PorscheDoc

The tach is bouncing when cranking so the reference sensors are getting a good signal from the flywheel and relaying it to the DME. The reference sensors take their signal from the pins in the flywheel. I still think that he is put out WAY too much fuel pressure if his 30 second output test is correct (1300cc's when i think he should only be putting out 750cc's), and the rail is not holding ANY pressure after you turn the car off. Those two would lead me to believe a bad FPR or damper, and fuel check valve back by the fuel pump. He has had the car running from time to time, and it will run for awhile then stall out, so push starting it isnt going to tell us anything. It may get it running again, but it will stall out eventually and we are back to square one again.

StupEd05

The first flow rate test I did was through the end cap on the rail. At that point the fuel hasnt got to the FPR yet, so this evening I will do a flow rate test on the return side of the FPR and see how well fuel comes out of it. If the FPR is properly functioning is it completely shut if no vacuum is being applied? If so, I shouldnt get much flow THROUGH the FPR right? Or is it not as ON/OFF as I am thinking it is?

StupEd05

Alright, got a fuel pressure gauge hooked up to it and I read 36 psi with jumped DME. And after 20 minute leakdown test... 8psi. However the guage is MacGyver'ed on there with a rubber hose so connections prolly arent exactly air tight.

Robby

"MacGyvered on there...."


OK- so you're saying that if the TACH needle bounces when cranking the car, that the reference signals are making the correct connection to the flywheel??? OK... I'm going to check this next time my car does IT'S thing.... shouldn't be long....

StupEd05

Yes, if its not getting a signal because of a worn or bad flywheel, the tach shouldnt bounce and the injectors shouldnt fire, nor should you get spark. Right, Karl?

PorscheDoc

Well usually when the tach isn't bouncing while cranking, it is usually due to bad connection where the reference sensor plugs into the DME harness, but same thing would happen if say the gap was incorrect between the flywheel and the reference sensor.

StupEd05

Gotcha. So, anywayz, anybody got any ideas... I got spark, got fuel, no fire. Weak spark maybe? Or air leak? Would a bad O2 sensor cause a no start? cause the plastic connector on the firewall that goes to the 02 sensor is broken pretty good.

User 41221

No, that will make it run rich, but won't keep it from starting. If you want to see a "really" broken one, come over and look at the one on the white '84 in my drive. It starts fine.

Regards,

Robby

Hey- did you guys ever meet, or know, Garrity Repta? I know he was in St Louis & not KC, but, just curious... He had a few people working with (or for?) him in a shop up there & I took my car to him almost 4yrs ago. I THINK he's in FL in med school- last I heard... Just curious....

User 41221

I know of him, and know people who know him, but never met him before he got out of the business. I heard he went to Med school as well.

Regards,

StupEd05

Alright, im gonna pick up a vacuum gauge and start testing lines. And then break out the multi-meter and get some readings.

User 41221

I have both available for you if you want to use them. It will take you about as long to go buy them as it will to make it to my place to borrow them... Give me a call if you want to.

Regards,

MHT

try disconnecting the air flow meter, these cars will start and idle with the meter disconnected, if it starts with it unhooked, look for a big air leak. Have you pulled the vac. hoses off the fpr and damper, is there any fuel in the hoses? Are the wires hooked up correctly? #1 is at bottom right, as you look at it from the front, and the wires go, in order, 1,3,4,2 in a clockwise direction, put the engine at tdc#1, ie flywheel at tdc and cam mark lined up, and make sure that the rotor points to about the 4 o'clock position. Check the condition of the wires at the coolant temp sensor, the blue plug below #1 intake runner, remove the connector and make sure it's not all corroded in there. If the wires are broken or there is a high resistance connection, the ecu sees that as a very cold signal and richens the crap out of the mixture.
Good luck

StupEd05

tried disconnecting AFM, no go. No fuel in vacuum lines but I have tried sucking on the fpr and get an aftertaste of fuel, no liquid though. Wires hooked up right. At TDC the rotor is at almost exactly 5 o'clock.

One quick question, should the AFM move at all when cranking? Does the throttle body open itself? How does air get "in" while cranking? Thanx...

Robby

WAIT A SECOND guys..... I went out in my car a few hours ago- had to start it SEVERAL times- the tach needled did NOT move- or, what are we talking about here? I mean.... it BARELY twitched- if I had to give a FULL range of movement based on rpms, it would be less than ~10rpms- it stayed at the bottom (0). the car was starting fine too- what are you guys talking about here, &, does this tell you ANYTHING at all since mine WAS starting at this time? I REALLY don't remember the tach needle ever moving before, really.....Any input would be GREATLY appreciated....

Thanks..
Robby