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Big Will

525iX won't start

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So I finally picked up my 1995 525iX touring about 3 weeks ago. The car is cosmetically in absolutely gorgeous shape with only 170K kms but had been off the road for the past 7 years as it was someone's project car in Germany. The dealer that was selling it had done some work (replacing fluids, spark plugs and exterior trim pieces, spraying on rust-proofing oil etc to keep it looking nice underneath).

I had it inspected by Dekra in The Netherlands and they spent half a day with the car, driving it etc. and gave me their 9 page report. It needed new fuel lines, new rear brake pads and ideally the front shocks replaced because a little rust had formed on the pistons - from cracks in the strut boots), and a new AC compressor. The dealer and I came to a fair agreement where they did all the labor and I supplied the parts. I took the opportunity to upgrade the front suspension to the "sport" struts and springs and all new hardware. The fuel lines were replaced, new fuel filter and some brackets etc., new rear pads and rotors and parking brake hardware, new AC compressor and drier.

 

After the work was done I went to pick up the car and began driving it back across Germany. What should have been a 5 or 6 hour trip turned into a 14 hour nightmare as the first time I stopped for a coffee the car wouldn't start! It cranked strongly but wouldn't get going. After a couple hours of trying on and off, it did until I had to stop for gas. I could hear the fuel pump priming and the battery seemed strong plus it had just driven over 200 kilometers so should have been charged up.

 

When I finally got to my city, I got a warning message on the dash of a "brake light electric failure - see owner's manual" (in German) and apparently didn't have brake lights anymore. This would come and go over the next two days until I got stuck at a gas station, absolutely couldn't start the car and had to have the car towed to a repair shop. We tried starter fluid before towing it and that did not work. The car spent over 2 weeks at an A.T.U. repair shop. They initially diagnosed it as a fuel pressure regulator noting that they were getting much too high fuel pressure and replaced that with a BMW part. The car still didn't start. I then supplied them with a new BMW fuel pump relay and Motronic relay and a new Hella branded CPS which was what I thought the problem was. No luck. The repair shop said they were finally able to "access the computer" and that the problem is the car's immobilizer and only BMW can fix this. As an additional detail, I noticed that when the car first wouldn't start, when I tried unlocking the car, the alarm would go off. During the couple days I had the car where it would sometimes start, I replaced the batteries in the remotes but was unable to pair them to the car. The procedure did not work. Of course I could still unlock the car manually with the key.

 

On Wednesday I had to have the car towed from this repair shop to the nearest BMW dealer. The dealer was given all the information as to what was done so far and spent yesterday trying to diagnose the problem. They claim to have their most experienced tech working on my car and so far he is stumped!

 

Any ideas for this mystery? Sorry for posting another "e34 no start" thread, but I thought this might be interesting. After 3 weeks I can't even register my car because it can't go through the inspection like this to get normal license plates.

 

UPDATE: BMW claims that the readings from the new Hella CPS are bad. They are going to replace it with a BMW sensor and see if it works. If not, they think it's the main computer...which I imagine is rather expensive.
I come from the Volvo enthusiast side and that's really not normally a problem. Is that common with e34s?

Edited by Big Will

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I think you need to go back to basics. When it will not start, do you have spark? Do you have the correct fuel pressure?  No disrespect to the garages but they may not have the older (ADS) diagnostic kit to check it out. BTW. Could you confirm if the car is auto or manual?

 

PS. Download the wiring diagram for your car from here. Have a feeling you are going to need it

http://www.wedophones.com/BMWManualsLead.htm

Edited by whiskychaser

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Thanks for the link to the wiring diagrams. Yes, I imagine I'm going to be needing those.

When I was stranded on my own I had no way of measuring fuel pressure but at the first garage they claimed it was too high leading them to replace the FPR. When that didn't get the car to start they asked me what to do next. Given that the starter fluid didn't get the car to start that lead me to believe fuel was not the issue but since the fuel pump and motronic relays are inexpensive we tried that.

