90 325i Cranks Forever, No Fuel, No Spark

[zavakos325i]

Hi guys, I'm new to the forums today and have a bit of an issue with my 325i.

In January, I bought a 1990 325i from a Goodwill Auto Auction. I am friends with the mechanic that works for that auction and he told me the engine was great and he had driven it already. Well, come auction time, when they went to start it, the battery was dead so they used their portable jumper. Crank, but no fire. So I got a decent deal on it ($800). The reason (I believe) that it hasn't started has something to do with the car dealers that come to the auction and mess with small undetectable (to non-experts, i.e. me) things to make the car not start so fewer people bid on it.

The car has not run since I bought it and it's driving me insane because I know it has to be a relay/wiring issue somewhere since it cranks but there's no spark from the plugs and the fuel pump does not kick on.

I have replaced numerous fuses/relays with no results so far. But one interesting bit I did find was that the Fuel Pump Relay and the Main Relay (DME Relay) were swapped. The Main (5 Prong) was in the FPR spot and the FPR was in the Main's spot. I swapped them back but no luck.

If this is the issue, which one is most likely to be fried and what are the specs on the relays so that I can get replacements at Advance O-ReillyZone (they're all the same)?

I have a multimeter from radio shack and was wondering how to test power "at the pump". Do I hook up the tester prongs to the two connectors towards the back of the pump (I'm assuming since there are only two connectors, one's positive and one's negative)?

Any suggestions would be GREATLY appreciated,

Thanks guys, hope to hear from you soon,

Zac

[zavakos325i]

Update: Just went on Pelican Parts to look at their relays and their Fuel pump relay is a tall black relay with 7 prongs. The one that was "Switched" with the main relay was only a 4 prong and from what I can tell, there are only 4 wires in the FPR socket to connect to. So I'm curious as to what this large relay is.

[Evan12]

mine used to crank for a while before it started...id just replace the relay..sparks. wires. if it still cranks try your injectors, mine was the same way but it tooke a while before it truned over, once i replaced the injectors it was perfect.

[jlevie]

The main relay on this car will be a 5 prong and the fuel pump relay will have 4 prongs. Since the relay sockets clip into the holder, you can't necessarily go by position as prior work on the car may have them in other than the OE position. The wiring diagrams from http://wedophones.com/BMWManualsLead.htm can be used to determine which socket should have which relay.

No spark and no fuel could be:

No START signal to the DME
No power to the DME
No timing data to the DME
Bad DME
Bad engine harness

[zavakos325i]

@jlevie: The relays were definitely swapped, the socket for the main relay has 5 wires running into it, fuel pump 4. I've replaced all fuses in the fuse box, I've tried jumping the 30/87 pins in the fuel pump relay socket and nothing gets power to the pump. How can I test/check off the things you listed as possibilities? I have a multimeter, and I have already tried a different (functional) DME and it had no effect.

The lot mechanic I bought the car from said the car ran like a horse the day he tested it when the PO brought it to the lot, and since some of the unscrupulous local used car dealers like to come to the Goodwill Auto Auctions and manipulate the vehicles so that they won't start, try to get them for cheap, then undo their "fixes" and sell it, what would be a quick, discrete way of disabling the car, so that I can undo their fix and actually drive my car?

Thanks guys

[gorilla]

crankshaft sensor sounds like to me

[nrubenstein]

Yes. I would try a known good crank position sensor before tearing my hair out with anything else.

[zavakos325i]

Ive tried the CPS swap as well with no results. And would that prevent the power to the fuel pump?

[zavakos325i]

I've been looking over the Bentley manuals and came across a few things I am unfamiliar with:

On-Board Computer Module
On-Board Computer Relay-Box

Also there was mention of some Code of some sort? Can anyone tell me where to locate these items? Thanks

[billybobjoseph]

There is a 50 amp fusible link about a foot from the battery on the smaller of the two positive ( black ) cables. It looks like a flat spot in the cable with a rubber cover on it. If it is blown you would have the problems you describe here.

[zavakos325i]

Thanks billy, much appreciated. Ill take a look tomorrow.

Someone mentioned a bad chassis ground.

Any thoughts anyone?

Thanks again

[Lrutts]

There is a 50 amp fusible link about a foot from the battery on the smaller of the two positive ( black ) cables. It looks like a flat spot in the cable with a rubber cover on it. If it is blown you would have the problems you describe here.

I had this blow on me once, but it resulted in no crank at all. No power to the engine at all.

[Cyrix2k]

jump the main relay & fp relay and see if the fuel pump kicks on... I bought my car not running and the only thing wrong was the main relay!

[billybobjoseph]

By the way I re-read your first post. On these cars the main relay and fuel pump relay are sometimes in different positions from the manufacturer. Mine are backwards from what the Hayne's manual says but according to the Bentley manual you have to see what color the wires are below it to make sure. When I get home I'll look up what colors pertain to this. Also, jump starting these things can cause all kinds of gremlins if you don't turn on the headlights and the blower motor to ease some of the current.

[billybobjoseph]

Well the Bentley manual says the main relay has 4 large ( 4mm ) wires to it and that's how you tell the difference between it and the FPR.