Maybe over my head. I hope not?

[acspecialists]

Hoping to get some solid ideas from someone. I bought a 89,000 mile 98' 740 that didn't run. Battery was dead and the DME was badly corroded. I repaired the DME and replaced some relays. It was running fine for a while but now it will not start, it cranks just fine. The fuel filter has been replace and I have verified that the fuel pump and air intake valve for the DSC is working. You can smell fuel at the tail pipe after a few attempts to start.

Here's what I have figured out from fourm searches and reading the Bentley manual. If there were a problem with the EWS it would not crank. If there were a problem with the crank sensor the injectors would not fire, the PO had them replaced. If the cam sensor was bad you could unplug it and the car should run. I have verified that the relay for the DME/spark plugs is working. All of the fuses have been pulled, cleaned and tested. At this point I'm going to check the DME pin out and make sure I did not miss something, the car was running so I don't have a ton of hope for this one. Next I'm going to check the grounds, thats the other half of the circuit. Then I'm just going to start poking around looking for a bad wire.

I have read many threads with people throwing parts and never really knowing what they are fixing, I hate that and it almost never works. Both the cam and crank sensors are Hall effect which can't be tested without an oscilloscope and are very robust. If anyone has an idea for something to look at in INPA while the car is cranking that would be a great next step.

[xboss]

Try another DME

[acspecialists]

That thought had crossed my mind. It's expensive due to the fact that it has to be virginized and coded to the EWS.

My daughter and I pulled some codes and did some more research online. We had some codes for the EWS so went went into the module and cleared the codes and copied the data. After that the car fired right up. After some further research we found that several people have had this problem. If the EWS is not happy with the key the engine should not even crank. Apparently the EWS 3.3 software which is an update with rolling codes works for a few weeks and then gets screwed up. Nice job BMW!

Anyone know how to update the software? I few people did this and it did not solve the problem but it may be worth a try if I can do it with INPA.

[Timm]

Start with the basics - check that you have a spark - do that by removing a coil-over-plug unit, stick a spare plug in it, reconnect the loom and rest the end of the plug on a metal part of the head and get someone to turn the ignition key and crank the engine.

Got a spark?

[Mayorchuck]

So the car is starting now? I know TxDarth hasd one that he constantly had to re-sync the DME/EWS. Not sure if he ever got it fixed or not.

[TxDarth]

So the car is starting now? I know TxDarth hasd one that he constantly had to re-sync the DME/EWS. Not sure if he ever got it fixed or not.

Several things - it was not constant, just after I installed the M5 cluster over the DUDMD tune. WE got that fixed long ago. You also stated that the car should run with the Cam sensors unplugged - not so. They are a source of failed starting many times - sometimes they will start but die shortly after - other times not start at all.

[Timm]

The M62 (not the M62TUB) runs fine without the camshaft sensor plugged in.....

[TxDarth]

The M62 (not the M62TUB) runs fine without the camshaft sensor plugged in.....

2000 740 should be a TU motor tho.....

[acspecialists]

Well I got it figured out and let me tell you I feel special. It is a EWS-DME problem. With the 3.3 version that has rolling codes it gets screwed up enough to not start but it will crank. According to Bentley's if the security system is active it should not even crank.

We hooked up INPA and went into the EWS module and there were several codes set. We cleared the codes and the car fired right up. I did some MORE! research online and I found several threads with people having the same problem. A few had tried to upgrade the EWS and did not fix the problem. I contacted DUDMD and he was very quick to respond and helpful. I asked about a EWS delete and he is not able to do it on a DME 5.1.2 which is what I have. He also said even the updated EWS has problems. The only thing that "might" work is to virginize a new DME and resync it with the EWS and keys. Because I have already butchered the current DME we might consider that option. The PO had the same problem for years, he would just leave the key on for five minutes and then the car would start. He failed to tell me that before I bought the car.

So for now my daughter will carry my laptop and if the car fails to start she can hook up INPA and reset the EWS. There is on guy who has been using this method for years.