[Eric_K]

The fuel pump doesn't run continuously unless the engine is running so listening for the pump is not a good test unless the dme relay plugs are jumpered.



You can buy a cheap spark tester at just about any auto parts store. It is bacically a light that goes between the plug wire and the plug. It makes it very easy see if there is spark or not.



Have you tried to start the car?

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[Cloud9...68]

Yes, once I saw that, to my surprise, I was getting spark, I went ahead and warmed up the oil in the sump with a pair of space heaters, jumpered the DME relay connectors, turned the key, and voila! It started! The lifters only clattered for about 20 sec or so, and the engine runs smooth and sounds great. The oil pressure at idle is much higher than it was before the rebuild, so the engine must have been more tired than I thought. And the best news of all - no leaks! I owe a huge debt of thanks to everyone who helped me through this challenging no-start ordeal - Lear35A, Joel, Flash, Banditsc, Eric, MB968, and Pete from RS Barn, who set me straight on the fact that the fuel pump doesn't turn on when the key is in the start position, as Eric says in his post above. Pete also told me to check for voltage at the coil, and when I saw that I was getting +12V at both terminals, this was the first indication that there was actually a signal coming out of my DME.



I suspect it probably would have started several days ago, had I not been using the lack of fuel pump hum, and the non-operational blink test, as my indicators. So, I don't really know if getting the wires correct on the 14-pin DME connector, or jumpering additional connectors of the air bag control module, were what did the trick, or if it was neither, and I was just not seeing the fainter-than-expected spark in my earlier tests. Even stranger, the blink test now works! No explanation for that - maybe something about actually firing up the engine (I can't tell you how good it feels to write those words!) somehow reset something. I'm going to sleep well tonight!

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[MB968]

You must be feeling pretty good right now. Congrats.

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[Langley968]

<img src="/forum/images/smilies/968/clap.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/clap.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/clap.gif" class="smilie" alt="" />



<img src="/forum/images/smilies/968/beer.gif" class="smilie" alt="" />

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[mbardeen]

That's great news, Cloud! Congrats! Now how long before it moves?

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[tamathumper]

Congratulations! That's awesome <img src="/forum/images/smilies/968/biggrin.png" class="smilie" alt="" />

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[kwikt]

Long awaited Cloud!!!!! Persistent pays. WELL DONE.

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[Rap]

When are you going to be able to take it to the track at lunch hour? Lol

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[Cloud9...68]

Thanks, everyone. The worst part of a problem like this is the uncertainty - I had read plenty of horror stories of people spending months chasing down a no-start problem. I think I would have sold the car for parts before going through something like that!



Now that my blink test is working, I need to actually perform it to confirm all the sensors and such are working. Then I need to put back the DME unit and the glove box, then tomorrow, tell the machine shop I need my drilled spindles (to accommodate the thicker ball joint pins in my Racers Edge heavy duty A-arms) asap, so I can put the suspension back on (not exactly sure how to install the rear coil springs...). I also need to check the fit of my fiberglass hood (probably awful), see what adjustments can be made to it, and have it, the splitter, and the brake duct scoops painted. I also need to buy tires, and a drivers seat (I know of someone who had a used Sparco Evo, which have test-sat, and I need to let him know I'm, ready to buy). Then I can start doing those lunchtime track sessions!

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[Lear35A]

Oh happy days!!!

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[flash]

i thought we went over this. fuel will not come on until the ECU sees that all is good with major components (i.e. airbags, alarm etc). all modern cars pretty much behave that way. this is to prevent fire and theft. it also will not come on until the "cranking" position of the key.



glad you sorted it out though.

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[Cloud9...68]

Somehow I got it in my head that the fuel pump turns on when the key is turned to the start position. I posted this somewhere (probably on R.L.), somebody corroborated it, and nobody disagreed, so I took the lack of fuel pump hum, and, more importantly, the lack of a functioning blink test, as evidence that there was no signal coming out of the ECU. My mistake was not checking for spark on the 21st, which was when I was sure I had gotten the 14-pin connector correct. I said I was going to, but never did. But the non-functioning blink test was telling me (erroneously, apparently) that the DME wasn't sending any signals out, so I ended up going down a bunch of rat holes with the ABCM jumpering, checking the wiring of the other 14-pin connector, <acronym title='throttle position sensor'>TPS</acronym> troubleshooting, DME swapping, etc. It's weird that I tested the blink test just before I started it, found that it didn't work, and then tested it again soon after shutting the engine down, and it suddenly started working.

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[JTP]

[quote name='flash' timestamp='1359311398' post='138055']i thought we went over this. fuel will not come on until the ECU sees that all is good with major components (i.e. airbags, alarm etc). all modern cars pretty much behave that way. this is to prevent fire and theft. it also will not come on until the "cranking" position of the key.



glad you sorted it out though.[/quote]



Too bad the DME doesn't sense when a mechanic didn't tighten the fuel lines like this poor guy. Fire destroyed his 944.



http://www.944online.com/cgi-bin/forum/f...tart=60#60

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[flash]

i think the problem might have been a communication one. the "starting position" is the one that springs back when you let go. this is the position that engages the starter. the previous two positions, starting from the left are: accessory (which in american cars is to the left) and then "ignition on".



the fuel pump does not come on until the "starting" position. the ECU comes on at the "ignition on" position.

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[Cloud9...68]

It all makes sense now, including why a leaky check valve can cause a hard-start problem, which I never quite understood before. Since the fuel pump doesn't energize until you turn the key to the starting position, the car is depending on a full charge of fuel in the lines - a leaky check valve compromises that.



My major lesson learned through this problem is to utilize the spark test (spark plug removed, re-installed in the plug wire, spark plug threads grounded, crank engine, look for (surprisingly faint) spark) as a means to test whether the engine is likely to fire. I was relying on too many ancillary things, many of which turned out to be inaccurate or red herrings, like the blink test working, and voltage at various DME relay terminals.

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[Eric_K]

Yeah! Must be a relief.



My money is still on the 14pin connector under the dash as being the culprit. If pin #2 was not connected correctly the DME would not know the engine is turning and wouldn't fire spark or energize the fuel pump.

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[flash]

makes sense - the problem had to be one of the initial ECU check points.

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[Cloud9...68]

Agreed.

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