Weak acceleration & occasional 4 flashes

[Kenny4d]

1986 900S 16v

First: When I am accelerating, it feels like the engine is being starved of gas (predominantly in the first 3 gears). The only way I feel any power when accelerating is if I pump the gas peddle in short bursts. Even if I take the RPM's up to 5000, still no power. I don't think it is the fuel pump... but I'm not sure what's going on.


Second: My check engine light comes on and flashed 4 times (I know this is a common post, but I don't have the tools to retrieve the flash codes). I can replicate when this happens by holding the RPM's @ 3000 in second gear for approx. 5 seconds.... then the light comes on. If I turn the car off and start it again, they don't typically come back. The lights also won't come on once the car is warm, even if I hold the RPM's at 3000.

I'm stumped and have no cash to take it to my mechanic.

Thanks.

[jetman]

I'm not sure to be honest, but I'm in Hamilton and I've got a fuel pump you can have for free if it gets you back on the road.

[ProfZ]

First off, pumping the gas pedal does not shoot more fuel into your fuel-injected engine as it would with a carbureted setup. All it does is add gulps of air, probably confusing the hell out of a bunch of sensors

Second, I doubt you have a fuel problem. The flashing check-engine light is the EZK (ignition) computer telling you it has picked up a problem. See Bentley, page 340-3 for the (easy) diagnosis.

The 4 flashes indicate either a bad knock sensor (or its wiring--the pins often come out of the sensor's connector; guess how I know), or a bad EZK unit.

Your poor driveability suggests the EZK unit itself is bad, or the ignition amplifier is dying (it's mounted directly across from the EZK unit in the front LH fender well). Try the tests on pages 340-8 and 340-9 in Bentley. FWIW, my money's on the amplifier.

*Caution* Do not confuse the ignition amplifier with the ignition pulse amplifier, which is unique to 1986-87 cars and lives in the fuse/relay box on the fender. It's not part of your problem; if it was, you'd get a no-start condition.

[cjaouich]

Hi, I used to have this all the time, accelerate and suddenly not more power. The check engine light and the 4 flashes when I am at idle. I recently cleaned my AIC and the problem did not re-occur. Previously, I had this problem for many months.

Cheers!

[4saabstoomany]

if you ask me it sounds like a timing problem... work on your engine lately? i'de get the timeing light out.. or buy one.. only 30 bucks for the cheap one at advanced auto... let us know if you need to know how to check it.. mine did the same thing.. i was off by 10 deg.

i had to edit this post becuase i obviously didn't read teh one above mine (adult ADD I think :-P ) Try his solution before buying a timing light.

[Kenny4d]

Thanks for the suggestions... I will check all of the above this weekend and report back.

This forum continuously impresses me