Papamurphdog

First, many thanks to all on this forum for responding to my various posts, the help is invaluable. So, after exhausting all options on my own no-start issues I finally found the problem and I'll bet that many have the same issue but don't know it, or it is lurking, waiting to happen...I don't have pics to post today but I will post them soon. Backstory: with help from all, in recent weeks I have found and replaced many connectors, the TDC and RPM sensors, etc. -- certainly work that needed attention -- and my car was still sitting in the garage, not running. As a last resort last Thursday -- with DE looming on Sat. --I finally hired a flat bed and sent it to the shop. They tested and diagnosed, discovering all my fixes were solid; so what was the frigging problem? As a last resort the female connector on the #1 injector was unplugged and the boot was cut open to discover -- ah ha! -- the two wire leads that were INSIDE the boot were bare, corroded and touching each other; creating a short only in the injector harness to the DME (which could have fried the DME, but it seems OK so far) preventing the injectors from getting as pulse signal from the DME, even though all the injector connectors still tested positive for voltage!!! Damn!! Once the wires were seperated it started right up! But wait...so, I splice and heatshrink a new'ish one, plug it in, still no-start! WTF!?! Desperate, I jiggle #2 and magic, it starts... so while the car is still running I jiggle #2 and it kills the motor! Opend the boot on #2 and sure enough the wires were worse than in #1. Fixed that. Started right up! For yucks I jiggle #3, KILLS THE MOTOR again! Lo and behold #3 was not quite as bad as the others, but it was also bare and corroded; fixed it...started. I fixed #4 for the heck of it! So... after years of intermittent no-start and engine dies issues, it was the damn injector connectors all along. If you have a no-start and the other related parts and wires seem fine, try cutting open the boots to see what you find. I would do the same thing for mystery engine cut-out too. I showed the injector clips to a few of the 944 guys this weekend at Road Atlanta and they were all a bit stunned. Moral? I would put two things at the TOP of the list: check and clean all the ground points in the engine bay (#1 thing in the 944 manual) and check and inspect the INSIDE of the female injector connector boots. It was a really cheap fix actually and easy to accomplish. I only wish I had discovered the issue a few years ago!! Also, I added a bit of length to each injector so that there is zero tension on the boot area with each wire coming straight off the injector and then making a wide, relaxed loop back to the injector rail, where I tied off the main harness. I've seen many, including my own, that were sort of stuffed and pulled; not good. Relax your wires today!!! I hope this helps someone in need... FYI, Road Atlanta was awsome this weekend. Low temps and PeachState runs a great event. Special thanks to "Kerry" for finding the actual problem and to "Tom," "Carl," "Pat" and "George B." for taking all my frantic phone calls... I finally fixed it for good by 7PM Friday night before this weekends event!! Wheeeew! See ya'll on the forum...

Spidey944

Congrats on finding the issue!! Had a few local PCA guys at RA this weekend too, said it was a fantastic time. Maybe add some spacing to your monster paragraph to make easier to read, just my nitpicking....

Papamurphdog

Thanks! Will remember the spaceing issue next time. Hopefuly I will no longer need to write such lengthy posts...

95ONE

should have been the first thing you checked. I warned this years ago.
but gauranteed, if you don't change out every wire iside a connector boot, it will fail soon. any sensor.

porshhhh951

glad you finally got it worked out. How long have you been having this issue?

951Tom

I had the same issue & new connectors cured it. Not sure if you did, but check the temp sensor plug. My wires were a mess under the boot.

jmj951

Is this just a problem for cars that drive on salt roads, etc.? Has anyone seen this on a car that has been a California car its entire life? There is not a spec of rust anywhere else on the car, but it's got 137k and the drivetrain is all original. I bought this 951 for DE events and I don't want to be left hanging in the middle of the day.

Papamurphdog

Agreed. Only been on the fourm a short time. Have changed many connectors so far and I am planning to update all of them... Thanks.

Papamurphdog

It's happened 4 times in over 3 YEARS and never has the "fix" actually been a fix. It has magically started; which has been attributed to all kinds of stuff. This is the first time I have applied a "fix" and the direct result was "it's fixed!" All other times it started after sitting awhile or for no apparent reaction to the fix. Much happier with this result...

porshhhh951

don't beat yourself up. Those things are hard to find alot of times. It could be so many things its hard to narrow it down to just one thing and that one thing fixing it.

Especially when you throw in half a dozen or so variables.

Papamurphdog

I am planning to do every plug in the engine bay. I have already spotted two other vital conectors that look suspect; throttle sensor and the temp II sensor. Both are bent and a little brittle...time to change them!! BTW, I don't think it is a "salt" problem...looks like heat and age to me. While there are few parts left on the car that aren't virtually new, the chassis and its main components are 22 years old and have 163K on them. Age is the main culprit I think...

jmj951

I'm definitely guilty of fixing things that aren't broken, I just prefer to eliminate known weaknesses than wait for problems to develop, at least if it doesn't cost much to address those weaknesses. These experiences are more than enough for me to do that. I checked the sites of a few companies I buy from and didn't find these types of connectors available as replacement parts. Did you need to fabricate these yourself from new wiring & connectors? If you just bought them ready to install, could you identify the source for the parts you bought?

333pg333

Thanks for the writeup. Damn that would have been frustrating for you, but glad it's fixed.

95ONE

motec sells a wiring kit that matches our 2 and 3 pin connectors perfectly. comes with connectors/pins and a little extra. $80 believe it or not. contact pro-technik in stafford texas or your local motec dealer

David Floyd

look like this ?


https://rennlist.com/forums/showthre...&referrerid=38