97' Rodeo confused computer?

[hylander1]

I'm truly at a loss, I've been reading these forums actually for over a year, trying various things as I can afford them. I have a 1997 Rodeo, 3.2L.

There are a lot of posts that seem similar but not exactly my symptoms. None the less I've performed most of the things found in these similar posts. I've most recently changed out the alternator with a bosch reman. It didn't help so I figure why not try and post.

The symptom is that while driving the vehicle, the rpm gauge will "randomly" (because I have yet to find the pattern) drop to reading zero. All of the dash lights come on as though I just turned the ignition switch on and the computer is running it's diagnostics. Now sometimes the just as quickly as the RPM's drop to zero they will a second later pop back up to a typical idle speed. However usually soon after the rpm's drop off the Vent blower will shut off, and the engine dies completely.

Since this has been happening more frequently lately and often when I'm driving down the freeway I've gotten very good at seemlessly dropping the car into nuetral, turn off the ignition switch, then turning it back on and starting the engine. This works pretty much all the time. I will then be able to continue driving barely skipping a step or dropping below 40mph. It often will do this two or three times more within 15-20min, but then just stop being a problem for another 50 miles/ or more... like I said I haven't found the pattern.

Anyway, I've been careful to watch the voltage gauge and during all of this (until the engine actually dies) it seems no lower then 13. Battery has been replaced, fuel filter, EGR valve cleaned.

I've noted that sometime when the rpm's drop (at first I thought the engine was actually stalling and dieing) the engine is actually still on. As I will drop it into neutral and attempt to just turn over the engine not turn off then back on and I will get the grinding you hear when trying to start an already started engine.

I truely am at my whits end and am not sure what could possibly be wrong. Any info would be greatly appreciated.

There are no check engine lights and I've checked for error codes there are never any there after this happens.

[rodeo02]

This sure sounds like your reman'd alternator, or battery is not up to snuff. It's pretty common to get a bad reman'd alternator. This could also be a corroded ground connection or battery connection. You truck needs to see 14VDC across the battery at idle. Any less can cause the conditions you describe. If you dont have one, pickup an inexpensive digital multi-meter & check voltage across the battery with the truck idling.
G/luck
Joel

[hylander1]

I get at least 14VDC across the battery at idle no problem. Battery was recently replaced and has been tested twice since installation, and the alt has been tested throughly by NAPA and myself before and after it went in. As I said even during the problem the voltmeter in the car shows well above 12, and it's only after the engine actually dies thus alternator not turning that the meter drops to 12. If it is the alt or the battery no warranty will replace either so requires me to pay out of pocket because tests show both of these components to be in great operating condition. Which I've done once already, and can't afford to do again. It was after reading posts here that led me to believeing that even though power didn't seem to be the problem, perhaps it was the reman alt that was previously installed, so I payed a premium and went to NAPA for special order BOSCH reman alt. And was quite disapointed when it made no difference.

Also possibly of note, it seems to make no difference whether I run the car with the AC on full or with all accessories completely off, same thing can and does occur.