87 944 Random, intermittent no spark/start

[whipmeister]

Very frustrating. No rhyme or reason to it. Will start and run great for days and then, without warning, no spark/start. Read all the tips I could find online. The one thing that seems a little different is mine will start when it feels like it. Most I've read about are dead to stay.

Replaced the DME relay. No change. Cleaned connectors/contacts going into DME. Tapped everything down. Cleaned contacts on alarm bypass. If I grab my meter and tools, like just now, and walk out there, it feels threatened and will start flawlessly, even though it would not last night. Once running it will run forever. Needless to say, need to figure this out.

Anyone run into this before?

Thanks in advance,

Jess

[kfray]

You could have a intermittent speed or reference sensor connection here you will find trouble shooting information:
http://www.clarks-garage.com/pdf-manual/elect-19.pdf

good luck

[whipmeister]

Checked the connectors before. Just did it again. Doused em good with contact cleaner. It's happy at the moment. It's the uncertainty that is so frustrating. Previous owner had had one of the sensors replaced not too long back. Car was great with me for a year, then started doing this.

[shadetree944]

I had an intermittent no-spark condition. Stranded me a couple times. Oddly, when I would mess with the reference sensors, it would start up. But they checked out good, and they were relatively new. Then, that quit having an effect, and I did some reading and decided to look inside the DME. Sure enough, there were cracked solder joints on the components (don't know if they are resistors? transistors?) that give power to the coil. I sucked the old solder off with copper braid, then resoldered them. Never had a problem since. My hypothesis is that the reason messing with the sensors worked sometimes is that it would change the resistance enough to make a connection? I don't know. Electricity is not something I understand very well.

Oh, yeah. Also my coil was bad. Failed resistance tests, so I replaced it. When it rains it pours!

[whipmeister]

Thanks. That's some good info I will definitely follow up on.

[Jordan2550]

Originally Posted by shadetree944

I had an intermittent no-spark condition. Stranded me a couple times. Oddly, when I would mess with the reference sensors, it would start up. But they checked out good, and they were relatively new. Then, that quit having an effect, and I did some reading and decided to look inside the DME. Sure enough, there were cracked solder joints on the components (don't know if they are resistors? transistors?) that give power to the coil. I sucked the old solder off with copper braid, then resoldered them. Never had a problem since. My hypothesis is that the reason messing with the sensors worked sometimes is that it would change the resistance enough to make a connection? I don't know. Electricity is not something I understand very well.

Oh, yeah. Also my coil was bad. Failed resistance tests, so I replaced it. When it rains it pours!

I had this same exact problem with an 83 944! can someone please tell me where is the DME, and how do i check the solders?

[Grandad#3]

I had the same problem of a no start on a 85.5, checked everything. Replaced the Ignition Switch Elect. Module forward of the Key and everything has been great ever since. The 83 module cracks and will give a variable start, no start condition. Sometimes the Ign. Sw. makes contact inside Ok and other times not.

Cheers,
Larry

[Jordan2550]

yea, i just got the ignition switch changed but no that other part. could that still be an issue? and if so, can i fix it without buying a new one?

[Grandad#3]

Did you change out the whole Ignition Switch Housing, or the Electrical plug on the back side of it that is held on with two screws?

http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=964-613-012-00-M100&catalog_description=Ignition%20Switch%2C%20Electri cal%20Portion%2C%20%39%34%34%2F%39%36%38%20All%20% 28%30%32%2F%38%35%2D%39%35%29%2C%20Each%20%20#

Cheers,
Larry

[kfray]

The early 1983 944 uses a simpler switch.
Pelican Parts - Product Information: 111-905-865L-M5293

[mytrplseven]

DME'S on later 944's are under the wood panel in the passenger forward footwell (right behind the firewall). Another note from an old electronics tech: if you can't find wire braid to suck the solder from a joint, get an ear suction squeeze thingy from the pharmacy. It's the kind the dr'r use to suck the snot out of babys nostrils. Heat the joint with one hand and squeeze the air out of it with the right and put the little tube quickly on the joint and let go the squeezy part. It'll suck the solder right off the joint.

[Grandad#3]

Kfray, Jess, has an 87, 944, Not an Early Model so the early switch will not work on his car. Jeff, please put your car model/year down in your Signature Block.

Cheers,
Larry

[kfray]

Granddad#3 I thought you where responding to Jordan2550 which has a 1983 in his garage.

Regards
Keith

[spec guy]

we have found that sometimes the port on the relay board gets worn and may need to be resoldered. when you have a no-start the engine may turn over . tap the relay and try again. if that does not work tap it while you turn the starter. then check one sensor and try again. point being check one thing at a time. good luck

[Dave Colangelo]

+1 for sensors,

When I got my 88 924S (944 motor, 924 body) I had a similar issue, except I had no spark. It turned out to be a toasted transistor in the ECU. Check it for lose solder joints and check the sensors but if all else fails you may want to consider having your ECU tested and possibly rebuilt.

Regards
Dave

[Jordan2550]

Thanks everyone, and sorry to create confusion about the different switches. but spec guy, which relay are you talking about? b/c if its turning over but not sparking, how could it be a relay?