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E34 (1989 - 1995)

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Old 04-22-2011, 08:36 PM
BMR_LVR's Avatar
BMR_LVR BMR_LVR is offline
Humble E34 lover
Location: Asheboro, NC
Join Date: Dec 2008
Posts: 5,464
Mein Auto: 1992 525i
EWS Delete / Bypass and no-start problem finally solved - VERY LONG read

Even though this relates to an E36, I’m posting it here because it has the same M50 engine and electrical system as the E34.

This is the story of a BMW lover’s journey through diagnosing and fixing a no-start situation. First of all, I want to express a sincere thanks to a fellow forum member, Roberto Baggio (aka RobertoBaggio20). I would have neither had the courage to do this nor would I have had the information necessary had it not been for Roberto. He found a link to a fellow that had information about bypassing the security system on the car. If I did not have this, I would not have been successful. So again, thanks Roberto.

My E36 would not start about 6 months or so ago. I was in no hurry to fix it as this is a spare car. I probably would have been done a lot sooner, but I had to have knee surgery in early December and that really slowed me down.

Now, on to the story. I have a 1995 325is with 236K miles. This has been a very good car and has only had about 4 no-start situations. The first was a failed fuel pump. This was before I joined the forum or knew anything about working on BMW’s. I had it towed to a mechanic. He diagnosed it and replaced the fuel pump for around $400. I had an old 85 Mercedes 300D that I was not a bit afraid to work on. I would adjust valves and service the transmission etc., but I was always intimidated about working on the BMW’s because (I’m almost embarrassed to say this) I could not even find the darn spark plugs! I know, it was silly, but all I would do at first is change the oil. Anyway, I found Bimmerfest and as the saying goes, the rest is history.

The second no-start situation was a bad fuel pump relay. By this time I had found out about the Bentley manual and was well on my way to becoming a much more savvy DIY’er. I removed the air filter and squirted a little starting fluid into the intake. It started for a couple of seconds, but would not respond to the throttle. I made a fused jumper with an on/off toggle switch per Bentley instructions and jumped the fuel pump relay socket and the car started and would run just fine. I replaced the fuel pump relay and all was well.

The third no-start situation was about 1 ½ years ago. At that time, I had followed my usual daily routine and turned the key to crank it, but I “stuffed it”, meaning I didn’t let it fully catch before I let go of the key. After that, it would not crank. The first thing I checked was the fuel pump relay, but that was not the problem. I went through the usual routine of checking things, but it just wouldn’t crank. I had no fault codes stored in the ECM. I messed with it for about an hour but it still would not crank. On the last try, it coughed a little and finally cranked. The frustrating part was, I never did figure out what caused it to not crank.

I continued to drive the car for another year with no problems. Then one day (a couple of days after a rather heavy snow fall), the wife got in the car and it wouldn’t crank. It would turn over, but it would not catch and run. So, I started the usual process of diagnosing it thinking that it would be an easy fix. I was so, so wrong. First, I checked to see if the fuel pump was working. I pulled the seat and confirmed that I had voltage at the connector. I plugged it back in and proceeded to remove the fuel pump relay and use my jumper that I had made per Bentley specs. Sure enough, the fuel pump purred like a kitten. So, while the fuel pump relay was jumped, I tried to crank the car. It still would not start. Now I was thinking that I may have an electrical problem. However, to try to rule out a fuel delivery problem, I got out my trusty can of starting fluid. Yes, I know, one should not use much when attempting to start the car. It still would not crank with the starting fluid. Now I realized that I had a no-spark situation. I had never dealt with this on a modern car. I started doing research on the forum and Google. Next, again wanting to do the easiest thing, I put in a new DME relay and a new fuel pump relay. Still it would not crank. I checked the relay sockets (once I learned how to pull them up to get to the bottom of them) and they all seemed fine and had no corrosion.

I remembered a problem about E36’s having a “wet DME” problem. So, I opened up the DME compartment, but it was dry as a bone. Next I suspected a failed crankshaft position sensor (CPS). I checked the resistance and it was about 500 ohms. Well, Bentley states on page 120-6 that it should be at 1280 + or – 10% (BTW, I found out later that it was a misprint in Bentley. It should have said 540 + or – 10%). So, I was way off or so I thought. I thought, okay, that must be it. I found a used one at a junk yard and bought it. When I got it home, it too was at about 500 ohms. I thought, great, now I have two bad CPS’s. But it just seemed to defy the odds that two CPS sensors would be bad. So, I tested the one on my E34. What do you know? It too was about 500 ohms. I thought, well, if I put the used one on it and it doesn’t crank, then I still can’t say for sure that the CPS is not the problem because I can’t be sure if the used one is good or not. So, I took the CPS off of my E34 (because I knew it was good since that car was running) and put it on the E36. It still would not crank. I put the original CPS back on and returned the borrowed CPS back on the E34 and it promptly fired up (remember this part for how it plays out later in the story).

