Electrical gurus please help!!!!!

Ok heres my problem now! My '90 with a 94 motor has a freaking electrical gremlin somewhere. It started last week when driving home it would idle very low. It has always idled pretty low to begin with. Somewhere around 500 rpm going by the dash. Well it then started to stall and not restart. It would crank and crank and crank and finally turn over. As the week went on it got worse and worse. So yesterday I replaced the TPS and CPS. The CPS had a crack in the wire cover exposing bare wire. Replaced everything and It fired right up with no problem. Therefore problem solved..... wrong!!!!!! One woulf have thought that given the symptoms described that those to sensors would have been the problem. Well driving home tonight I stalled again and it wouldnt restart. I sat in my lane in traffic trying to get my car restarted. I put my flashers on and Then I noticed that my flashers would flash at the given interval and then all of the sudden skip. Example: flash...flash...flash.flash...flash...flash.fla.flash... and so on. So once i got it restarted and got it home I let it idle in the yard with the flashers on and i noticed that when my idle floated a little thats when the flashers would skip. Where would I even begin to diagnose this problem. Could it be a bad coil? Bad Ground? Or is something arcing somewhere? Any suggestion is going to help cause at this point im gonna torch it!!!!!

Thank you!

I would think that the electical flow for the whole vehicle is increasing and decreasing. Seems like a ground problem. Disconnect, polish, examine and reconnect all grounds.

Wow. That's ... new.

I'd say also to start with the grounds - it's amazing just how many automotive electrical troubles have come back to shonky grounds. Since it's a 1990, pay particular attention to the braided strap from the rear of the cylinder head to the firewall - this is the primary ground for the chassis, which makes it the primary ground for the ECU and such, and it's called "The RENIX Killer" for a reason.

Check and clean the contact patch with the chassis down to bare metal and apply corrosion inhibitor on reassembly (not RPT NOT "liquid electrical tape" or WD-40 - especially not WD-40! It has no electrical uses whatsoever!) You can find corrosion inhibitor in the electrical section of your local hardware store, I tend to use Gardner-Bender Ox-Gard.

Check and clean the battery terminal clamps and posts - particularly the negative one.

Check and clean the ground cable contact at the engine block (follow the cable - it should contact somewhat behind and above the distributor.)

Consider adding a ground directly from the battery negative post to the fender liner - repeat the "bare metal" thing, and use a minimum wire size of 6AWG.

I've often traced oddball electrical problems back to ground contamination, so it's just automatically where I start. Since it's affecting engine running, you're going to want to start with main grounds, and not just ancillary chassis grounds (for lighting and suchlike.) This is a global problem, start with the mains (I say "global" because it's also manifesting in the flash rate of your hazzards. Do your turn indicators do the same thing, BTW? The flasher for those is a separate circuit...)

Old-school flashers are just fancy circuit breakers that go on and off as they heat up from current. Most likely you have poor alternator current from the low RPMs, which in turn is producing sporadic behavior in the flasher. I get this from your comment about it only happens at low RPM.

Replace the IAC, it's stuck.

ehall said:

Old-school flashers are just fancy circuit breakers that go on and off as they heat up from current. Most likely you have poor alternator current from the low RPMs, which in turn is producing sporadic behavior in the flasher. I get this from your comment about it only happens at low RPM.

Replace the IAC, it's stuck.

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Actually I first noticed it when I was a stuck on the road when it stalled. The first thing I did was Put the flashers on.


5-90 I havent noticed if the turn signals do it as well I shall check in the am!

ehall said:

Old-school flashers are just fancy circuit breakers that go on and off as they heat up from current. Most likely you have poor alternator current from the low RPMs, which in turn is producing sporadic behavior in the flasher. I get this from your comment about it only happens at low RPM.

Click to expand...

True - which could also be a shonky ground issue. Once the alternator gives with higher output, the resistance of the contaminated ground can be overcome, which makes the problem go away.

You can never go wrong checking your grounds first - even if it wasn't the problem, it's still a safe thing to do, and a half-hour well spent. And, it eliminates it as a possible problem for future troubleshooting.

Well I found a potential problem. When I removed the Neg battery cable there where other smaller wires grounded there as well. well on off them was attached to the ring connector by only a single strand which broke upon touching it. So im waiting for my friend to bring me some ring connectors. We shall see. There was some corrosion on the ground strap but i dont think it was enough to cause a short.

Consider soldering your wiring connections. The solderless connectors are prone to corrosion just like any other metal, but if you solder the corrosion happens on the outside of the joint not right in between the conductors. I have had more trouble with solderless connectors than I care to think about. They are just as bad as wire nuts.