ERAU-944

well, its about time to get workin on the car - here's the issue:

at idle - the injectors sound like they are ticking WAY WAY WAY too fast! if i give it even 1/2 in of gas pedal travel the car dies, and sometimes backfires.

things i have tried are as follows

AFM
DME
DME relay
speed & reference sensors
throttle position switch
wiring harness

so far this really has me stumped!

i'm thinking about trailoring it to Louisiana, and having some voodoo magic done or something!

does anyone have an idea as to what might be causing the injectors to fire that much?

-Mike-

p.s. i'll owe a case of brews to whoever solves my problemo

Mongo

Mike did you replace the DME on that list or swap? I haven't heard of injectors firing too fast before but my first bet was on the DME, and if you sorted that one out, then I'm really sorry but I'm stumped too.. I hope you find it though...

Andy

seb928s

Have you checked your injectors? Also did you check the persure at the fuel rail?

Legoland951

The only way you can get backfiring is wrong timing (improper belt timing) or sparking at the wrong time while the valve is open igniting fuel in the intake manifold or exhaust. Check your firing order may help too.

ERAU-944

thanks andy, yeah i did replace the computer with a different one to no avail.

seb, what would be wrong with the injectors? the only problem i have with them is that they are opening too much. the fuel pump is also hotwired, but i doubt that's causing a problem. i don't think high fuel pressure is a problem - even if the pressure regulator/dampener were dead, it wouldn't cause the injectors to fire that much! so basically, the problem is that the injectors are firing WAY too much, like instead of a nice steady tick tick tick, there are an extreme number of ticks coming from the injectors - and that is just at idle! this is causing a LOT of fuel to be delivered, and causing a VERY rich mixture

lego - the timing belt is lined up, and everythign is firing in the proper order, just too much!

i'm stumped! i really hope i don't have to take out the whole harness and basically make a new one

Danno

hmmm, you should get 8 injector clicks per engine revolution, so that's pretty fast. It's not the number of times that the injector opens & closes, it's how long they stay open per click that counts.

Measure your AFM's output voltage at idle. It should be 0.79-0.85v or so. Also on an NA, the TPS wouldn't have much of a function unless you're at idle or full-throttle.

ERAU-944

let me tell you danno - it's a lot more than 8! i mean, i can start my car and listen to it, and pretty much count the clicks, but when i start the track car, it's clicking so much it's insane!

maybe tonight i'll be able to test the afm output.

thanks,
Mike

bader$

could your speed and ref sensors be crossed? and even though the fuel pump is straight wired the pressure could be low causing excessive pulse width. But if they are truely firing to frequently it would be something telling the dme that the rpms are higher than they really are.

ERAU-944

hmm the car won't run with the s&r wires crossed. i'm with you - i beleive the DME is getting a wrong signal and thinks it's running closer to full 6500 rpm so the injectors are firing a whole heckuvalot. i need to figure out what could be sending the DME the faulty signal... so far everything i've replaced hasn't helped - anyone else have any ideas?