A little history, I replaced the blown motor in my 87 na with a motor out of my 85.5 car before putting the engine in the car, I installed new clutch, took the flywheel and clutch housing off the 87 used them on the 85.5 engine. I replaced main seal, pilot bearing, oil cooler seals, water pump all belts. Took the oil pan off the 87 ( as it has the oil sensor in the pan the 85.5 didn't) . I replaced rod bearings, swaped out wiring harnesses and fuel rails between the two engines. ( so the 87 harness is on the 85.5 engine) got the engine back into the car. Filled up all the fluids and attempted to start her. What I get is one whine from the starter. And then it dies. I have to turn the key on and off again to try and restart, but it is always the same results. Here is what I checked and done so far: battery fully charged and checked out good for load / all of the grounds have been removed all surfaces cleaned and reinstalled / used two different working starters one from the 87 and one from the 85.5. Both starters get the exact same results / swapped out both ignition relays ( just in case) the voltage according to the cars dash is over 13 as well. And the starter has two heavy power wires and one light blue wire. The two heavy wires are on one stud while the smaller blue wire is on what I believe to be the solenoid. Also there is one other wired thing but I believe it to be an isolated matter from the starter problem ( I seem to have one extra plug on the engine wire harness it is a two wire plug that runs under the exhaust manifold two the reference sensor plugs on the back of the engine. I can not find anything for this two plug into) keep in mind this is an 87 harness on a 85.5 engine I was thinking that they used the same harnesses between the turbos and na cars and this was a plug for the other model? Anyways any help is apreciated

Thx

 

Are the bell housings different? I know they are on the turbos... (Because I once had a bell housing that pushed against the flywheel, thus preventing the engine from turning over.) Perhaps you have the opposite combination, and the starter is too far from the flywheel to engage.

 

I would start with checking the voltage at the starter (or at the battery). Low or weak battery, it's not to going to engage the starter.

I've got workshop manuals and vaguely remember some changes being made in the flywheel / starter area between the years of '85.5 and '87. Please note that I've had two TBIs and my memory is not what it once was. I'll check the manuals and get back to this thread.

 

Hi Van, Never thought of that clutch covers being different....... But the covers are indentical and so are the starters.

Hello NCporsche, I have two indentical batteries one from each car. both are 100% charged and I had them checked for load and they both checked out good. The starter does engage for a second but draws to much power and dies. I was able to turn the car over without depressing the clutch pedal the car moved forward so I no it is engaging. It is wierd the starter just gives me one little vrummmmp and shuts down. Next step will be to test the ammount of ohms at the starter before and during cranking. If you could come up with any possible changes to the starting issue between 85.5 and 87 it would be really appreciated.

Thanks for the help guys

 

I think I have found your problem.

On the wiring for the 85.2 starter, You have three wires connecting to two terminals. You have one red/black coming from the fuse box (smaller wire) The other two wires (both black, one from battery and one from alternator/starter/wire harness) connected to main starter terminal.

On the '87 starter you have four wires connected to two terminals. The red/black from the fuse box is connected to the smaller terminal. The other terminal has three black wires. One from the battery, one from the alternator/starter/wiring harness, and one from the "NUR RL 10.0 -> A91" I'm not sure what this last electrical designation means but there is an extra black wire on the '87 that is not used on the '85.2

The above info is from Porsche Workshop manuals volume 4 pages 97-52h and 97-111 respectively.

 

I don't know if this will help, but I know for a fact that the bellhousing starter hole is milled a bit different on the 951 than NA to allow a slightly larger flywheel diameter. A 951 bellhousing on an NA won't work and I doubt a 951 flywheel in an NA will either. The difference between the two are very slight though but enough that they are not interchangable.

 

NCporsche. I checked outt the manual and your correct it looks as if there is one more wire, but when I took the starter out I only remember 3 wires. Does anyone know what this is "NUR RL 10.0 -> A91". Or where we might find it?

 

The smaller red/black wire going to each starter runs through the DME. Does the '85.5 take a different DME than an '87?

 

The part numbers are the same on both dme relays. Would this other wire hook up directly to the starter or could it be connected somewhere else, like maybe on the white plug that is right by the fuse box it has the blue and (red and black stripe, which is the heavier gauge wire? ) also I just ran out and swapped the dme relay with the one in the 85.5 it did not make a difference. It just seems that the starter is not getting enough juice. It just goes "Errrrnnnt" and dies.

Hi JimV8, both cars are NA cars I checked the fly wheels / clutch housings side by side before instaling the newer ones on the 85.5 engine. Plus when I did the belts I cranked the engine over by hand to make sure everything was turning freely including clearance for the reference senders etc. but I would have never guessed the 951 housing to be different, that is good to know for the future. The engine in the car is spinning freely we put it in 5 th and rolled it let out the clutch and she turned over a few times. It is just so frustrating right now I worked on these cars for two and a half months by myself pulling the engines and replacing all the parts and now I am supposed to be on the home stretch. And not seeing the fruits of my labor just sucks.

 

My neighbor was one of the top Porsche mechanics in the State. He's gotten older and is not well. If I get a chance tomorrow I'll present this extra wire problem to him and see what insight he might have.

I try not to bother him but he loves talking Porsches.

 

Thank you NC it's much apreciated

 

Before bothering my neighbor, he will most likely ask if you have tried a remote starter, bypassing the electrical system?

 

No I haven't. But I will try anything. Do you know how to do this or is there a site that you know of that will explain the steps?

Thx

 

Clark's Garage is your 944 friend. http://clarks-garage.com/ Go to shop manual, then starter...

Search for ELECT-16 This will explain how to install and use a remote starter.

 

Will do I used his site quite a few times already ( a very good site) I
Will try it out tonight after work