Won't start- Fuel pump won't come on

Flormat · Flormat's Garage

It ran great the other day. Then I decided to clean the fuse/relay board with some contact cleaner. I separated the top and bottom halfs enough to spray in there. Now with it back together the fuel pump won't come on and so she won't start. Could I have screwed the DME relay up? Can I jump DME Relay terminals to get power to the fuel pump? And if so, which terminals?

carsontc · 05-28-2003, 06:22 AM

see:

http://www.frwilk.com/944dme/dmerelay.htm

AFJuvat · 05-28-2003, 06:24 AM

You have either botched the relay, or some of the wires got disconnected from the relay board when you separated them.

Also, check the fuel pump fuse to make sure that is in place and not blown

Don't recall which terminals to jump.

AFJuvat

highboost951 · 05-28-2003, 07:05 AM

term 30 and 87B

highboost951 · 05-28-2003, 07:08 AM

Also, what do you mean you separated the "top and bottom" halfs? The relay board has two screw in each corner, once loose the whole board comes up w/ the harness still attached. You have to pull a release and the side covers to release the individual harnesses. There really isn't anything to separate as far as halfs. We're talking about the '87 correct?

Flormat · Flormat's Garage

Thanks for all the respnses. The fuel pump fuse is ok- first thing I checked. Yes it's an '87. Once you pull the whole board out, look on the side all the way around. You can see where the top with the fuses and relays mates with the bottom that has the plug connectors. Little plastic snap type things- just unsnap them and pull apart the top half from the bottom half. I was able to separate mine quite easily.

Flormat · Flormat's Garage

AFJuvat was right, I botched the relay. I jumped terminals 30 & 87b as highboost said and the pump came on. The car still wouldn't start with the dme relay removed and the pump jumpered, but as soon as I plugged the relay back in the car fired right up and ran until it used up all the gas. Looks like I need a new relay. Thanks guys!

carsontc · 05-28-2003, 05:19 PM

and it's all on frwilk's webpage

Flormat · Flormat's Garage

That's a great page, I printed it and took it out to the car as a reference when I was testing the relay. Good stuff.

Flormat · Flormat's Garage

Ok, I was wrong- it's not the relay. With a brand new relay it still won't start. If I jump all three large prong terminals of the dme relay it starts up and runs fine. But then when I put the relay back it sometimes it won't start at all other times it will try to start. One time I got it started and immediatley quit. Could this be crank, or reference sensors? How can I check those?

944turrboo · 06-02-2003, 09:59 AM

My car did the same exact thing.. i put in a new relay and it wont start.

Flormat · Flormat's Garage

Did you get yours fixed? If so what was it?

carsontc · 11:01 AM

on a 944 the speed sensor (the back one of the 2 flywheel sensors) tells the fuel pump to start if the engine is turning...944S..?..I'll have to defer to others...is this the model with 1 sensor on the cam? can't remember.

I would think if the speed sensor was bad even if you bypassed the relay to get the pump to run it would not run properly since the speed sensor tells the DME unit to do other engine management besides turning on the FP...dwell etc

Britwrench · 06-02-2003, 04:27 PM

NO, if you by-pass the fuel pump relay the pump should run.
If the speed or reference mark sensors are faulty then there is no fuel or ignition signal.

carsontc · 06-02-2003, 07:01 PM

are you saying if he by-passed the fuel pump relay and it runs - the reference sensor is good...but the speed sensor is bad?

944turrboo · 06-03-2003, 07:22 AM

try checking the fuel pressure... even thought my pump was going i was getting little to no pressure going through...

944turrboo · 06-03-2003, 07:24 AM

when you jump the relay more power goes through the pump... but at regular voltage maybe its not pumping as much as when you jump it.

carsontc · 06-03-2003, 08:57 AM

Quote:

Originally posted by AFJuvat
or some of the wires got disconnected from the relay board when you separated them

I think you may need to go back and check Juvy's suggestion one more time

Flormat · Flormat's Garage

I did just that. I took the relay board apart again and thoroughly scrubbed and cleaned every contact. Then very carefully put it all back together making sure everything was in order. Plugged the connecter plugs into the bottom of the board, double checking each one making sure it's in the right place. Now not only will it still not start, but now many other functions on the car will not work, such as hazards, windows, blinkers, wipers, etc. On certain things, I can push down very hard on the relay and the corresponding device will work- such as wipers, seatbelt/ door chime. I jumped the dme relay sockets again, and now it won't even start doing that. So I think my problem lies in the relay board, because each time I mess with it things get worse. Any suggestions? Thanks for all the ideas so far.

944turrboo · 06-03-2003, 11:13 PM

have you checked to see if you have any gas in the car?