1981 Euro e24 with Motronic 1.3 - No start. Spark present but no fuel pressure.

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Quietlion79
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Joined: Sat Nov 16, 2019 10:29 pm
Location: Los Angeles

1981 Euro e24 with Motronic 1.3 - No start. Spark present but no fuel pressure.

Post by Quietlion79 »

Hello, I have a 1981 Euro e24 with the Motronic 1.3 upgrade from a 1991 535i (Thanks Tom!). It was running beautifully (Drove it back from Denver, almost 1000 miles! I made a few small fixes, and also installed an adjustable fuel pressure regulator, which REALLY made a difference in power) up until a couple of weeks ago when I went to move it and it would not start.

Starting fluid test in the intake make it sputter, so I have spark.

I checked the fuse. Seemed fine, but I swapped it with another one. No change.

I checked the sending unit & strainer in the tank (No booster pump), looked very clean. Hoses were original, so I cut about an inch off of each, which eliminated the cracks. No change.

I swapped the orange relay with another relay. No change. Did not hear/feel the pump turn on.

I jumpered pin 30 and 87. The AC condenser fan turned on(?) No change. Did not hear/feel the pump turn on.

I pulled the passenger rear tire put a multimeter to the fuel pump power wires. While the engine was cranking, it appeared that I was getting 9.3V (?) at the pump. I replaced the pump and cut about an inch off the original hoses. No change.

I read that it might be the CPS. I located it, and attached a multimeter to it. Reads 527 ohms. I read somewhere else online that it should have a reading of 540 +/- 10%. Another site said 500-600. I also read that the CPS is most likely at fault if you do not have spark or fuel pressure. Should I go ahead? I can buy one for $60, but I don't want to just throw parts at this thing. I was thinking that perhaps there was a way to jumper the pins on the harness side of the connector, to fool the ECU into thinking the CPS was operative and happy, not a good idea?

I believe the Motronic 1.3 conversion setup was used to begin with.

I want to get this thing registered and on the road soon, and have amassed all the parts I need to do the CR 5 speed conversion, which would be a great time to do it, aside from the heat. I just need to be able to move the dang thing into a better position.

Any help would be appreciated.

Thanks!
1952 Austin Sheerline Limo
1960 Studebaker Lark
1963 Chrysler 300J
1963 Studebaker Avanti R2
1964 Jensen CV8 Mk2
1970 AMC Rebel Machine
1972 BMW Bavaria
1981 BMW Euro 635CSI
1989 Chrysler Conquest
2001 Honda Insight
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Ralph in Socal
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Re: 1981 Euro e24 with Motronic 1.3 - No start. Spark present but no fuel pressure.

Post by Ralph in Socal »

The CPS for Motronic 1.3 is the single unit at the front of the motor. I’ve not had much experience with those sensors and their fragility when compared to the bell housing sensors

I would think a bad sensor would cause no spark condition

No fuel would likely be fuse, relay or pump issue but seems you’ve already looked there

Replacing the hoses is recommended as the system is under 45 psi pressure. A leak in the large 12 mm pump inlet hose will cause no fuel as it will pull air instead of fuel from the tank

Verify the pump is actually running during cranking. 9.3V seems odd as it should be 12V

Good luck

Ralph
There is a very fine line between "Hobby" and Mental Illness.

85 635csi Zinno Auto
84 528i Euro
83 635 Euro Arktik
81 528i Kastanien 5-speed
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chimi-changa
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Location: MA USA

Re: 1981 Euro e24 with Motronic 1.3 - No start. Spark present but no fuel pressure.

Post by chimi-changa »

I just did a 1.3 deal on a Euro 635csi motor. Having spark is a good thing. Running a 3 bar FPR yes?

Pull the negative ground off the battery, on the fusebox pull the number one fuse out. Then jump that blade with the number four fuse (blue fuse)- carefully replace neg ground for power ( that fuse 4 is hot all the time) and you should hear the fuel pumps kicking in and hopefully fuel wooshing through the fuel rail.

