ok i tested the fuel pump and it works. i put a new filter in . and still no start.
i uhooked the battery and changed the computer. still nothing.
i uncapped the fuel rail and cranked it over gas shot everywhere, so i assume it has pressure.
i put a little starting fluid in the j boot and it fired for a few seconds and died .

anyone have an idea what it may be?


how much presure should be at the fuel rail ?

 

Fuel preasure should be around 35PSI. Did you swap out the DME relay? Could be the injectors are not getting power. What model and year car do you have?
http://www.clarks-garage.com/shop-manual/fuel-01.htm

 

yeah i have a spare relay but i dont know if its good or not. test light shows power to the pump . and it works because i jumped it from a jumpbox. and i put the test light to the injectors it cam on when i turned the key and pulsed when i cranked it over. i assume the injectors arte good , i drove home for lunch today and went to go back and it wouldnt start.

 

Sure sounds like the DME relay is intermittent. Next time it will not start, jumper it out and bypass the relay.
http://frwilk.com/944dme/dmerelay.htm

 

is this it? the little prong looks like it has sank down inside the relay , and it sounds broken when shaken. i jumped the relay box like the picture said . it still didnt start

 

is there any way to test a coil ? i bought a new blaster coil today thinking it was the coil . still nothing , i put a sparkplug in the coil wire and cranked it over ,and got no spark . what would cause that? and why will it try to start when starting fluid is sprayed in the j boot?

 

Check your MAF connections...

 

If you have no spark start with a known good DME relay. That relay is acutally a dual set up and controls spark and fuel.

Does the tach jump when you crank the engine? If not then check the reference sensors. Actually, check them anyways. Many times the wires in the ref sensor harness break and cause all sorts of intermittent problems. We just went through this on my friend's 951. It turned out that the shielding inside the ref sensor harness was broken. The factory manual has a great test procedure for wringing out the wires.

 

where is that harness located?

 

The reference sensors are at the back of the engine attached to the bell housing. Their connectors are most likely in a metal bracket at the back top of the engine. There are two three wire connectors which often crack under the rubber boot so you can't see the cracks.

 

If the reference sensor were bad, it wouldn't run with starter fluid. That DME relay looks broke, you need to replace it and fix that problem. Also, look at the terminal that sunk relay pin plug into in the fuse box to insure it wasn't damaged. I think you are fighting multiple problems so eliminate them one at a time. Did you check your fuel preasure?

 

I thought the reference sensor cut off fuel, not spark, so starter fluid should work? I could be wrong on that though.

 

The reference sensors controls both spark and injector timing.

 

ok i got them out and they had black gunk on them . i cleaned it with a rag. how do i clean the flywheel side? on the top conector by the intake was loose.
these things look exspensive .. . . i hope not

 

They are expensive, >$125 each. Don't need to clean the flywheel and the black residue is common. Be sure to install them just like they came out or you can tear the bottom out of the sensor. The loose connector could be contributing to the intermittent nature of the problem.