michealmalad

I just installed a new head on my 86 n/a and upon completion found no fuel pressure/activity. What could I have done to interupt fuel flow or stop the fuel pump from working???
Any help is appriciated.
Mike

KY944S

Did you check your DME relay?

Chris_924s

check the DME/ fuel pump relay- did you pull the relay out to draw the fuel pressure off of the fuel rail?

michealmalad

checked that, it clicks when I plug it in. seems to be working. Any other wiring that I might have unplugged while taking off the head?

michealmalad

this is for chris. I did not pull the relay to draw the pressure off.

SoCal Driver

Fuel pump does not run until you crank the engine over or it is running over 400 rpm. Position a helper back by the rear wheel on the passenger side. They should hear the fuel pump run for a half second or so after you stop cranking it.

Chris_924s

clicking usually indicates the relay is moving.. can you hear the fuel pump when the key is turned past position # 1?
You may need someone to turn the key while you stick your head behind the passenger side rear wheel. You should hear the fuel pump working.

EDIT- SoCal beat me to it!

SoCal Driver

Really wasn't trying to beat anyone. Think it's important that all know how these things work. At least the basics. Five minutes with a voltmeter can tell you 90% of the problem.

Chris_924s

I was just kidding SoCal.. and agreed- power and grounds are a constant source of issues!

michealmalad

Thanks for you help guys. Got dark and couldnt work anymore last night. This is my story if it helps any. This is a race car that broke its timing belt and we installed a new head about a week ago. The back of the car is exposed to rain and the cabin is not protected very well either, so moisture and corrosion are definately an issue. I am looking for possible areas of vulnirability to moisture and/or wiring in the engine bay that I may not have plugged back in or may have damaged from removing and installing a head. Any Ideas???? Thanks for all your replies. Mike

StoogeMoe

You may have disturbed the reference sensors. If the DME can't detect that the engine is turning, it won't turn on the fuel pump.
__________________________________________
1986 944 NA Guards Red all original 90K mi.
1983 944 NA Platinum Metallic w/LSD ~120K mi. beginning a new life!
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1984 911 Carrera Coupe (gone, but not forgotten)
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