Now I was becoming really frustrated and felt that I was reaching the limit of my knowledge and ability regarding diagnosing the problem. Just for kicks and giggles, I replaced the plugs. After all, they had (ahemm, clears throat) at minimum, 138K miles on them, but obviously they would not all fail at once. I decided to check the coils. They were getting proper voltage and had resistance within specs per the Bentley. But, I had no spark with trying to crank the car.

At this point, I basically narrowed the problem down to the DME. That’s usually not a big deal right? I mean, after all, you just go to a junk yard and get one or buy one on Craig’s List. So, I started my research. Well, I was not too happy on what I was finding. You see, the 1995 325 is a unique car in that it is the first year that BMW put the EWS II security system on the car. This is a system whereby there is a very small chip in the ignition key. There is a EWS antenna ring around the ignition tumbler. The DME is paired with the key and the EWS module. When the proper key is inserted, the antenna receives the signal from the key chip, it is sent to a unit that amplifies the signal. That signal is read by the EWS module which communicates with the DME and gives the go ahead to allow the car to crank. If the incorrect key is used, then, when the key is turned, all of the gauges and such will come on, but the engine will not turn over. This was confirmed when a while back, I had the very early stages of the dreaded “key spin”. I tackled it as soon as I had the first signs of it so it was not bad to do. Anyway, I replaced my ignition tumbler and forgot to install the antenna ring. I tried to start the car and nothing. I just about left a big brown spot in my underwear until I realized that I forgot to re-install the antenna ring. Once I did, the car cranked fine. Whew!

Now, back to the story. The DME that is in my car is what is called a “silver label” DME. It is specifically for the EWS II car. So in researching, I found out that my options were pretty limited and the cost of repair was going to be quite a bit. A re-manufactured silver label DME was going to be almost $1200 from the dealer and on top of that, I would have to have the car towed to the dealer to have the new DME “re-coded” or “re-synched” to my specific car. Needless to say, I did not want to chunk down this kind of money on a 15 year old car with 236K miles. So I also looked into having mine re-built. I came across these guys at bmwdme.com. They will test the DME for $50. If there is no problem with it, they send it back to you after you pay the $50. If it is bad (assuming it is not massive damage from a fire, drowning or severe electrical shorting), they will repair it for $475. This was certainly better than the approximate $1300-$1400 it would cost with a remanufactured one (taking in to account the tow and labor at the BMW dealership for re-synching it).

Here is where Roberto really came in to the picture. He was kind enough to research this problem for me (without me asking him to do so BTW). He came across this fellow’s blog. His name is Richard. Here is the link: http://qcwo.com/technicaldomain/ews-deletion-chip. He communicated back with Roberto and advised that a standard “red label” 413 DME (for the 1992-1994 M50) would work if the EWS system is bypassed. Roberto forwarded the information to me. I started my search for a red label DME. I am located right between two gold mines in the form of Pull-A-Part junkyards. There prices are unbelievable. A DME would cost about $30. Only problem is, people know this and the on of the very first things that gets snagged is the DME. So I constantly searched for a red label DME. One day they put a VANOS M50 E34 on the lot. I got there the very same day, but the DME was gone. I also searched Craig’s List. I finally found one from a 93 325i and got it for $60.

I had to remove the glove box to access the EWS module. Bentley leaves out one important information about a bolt that holds the glove box assembly in the car. It is a 10 mm bolt that is located above the glove box light. Pop the light out and you have easy access to it. Locating the EWS module was the next challenge as there are several modules in there. The instructions given were to cut wire #4 (green) and then cut and bridge wires #1 and #3. The wires are not labeled this way so it was a challenge to figure this out as well. With the assistance of the wiring diagram in the Bentley manual, I was able to determine which module it was (it was the module in the lowest bracket with a yellow connector) and locate which wire to cut (the green #4 wire is the very small, solid colored wire), and which wires to cut and bridge (#1 is black/yellow and #3 is green/black).

I consider myself an electrical moron, so I have to tell you, I was scared to start cutting and bridging wires. So, I cut the green wire #4 and capped off each end. I then cut wire #1 and #3 at the EWS module and spliced them together. I put the red label DME in the car. I turned the key and the dashboard lit up as usual, but the engine would not turn over. Remember me mentioning how the EWS was activated when I forgot to put the antenna ring back on the ignition tumbler when I replaced it? Well, I knew that the EWS was being activated because it was the exact same scenario. So, I also spliced wires #1 and #3 on the DME side as well. Again I tried to crank the car. This time the engine would turn over, but it still had no spark and would not crank. Now I was really ticked off and thinking that I had no chance of fixing this thing. So, I just put the wiring back to as it was from the factory and I put the silver label DME back in it with the intention of having it towed to my mechanic.

