[Lord_Galva]

I've been diagnosing my cranking no start for just over day and this is what I have found.

I have a spark at the plugs.

DME works in another Porsche.

Smelled fuel when the spark plug was out and engine was cranking.

Fuel pump running.

Timing belt mark lines up with TDC.



I plan on trying 3 other tests due to idea's I got from various sorces.

Could be a gummed up fuel filter

Could be a gummed up starter

So I have a spare starter that I was planning on swaping so I will try that first.

If that doesn't work I'll try an alarm bypass.

And finally order a new fuel filter for Monday.



Any other ideas?

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[jaap]

If you can hear the engine cranking I think you can rule out the starter.



Jaap

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[Scott Collins]

I had a similar problem once, and found that I had forgotten to reconnect the distributor wire to the ignition coil. If you have spark, then it's probably not that, but I just thought I would mention it.



Could there also be a vacuum line leaking or disconnected causing this?

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[kwikt]

Maybe fuel pressure regulator. What psi at the rail?

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[Lord_Galva]

Havn't checked the fuel pressure yet.

I just finished installing the starter and no change <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" />

Going to try the alarm bypass before checking the fuel pressure.



However, wouldn't I notice a change in fuel pressure while driving?

The car had been sitting for 3-4 hours before the no start happened and it was running fine.

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[flash]

i assume by "DME" you mean the DME relay, since the DME will only fit the 968 - that being said, i would not assume it is good, just because you stuck in in another car - that only means that it worked when you did that - DME relays fail due to heat - when they cool down, they often "work" again - you can try the DME relay bypass to determine whether or not this is the problem - do a search here for that to see what pins to connect

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[kwikt]

Possibly could be the crank positioning sensor in the top rear of the motor. Try plugging and unplugging all your connectors first along with the relays. There is a starter relay in the fuse box. Check it out. Maf, hal sensor, crank sensor,throttle sensor, cold start sensor (If smelling gas it can be this),etc. When running how is the idle??? Idle control valve stuck open?

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[Lord_Galva]

Thanks Flash and Kwikt.

I will try unplugging and replugging the relay's cuz frankly it couldn't hurt.

I also have 4 DME RELAY's that I can swap out so I will try that too.

Gonna keep my fingers crossed. <img src="/forum/images/smilies/968/unsure.gif" class="smilie" alt="" />

[quote name='kwikt' timestamp='1302997707' post='108513']

Possibly could be the crank positioning sensor in the top rear of the motor. Try plugging and unplugging all your connectors first along with the relays. There is a starter relay in the fuse box. Check it out. Maf, hal sensor, crank sensor,throttle sensor, cold start sensor (If smelling gas it can be this),etc. When running how is the idle??? Idle control valve stuck open?

[/quote]



Where can I find the idle control valve?

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[Lord_Galva]

Update

No go on the relay unplugs

I even cycled 3 DME relays in and out still nothing.

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[DaveN]

That's really baffeling, spark and fuel but no start. That only leaves not enough compression <img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" /> Is it possible that there is a belt broken and the cam is holding the valves open just enough? Just fishing here.

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[tamathumper]

Is it a strong spark? A very weak spark sometimes won't be enough.



Is your wiring original, or has a remote starter been added?

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[banditsc]

Is your tach moving when you crank the engine?

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[rl968]

Are you sure the DME relays that you are trying are the right ones? They are very specific for each car. The old ones are crap, the new ones work much better. Here is the part number



993-615-227-00



Also, clean the contacts for the relay switch in fuse box. use a small flat-tipped screwdriver and some wd-40.

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[Lord_Galva]

Tach is moving on cranking

I don't know if its a weak or strong spark. All I can tell is that there is one.

Part number for the relay matches



Really starting to think the fuel pump sound I am hearing is a failing fuel pump.

But I am throwing in the towel and having the mech look at it. <img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" />

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[Cloud9...68]

Just one quick thing to try before you take it to a mechanic. You seem to have access to another Porsche, and the coils on many Porsches are interchangeable. Try swapping coils and see if that makes any difference.

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[DaveN]

Really easy to pop off the fuel rail and put a bucket under it. Have someone crank the car over and see if you get fuel flying out of the pipe.

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[unknown4u]

Do not crank but jumper the DME. Gives a better result because engine is not "shaken" and you can measure the flow.

And do the blinktest as well. maybe an error has occured and stored in the motronic.

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[Cloud9...68]

I agree on both points. Years ago, when I was having a hesitation problem with my car, I ran the fuel volume test, and it was pretty straightforward. The hardest part was cracking the lines open - those nuts tend to be very tight! And I had thought of the blink test, but I don't see how a sensor, which is most of what the blink test tests, could cause a no-start problem, but since it's free, it's worth a try.

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[DaveN]

Good point about the jumper - I'm old. I still revert back to the pre-ECU days sometimes when troubleshooting. But not back as far as the "crank" days thank-you <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" />

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[Lord_Galva]

Ding, Ding, Ding!

And the answer is.......

Timing freakn belt!

I didn't notice that the camshaft wasn't moving while we were cranking the engine.

I don't have a clue how I didn't notice that but I just paid $300 to have someone else tell me.

Talk about opid-stay

At any rate, the mech are going to do a leak down to make sure the valves and head are ok but I am confident they are just fine.

This also explains why I was getting spark and fuel.

The camshaft was stuck at TDC so the fuel and spark would work but only for cyclinder #1



Going to order a nice kit from Pelican http://www.pelicanparts.com/cgi-bin/smar...%20Each%20



Oh, and please no negative comments like "oh, your engine is broke'd" I want to stay positive. <img src="/forum/images/smilies/968/cool.gif" class="smilie" alt="" />

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