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Bone stock 1989 Trooper S 2.8.
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Discussion Starter · #1 ·
Okay, this is such a strange combination of problems, there HAS to be a common cause.

After my trooper was broken into, I have the following problems:
  1. Alternator does not charge
  2. Oil pressure gauge settles to a random location when the key is “on” and the engine is not running
  3. Cigarette socket stopped working (this may be a red herring)
  4. My CEL is flashing rapidly. No code, just flashing like mad
If I turn the key off, the oil pressure gauge will slowly settle lower on the scale, but not off. When I start the car, it goes way up. Doesn’t peg it, but it’s up there.

I’ve checked all the fuses in the box, and the fusible links by the battery. Everything seems fine.

These have to be connected, right?!?!
 

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1989 Trooper R/S
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If I'm remembering right, they took your battery, and in doing so they may have just ripped or broke a wire, or disconnected something that would be common to all these items. I would start with a meter or test light and make sure all the fuses have power to them, and thru them and out the circuit side. Make sure the grounds are all hooked up, battery ground to body and then to engine. Fuses have 2 nice small holes through to metal that can easily be probed with a meter and checking for power to both will confirm power to the buss and through the fuse to the output side fuse
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Bone stock 1989 Trooper S 2.8.
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Discussion Starter · #3 ·
Yeah, it felt like a bad ground to me, but everything checks out. The rapidly flashing CEL has me very concerned.
 

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Just a wild-*** guess. You say the oil pressure gauge is wonky. Does it return to zero when the battery is disconnected? If so, maybe stray voltage is making it's way somewhere it isn't supposed to be? I've seen poor grounds do wierd things before, as well. I'd look real hard for a damaged wire.

Mike
 

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Bone stock 1989 Trooper S 2.8.
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Discussion Starter · #5 ·
I’ve checked everything several times, but then that doesn’t really mean much. A bad ground was my first thought.
At this point, I’m most concerned about the flashing cel light. It is NOT a code - it’s too rapid and rhythmic for that. I’m concerned that the ECU got damaged somehow. Although, the engine runs great, so that’s probably not it.
The O2 sensor is still disconnected, so maybe that’s part of the problem. But again, it’s not flashing a code.

The rain has stopped so maybe I can find something after work today.
 

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Are you using a multimeter to check resistance at your ground connections? Things that look good on the outside can be a fuzz factory on the inside where it isnt always visible. If your break in / theft started under the hood that is where your issue is likely located
 

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Bone stock 1989 Trooper S 2.8.
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Discussion Starter · #7 ·
I went through all the alternator and ground connections with the meter. I haven't checked the rear engine ground connector with the meter yet. I know I had it disconnected while I did battle with the crazy dizzy lockdown bracket, and it looked fine, but you never know.

I'm going to have the alternator bench tested today as well, just to eliminate that as a potential problem. I know it's not working in the vehicle, but that could also be a wiring issue.

The only wiring issue I can think of is the capacitor in the dizzy. When I moved the wiring from the old to the new dizzy, I noticed that the wire to it was broken. In the old rigs, this would mean a lot of arcing in the points, but I don't think it has that same job in a magnetic pickup coil. Since the rig ran great, I wasn't too worried about it. I suppose that could set the ECU off, but I really doubt it.
 

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Discussion Starter · #8 ·
The alternator failed bench testing at Autozone, so a new one will be here in the morning.
In the meantime, I discovered the weirdest thing! I was running the engine with the diagnostic jumper on the ECU disconnected to see if that made a difference. Boy, did it! I was holding it at around 3,000 RPM, and when I hooked up the jumper, the engine started to run like crap and the RPM’s dropped to almost 2,000. It wasn’t “missing”, but it really sounded BAD. And, of course, with it disconnected, there’s no flashing CEL. I hope I don’t have a fried ECU as well. Although I do have a spare.

I don’t know if a bad alt would cause all this, but I guess we’ll see tomorrow.
 

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Discussion Starter · #9 ·
Oh, and to REALLY blow your mind, how’s this?

I ran it just long enough to get the oil warm, changed the oil…..

And now it WILL NOT start without a shot of starting fluid or a squirt of gas.

I’m like, “SERIOUSLY? I just changed the OIL!”
 

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Discussion Starter · #10 ·
New alternator is in, but I still have a rapidly blinking CEL if the timing connector is plugged in. Again, no codes, just rapidly flashing. And it runs terrible when it's connected. Seems to run GREAT with it disconnected. I'm going to do a road test this afternoon.
 

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Discussion Starter · #11 ·
More testing and a short drive later and I’m about to pull my remaining hair out over this thing.

Every time I start the rig, I have a different symptom. I’ve VERY carefully set the base timing to 12 degrees advanced, but it still runs like crap when I reconnect the timing wire. Like night and day.

At completely random intervals, it won’t idle. Sometimes, as the idle speed starts falling, a relay under the dash next to the heater clicks madly.
At other times, it idles just fine.

Sometimes, the CEL blinks fast with no pattern. Other times, it blinks slow with no pattern. Sometimes, it’s just “on”.

Sometimes, it won’t start because the fuel pump isn’t running. Other times, it won’t SHUT OFF when the key is turned off.

Don’t like how it’s running? Turn it off, wait 5 minutes and start it again. You’ll get all new issues!

I swear, this thing is gonna turn into a parts car soon.
 

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Try your spare ECU before you pull all your hair out!;) Is it known to be good?

Mike
 

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Discussion Starter · #13 ·
As it turns out, it was a perfect storm of bad assumptions and bizarre coincidence.
Somehow, the punks who stole the battery managed to ruin both my alternator and my oil pressure sending unit in addition to the O2 sensor. That led me down a rabbit hole of bad grounds, etc.

I also followed the lead of the PO and had the WRONG connector unplugged to set the timing. The rig has never had much power since I got it - because it was in “Diagnostic mode” the entire time.
She’s back and has WAY more power than it ever has. Under load, the power doesn’t “waver” like it was.

I’m over the moon. LOL

Thanks to all for your help!
 
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