Instrument cluster power loss - does't start

[Stoic]

Gentlemen -

I have a somewhat strange situation on-hand. I'm getting ready to move in the next couple of weeks... and the car doesn't want to work.

Before I get into what symptoms I've found after some work and troubleshooting, I should explain exactly what I'm dealing with here - the car is a '92 Ford Probe with an '89 SHO engine swapped in. It had been working quite well for a good while, but after I'd gone on a deployment, I came back and found the battery quite dead (despite being unhooked, sigh). I replaced the battery with a new one and got it working again. And then it stopped working.

I apologize ahead of time for the long post. It'll take me a while to get through this, and I appreciate any help anyone can offer on tracking down this issue.

So, after I got back from a deployment and some training (again), I went out to start it up. First thing I noticed after reconnecting the battery was that I had no instrument cluster lights or indicators, etc. Just a dead panel. That immediately had me worried, so I turned it over. Cranked just fine, but never started. I started poking around in the engine bay, checking some connections and such, and didn't find anything, so I pulled the battery terminals to check them and checked the fuse box. Everything looked fine. It continued to exhibit the same problems.

Somehow, and I still haven't figured out when it happened, but it was after the above part and before the below part, and that's all I know. I got the battery terminals reversed and blew the 100A fuse in the main fuse box. I replaced that and found myself back at the same place as before - no instruments, engine turns over but doesn't start. I turned it over while a friend was shooting some starter fluid into the intake and it caught a few times, but that's pretty much it.

My friend got the idea to check all the other electronics to see exactly what I was missing, and when I turned on the headlights, wipers, etc., they all worked. The console lights on the instrument panel came on, but I still wasn't getting anything I checked and tested all the fuses in the engine bay and under the driver's side, they're all good.

We decided today, after playing with it, that perhaps somewhere along the line the ECU stopped getting power or perhaps blew out. That's just our best guess, figuring that the injectors wouldn't be working (start issue) and none of the gauges are reading anything from the ECU. Perhaps I'm very far off. In any case, I'm not sure when that would have happened, as the symptoms were the same before I knocked out the 100 amp fuse. Does anyone know where I might begin to try and track down the issue - how I might determine whether or not the issue lies with the ECU or elsewhere, and what I might look at to fix the matter?

I'm moving in a few weeks and would really prefer to save the money on towing the thing across a state or two, if I can get it running again. Again, thanks for any help.

-Stoic

 

[deercrusher]

I'd try another ECU if you have another laying around. Sounds like it shorted the board.

 

[Stoic]

Thanks for the reply ... battery's gone dead again, so once I get it recharged, I'm going to check spark and fuel flow (which, stupidly, I didn't do already). After that it'll probably be on to the ECU.

As a sidenote, does anyone know what grounds I might check to see if perhaps something has come loose or whatever..? I am pretty terrible with the electrical system in this car, and it's complicated by the fact that it's a SHO engine strapped into the probe - I've got lots of connections that are just chilling, not connected to anything.

-Stoic

 

[deercrusher]

The dis system needs to be grounded properly. You should have the four small dis mounting bolts in place holding the dis to the side of the intake. From there the ground path goes through the crossover tube then through the bolts that hold the crossover tube down. Check the ground strap on the back passenger side of the motor and follow it to the firewall or wherever you made it go on your probe.

 

[Stoic]

So, got some updates.

Current status is: no instrument cluster information, no fuel from pump, and no spark. Car turns over but (obviously) doesn't start.

I got a new ECU and swapped it in today, no change to anything. Pulled the rear seats out to get to the fuel pump access panel and as far as I can tell, it's getting no voltage at all. Planning on finding where the pump relay is in the engine compartment and checking on it. Also have a new coil pack that I picked up from a scrap yard; thinking about eventually swapping it in if I can confirm that it'll work with the car (need to check part numbers to make sure it's the right one).

So it seems that there's a common point of failure with multiple electrical systems getting nothing and others still working. Wipers work, lights work, engine turns over, cabin lights work. But that's about it. Trying to find a common point of failure for the remainder of the systems... looking at replacing a grounding strap that got tweaked when I pulled the intake manifold a while back.

Suggestions appreciated for where I might start looking, and thanks for the help so far!

-Stoic

 

[deercrusher]

Ccrm. You do have one right? I'm not familiar with your setup but if your ccrm is bad it can cause power loss to the fuel pump. When you turn the key to the on position but not start it you should hear the fuel pump prime.

 

[Stoic]

Long delay. Just moved to a new location, so I've been too busy to work on the car lately. In the meanwhile, my other car (04 RX-8) blew an apex seal, so that's in the shop while I argue with Mazda over warranty coverage. Joy!

Anyway - I did find and replace the CCRM. Based on what I read about its function, I had some pretty high hopes... but replacing it didn't seem to affect anything. It's very frustrating.

So, the only problems that I've managed to determine are:

- Fuel pump isn't activating. I pulled out the back seats on the car and whatnot to get to it. I had my brother listen while I played around with the ignition and cranked over the engine a few times - nothing. I'm wondering if my cut-off switch has gone bad, since I found that it'd been sitting in a pool of water (no idea) for God knows how long. I just need to find out how to bypass it (or replace it) to see if that's the problem.

- I haven't tested spark since I replaced the CCRM, so I can't say immediately whether I'm still getting anything. I wasn't before though, so who knows - is there a way to test the coil pack and/or DIS module for functionality with a multimeter? I was helping a buddy of mine work on his Subaru 2.5 RS a few months ago after we put it into the drink (long story) ... there was a specific resistance (I think?) reading he was supposed to get by touching the leads to the connectors on the coil pack. Any ideas?

- No power or information whatsoever to the instrument cluster. I expect that this is a more Probe-related problem, though. Still looking for information on where exactly the instruments get power and whatnot from. Frustratingly, I haven't found any bad fuses anywhere.

I'm going to go test out a few more things, see if I can't find some common point of failure.

Thanks much for the help.

:thankyou: