painkiller

Hey guys. Love the forum and all the great advice and tips. I've searched the archives and found a lot of information but have a couple of questions. My 86 951 had the belt, waterpump and reseal at 87K. The car was a daily driver then sat for two years. I'm finishing up cosmetic/mechanical restoration, the car runs great with no leaks at all but I'm worried about the belt. I believe the service was done about 4-5 years ago. The car now has 95K on it and I'm about to jack it up and do all the coolant hoses and external belts, reference sensors, venturi delete, lindsey fuel rail, etc. Other than obvious cracks is a visual inspection accurate or should I just do the whole shebang and be able to forget about it for a while. I plan on keeping this car so is it worth forking out the cash for the factory tensioning tool or does anyone have any experience with the little inexpensive tensioning tool I've seen on here (can't recall vendor but its measures tension through a pivoting lever)

Also what about the water pump-I have no leaks and it only has about 8k on it, but should I do that too? I know they are cheap but thats $250 that could go for other stuff.

My other question is about the dme. I've taken it and the klr out, cleaned what contacts I could, pulled the chips, cleaned replaced, and I still have an intermitent no start and occasional stumbling while driving. Tach jumps so its not reference sensors and a 3D cell maglite works wonders on the left side of the floorboard. Is there a easy way to troubleshoot the dme to find what I assume is a cold or cracked solder joint somewhere?

TIA and look I forward to your responses

MHT

take the dme control unit apart completely, the usual failure is the ignition drivers joints. The driver is a disk shaped part about 19mm in dia. and is mounted at right angles to the board. There is a 3 connector ribbon between it and the board, sometimes the connections at the three pins crack and sometimes the connections on the back of the board crack, resolder all of them and your problems are gone. You can usually see the cracks with the naked eye.
Good luck

tconn

I was told by Porsche expert Jim Pasha
that the belts are good for a max of 5 years no matter how low the millage on the belt is. I guess the rubber deteriorates with time.

Tom M'Guinn

I'd change the belts, but probably leave the waterpump if it is working ok. (The waterpump is a "while you're in there thing, but you do have to remove more gears and pullys to replace it, and a good pump should not go bad in 5 years and 8k miles.) Personally, I bought the tensioning gauge for peace of mind. For the DME, have you replaced the DME relay yet? If not, that is a must try. Then, if there is anyway to do it, try to trade DME's with someone for a while and see if the symptoms remain in your car or move with the DME to the other car.

painkiller

OK guys, I know its been awhile. I just saw the newbie rules about posting follow-ups to problems.
MHT nailed it right on the head. Took DME out, with magnifing glass distinct circular cracks could be seen on all three back side posts (opposite side of circuits and caps etc...) re-soldered all three, replaced and car fires right up, no stumbling. Thanks to all for their responses. Tom thanks for your input, I am aware of the relay issue and have a couple on hand.