highboy

hey...are there any rennlisters in northeast ohio? i am having "no start" issues with my '88 944 Turbo and i think it may be the DME...therefore, i would really like some assistance in the way of...swapping out the DME in a working car to see if my theory is correct prior to dishing out 500 bones on a new DME...it's the old adage of trial and error...there is tall cool one in it for you as well as some good P-car chat...

little history - the DME relay is new, the fuel pump is new, i hope to be able to check out the reference sensors and alarm system tonight...but i really think it is the DME unit due to the past 1.5 week of wet weather and a leaking battery box...i think she shorted out!

anyways...calling all assistance...please !

t

kasturbo

There are several members in your area. I hope they see this and can help. I would help, but I'm a little too far south.

What does the car do? Does it try to turn over and just not fire? Is it getting fuel, spark?

Skip Wolfe

I can probably help you out. I'm in Richmond Heights - where are you?

highboy

i'm in Madison on the Lake (40 mins east of Cleveland and 40 mins west of Erie, PA)

...OK, let me give you the run down on the test:

- jumped the DME Relay and the fuel pump ran fine - BUT no start.
- checked voltage supply from battery to relay board - good
- checked voltage at primary coil - good
- checked voltage at primary coil activation (DME harness) - little weak, but with in the range
- speed and reference sensors seem to be tight - still need to run the checks
- pulled the DME and checked to see if there were any breaks in the solder - nothing that I can see

OK, back to your question about fuel and spark - I need to do those checks, however, fuel was surely one of the causes. This whole thing started when she wouldn't start a few days ago...so the first thing I checked was the fuel pump (i've already replace one)...notice the fuel pump was not switching on with the key...so I took a chance that the DME relay was bad - replaced it with a new one...still nothing...so, the testing began (as detailed above). So, I should check for spark - dumbass!

however, I am thinking the DME may be the problem - reasoning:

-the battery tray has leaked many a times and the area in pretty moist
-never been replaced...BUT I am always up for suggestions!

i did read somewhere that a easy check to see if the DME is bad is if the key is in the "ON" position and the boost gauge is not reading 1 atm (no reaction at all), that the DME may be dead...is this true?

tonight I will plug my DME and KLR back in and check to see if I have spark.

thoughts, comments, suggestions...drink a beer?

thx tom

kasturbo

Sounds like you've got all of your basis covered. Did you get that leak fixed yet. That is one place on the car that is bad for leaks for sure.

You didn't say what the car does and acts like when you try to start it. You have juice right?

highboy

well...as long as i jump the DME relay i have juice! as for the leak, i have a band-aid fix at the moment...don't tell any one - BUT i filled the rust holes with squirt in expandable insulation foam...BUT now i have to vaccum out the rain water when ever she gets full.

my intention is to rebuild a 89 951 S motor over the winter and drop it in the car next spring...and at that time cut out the battery box and weld in a new one.

she cranks over strong, just doesn't want to fire. again, when i jumped the DME relay the fuel pump ran, but still it did not start. however, when i re-installed the new DME relay and try to start her up the fuel pump does not switch on! So...spark may be an issue...what about the alarm system?

944Fest (aka Dan P)

Heya Tom, I got your email and MIGHT be able to help, but just a little. I do have a spare DME, but it is not for sale, but I'd loan it to you for troubleshooting purposes. Let me know what you want me to do! I've also got a spare DME relay, same situation.

Best of luck.

Dan P

highboy

thanks dan...yea, the loan idea is awesome! let me know where to pick it up and i'll be there!

i'll surely owe you a couple of beers!

Mike1982

Hey there, sorry I haven't said anything yet, Paramedic school keeps me busy!! Anyways, for a no start you have the ref. sensors, DME relay and DME. If you have switched out the DME with a known good one for sure, then try the actually DME from Dan P. I died on me last spring (sucks!) so I know it sucks if you have to pay to get a new one. If you do find out that is the weak link, let me know because I might be able to call a few people and get you a used good one.

If you STILL have a no start issue, next would be looking at the ref. sensors then.

highboy

well...i thought it was the DME...wrong! Thanks HUGE to Dan P. for letting me borrow a good DME unit to check that off the list...

and Dan, i'll have your DME in the mail this afternoon!

so...i get home to try Dan's DME and nothing! - at this point it is close to 10 pm on Weds and i decide to crawl into to bed and cry myself to sleep after slapping the battery charger on the NOW weakening battery. thursday, i get home from the office - regroup and decide to hook up the battery and give her a shot - as if porsche fairies had come in and fixed her over night!

SHE FIRES RIGHT UP....hmmm has anyone seen this before - let me back-up, thru all my testing of the DME relay, ignition, primary coil...i was reading good voltage from the battery - i slap on a charger and get full charge over night and she fires right up! during all these past few days of diagnostics, the motor was cranking over just fine - bad battery cell - do i have a hiden cause?

due to this battery find...i swapped out the current battery with a brand new OPTIMA battery. she fires right up! now i am noticing that the volt gauge is reading 14 and if i flip on anything that would draw current the gauge to twitching....time to go thru the charging system...?

thanks for all the help
tom

944Fest (aka Dan P)

Heya Tom, well, at least she's making noise. Don't ya just HATE those intermittant issues. Here is two small thoughts for ya, just in case you haven't thought of them.
In the no-start mode, if you crank and the tach doesn't hop, suspect the sensor. If it only runs with a full charged battery, suspect the sensor GAP. (ask me how I know)
As for the DME, is it now running with either your or my DME? If so, I guess that is good news, your problem probably won't cost ya $400!

highboy

Yea she's running...drove her to the office today! Sensor GAP (?)...I need to ask because I'm still a little leary that I haven't found the problem and she may quit on me soon enough...

Are you suggesting that I replace the sensors on the back of the motor?

Thanks again for the DME!

T

944Fest (aka Dan P)

Well, the sensors need a set gap to work properly. At one time, my gap was off, and the car would not start if the battery was low. When I cranked it, the tach would not move. Put a full charge on the battery, and then the sensors had enough juice to bridge the gap, the tach would bump when cranking, and it would fire right up. Since you haven't changed your sensor gap recently, maybe that is not it, but it was a very similar problem I had.

Gapping them is tough, darn near impossible for those with big hands. The procedure is in the service manuals.

Skip Wolfe

Come on now Dan. No one belives the "big hands translates to being big down below" adage anymore so quit talking about your hand size for Pete's sake.

944Fest (aka Dan P)

Maybe if YOUR hands were a little bigger, the wife would not need them to help HER go shoe shopping on a Saturday track night!! DOH!!!


(That didn't make any sense, but sorry, I couldn't resist)