For the past few days now I've had a problem where my car ('92 745t) will turn over but won't start. Sometimes the car will have been sitting for an hour or two, and at other times 5 or 6 hours. It's been in the 90's here the last few days though.
I try and start it 2,3 or 4 times then one time on a whim I shifted it out of Park and then back and it worked, although sometimes this doesn't work and I'll shift it into Neutral and after a couple more tries it starts - so I don't know if the shifting is coincidence or is actually related.
Headgasket was replaced a few months ago, at the same time all the front seals and belts and plugs were replaced. Oil & filter were changed over the weekend. Air filter is clean, as are connecting tubes and air box etc. OD relay was resoldered a couple of weeks ago (to fix intermittent OD going off). A/C was just recharged but leak was found in condenser and all charge leaked out in a week (Converted to R134a many years ago)I finally found the noise/radio supression relay and resoldered that but that didn't correct the problem. I think I resoldered the FI relay when I replaced the RPM sensor back in March, but I'll check that again.

HELP ;(
any suggestions very much appreciated
Ian

Your car probably has an identical relay to the one you resoldered. It may or may not have been the supression relay you soldered. There is one like it for the electric fan on the radiator. Sometimes they are mounted side by side on the passenger shock tower, on our 91 745t there is one on the shock on the passenger's side and the other is on the driver's side shock tower. Try to locate the other relay and resolder it as well. At least then you will know to look somewhere else for your problem.

If resoldering both relays does not cure the problem you can try swapping they out for each other. Perhaps resoldering just didn't make the necessary changes to make the relay work as designed.

Randy

there is a relay in front of the battery, in a case labelled 'electric fan relay', I might try and swap them out, but I'm pretty sure I go the right one.

Ian

Of course you would only want to swap them out if they are the same part number as displayed on the case.

Randy

Interesting thing just happened that may or may not be related. Put my foot down on the highway and the transmission stepped down a gear but then refused to move back up when I lightened my foot pressure.
Didn't know if this might help anyone figure out what the heck is happening or not.

Ian

That sounds more like a kickdown cable hanging up in its enclosure. I don't think that would have any bearing on the no start situation.

Randy