‘87 3.2 no start - no fuel & ignition

[PeterM]

Never had any start issues in my 13 years ownership, but now it is completely dead :

Starter turns fine

Not a single pop from the engine

Changed the DME relay, still the same

No ignition and plugs completely dry, so no fuel either

Suspect the immobilizer, so bypassed it with the emergency code : still the same

Any suggestions what next ?

[Hnichols]

Could be the speed and reference sensors or a cracked solder joint on your DME (not the relay, but the ECU itself). My guess would be the DME.

If you know someone in your area with a 3.2, you can put remove your DME, install it in their car; if it doesn't start, contact Sal Carcellar (sp?) on this site and he will re-solder your DME for a very reasonable charge.

If it's the sensors, you can replace them yourself -- a tight fit but a DIY job. If you buy new sensors, buy the BMW counterparts -- same part, almost half the price. I wouldn't replace them unless you do some tests to determine if you really need to replace them. You can find info about testing from the archives -- I've since forgotten the details -- or someone will reply here with helpful info.

Good luck!

[ischmitz]

Check if you have power to the DME (key ON -> ICV vibrates). Also check for fuel pressure (make sure the pump runs during cranking). If yes that rules out the alarm and DME relay.

Next, if fuel and spark are missing check the sensors with a DVM inside the 35 pin connector (Ohm: ~ 1000, In AC setting about 2V on speed sensor and very little on reference sensor when you crank)

As others said, replacing these sensors is the next step unless your willing to buy a cheap (~30$) oscilloscope to measure sensor outputs while cranking. That will tell you if the sensor(s) are the issue.

If the sensors are fine or replaced and still no fuel and no ignition this points towards the DME. And it's not a simple re-solder. The re-solder so many talk about addresses a poor or cracked connection for the ignition output. But if both fuel and spark signals are missing it's either the sensor decoder or the digital part of the DME (MCU, chip, watchdog, etc.) at fault.

[autojack]

How are you verifying no ignition? I only ask because I mistakenly thought I had no spark and spent a lot of time chasing ghosts before I tested the fuel pump and discovered it was the culprit. 88 3.2 in my case. Testing the pump is a lot easier than replacing the crank and reference sensors.

[bobeisenberg]

Have been battling a no-start on my ‘87 3.2 for a couple of weeks. Turns over fine but won’t start. Replaced DME relay, reference & speed sensors but no luck. A bit of a newbie DYI shotgun approach. Did most of the recommended tests from the many no-start posts — seem to have spark and don’t seem to have fuel (I can jump the DME relay to get the fuel pump running but it doesn’t get power to the fuel pump fuse when key turned to on — only when cranking). I have not checked for fuel pressure or pulses at the injectors as I don’t have the tools to do so (yet) but I do not smell fuel.

The odd tests results I found were the following:
1. No ground at DME relay terminal 85b when cranking.
2. No voltage at AFM terminal 3 with the key on (not while cranking the engine).

I suspected there may be an issue with the DME itself based on the above. Opened up the DME, cleaned up the boards a bit and found 2 electrical components (capacitors I think) that seem to be cracked and leaking. No obviously messed up solder joints to my untrained eye. The attached pic shows the concerning components, one of which is quite close to DME pin 20 which leads me to think this could be responsible for the problem with the ground at relay terminal 85b. Any thoughts? This may be a job for you, ischmitz. :-)

[Sajan]

Originally Posted by bobeisenberg

Have been battling a no-start on my ‘87 3.2 for a couple of weeks. Turns over fine but won’t start. Replaced DME relay, reference & speed sensors but no luck. A bit of a newbie DYI shotgun approach. Did most of the recommended tests from the many no-start posts — seem to have spark and don’t seem to have fuel (I can jump the DME relay to get the fuel pump running but it doesn’t get power to the fuel pump fuse when key turned to on — only when cranking). I have not checked for fuel pressure or pulses at the injectors as I don’t have the tools to do so (yet) but I do not smell fuel.

The odd tests results I found were the following:
1. No ground at DME relay terminal 85b when cranking.
2. No voltage at AFM terminal 3 with the key on (not while cranking the engine).