Also that inboard blade on fuse 4 ( not spring) should have battery voltage with power hooked up

edit- Do you have another ECU to swap in and test?
Quietlion79
Posts: 45
Joined: Sat Nov 16, 2019 10:29 pm
Location: Los Angeles

Re: 1981 Euro e24 with Motronic 1.3 - No start. Spark present but no fuel pressure.

Post by Quietlion79 »

Thanks for the responses. Aaaaaand I went out to double-check the spark. Nothing now. No spark, no fuel pressure. Seems like things are pointing to the CPS. Will update when i find out more. I may also take a look at the ECU. The rubber baffle in the firewall is missing and perhaps with all the rain we've received, that the ECU got wet? But I tried to start it over a week after it stopped raining. Guess we'll see. I appreciate the responses.
1952 Austin Sheerline Limo
1960 Studebaker Lark
1963 Chrysler 300J
1963 Studebaker Avanti R2
1964 Jensen CV8 Mk2
1970 AMC Rebel Machine
1972 BMW Bavaria
1981 BMW Euro 635CSI
1989 Chrysler Conquest
2001 Honda Insight
chimi-changa
Posts: 10
Joined: Mon Apr 15, 2019 4:27 pm
Location: MA USA

Re: 1981 Euro e24 with Motronic 1.3 - No start. Spark present but no fuel pressure.

Post by chimi-changa »

Did you try jumping the fuse box for fuel pump activation, fuel sound wooshing in rail and check voltage at fuse 4 (non spring with fuse out) approx. 9.3 when cranking is bout what mine does. 12v when just connected

I doubt your CPS would just fail if it was running previously. But yes, it is the start of the ignition system and have to start there and rule out things down the line all the way to the plugs.

Are you running 3 bar Fuel pressure?

Do you know if you have a e34 m1.3 harness or maybe an e28 super Eta harness?

Check/confirm grounds.

179 Ecu? have another unit to swap in? ( they are inexpensive I just bought a spare for 40 shipped and it works) It is not the wire seal through the firewall.
Quietlion79
Posts: 45
Joined: Sat Nov 16, 2019 10:29 pm
Location: Los Angeles

Re: 1981 Euro e24 with Motronic 1.3 - No start. Spark present but no fuel pressure.

Post by Quietlion79 »

chimi-changa - Thanks for getting back to me. It is definitely a no spark & no fuel pressure situation. With this in mind, I got a good deal on a new Hella CPS ($35 + $5 shipping) and installed it. No change. I just pulled and checked the ECU to verify what number it is and it is indeed a 179. I will likely pick up a spare, as they are pretty inexpensive and swap it in. I am not sure which E28 wire harness it is, I will have to check the PO's build thread. I did try to jump the spade terminals but did not get any action at the pump. I will likely try your suggestions again just to make sure.

Appreciate your help!
1952 Austin Sheerline Limo
1960 Studebaker Lark
1963 Chrysler 300J
1963 Studebaker Avanti R2
1964 Jensen CV8 Mk2
1970 AMC Rebel Machine
1972 BMW Bavaria
1981 BMW Euro 635CSI
1989 Chrysler Conquest
2001 Honda Insight
chimi-changa
Posts: 10
Joined: Mon Apr 15, 2019 4:27 pm
Location: MA USA

Re: 1981 Euro e24 with Motronic 1.3 - No start. Spark present but no fuel pressure.

Post by chimi-changa »

You should hear the fuel pumps turning on jumping fuse 4 in the fuse box. From the sound of it, might be an ECU issue. I bought a spare for $40 and works great. Does your non spring clip on fuse 4 have voltage? ( with fuse pulled)

May want to also double check where the harness is grounded, my install would not spark until I switched ground location. This thread on the e28 board might be valuable also if you have not seen.

http://www.mye28.com/viewtopic.php?f=3&t=60306
Quietlion79
Posts: 45
Joined: Sat Nov 16, 2019 10:29 pm
Location: Los Angeles

Re: 1981 Euro e24 with Motronic 1.3 - No start. Spark present but no fuel pressure.

