924Board.org

kevrl · Joined: 27 Nov 2002 Posts: 84

Up until today my 931 has never let me down. When I started it everything was as normal, I let it idle for about a minute on the driveway whil I got myself comfortable, then just as I moved forward it began to misfire BADLY. I looked at the tach, and it read about 3000RPM, but the engine was obviously not revving that high as the car was at idle. After about 30 seconds the engine just stopped - I can't get it re-started, doesn't even fire.

I went back to the car after an hour or so, and it still wouldn't start, but I noticed as soon as I put the key in the ignition and turned it to position 1 the fuel pump came on, and the tach needle went up to about 3000RPM and started waving around

, and all this was without even attempting to run the engine on the starter !

Surely the tach shouldn't show any revs and the fuel pumps shouldn't start until I try to start the engine ??

I suspect one of 4 components,
1) DITC
2) Coil,
3) Crank pick up
4) Ignition Amp (Igniter ?)

Do any of you have an idea where I should start ?, I am not really sure what the differant roles of the DITC and Igniter are ?, I guess that one of them must be giving a firing signal of 3000 RPM, which is why the fuel pumps are running, and the tach shows some revs ?

Do these weird symptoms point to any one particular faulty component ?

The car is a 1982 931.

Any help appreciated.

Kevin

AznDrgn · Posted: Sun Jan 19, 2003 4:09 am Post subject:

Do you have spark? Pull one of the plugs and run a spark test. I am not very familiar with the setup of the 931 igntion system but on the 924NA there are two tach pick up wires that are plugged into the distributor, a while back one of those wires broke on my car and it kinda did what your describing. Check it out and let us know what's happening.
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-'87 Jeep Cherokee 4.0L 6" of lift 33" Super Swampers

-'83 Callaway 944 2.5L turbo, 300HP, 1 of 42 ever made

924RACR · Posted: Sun Jan 19, 2003 4:18 am Post subject:

Sure, check the wiring to the tach and coil, but I suspect your problem lies in the DITC. Scroll down and read up on my posts in there, I had a flaky DITC in my 82. I've also added a bit of info just recently in the Tech Section. I was able to successfully clean and repair it!
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Smoothie · Posted: Sun Jan 19, 2003 5:04 am Post subject:

Kevrl - This might be your lucky day. As horrible as the symptoms seem, the fix might be as easy as an unplug-replug. I had exactly your symptoms 1.5 years ago, but wasn't lucky enough to have it happen on my driveway - it was about 1AM a few miles from home and I had no idea what it was. Anyway the prob was with the rectangular 12 pin connector on the DITC box easily accessible from the left side on the center hump behind the radio. Just unplug that, look at it menacingly, give it a brushing with a toothbrush or small clean wirebrush, and plug it back in. This fix works like magic - and keep it in mind - I've had to do it again probably twice over the last 1.5 years, but it's that easy and can be done anywhere. Just unplug-replug. It's mentioned in the technical FAQ here and a few of us have had the prob.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

924RACR · Posted: Sun Jan 19, 2003 5:41 am Post subject:

I should mention, I also had a problem with a bad contact, but it was on the 3-pin flywheel pickup sensor, and it was due to corrosion. Finally cleaned it all off. That was also on the '82.

http://www.924.org/techsection/5ignition.htm
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

kevrl · Joined: 27 Nov 2002 Posts: 84

Thanks for your replies, Smoothie and 924RACR, in the morning, i'll take a look at the DITC box and check the connectors -great pics of the DITC in the tech section - thanks.

Azndrgn - No I don't have the pickups in the distributor, but I think the flywheel pickup performs the same functions, so i'll check that as well.

I'll let you know what happens, thanks again.

Kevin

kevrl · Joined: 27 Nov 2002 Posts: 84

Thankyou Thankyou Thankyou

It was exactly what you suggested, bad connector on the DITC with some corroded round pins. I cleaned it up and re-connected it all , and the engine started first try.

If any one else has this problem another tell tale sign as well as what is written in FAQ and Tech section, is that I could hear the coil sparking with the ignition in the position 1, but with the engine not turning. I guess the coil was sparking enough for 3000RPM, even though the engine wasn't turning.

Many thanks

Kevin

924RACR · Posted: Mon Jan 20, 2003 12:20 am Post subject:

Sweet!!! Gotta love those cheap fixes! I'll have to add your experiences to those tech pages....
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype