1979-1993 & 94 Conv [Subscribe to Daily Digest] |
My 89 NA suddenly lost power going up a big hill on the interstate yestiddy, and I coasted to the top and into a turnout where the staties used to park and run their radars. Discovered motor was still running, will start and run, won't go above around 1,500 rpm. It has NO power, other than coaxing car around parking lot.
I hiked a mile and a half, then a gal out in a yard let me use her cell phone to call AAA. They towed it to a nice garage where I've been trying to figure it out.
First I suspected fuel pump but cracking banjo bolt off fuel rail, it pumps out at pretty good volume with fuel pump trigged to run all the time. No pressure test done (no tester), but volume looks good. Fuel filter is pretty new and as I said it passes pretty impressive volume, it's not starving the injectors.
Then I suspected quality of fuel. But I pumped out everything that was in the car and replaced with fresh gas, and primed the line. It still only gets to 1,500 rpm, or rather, hunts between 1,400 and 1,600, pretty rapidly.
Then I thought, some weird spark plug thing? So I pulled them, pretty new NGK BCP6ES-es, and replaced them with a sparkling new set of Bosch Supers I found in a 90 in a real nearby junkyard I frequent. No difference. (The NGKs are going back in once I beat this problem.)
Then I thought, could the cat be plugged? So I dropped the front three bolts and separated things, but it STILL only got to 1,500 rpm, hunting, but also roaring.
Played with about everything else. Tapped AIC valve, even disconnected it, no change. Tapped AMM, even disconnected it, no change. Unplugged and re-plugged Throttle Position Switch, no change, either way. Unplugged and re-plugged NTC sensor, no change either way. No obvious massive air leaks.
When I went to the junkyard I bought an ECU and an APC, but they were from a 1991. APC box made no difference. ECU though, let idle get up as high as 2 to 3 grand when I fluttered pedal, but still no power and it plainly wasn't the right box for the car.
That encouraged me and now I'm back at my parts stash and gonna return to car with PROPER NA ECU for that engine, and proper APC.
This all sounds very familiar and I'm going to do a bunch of searching on here before I hit the road again, but any ideas?
It hit suddenly, after about an hour on the road, stop and go driving, with no warning of any trouble.
Well, I've got to confess, the same kind of loss of power hit very briefly about 3 weeks ago, one evening, cruising home on a residential street at 20 or so, a slight downhill. I got it into the drive and next day it started and ran fine. I began to think I'd imagined it.
Also I need to add as a footnote that I have been adding a pretty high percentage of 99% isopropyl alcohol to the gas, for several weeks. It has been getting rid of the alcohol, a goal of mine, and has seemed to run fine. Could this have done something to the car, and if so, what?
I haven't tested compression but it doesn't seem as if anything's wrong there, car starts relatively quickly and well. I can't feel any compression pulses coming out the oil fill tube. Nothing's coughing or backfiring, and engine runs totally even, not pulsing as if only running on 2 or 3 cylinders.
As I've mentioned I purged all the fuel out of the car and have been tring it with fresh gas for long enough to have burned any bad gas remaining in the fuel rail, filter, etc.
No overheating episodes. I'd think fuel injectors but how could alcohol hurt those, if they spray gas I'd think they'd spray alcohol mix just fine. And IF any problems how could they have happened simultaneously to all four injectors and allow smooth weak running up to a point, then nothing faster?
So my money is still on the ECU, which I'd better go dig out, then search on here for others' histories.
Then I'll check back here for any theories from you, all good and wise co-Saabers.
posted by 71.241.217...
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.