m20 woes

[SiGmA_X]

Updates?

[Edev]

i didnt think we had voltage at coil when car was off

I didn't. But he's saying with the KEY on, and engine off.

[Edev]

Got your PM. I don't think I'll be able to make it up there any time this weekend/week. I'm swamped with work 8-5, homework (taking 3 classes) and working on cars down here. I haven't even been able to touch my customers 325 yet, and the motor is already ready to get OBD1 swapped and dropped in.

The wire they are talking about goes around the #6 wire, but up by the distributor, as was stated above. I'm not entirely sure if your motor has it.

Is a 89 and 90 325i the same M20B25? I hope so. The following info is from the 89 325i ETM. (ETM PNW's the Bentley hard, IMO, but gives no text troubleshooting advise, you have to know what to do with it http://wedophones.com/Manuals/BMW/19...g%20Manual.pdf)

Questions:
- Do you have voltage at terminal 15 on the coil (2.5mm green wire), w/ the key on engine off?
- Do you have voltage at pin 18 on the DME, w/ the key on engine off?
- Do you have voltage at pin 27 on the DME, w/ the key on engine off?
- Do you have voltage at pin 37 on the DME, w/ the key on engine off?
- When cycling the key from off to run, do you have ground at pin #3 on the DME for something like 2 seconds? (Fuel pump relay ground)
- Do pins 2,14,19,24 all have very low resistance to ground (Under, say, 0.3ohm)
- Does your check engine light come on with the key in run, engine off?

If all the above check out... You most likely have a triggering issue. As I see if, providing the DME IS indeed turning on correctly, its a triggering issue or spark issue.


ONE thing to check/answer first. Do you have an onboard computer?? Apparently, there is an Onboard Computer Relay (see that ETM above, pg "1360-4" [aka page 36 in the PDF]). I can't say I have any idea where this relay is, but to see if it is the problem, providing you do NOT have power at t15 on the coil (green wire), I would check for voltage on the input from the ignition switch to the relay (1.5mm green wire) and if there is +12v there, and NOT at the 1.5mm green/red wire, I would jumper the relay, and see if the coil then has power, and if the car starts.

Questions:
- Do you have voltage at terminal 15 on the coil (2.5mm green wire), w/ the key on engine off?
-Yes.
- Do you have voltage at pin 18 on the DME, w/ the key on engine off?
-Yes.
- Do you have voltage at pin 27 on the DME, w/ the key on engine off?
-Yes.
- Do you have voltage at pin 37 on the DME, w/ the key on engine off?
-Yes. You have to use a jumper wire from pin 2 and 36 (as says so in the Bentley).
- When cycling the key from off to run, do you have ground at pin #3 on the DME for something like 2 seconds? (Fuel pump relay ground)
-Didn't have anyone to help crank it. But when I jump the main relay, the fuel pump turns on and injectors start firing.
- Do pins 2,14,19,24 all have very low resistance to ground (Under, say, 0.3ohm)
-Will go double check. Not sure how to figure out the ohm function. But all those numbers are the grounds on the ecu harness.
- Does your check engine light come on with the key in run, engine off?
-Don't have one.

I do have an OBC, but I'm getting voltage at the coil with the key on, engine off.

[SiGmA_X]

Got your PM. I don't think I'll be able to make it up there any time this weekend/week. I'm swamped with work 8-5, homework (taking 3 classes) and working on cars down here. I haven't even been able to touch my customers 325 yet, and the motor is already ready to get OBD1 swapped and dropped in.

The wire they are talking about goes around the #6 wire, but up by the distributor, as was stated above. I'm not entirely sure if your motor has it.

Is a 89 and 90 325i the same M20B25? I hope so. The following info is from the 89 325i ETM. (ETM PNW's the Bentley hard, IMO, but gives no text troubleshooting advise, you have to know what to do with it http://wedophones.com/Manuals/BMW/19...g%20Manual.pdf)

Questions:
- Do you have voltage at terminal 15 on the coil (2.5mm green wire), w/ the key on engine off?
- Do you have voltage at pin 18 on the DME, w/ the key on engine off?
- Do you have voltage at pin 27 on the DME, w/ the key on engine off?
- Do you have voltage at pin 37 on the DME, w/ the key on engine off?
- When cycling the key from off to run, do you have ground at pin #3 on the DME for something like 2 seconds? (Fuel pump relay ground)
- Do pins 2,14,19,24 all have very low resistance to ground (Under, say, 0.3ohm)
- Does your check engine light come on with the key in run, engine off?

If all the above check out... You most likely have a triggering issue. As I see if, providing the DME IS indeed turning on correctly, its a triggering issue or spark issue.


ONE thing to check/answer first. Do you have an onboard computer?? Apparently, there is an Onboard Computer Relay (see that ETM above, pg "1360-4" [aka page 36 in the PDF]). I can't say I have any idea where this relay is, but to see if it is the problem, providing you do NOT have power at t15 on the coil (green wire), I would check for voltage on the input from the ignition switch to the relay (1.5mm green wire) and if there is +12v there, and NOT at the 1.5mm green/red wire, I would jumper the relay, and see if the coil then has power, and if the car starts.