I suspected there may be an issue with the DME itself based on the above. Opened up the DME, cleaned up the boards a bit and found 2 electrical components (capacitors I think) that seem to be cracked and leaking. No obviously messed up solder joints to my untrained eye. The attached pic shows the concerning components, one of which is quite close to DME pin 20 which leads me to think this could be responsible for the problem with the ground at relay terminal 85b. Any thoughts? This may be a job for you, ischmitz. :-)

Did water get into this DME at any point?
Otherwise, what is all that random moisture/residue?

And ichmitz is the one that looked at my DME. He converted it to a 28 pin and also found one area of concern that he fixed.

[bobeisenberg]

… and that’s the residue that’s left after I cleaned it up! I’ve only owned for four years, but it must have gotten wet previously. It’s a targa — of course it’s gotten wet!

[pavegeno]

This may help. A DME Relay that analyzes itself and displays visual indications.

https://www.ftech9.com/new-products/911-ssr-pp

[ischmitz]

@Bob: What you see is essentially rust on the wire-wound resistors that measure current for injectors and ignition output. While not pretty it is not root cause for your problem. I have seen these resistors in MUCH worse and they still work.

Pin 20 isn't related to these resistors at all. The DME relay needs to turn on even if your flywheel sensors are not working. The DME looks for the starter signal on pin 4. As soon as the key is in START position and the starter spins pin 4 gets 12V and that needs to turn the second stage of the DME relay on running the fuel pump and the O2 heater.

Go methodically and verify you have power to the DME (key ON -> ICV needs to vibrate). If that isn't happening your alarm or immobilizer is at fault. Next, if you see +12V during cranking on pin 4 but no GND to the DME relay from pin 20 the DME is bad.

[bobeisenberg]

Originally Posted by ischmitz

@Bob: What you see is essentially rust on the wire-wound resistors that measure current for injectors and ignition output. While not pretty it is not root cause for your problem. I have seen these resistors in MUCH worse and they still work.

Pin 20 isn't related to these resistors at all. The DME relay needs to turn on even if your flywheel sensors are not working. The DME looks for the starter signal on pin 4. As soon as the key is in START position and the starter spins pin 4 gets 12V and that needs to turn the second stage of the DME relay on running the fuel pump and the O2 heater.

Go methodically and verify you have power to the DME (key ON -> ICV needs to vibrate). If that isn't happening your alarm or immobilizer is at fault. Next, if you see +12V during cranking on pin 4 but no GND to the DME relay from pin 20 the DME is bad.

Thank you very much for responding with this info. Am I correct that the +12v on pin 4 during cranking needs to be tested while the harness is attached either to a breakout box or to the DME itself with the plastic cover off of the harness so the pins can be accessed from the back of the harness? I ask because the Bentley manual provides some testing methods (for the Reference & speed sensors) that can be done on the harness pins while it is not plugged into the DME. Thank you again!

[bobeisenberg]

Originally Posted by pavegeno

This may help. A DME Relay that analyzes itself and displays visual indications.

https://www.ftech9.com/new-products/911-ssr-pp

Interesting. Thanks for passing this along. Hadn’t seen this previously.

[bobeisenberg]

Originally Posted by bobeisenberg

Thank you very much for responding with this info. Am I correct that the +12v on pin 4 during cranking needs to be tested while the harness is attached either to a breakout box or to the DME itself with the plastic cover off of the harness so the pins can be accessed from the back of the harness? I ask because the Bentley manual provides some testing methods (for the Reference & speed sensors) that can be done on the harness pins while it is not plugged into the DME. Thank you again!

And ICV does vibrate with key on.

[mysocal911]

Start your diagnosis here; 911 3.2 No-Start Troubleshooting

At most a 15 minute effort! It's that simple. No need to remove the "connector cover".

[bobeisenberg]

Originally Posted by mysocal911

Start your diagnosis here; 911 3.2 No-Start Troubleshooting

At most a 15 minute effort! It's that simple. No need to remove the "connector cover".

Thank you. Need to get a noid before the store closes!

