turns and you should be fine. pictures don't hurt ether if you are putting in a new one. that way you are not asking us how to find TDC after changing the distributer and it not starting.
With the markings you should be able to get it close, but you'll still want to check the timing with a timing light.
Ayup, it will and is a lot cheaper to have a shop do that than R&R a distributer, we used to set them by ear and with a beer can on the air cleaner when I was a kid.
No smart remarks, my kids already say I am older than dirt and I am beginning to believe them the way I feel this morning.
most parts stores now have a lone a tool program where you put a deposit on a tool, usually about what it would cost to buy it in case you don't bring it back. bring the tool back undamaged and you get your deposit back. \
Steve
[This message has been edited by 84fiero123 (edited 05-25-2014).]
You can have your ICM's tested. O'Reilly's, Zone, etc, will check for free. Harmonic balancer can slip, making it hard to set timing properly. You might want to check for loose, brittle wires. It's hot in the engine compartment. After thirty years some wires may be just barely there.
More of that old overthinking thing. I say its the ignition module...thats how they act...ive had them go just like that. You already got a spare...stick it in, clean all the connectors good for the module and coil and see if the problem goes away. Ill bet its solved. If you do change out the whole distributor, I make a paint dot on a mounted part near it to mark exactly where the rotor bug is pointed...or just make sure its pointed straight forward or backward, and intall the new one exactly the same. If you do that carefully, you wont change your timing hardly at all. DONT take the plug wires out of the cap...leave em alone.
