This idiot can't figure these idiot lights (89 Trooper)


#1

I have a 1989 Isuzu Trooper with 215k miles on it. 2.6 liter 4 cylinder, 5 speed manual. A beater, but up to now reasonably reliable.



For several months the “Check Engine” light has been coming on intermittently. The car briefly runs kind of doggy & won’t accelerate, then light goes out and things go back to normal.



The other night I was driving home & a bunch of idiot lights came on all at once: low fuel warning (tank is full), O2 sensor, alternator & brake warning lights, & check engine. I made it home but when I try to start car, it starts, runs for about ten seconds with all of aformentioned lights glowing, then check engine light goes out and it dies.



I did a computer code check and got reading of 44, check O2 sensor. I replaced O2 sensor and fuel pressure regulator (new) and ignition module and computer (used). Fuel pump pumps fuel into a can when I take hose off. Still the same symptom: start, run 10 seconds, die.



Staring at wiring diagram I see the glowing idiot lights all run off the same fuse, which I have replaced. It seems to me there must be some electrical short that is affecting all these lights and possibly some sensor or the computer. Anyone have any suggestions?


#2

There may be a problem with the ignition wiring or switch causing this problem to happen. Another possibility is the alternator is having trouble. Have it checked by doing a load test on it. Since no fuses are blowing it doesn’t appear that anything is shorting out but there sure seems to be a problem with a connection to power somewhere.


#3

Have the alternator tested for a bad diode. This will put an A/C ripple into the system and computers don’t like that!


#4

I also vote for an electrical problem. Have the charging system and battery checked Also try removing both ends of the battery cables (both of them) and cleaning both the cable and where it goes very well and reattaching making sure they are secure.


#5

When multiple warning lights come on at the same time for no apparent reason, it is usually an indication of an alternator that is about to die. As other have already said, get that alternator checked and you will probably find the source of this problem. And, if the alternator’s output has been flukey for awhile, don’t be surprised if your battery is now in bad shape also.