[mysocal911]

Originally Posted by bobeisenberg

Thank you. Need to get a noid before the store closes!

You can use a regular testlight (bulb type), but the clip end is connected to 12V and NOT ground.
While cranking, touch each injector connector pin separately. You can disconnect the temp sensor and the light will flash brighter.

[ischmitz]

Originally Posted by bobeisenberg

Thank you very much for responding with this info. Am I correct that the +12v on pin 4 during cranking needs to be tested while the harness is attached either to a breakout box or to the DME itself with the plastic cover off of the harness so the pins can be accessed from the back of the harness? I ask because the Bentley manual provides some testing methods (for the Reference & speed sensors) that can be done on the harness pins while it is not plugged into the DME. Thank you again!

If you have the DME open it's probably easiest to get to the connector pins inside the DME rather than opening the 35-pin plug.

The +12V will show up on the 35-pin DME connector w/o the DME connected to it. It is simply the same signal (T45, yellow wire) that also goes to the starter solenoid. But the GND from the DME low-side switch controlling the DME relay obviously only can be tested with the DME connected to the harness.

[bobeisenberg]

Thank you for all of the guidance. I love this forum! Will post the results a little bit later.

[bobeisenberg]

Well, I was expecting that a lack of ground from the DME’s pin 20 was going to be the problem, but my tests suggest otherwise. When cranking the engine I got voltage on DME pin 4 (about 9.7v) and then confirmed pin 20 was providing a ground. Suggests a problem in the wire between pin 20 and the DME relay’s terminal 85b which doesn’t show ground when cranking (if I understand correctly that pin 20 feeds ground to 85b).

Will follow up with mysocal911’s tests — probably Tuesday night after I’ve picked up the proper tools for the job. Couldn’t even find my incandescent 12v tester even though I know I had it just a couple of days ago. To say I’m frustrated would be an understatement, but I’m so appreciative of the help here. Thanks so much.

[mysocal911]

A review from the initial post:

Originally Posted by bobeisenberg

Have been battling a no-start on my ‘87 3.2 for a couple of weeks. Turns over fine but won’t start. Replaced DME relay, reference & speed sensors but no luck. A bit of a newbie DYI shotgun approach. Did most of the recommended tests from the many no-start posts — seem to have spark and don’t seem to have fuel

Given you have spark, then both Ref & RPM sensors are OK. So your key problem is lack of fuel.
Just spray carb or brake cleaner into the air cleaner. If it runs, it's only a fuel problem.

Originally Posted by bobeisenberg

(I can jump the DME relay to get the fuel pump running but it doesn’t get power to the fuel pump fuse when key turned to on — only when cranking).

Then the DME ECM is controlling the fuel pump via the DME relay. Great!
Again, spray carb/brake cleaner into the air cleaner. Maybe a bad pump or Mickey Mouse alarm added.

Originally Posted by bobeisenberg

I have not checked for fuel pressure or pulses at the injectors as I don’t have the tools to do so (yet) but I do not smell fuel.

So focus on the fuel problem by jumping the pump fuse to the battery +12V.

Originally Posted by bobeisenberg

The odd tests results I found were the following:
1. No ground at DME relay terminal 85b when cranking.
2. No voltage at AFM terminal 3 with the key on (not while cranking the engine).

You said above that you got power to the pump fuse while cranking??????

Originally Posted by bobeisenberg

I suspected there may be an issue with the DME itself based on the above. Opened up the DME, cleaned up the boards a bit and found 2 electrical components (capacitors I think) that seem to be cracked and leaking. No obviously messed up solder joints to my untrained eye. The attached pic shows the concerning components, one of which is quite close to DME pin 20 which leads me to think this could be responsible for the problem with the ground at relay terminal 85b.

DME ECM components rarely if ever fail, i.e. likely less than 5% of the time.
Typical problem lately, last 5 years, has been the injector driver output, where the alternator over-charges the battery, i.e. > 18-20 volts.
The other more common problem is an intermittent spark output. But you said you have spark, right?

[autojack]

This thread is getting a bit confusing as we are now discussing no start issues for two different people...