 

As the CPS seems to be a common problem and isn't so expensive, we tried that next. If it turns out that the Hella CPS is defective and a Genuine BMW part fixes the issue, then I'll have learned my lesson. I was always under the impression that Hella carries OE quality parts?

 

The car has a manual gearbox :)

 

By the way, this is a great forum. I look forward to participating more once I get the car up and running.

 

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Not good that your garage is asking you how to fix the problem. If the engine were flooded, for example, adding extra fuel would make it impossible to start. Procedure for checking fuel pressure is in Bentleys and FWIW it is 51psi with engine stopped and fuel relay jumpered. That will go down to about 40 with the engine running as the FPR then comes into play.

A simple strobe will tell you whether you have spark or not. And removing a plug and finding it stinks or fuel is also a big clue. No disrespect but what you are doing is throwing bits at it in the hope of solving the problem.

 

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I appreciate that the same old questions get tiresome. This particular situation seemed like it could be more engaging given the difficulty it's given both an independent shop and BMW dealer. Whiskeychaser, you write as if I should have been the one grounding spark plugs to see if they spark and measuring fuel pressure while the car has been at two different shops. I had just bought the car. This began to happen at night on my drive from one country to another and the car would start eventually on that drive back hence why a 5 hour trip took 14. My tools are on another continent. It's not like I have a convenient place to work on it and the day after getting it to where I live, the car truly wouldn't start no matter what. I was sitting in front of a gas pump...there's a limit to what one can do when you're blocking a lane at a gas station.

 

I'm not throwing parts at it thank you very much. I didn't tell the first garage to replace the FPR, they did that on their own after apparently determining that the fuel pressure was too high. When that didn't work, they were stumped and called asking me what I wanted to do. I asked if they had checked the CPS knowing that it's a common no-start problem. They said they thought that was a possibility but had not. It seemed worth trying a new CPS before paying to have the car towed from their shop to BMW. When that didn't work, they told me they had "accessed the computer and it's an immobilizer problem" and only BMW can fix that. The car has a production date of 09/94 and my understanding is that it therefore has EWS I and if I understand the system correctly, if the immobilizer were causing a problem, the car wouldn't crank at all as the starter would not be engaged so to me, this explanation wouldn't make sense as the car cranks. But given that the car alarm and hazard lights go on when you try to unlock the car with the keys (manually not electronically) ever since the first time this happened on my back from picking up the car, I figured maybe there's something I don't understand about this anti-theft system. These details were all in the hopes that maybe someone on here has had something similar happen.

 

The car is at a BMW dealership. I would hope they know what they're doing and after what I understand was many hours worth of data collection and practically every technician they have contributing and baffled, they believe that the problem is indeed the CPS but that the new Hella unit is defective as it's reading out of spec. I wouldn't have expected a Hella part to be defective out of the box but I hope that's the problem.

 

 

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I think what whiskey chaser is alluding too is they are not desperately complex engines these days. 

 

A garage should be able to try some fairly basic checks to determine if it's a fuel or spark issue.

 

They do also have an obd port and software like carsoft can check for a fault code which would pin point a cps or similar failed component.

 

failing that a manual like Bentley gives ways to test components so some rudimentary old school checking should see you right. 

 

Suggest BMW themselves are not the ideal garage being as they where new 25years ago. Bet many techs have never worked on one. 

 

An independent used to older bmws or your own checks with forum guidance would be the way!

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That's fair.

You're probably right that a BMW dealer doesn't regularly see these older cars. I know of one independent BMW garage with a good reputation in Berlin but it's quite far away on the extreme western edge of the city and was way outside where I was able to get towed. My shop options were pretty limited initially. I'm also at the mercy of needing to get the car running so it can have and pass its HU/AU (inspection) in order to get properly registered.

