Author Topic: 1995 318i Cranks But Won't Start (Read 3575 times)

Harsh · « **on:** April 29, 2020, 12:00:22 PM »

I am helping my neighbor troubleshoot his '95 318i with a standard transmission. He replaced the motor due to a valve chain guide breaking. He installed a rebuilt M42 engine. The car did start and run with the new engine and from what I have been told it ran very well. It started and ran numerous times while in the garage and on jack stands. He took it off the jack stands, restarted it, and drove it just outside of the garage where he left it idling. I am not sure how long he left it idling, but he said after a little bit it started to spit, sputter, and backfire then shut off. After that it would not restart. He is an old school engine builder and not an electrical guy so he has been throwing parts at it. Which is where I come in. I have been an electronics technician for the past 30 years and have built and repaired a number of engines in my days.

Before I got involved the owner had replaced the fuel pump, fuel pump relay, and DME relay. I have also tested the oxygen sensor relay and it is good. All of the fuses test good. The owner stated he had 200 psi of compression across the board. I am sure each cylinder wasn't exactly 200, but I am willing to say they are close.

The cam and crank position sensors, fuel filter, idle air control, throttle position sensor, coil pack, battery, ignition switch, starter, ignition switch, plug wires, and plugs are all new.

The coils all measured .6 ohms, which is in the middle of what they should measure. The plug wires were (1-4 respectively) 5.4K, 5.3K, 4.7K, 5.4K ohms. Number three is a bit lower, but It should be fine.

I checked for spark on each plug by pulling them, grounding the body, and looking for spark when cranking. Each plug has spark.

The crank sensor reads 542 ohms and the cam sensor reads 1326 ohms. Both are within the � 10% margin.

Fuel pressure is 48psi when cranking.

I back probed the injectors and they are receiving pulsed signals from the DME. They are also receiving correct power. Pulled the intake manifold to pull the fuel rail. With the fuel rail removed I jumped the fuel relay to make sure I had flow to the rail. That would confirm there isn't a pinch or blockage from the pump to the fuel rail. Good to go. With the fuel rail pulled and fuel lines extended and reconnected I placed a large pail under the injectors and cranked the engine. The injectors pumped fuel in what looked to me a nice strong ^ pattern. The return line had plenty of fuel coming out of it as well.

Blew air into the return line to the tank to make sure there isn't a blockage there. All good.

Cleared the cylinders by removing the plugs, putting a little bit of oil in each cylinder, pulled the fuel pump fuse, cranked the engine for 15 seconds.

Opened the DME and found a little bit of corrosion. Cleaned that up and with a magnifying glass looked at every solder joint for cracks or bad connections. None found.

Before I got involved the owner hooked up an OBD1 scan tool, but it did not pull any codes. I performed the stomp test, but I can't even get it to go into the initial routine. The CEL just stays solidly illuminated.

I did some reading on DME's and the EWS systems. This car was manufactured in Jan 95. However, it does not have the ESW II system. The VIN on the DME matches the vehicle VIN plates. FWIW the DME has the maroon sticker on it.

All of the fuel has been drained from the tank. I even pulled the fuel pump and manually removed what little fuel was left in the bottom and the plastic cup that surrounds the fuel pump filter. 5 gallons of new fuel was added. Hooked up an extension on the output of the fuel rail and jumped the fuel pump really to push any old fuel out of the lines.

Checked the air flow meter and I have correct voltage going to it. I also have a varying resistance as I manually operate the door. When trying to start the car you can see the door open when the car chugs occasionally like it wants to start.

When we try to start the car it just cranks over. Every now and again it chugs a bit and will run for maybe a second before it stops. About the only thing left I can think of is that the DME is bad.

Tried spraying with starter fluid. It doesn't change much in how the engine tries to start.

I am leaning towards the DME being bad, but fully understand it could be something else. If anyone has any suggestions I am all ears. If you happen to be in the Hampton Roads area of Virginia and can lend a hand or have a DME we can swap in to see if the car will start even better.

Pics of the corrosion in the DME.

Videos of car trying to start

https://www.youtube.com/watch?v=WdBm_6h20qo&feature=youtu.be&fbclid=IwAR05zt--9KDTBuDZEmnrJ6Smktk7Vbr-OGybamjgw2Jlz3lsRU7HU5eyf5s

https://www.youtube.com/watch?v=jCSjVsjHrMY&feature=youtu.be&fbclid=IwAR0e7xE_TsklygngYT4vgiD8wIDNmlu6noLobDUKqNB6mMD3fSzF-F4Vhh8

https://www.youtube.com/watch?v=otZl48iXqfY&feature=youtu.be&fbclid=IwAR0mGsUy7_m9ED70VM5wUOYKKHGGwrMZXpKDeEucaKnMaf2GOt8PZPV_Wus

DesktopDave · « **Reply #1 on:** April 30, 2020, 10:15:47 AM »

Wow, that's quite the first post! You've comprehensively covered everything that could go wrong with the car, it seems. It's unusual that the car ran so well until it idled for a while.