[Edev]

not really, we can check but daylight is easier, by cycl 6 huh?


i guess well see, what the hell is it for haha, but it getting nicked would make sense

yeah I never noticed it. It's so cold out, but soooomeone gotta do it! :D

[Edev]

god eric if its 1 wire! haha

Then I would be VERY VERY thankful! lol. But I don't really recall seeing a wire there..do you? I'm going to go check it out in a couple of minutes.

[Edev]

It is a small wire from #6 by the dist cap. It follows the same path as the CPS wire and connects right next to it by the port. Its about a mm from the front pulley and it easy for it to get frayed if the covers not in place.

K

And this info is for an m20b25, correct? I've had a few PM's of people trying to help (thanks :)) but giving me info on an m20b27 eta motor.

[Keith M]

It is a small wire from #6 by the dist cap. It follows the same path as the CPS wire and connects right next to it by the port. Its about a mm from the front pulley and it easy for it to get frayed if the covers not in place.

K

[Edev]

Have you looked at the (trigger wire??) It goes from #6 plug wire, snakes along the front of block and connects by the diagnostic port.

Keith

Never heard of the 'trigger wire' before. Not too sure what it looks like. Is that the cps? The CPS snakes along the front of the block and connects by the diagnostic port.

[Keith M]

Have you looked at the (trigger wire??) It goes from #6 plug wire, snakes along the front of block and connects by the diagnostic port.

Keith

[daniel]

one of my favorite songs ever.

[Edev]

You're hopeless. Most likely you'll end up finding bad resistance in the CPS. If I wasn't so damn busy with school, work, and projects here in Portland that I am being paid well to do and can't find time to work on, I'd come fix it for you.

I'll make a trouble chart instead:

1. Do you have a Bentley?
Yes -> 2
No -> Get a Bentley
2. Do you have a Multimeter?
Yes -> 3
No -> Get a Multimeter
3. Open the Bentley and find engine wiring troubleshooting (I hope this is the title.. Seeing as how I've never used an e30 Bentley for troubleshooting, I'm not really sure :p)
4. Follow instructions
5. Find bad component
6. Verify bad component
7. Are you forgetting anything?
Yes -> Go to 6.
No -> Go to 8.
8. Is component bad?
Yes -> Replace component
No -> Replace user


Basically, RTFM. This sounds like a really simple problem. If you already swapped DME's, and your coil runs another car just fine, there are not that many things that will prevent your M20 from having spark! Its a freaking M20 for pete sake! Its basically a tractor motor, very easy to diagnose and fix!

Also, what year/type is the car?

I've been using the Bentley for the past few days. Same with the multimeter. Speaking of those, I just came back inside from using both on the ecu harness.

Lol I know! But I not mechanically inclined at all (make jokes saying it's so easy a caveman can do it :D). But yeah, I'm just stumped. I'd like to try another CPS BUT no one has an extra or will let me borrow theirs. The motor is from a '90 325i. Oh, I have been reading the manual but no luck.

You can head over right now and I'll buy you coffee tonight, and then lunch whenever :D

[SiGmA_X]

You're hopeless. Most likely you'll end up finding bad resistance in the CPS. If I wasn't so damn busy with school, work, and projects here in Portland that I am being paid well to do and can't find time to work on, I'd come fix it for you.

I'll make a trouble chart instead:

1. Do you have a Bentley?
Yes -> 2
No -> Get a Bentley
2. Do you have a Multimeter?
Yes -> 3
No -> Get a Multimeter
3. Open the Bentley and find engine wiring troubleshooting (I hope this is the title.. Seeing as how I've never used an e30 Bentley for troubleshooting, I'm not really sure :p)
4. Follow instructions
5. Find bad component
6. Verify bad component
7. Are you forgetting anything?
Yes -> Go to 6.
No -> Go to 8.
8. Is component bad?
Yes -> Replace component
No -> Replace user


Basically, RTFM. This sounds like a really simple problem. If you already swapped DME's, and your coil runs another car just fine, there are not that many things that will prevent your M20 from having spark! Its a freaking M20 for pete sake! Its basically a tractor motor, very easy to diagnose and fix!

Also, what year/type is the car?

[Edev]

Yes, it's in the Bentley manual. You jump some pins, grond others, just get a couple pieces of wire and go down the chart. You can switch relays, run the fuel pumps, check resistances for the sensors, etc. The only thing i couldn't check was the complete operation of the O2 sensor, since it must be hot, and the car wouldn't run (obviously)

Okay, and if I do find an error with it..would I just have to get a new harness?

[whiltebeitel]

So I take the ECU off of the harness then I turn the key to the on position, right before you actually start the car. Then I take the multimeter and use it on the harness side of the ecu?

Yes, it's in the Bentley manual. You jump some pins, grond others, just get a couple pieces of wire and go down the chart. You can switch relays, run the fuel pumps, check resistances for the sensors, etc. The only thing i couldn't check was the complete operation of the O2 sensor, since it must be hot, and the car wouldn't run (obviously)