86 951 no start

[jamess2]

I picked up a cheap 951 off craigslist last night. the po stated that the car was running fine and He got into move it and it cranked he shut it off and came back to it later and no start. He said he checked and was getting no spark to plugs

First off not 100% sure its not getting spark because I have no one to check it while I spin it over. Now I have had a chance to do some minor trouble shooting...I do have tach bounce while cranking but I have ALOT of bounce. It will bounce up to around 2,000 rpm on the gauge during cranking...I don't think that is normal. Next I changed the plugs, I didn't figure it would help but I had them. Next I bypassed the alarm module. In changing the plugs I noticed that the car was wired wrong, they had the firing order way off... I fixed that. The dme relay has been jumpered so the relay isn't the problem. I also tried a spare coil. The only real suspect I see is that the wiring harness on one of the crank sensors is completely gone and some one has wired it up and wrapped black tape around it. I have some spares I can try but ran out of time this morning before I had to be at work. Any body got any ideas? I pulled the distributer cap and the belt is on and tight as well so the timing belt should be good.

Thanks in advance for the help.

[Ky914Newbie]

I know you already know this. Spark fuel air are the keys. With the tach bounce like it is, I think it is safe to assume the speed and ref sensors need to be changed out. While you are getting those parts, I recommend you also:

1. confirm the rotor inside of the distributor is attached properly and the set screw hasn't backed out.
2. get a compression check on the cylinders.
3. check the plug connector at the afm to make sure it is secure.
4. triple check the firing order (don't ask why I suggest this).
5. set the engine to TDC and confirm the timing marks.
6. consider cleaning the grounds.

Does the car have any mods from stock?

[jamess2]

The car is modded. But I'm unsure of all the mods...Its got a lindsey stage 2 kit on it and magnaflow exhaust and a turbo s turbo. That is all the po told me.

[Ky914Newbie]

My big question on the mods is if you have a MAF vs the AFM. The AFM is quirky, especially at the plug connection. The MAF is quirky, especially at the grounds. My biggest concern is the tach bounce and the description of the connection being wrapped together in electrical tape.

Sounds like you bought this car:

"This is a non-running 1986 porsche 944 turbo. As of right now it is having an electrical issue causing no spark to the plugs. I'm tired of working on it and i'm taking the losses finally. It could very well be something simple, I just haven't had the time nor the money to devote any serious effort into troubleshooting.

It has 120,xxx miles. All original. It's lowered on koni coilovers and borbet type a wheels. The engine/performance has been upgraded with a Lindsey Racing Stage 2 kit, a slightly larger turbo, magnaflow muffler, and an aftermarket ECU. It's currently set on 10lbs of boost but the tune is most efficient at 14lbs. It was easily one of the fastest cars i've been in. Other than the sudden loss of spark, I've had no issues with it. "

If this is the car, I am concerned about the aftermarket ECU as that throws a big question mark into any troubleshooting. Was it ever running with the aftermarket ECU?

[jamess2]

That is the car...lol. As far as the after market ecu... It just has lindsey chips in the stock computer...That was one of the first questions that I asked the guy. I will change out the crank sensors tomorrow with some spares I have laying around.. I will report back my findings.

[jamess2]

Ok. I had a chance to work on the car some more today. I changed out both crank sensors and the tach went from jumping all around to bouncing like normal. Still no spark. I also inspected the alarm module more closely. I noticed on the circuit bored one of the diodes is split and the module gets hot while trying to crank...I bypassed it per clarkes garage and still no spark. Now could the alarm. Module not work even bypassed with the split diode? It has a burned spots in several places on the circuit bored. I can also here the module clicking when I start to get out of the car...I can lightly tap the box and it stops clicking. Any more thoughts or ideas?

[Ky914Newbie]

I don't have any experience with the alarm system. I will have to defer to someone that has some experience with that.

[jamess2]

Pulled dme out of car tonight and dissassembled. Decided I would check the solder joints and stuff. I found a burned trace that leads to pin one....the main ignition pin....me and my dad soldered it back and we have spark!!! The car still isn't running yet...now I have to figure out why I'm not getting gas. I know the pump is running but the gauge at the rail isn't moving...its stuck around 20lbs and doesn't move while trying to crank. Any thoughts ideas?

[TrailRider]

Try jumping the DME relay per the "emergency jumper" as documented here on Clark's Garage -

DME Relay Information and Testing

Does that increase fuel pressure at the rail? If so, then your fuel pump is okay. It may be a bad DME relay.

If no increase in fuel pressure, then I would check the voltage to the fuel pump and or the fuel pump as being bad.

[jamess2]

The relay is already bypassed. I wanted to add that I tried a different dme computer today as well. Still have spark but no fuel. I beginning to think that I have a bad fuel pump.

[jamess2]

I got the car to start off starting fluid...so I'm positive the fuel pum has quit. She will be up and running soon.

[prooutlaw]

James , are you shure it has gas in the tank ?

[jamess2]

That thought crossed my mind but the gauge shows half a tank. I might grab a gas jug and go get some just to see after I get off work. In a way that would seem logical..I know the pumps on these cars don't fail often.

[rhett]

The fuel pump cable plug can be a cause of problems as a bit of oxidisation on the contacts will stop the pump from running. Pop open the connector, clean both sets of contacts, spray a bit of WD in there and clip back together. You should be able to hear the pump run when you turn the ignition on.

although these pumps are generally reliable in operation, they really do not like just standing around...

[jamess2]

Ok I had a chance to mess with it for a few minutes this mourning. I pulled the gauge off the rail and checked for gas at the rail...try to crank and it has plenty of pressure...I originaly thought the fuel pump was bad bc I pulled the gauge off the other day and there was no fuel at the rail at all...but didn't. Try to crank. I guess the injectors are not firing...I guess the next step is to get a noid light and see if they are actualy pulsing ...I'm starting to suspect the used crank sensors that I installed could be bad? The connectors on them were no better than the ones that were pulled out of the car. I also inspected the injector harness and the grounds all seem to be good. Any other ideas...imrunning out of stuff to try. Already once again..
Bypassed alarm
Tryed another dme
Swapped crank sensors w some used ones I had. Any more help would be greatly appreciated.

[simssj]

You and I seem to have parallel posts; I've got a starting problem thread going too.

I mentioned this morning that I was pleasantly surprised to see that AutoZone had NOID lights in their "free"* tool rental program. Do you have an AutoZone near you?

* 'Free' is defined as: you pay them for their tool and then you bring it back for a 100% refund. I don't know if there's a time limit or anything.... The counter guy at my local store said "forever." So, cool!

[jamess2]

I actually work for auto zones competition LOL. I have acesss to the noid light at my work...if you solve your cranking issue let me know. And good luck

[simssj]

Whoops! (If it's any consolation.... I tend to spread my parts dollars around liberally!)

[jamess2]

Ok we figured this thing out today. I decided to give it a try this morning and try to start the car. It cranked up and ran for about 30 seconds and died. That was the most it had tried to run since I got the car. Tried to start it again and car would not start. My dad leaned in and put his hand on the fuel rail and injector harness and the thing cranked up and idled...He removed his hand and it would die and not crank. We ended up finding a broken wire in the #1 injector harness. I repaired it with a harness I had on a spare motor I had. I tried to crank and she has started every since and I even drove it down the road. Now the real fun begins with getting the years and years of filth and neglect out of this car.

[944tothefloor]

Congrats! great success story.