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Will, as I said, no disrespect is intended.  Yes, we know it cranks but we don't know even know if you have spark. Yes, it could be an immobiliser issue but we don't know exactly what the fault code was or if any tests were done to confirm/locate the fault. If push comes to shove, you can always bypass the immobiliser. It could be the crank sensor. Equally, it could just be a dry joint on the DME or fuel pump relay. That would account for you being able to drive it a couple of hundred miles. But when you stop, you get heat soak - the contacts break and you can't start it again.  You will have to excuse my somewhat pedestrian approach. But accurately confirming the symptoms and checking each suspect methodically is the only way I know. It also helps if you have a laptop with DIS on it

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Hello from a fellow iX owner.

 

If it is an immobiliser problem, I would get the DME chip recoded and delete EWS rather than repair the EWS.

 

I would also try unplugging the alarm system, these aren't £40K cars anymore so you don't really need the protection (and problems) that they offer and you can still protect the car with a steering wheel lock.

 

Does the car have a double sunroof?  If so, look for water ingress problems as the sunroof channels block and water gets where it's not supposed to be causing no end of weird problems.

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Just another thought.. Had trouble starting my iX last week - similar to you i had driven without problems earlier in the day. The engine cranked over strongly but i could tell it was never going to catch. I was also getting spurious light failure messages on the dash. It turned out to be a loose bolt through the positive battery terminal resulting in a poor connection for one of the thinner diameter wires running off it. prodding the wire resulted in a switch or relay chattering, and once it had been tightened the engine started immediately.

 

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Hey thanks for all the additional tips and things to look into. I did indeed check for a loose battery cable initially though that would certainly be preferable to a failing DME for example!

It does indeed have the double-sunroof.

 

Hopefully I'll be able to report back today.

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The diagnosis is in:

After replacing the CPS with a Genuine part, the readings from the sensor were apparently in range but the car would not start. They did indeed check the EWS and confirmed that it was not preventing the car from starting. One of the technicians apparently has the same car and put his DME into my car and it fired right up.

So now I'm searching for a used DME pn: 12141427006
EDIT: It's an M3.3.1 unit (incorrectly wrote 3.1 earlier)

 

Edited by Big Will
correction

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Thank you! Yes I guess that happens with age :P

 

And the intermittent brake light failure warning is related to the previous owner's bad wiring job of an aftermarket trailer hitch which I'm guessing was poorly grounded.

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2 hours ago, Big Will said:

The diagnosis is in:

After replacing the CPS with a Genuine part, the readings from the sensor were apparently in range but the car would not start. They did indeed check the EWS and confirmed that it was not preventing the car from starting. One of the technicians apparently has the same car and put his DME into my car and it fired right up.

So now I'm searching for a used DME pn: 12141427006 which I gather is a Motronic 3.1 unit.

 

 

 

Sensible BMW tech - running a classic BMW rather than a modern BMW.  Couldn't do that repair to an E60 or later very easily

Edited by Dongiov

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Agreed :)

 

My other car (in the U.S.) is a 1998 Volvo V70 AWD and through 98 you can swap the Motronic 4.4 ECUs as you wish. 99+ goes to ME7 and its all coded to the car so it's only possible to swap ECUs with the help of someone with sophisticated software.

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3 hours ago, Big Will said:

The diagnosis is in:

After replacing the CPS with a Genuine part, the readings from the sensor were apparently in range but the car would not start. They did indeed check the EWS and confirmed that it was not preventing the car from starting. One of the technicians apparently has the same car and put his DME into my car and it fired right up.

So now I'm searching for a used DME pn: 12141427006 which I gather is a Motronic 3.1 unit.

 

 

 

Actually 12141427006  is a 3.3.1 Motronic Unit.

 

See the link below.

 

http://www.realoem.com/bmw/enUS/showparts?id=HJ82-EUR-12_1991_E34_BMW_525ix&diagId=12_1689#12141427006

 

I have here a 12141703563 which superceded to a 12141703724 which is listed in the link above.  It's from a Sept 93 build auto iX and should be minus EWS.  It should work in your car and also delete the EWS problem as it simply won't be looking for an EWS signal, please PM me your address and I can get a price for postage.

 

Cheers

 

Geoff

 

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