dbarclay

'87 951, runs great until 20-30 minutes of driving on a warm day. Will suddenly begin to sputter, backfire. Can throttle through it for a short while, until it stalls. During which the tach jumps up and down. If it stalls, will not restart until it has sat a hour or so. Sometimes fails to restart after periods of trouble-free driving.
Have replaced TPS, plugs, wires, coil,reference sensor, DME relay and DME brain. Where from here? Where does the coil signal come from? KLR? Thank You

Rob

The coil signal comes from the DME. You might want to check it for bad solder joints. Check out this thread:

<a href="http://forums.rennlist.com/scripts/rennforums/ultimatebb.cgi?ubb=get_topic&f=15&t=000777" target="_blank">DME thread</a>

they talk about replacing the transistor that drives the coil signal.

Rob

dbarclay

[quote]Originally posted by Rob:
<strong>The coil signal comes from the DME. You might want to check it for bad solder joints. Check out this thread:

<a href="http://forums.rennlist.com/scripts/rennforums/ultimatebb.cgi?ubb=get_topic&f=15&t=000777" target="_blank">DME thread</a>

they talk about replacing the transistor that drives the coil signal.

Rob</strong><hr></blockquote>

Thanks for the reference, Rob. I'm going to follow those instructions. I still have my original DME. Do you think it is possible for the driver or its connections to cause an intermittent symptom? Most of the time I hear that they're working or not, no in between. Other than the reference sensor, TPS, etc, what are the other inputs for the ignition signal? Temp sensor in the Air Flow Meter? I appreciate your help.

Rob

I wouldn't think that the driver itself would cause an intermittent problem, but I do think bad solder joints could, especially with changing temperatures. After re-reading your first post I realize that you have replaced the DME so it's doubtfull that both had this problem. The KLR can also cause no start condition/no ignition condition. I have read that in factory manual is written that you can unplug KLR unit and bridge 9 and 16 terminals for test purposes and in emergency. The car will run at reduced power. Are you sure it is ignition? If not, have you checked your AFM and its connector? I've also heard that too much fuel pressure can also cause a no start that can be checked by unplugging one of the injectors.

Rob

dbarclay

Fuel pressure is right on. I know I'm missing spark when this happens-I had an hour on the side of the road with it one night.
I'm going to check my original DME, just in case I have 2 bad units. I may also try the KLR test. Where can I find a PIN diagram (to find the 9 and 16 terminals), or can you tell me which way they count.
Temperature is a big factor. Bought the car in late October, obviously didn't test drive it long enough. Weather in the 70's , 30 minutes after picking it up it started this #@!#!
When it got cold in November- first week of January, it didn't cut out at all in around town driving. (didn't take it on a long trip)
Last week, the temps shot up to the 70's and guess what, it started again.

Rob

I'll e-mail you the pinouts for the KLR connector.

Rob