1990 740 turbo wagon, transported up from Palm Beach, FL, in april, has
run flawlessly, until our first sub-freezing NJ morning,cranks over at
approximately the normal speed, per theForum/archives i found a tear and
a hole in the turbo inlet hose, $160 later,replaced it, and no change,
replaced the fuel filter, old one had a fine, black sediment/powder in
it, still cranking, no-start, no sputter, cough anything, does not
seem to be getting spark at the plug, seems to have continuous, uninterupted
12v at both coil terminals,pulled upper timing belt cover off to verify
operation,replaced cap,rotor,wires and plugs, no change.
Alldata says there were cold start Technical Service Bulletins for '90 740T's
and a Dealer Recall/Eprom Replacement Program................
getting frustrated,my electrical diagnostic capabilities end at the test
light/voltmeter level, not fluent in ohms/amps.
hate to give in to my own shortcomings, and tow it in to the dealer,but it's
been 2 weeks, and i don't know what to check from here, pretty intimidated
by the electronics, my Rabbits and 320i's don't have that much, and apparently
my comprehension ends with '80's technology!

Don't replace anymore parts until you know more about the cause of your no start. In replacing parts you may create an additional problem to really confuse the issue.

If cam is turning your problem is no spark or now no fuel.

Your comment about spark is vague. First and always first check for spark at the plugs. You must have spark to start. If spark is present at plugs then check operation of the fuel pumps. There is much info on how to do this in the 700/900 FAQ section.

The electronics in your car are not complex and in fact make it easier to diagnose. Have you checked for error codes in the on board diagnostics?

Depending if your have spark or not some posssible causes.
No spark: crank position sensor, power stage.
Spark but no fuel: Fuel pump relay
Post back your findings after you know about spark.
--
David Hunter

or a defective coil? they can go in strange and unpredicatable ways...

I have a basic question....

if you take a plug out, reconect to HT lead and hold against he block with insulated pliers do you get a spark at all 4 plugs this way...

if the answers no...then its electrical, if the answers yes then its (probably) fuel related!

if its electrical (as you seem to suggest) and your getting juice to the coil then its either:-

sensor, distributor, coil, ignition module, ht leads, distributor cap or spark plugs...


see the faq...

if you get fed up and its definately not sparking call an autoelectrician...thats what a shop will do anyway so save yourself some money and get one in yourself...

basically juest remember:-

air+petrol+spark (at the right time!) +enclosed space = working engine

so which one are you missing....