Post by Quietlion79 »

Just put in the spare 179 ECU that I bought. It was said to be good and cost me $40 as well. No change from what I can tell. I will try jumpering again as you suggested and check the grounds. Not much else except possibly a fault within the fuse box. I might unbolt that from the fender wall and take a look on the underside. The area around the fuse contacts for the AC is melted a bit, but it was like that when I bought the car. I don't think that is the issue.
1952 Austin Sheerline Limo
1960 Studebaker Lark
1963 Chrysler 300J
1963 Studebaker Avanti R2
1964 Jensen CV8 Mk2
1970 AMC Rebel Machine
1972 BMW Bavaria
1981 BMW Euro 635CSI
1989 Chrysler Conquest
2001 Honda Insight
Quietlion79
Posts: 45
Joined: Sat Nov 16, 2019 10:29 pm
Location: Los Angeles

Re: 1981 Euro e24 with Motronic 1.3 - No start. Spark present but no fuel pressure.

Post by Quietlion79 »

Well, it is running well again, with the exception of a surging issue in gear when the car is stopped and in gear that has been intermittently happening for awhile. I think it is airflow related because I noticed that occurring in a very minor way in Denver, but as I drove home and dropped in altitude, it became more pronounced. I took it out for a drive last night, seemed fine.

I tested and reseated the relays in the power distribution block for the 1.3 conversion and noticed that some of the wires that were cut in the 1.3 harness may have been making contact with the body of the car. I moved everything out of the way, but I will likely reroute the harness when I remove the brake booster to be rebuilt as I am doing the 5 speed conversion. After I did that, I turned the ignition on and heard a faint buzz from the ECU that wasn't there before. I was about to do the power test, but I guess I didn't need to.

Thanks for all the help and suggestions. Sorry I don't have a more comprehensive answer. I had the hose to the fuel rail off and it started pumping. A little at first, then the car started up and idled happily as it always did. But having a spare 179 computer is a good thing.

BTW, if anyone needs an 008 ECU, there is one near me that I can pick up and mail to you.
1952 Austin Sheerline Limo
1960 Studebaker Lark
1963 Chrysler 300J
1963 Studebaker Avanti R2
1964 Jensen CV8 Mk2
1970 AMC Rebel Machine
1972 BMW Bavaria
1981 BMW Euro 635CSI
1989 Chrysler Conquest
2001 Honda Insight
Quietlion79
Posts: 45
Joined: Sat Nov 16, 2019 10:29 pm
Location: Los Angeles

Re: 1981 Euro e24 with Motronic 1.3 - No start. Spark present but no fuel pressure.

Post by Quietlion79 »

Ok so it stopped running again, but I think I actually figured it out! There are two relays with the conversion, a Bosch 0332014112 relay for the fuel pump and Bosch 0332014415 for the ignition. I tapped the fuel pump relay and the car started up again. I shook it and there was something loose inside, so I ordered replacements for both. Lucked into a new pump relay for $13!
1952 Austin Sheerline Limo
1960 Studebaker Lark
1963 Chrysler 300J
1963 Studebaker Avanti R2
1964 Jensen CV8 Mk2
1970 AMC Rebel Machine
1972 BMW Bavaria
1981 BMW Euro 635CSI
1989 Chrysler Conquest
2001 Honda Insight
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tschultz
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Re: 1981 Euro e24 with Motronic 1.3 - No start. Spark present but no fuel pressure.

Post by tschultz »

Sorry to hear about the challenges, but I guess that might be expected for a car that was pretty much off the road for 3+ years and an owner who didn't seem to really know how to fix things themselves.

Any use from the car this summer? Any photo updates? [-o<
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