The corrosion does seem a bit worrisome. Did he take apart the wiring connector to verify that it's clean internally? The E36 had problems with a drainage tube on the firewall, we've seen a lot of them that were damaged by car washes or heavy rains.

The one thing that stands out to me is the CEL not turning off. That indicates a dead DME from what I've heard. Replacements are cheap on eBay; I believe they are differently coded for manual and automatic transmissions. If the vendor isn't sure, it's easy enough to verify with the VIN.

I have a couple dead E30 M42 DMEs, LOL. No good ones except a silver-label 282 EWS unit.

Harsh · « **Reply #2 on:** April 30, 2020, 12:32:07 PM »

Thanks...I have been pecking away at this for a while.

I have not taken apart the backshell of the connector, but certainly can give it a look and see what that entails.

The CEL staying on is part of what has me leaning that way. As well as the code reader not pulling anything or really communicate.

The DME is coded for a manual or automatic trans. If you look at the sticker in the lower left hand corner. The middle row of info dictates manual or auto. 801E is for manual and 821E is for automatics.

The owner supposedly has a DME being shipped to him from someone he knows. It has been a couple of weeks now so I am beginning to think it isn't going to show up.

I still really want to check the timing, but the owner is dead set against it. Why I don't know. The entire process would take maybe an hour and would rule that out as a reason why the car won't start.

DesktopDave · « **Reply #3 on:** April 30, 2020, 01:24:27 PM »

I'm with you on the DME, but it wouldn't hurt to check static timing.

The Motronic connector shell is easy to take apart, usually just a clamshell with some pozdrive screws. I'd be looking for corrosion due to water intrusion, perhaps a burned wire or two. According to the late '95 ETM, the CEL is powered with a green wire from DME pin 8. That's different than earlier versions, when the DME grounds a gray or gray/red wire.

You can get all the ETMs here.

There are two other relatively uncommon timing-related problems you can check for. First off, check that the crank pulley assembly is solid. The crank wheel is also a two-piece vibration damper, cast together with rubber. The rubber fails, wheel gets unbalanced, CAS can't read the crank angle. We've had more than one of those failures here, they're getting more likely as time goes by. I'd rate it as unlikely but not impossible.

The second timing problem is only with the earlier M42 engines, like pre-'93, largely E30 chassis. I'm not sure what version he's swapped into the car. They have an idler wheel instead of a cam chain deflector; the wheel has a bearing that can fail. BMW updated the chain tensioner to fix that problem. I'd personally avoid doing that with a high-mileage M42 unless you rebuild the entire cam chain assembly...the updated tensioner tends to blow out the bearing or even breaks the idler wheel mount right out of the cam chain rear casting. It's similar to the Porsche IMS problem, now that I'm thinking about it.

Harsh · « **Reply #4 on:** April 30, 2020, 01:44:19 PM »

Thanks for the info. I have the ETM and the Bentley manual.

I completely forgot that I checked the crank pully and balancer. They looked good, but I swapped them with the set that was on the original bad engine. It made no difference.

I am fairly certain that the replacement engine was the exact same as the one he took out, but I am not sure how to check to tell. I am fairly certain that the mount is what broke on the bad engine. Looking at the block there is a chunk missing near the left hand side where the chain runs.

Harsh · « **Reply #5 on:** May 03, 2020, 06:05:52 PM »

WE HAVE A RUNNING CAR!!!!

The guy finally came through with a DME to swap in. As soon as we plugged it in, cranked the car, it came to life and ran smooth as butter.

He said the DME we had was for a 6 cylinder. I question that. The VIN that is on the computer matches the cars VIN. Decoding the VIN it shows to be a 4 cylinder car so I don't understand how it could have changed. Regardless, the car runs so it really doesn't matter to me.

Thank you everyone for your assistance.

Pic of the DME that works.

Author Topic: 1995 318i Cranks But Won't Start (Read 3575 times)

Harsh

1995 318i Cranks But Won't Start

DesktopDave

Re: 1995 318i Cranks But Won't Start

Harsh

Re: 1995 318i Cranks But Won't Start

DesktopDave

Re: 1995 318i Cranks But Won't Start

Harsh

Re: 1995 318i Cranks But Won't Start

Harsh

Re: 1995 318i Cranks But Won't Start