By chance, I thought I would get a used camshaft position sensor and replace it, but to my understanding, a bad camshaft position sensor will not cause a no-start situation, but can cause the car to run poorly. So, off I went to the Pull-A-Part and found an M50 that had had the intake removed, so it was a breeze to pull it. Due to weather and issues with my knee, I didn’t work on the car for a couple of weeks. The other day it was nice out and my wife was doing some things and I commented to her that I had just decided to have it towed to my mechanic. My fear is that he would spend a couple of hours (at $80/hr.) just to diagnose it and he may well say it had a bad DME. So I would then have to send the DME off for a $475 repair. As I told her this, she said “what about that wire you bought?” I asked “what wire?” She said “you know, the one you bought at the junk yard the other weekend.” I was like “oh yeah, the camshaft position sensor I pulled at the Pull-A-Part”. So, I opened the hood and began trying to figure out how I was going to get the VANOS off so I could remove the sensor. As I looked around, I saw an electrical connector under the intake manifold that was not connected.

I traced it and found that it was the connector for the CPS. Remember earlier in the story when I took the CPS off of my E34 and put it on the E36 and it still would not crank? Earlier when I was swopping the CPS from my E34 to the E36 and it didn’t work, I proceed to take the CPS back off and put it back on the E34. I bolted the original E36 CPS back on the front of the engine at the toothed wheel. Well guess what, I didn’t re-connect the sensor (doh). I was like, “well crap, that explains why it wouldn’t crank with the red label DME”. Just for kicks and giggles, I re-connected it and tried to crank the car with everything stock (silver label and stock EWS wiring set up). But just as expected, it would not crank and seemed to have no spark. So, I proceeded to do the red label DME swap again. I put it back in and re-did the EWS delete wiring bypass.

I tried to crank it again. It would not crank, but sounded like it wanted to. So I tried a one second squirt of the starting fluid in the intake at the MAF. I tried again and still no start, but it sounded like it wanted to crank even more. So, what the heck, if one second is good, two seconds should be better right? So, I gave a good two second squirt and tried again.

It did not crank up immediately, but just like something winding up, IT FINALLY CAUGHT !!!!. It ran rough for a couple of seconds, then smoothed right out. I didn’t let it run long because I had not yet filled and bled the coolant system. I shut it off and waited about 5 minutes. I tried it again and it cranked up immediately. So in the end, it was the DME that was bad and the red label DME swap into an EWS II equipped car does indeed work. After about 6 months, the lifters were noisy on start up. This was due to leak down of the lifters over time. Also, the VANOS was rather noisy. After bleeding the coolant system and making sure everything was okay, I took it out for a short ride (7-8 miles) without revving beyond 2500 PRM. By this time the lifters had pumped back up and the VANOS quieted down.

Here are some morals of the story that I learned:

If you have the desire, persistence, a good repair manual, some decent tools and some basic mechanical skills, you can do most anything on the BMW’s (well, at least the older models like E36, E34 and earlier). Realize however that you may have limitations on your abilities. I’m not at the point that I would feel comfortable doing and R&R on a head gasket or head. Sometimes you just have to take it to a mechanic.

Don’t be afraid to ask for help from other BMW owners who may have experienced the same problem. Listen to their input. This forum has some of the nicest and most knowledgeable people around.

Be willing to do research on the problem. Remember, Google is your friend. Search it and search this forum as a lot of the problems have been experienced before.

Don’t just throw parts at a problem. Try to be methodical in your approach. Think things through thoroughly. If you get stumped or frustrated, take a step away from the vehicle (sounds like you’re being arrested lol) and take a break. Take time to “re-charge” your batteries so to speak. Sometimes during that break a moment of clarity will come that will point you to the problem.

Always double check your work. Had I realized that I failed to re-connect the electrical connection side of the CPS, I would have had the car running a couple of weeks sooner.

I hope this long winded dissertation has or will help someone who faces a no-start situation.

Best regards,
Most problems are usually something simple !

Originally Posted by noego View Post
It's Deja Poo - as in, I've heard this **** before.

Calypso Red 1992 525i with 225K miles

1991 735i - Sold
1992 525i - Sold
1995 325is - Sold
2000 528i - Sold

Last edited by BMR_LVR; 04-23-2011 at 06:52 AM.
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