Expert: Dave Ward - 8/23/2006

Question
Working on a 1985 944 Porsche, automatic transmission.  The car will start and then dies as if it is losing fuel.  Checked fuel pressure, air meter, etc. everything there is good.  Pulled the DME relay and jumped pins 30, 87, and 87B.  Car started and ran great.  Accelerated properly.  Purchased a new DME relay, put it in.  The same problem.  Starts, dies out.  Jumped the same pins again.  Ran great.  Any ideas?

Answer
Hi Jeanne,

You'll get an erroneous message indicated your question won't be answered.  Please ignore it.  It was caused by my typing finger getting all excited and hitting the wrong key.  It won't happen again.  Now I have my typing finger tied behind my back.   Anyway, here's what I think about your 944's no fuel problem.

Jeanne, have you every played the hide and seek game where someone watches you and says your warm, getting warmer, etc?  In your case you are burning up...you've found the problem!

I'm going to describe what I see on my wiring diagram and I'd like you to verify you car looks like what I'm describing.

Here's what I see:

The DME relay that you refer to is that by name, but it actually controls two things:  it sends a signal to the A/C compressor allowing the compressor to run whenever you switch it on AND when certain parameters are correct (like the engine coolant temp can't be too high).  The relay also powers the fuel pump itself.  Both these components take their cues from the DME Control Unit, so perhaps that's why the relay is named as it is...and not the A/C and Fuel Pump Relay.  Don't ask me!

Your "jumping pins" sends power to the compressor and the fuel pump...the car should run great...as it does.  The "jumping pins" is also the test to alert you to a possibly defective relay.

To prove the relay (the brand new one) is defective, take it over to the battery and connect two jumper wires to the relay's 85 and 86 terminals and the other ends of the jumper wires to the pos and neg terminals of the battery.  Actually, connect one and just brush the other onto the terminal and off again when you're ready to do the test.  When you touch and release the unconnected wire to the battery terminal you should hear the relay make an internal click sound.  Each time the connection is made the relay will click once... or it is toast just like your first one.

See, You're HOT.

Dave