Guys

Re 740 1991 wagon (Aussie specs) which stalled in hot weather:

Symptoms: stalled while driving in hot weather; felt like fuel pump failure or vapour lock; fuel pump working; power OK to spark plugs.

The friendly auto-electrician has fixed it. Cost for the part: $A 700!! (c. $US 400). The problem turned out to be the computer for the fuel injection system. For Oz spec vehicles, it is located behind the panel next to the accelerator pedal (RHD).

I asked to see the replacement part and he showed me an aluminium box about the size of a VHS video box with a 26(?) pin female connector at the base. Part number: Bosch Jetronic 0280 000 595. I asked if I could take it home and pull it apart to see what costs $700 and he said that he would need a deposit. I asked why and he said that the computer units are "on exchange".

Now that is quite interesting: for example, does that mean that Volvo/Bosch recycles these things and resells them as new? To be fair, I can understand why they might want to do that, if the problem might be a faulty chip/PNP transistor etc. which could easily be replaced by the factory. But surely the customers should be told that the part they are buying has been recycled? Has anyone else heard of this practice?

Thanks

CH

I just replaced a bad LH Jetronic fuel injection computer on one of my '86 240's. (I won't tell you what I paid. Bought it from a junk yard)

Inside it is a large printed circuit board. I imagine, like circuit boards in relays, a thing as simple as a broken solder joint could cause a failure. Likewise, a retouch of colder could solve it.

Mine was fried. It looked as if a meteroite had struck the top of it. Under the board, a large transistor was split in two, top to bottom. There was even an "exit wound" on the bottom of the board.

Looks like a couple of the circuit "lines" (whatever they are called) nearby the crater are also affected.

I believe I killed my unit while trying to ground the idle control valve (which disables it as part of a diagnostic test). Could be I grounded the Oxygen sensor instead -- which the manual says will kill the LH.

BTW, I have had to make several resistance and continuity tests at the pin connector to this computer. I don't see where it could go wrong, as one person said, causing problems like you had. Maybe if it was not re-coupled correctly.

Interestingly, the problem may NOT have been the ECU, but rather a poor connection at the ECU pin. Lots of techs fault isolate on an exception basis down to the ECU (if everything else is good, last stop is replace the ECU), replace it with a known good one/remanufactured, the car works, and the customer goes home lighter of wallet. Six months later the problem returns but the reman warranty is out and then they find a poor ground or bad connector.

Keep your receipt.

The ECU he put in your car was also a "reman" ECU because new would cost alot more money. Volvo and all other manufacturers exchange many parts like control units (etc,etc), it's a common practice these days. They rebuild the old problematic parts, finding the cause of it's failure and repairing it.

They're not then resold as "new", they're called "remans" and always far more reasonably priced than new.