Kenny911

I recently bought my first 944. Love it. One morning it wouldn't start. Neighbour kindly offered battery charger. It had a boost feature .... need I say more?

Car hasn't started since. I've also learned a lot about the car (especially what fires it up) since. Good spark at all four cylinders, fuel pump delivery good, DME relay good, coil good etc.

Have I burned the DME unit?

Bypassing DME relay makes no difference (presumably if the DME is fried the bypass wouldn't make a difference anyway?). Car cranks well ... just won't fire.

I don't know anyone to borrow another DME unit from for testing purposes so I'm just trying to cover as many possibilities as I can before leaping in and getting a new unit.

I'd be obliged for any help offered.

Kenny

Mighty Shilling

do you know if you have spark? check the coil, distributor, plug wires, and plugs themselves. Also, check to see if you're getting fuel. If you're not getting fuel, there are a couple things to check:
fuel pump
DME Relay (aka fuel pump relay)
injectors
injector wires

What is your location, and finally, welcome to Rennlist! I'd reccomend starting a thread introducing yourself, your 1988 944S, and with pictures if possible!

Many of the people here are very friendly and glad to help.

Bypassing the DME isn't a great idea, as it takes the measurements for the throttle, air induction, and engine speed, and calculates the ammount of fuel from those measurements.

One last thing to check, the engine speed sensors are located on the bell housing on the drivers side. Make sure those are in propper position, bolted down, and plugged in. if those go bad, car won't start...I know this from experience.

Good luck!

Kenny911

Thanks for your response P924. Very nice of you. I've lurked for a little while and it certainly seems like a friendly place. Great to find people so enthusiastic about the ultimate machines.

Introductory thread seems a good idea. I'll do that soon.

I'm from Glasgow, Scotland.

I have good spark, coil, fuel delivery, the DME relay is good and the car cranks well. Just won't fire.

Cheers again.

Kenny
1988 944S 2.5l 16v Black

ijohnston99

Hi Kenny,
Another lurker here...must be something about the Scots

Check out clarks garage for a comprehensive checklist.

http://www.clarks-garage.com/shop-manual/ts-01.htm

Good luck!
Ian
Whos' near Falkirk

7thStranger

The S has an ignition control module, It is a black square thing by the left side headlight. I believe it will take a hit before the dme will.

Although if you have good spark, and fuel, and don't think the DME, or the ignition control unit is the problem.

ijohnston99

It depends where the fuel is being seen. I have seen a couple of faulty DME's that fire the fuel pump but not the injectors.

Ian

Kenny911

Thanks very much lads. Another session under the bonnet for me tonight. Let you know how I get on
Kenny

my87944s

If there is NO difference between the 87 and 88 Motronic computer, I have a spare I can send you for troubleshooting purposes. I do not want to sell it, but I can loan it to you...
But I am unsure if there is a difference between the two years.
I just checked my shop manual for the S model and their appears to be different part numbers for an 87 and 88 DME.
The 87 is listed as 944.618.124.00
and the 88 is listed as 944.618.124.01

jonnybgood

I would think that if you have spark then the DME is functional. The idea of the ignition control unit going bad seems like a good direction. 944S only has one reference sensor and I would not check that until some of these other items are checked. Seems like the battery would take all the extra current. Did the charger have a volt meter on it? I think the DME can take more than 16 volts without damage.

Zero10

My dme took about 19 volts for a few minutes, and still functioned fine

993inNC

A friend of mine just bought my 88 944 and wouldn't you know after 3 years of flawless use, the same thing hapened to him just after he got it from me. What was found is the screw that holds the rotor button on had come loose and was positioned wrong on the shaft. Still had spark, fuel, everything, just at the wrong time Worth a look at.

Bluesky4x4

We had a similiar issue recently with my buddies hotrod. Spark, Fuel and everything looked great. What we didn't have was fuel "pressure". The tank was very empty and the dual pumps were just pushing some fuel through. Not the necessary 45psi or so required by that engine. Filled up the tank and vroom.

Kenny911

Thanks very much guys. I have a new ignition control unit on the way as it's a relatively inexpensive potential fix. I'll also be trying the other suggestions.

I didn't notice the voltmeter on the charger but I did have an eye on the (presumably fairly inaccurate) voltage gauge on the car as it was initially rising and I wanted to make sure it didn't get into the red (which it didn't).

my87944s - very kind offer - I may take you up on that there would certainly be a few beers in it for you. Where are you? Incidentally my part number is 944.618.124.00. As far as I can tell from the factory manuals the 00 and 01 parts are both ok for the 87S and the 01 is for the 88. My car was registered May 88 but I must confess that I haven't checked to see whether it was manufactured in 87. Must do that. Bearing in mind my part number, both units woulds suit my car.

Will post progress.

Cheers.

Kenny

Peckster

I think you're making too many assumptions, including one that abattery boost somehow ruined your DME. You don't know that, you're just guessing, imo. There's a standard procedure for diagnosing no start situations, much of which is outlined in Clarkes garage, but they apply to any car. Have you checked for gas in the cylinders? That should be one of your first steps. Stop buying parts and start doing the brain work, or take it to a mechanic before you waste more money.

Over!

Tom Carson

you didn't say if your injectors are pulsing. you need a simple noid light tester - something like:

http://cgi.ebay.com/ws/eBayISAPI.dll...948785154&rd=1

dunno if Halfords stocks them...(I don't believe they do)