1997 e36 M3 - Cylinder 1,2 and 3 not firing

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Car: 1997 e36 M3 manual
Miles 168344
Changes during head refresh:
- I blocked off the air pump piping at the headers but left everything plugged in. Intake manifold vacuum port blocked.
- I used an ASC delete hose and for now left the ASC throttle plugged in and sitting on the strut tower.

I removed the head to change the head gasket as it was blown. The car drove fine except it would overheat due to the head gasket, drove it into the garage. Started on August 23 and finished yesterday.

I tried starting it today and it runs poorly as in 4 cylinders or so. I touched the headers and can tell that cylinders 1, 2 and 3 are not firing at all. I also checked with a FLIR camera and the front cylinders are not firing.

I did try and read for stored codes and there is nothing.

I am 99.9% sure everything is properly plugged in where it should be. The radiator is off the car as is the air filter.

Any ideas before I start taking apart things?

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Obviously I made a mistake somewhere in the process, hopefully it is not the timing.

I really do not want to take the VANOS off again, or any of that. I took great care in marking everything and it all lined up properly upon reassembly. I did turn the engine by hand multiple times over to make sure the valves and pistons where not trying to occupy the same space. I also removed the fuel pump fuse and cranked it for a while to lubricate and make sure the valves were not touching the pistons.

Here are some pictures, hopefully they are big enough.

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[MarcoZandrini]

Have you done a compression test on the bank 1 cylinders? If the engine is anything like an M52/54, both banks have their own ground strap for their coils. Pull the plugs and see if they are wet and check the bank 1 cylinders for gas smells. That’ll tell you if the bank is getting fuel. If it is getting fuel then spark is the problem. A VANOS problem would affect both banks.

[dworthy]

+1

So to add I would first check fuses first, as there are around 5. Next would be the grounds, as there are two, one for each bank IIRC. Coils 1-3 run on a separate driver, so I suspect that it isn't getting to ground, or that driver is bad, which is less likely. Since 4-6 is firing, the unloader relay would be good.

[Slippery]

Thanks guys for the suggestions. So far I got:

- Compression check: I need to get the gauges from my brother, will do later this week. The engine sounds healthy when cranking tho.
- Ground straps. I remember 2 on either side of the valve cover plus a skinny brown wire in the middle. Are there any others?
- Check for gas. I will try and check, I know the rail has pressure. Will check the front cylinders.
- Fuses. You mention 5, which ones? I only removed 18, never touched anything else.

Again thanks for all the suggestions. I will post as soon as I can check any of these.

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Ok, here we go:

1. Compression 1-6: 180/190/190/170/165/187
2. Both grounds on coils 1 and 6 tight. The brown wire in the middle tight. The ground strap to the pass side motor mount tight.
3. Fuel: 1,2&3 no fuel / 4-6 fuel
4. All fuses in the box by the driver’s side tested ok for continuity.

Looks like I have a fuel problem on 1-3 and slight low compression on #5 (might be the cheap Harbor Freight gauge).

Any ideas what would cause injectors 1-3 to not fire? Does that even make sense?

Thanks!

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I am going to check the rail wiring following the Bentley instructions tomorrow. Sorry about the sideways pics, its my phone.

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If anyone else has any other suggestions, I am all ears.

Thanks.

[CorvidX6M]

Here is a wiring diagram. It looks like all injectors share power, and each one is driven by an individual driver in the PCM. Weird problem for sure.

M3 wiring diagram.png

[dworthy]

Something is telling Bank 1, cylinder 1-3 to shut down. I think it's time to talk to the DME using a scanner to see why it's shutting down bank 1.

[MarcoZandrini]

Yup, the injectors get common power and each injector is controlled by a metal oxide substrate field effect transistor (MOSFET). But, I doubt that all 3 bank 1 MOSFETs crapped out simultaneously. No, something in the engine computer (DME in BMWspeak) is shutting down the fuel supply to bank 1. Can you check to see if bank 1 injectors are getting power. The MOSFETs supply the ground when it’s time to fire an injector. I’m not familiar with the E36 as I skipped that generation (I went from an E30 to an E46). Where does that power come from? Darin, do the 2 banks of injectors get power from 2 separate sources?

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Tonight I will check to make sure all injectors have power. I know they have common power, but maybe a wire got cut in the middle somehow?

From what I have been reading your assessment is correct Marco. I can ground the DME while cranking and the injector should open if it has power.

I will try and check all this.

A few more things:

- Remember this car was running properly until I removed the head. So the DME should be fine as it was not touched. I am more inclined to think I pinched a wire somewhere.

- Can this be cause be a tooth being off on the main timing chain? Will the cam position sensor cause all this?

- How many teeth can you be off on the main chain before there is valve to piston contact?

Thanks guys!

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Corvid.

Is that wiring diagram something anyone can access online? I like that the wires are color coded, but when I print it it comes out fuzzy.

[shadowpuck]

that looks like a redrawn diagram. maybe a higher res version can be posted.

you can also check the diy version of alldata and i think mitchell has a service too. they aren't that expensive.

i don't recall if they are redrawn or not.

[Slippery]

This part of the diagram Corvid sent is what has me thinking maybe the timing is off. I know I was very careful, but I have been know to screw up a time or two.

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Is the engine turning smoothly and no piston to valve contact a sign of the timing being correct? Or could I have missed by one tooth and still not have piston to valve contact?

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Thank you Shadow. I did not know alldata had diy access, I will check it out.

[CorvidX6M]

It's an Identifix wiring diagram. I can try to post a bigger resolution; it was being funny last night.

Timing being off probably wouldn't make only three injectors (Bank 1) not fire. They all share common power, there is no way to shut off power to just one bank. I'd agree that OP should look for damaged wires, and look for codes to see if it's disabling bank 1 for some reason.

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I don't know if that's any better for you guys. My Print Scrn only has so much resolution.

[dworthy]

Yup, the injectors get common power and each injector is controlled by a metal oxide substrate field effect transistor (MOSFET). But, I doubt that all 3 bank 1 MOSFETs crapped out simultaneously. No, something in the engine computer (DME in BMWspeak) is shutting down the fuel supply to bank 1. Can you check to see if bank 1 injectors are getting power. The MOSFETs supply the ground when it’s time to fire an injector. I’m not familiar with the E36 as I skipped that generation (I went from an E30 to an E46). Where does that power come from? Darin, do the 2 banks of injectors get power from 2 separate sources?

To answer your question, it's a common power. The DME controls the trigger for the injector to fires, and they sort of share a common ground as well inside the DME.

As for the OP:

You can be a tooth or two out and the car will run, not very well, but it will run. I think three or more would put the head in danger of valve impact. I don't think a cam position sensor would cause this, so I am thinking that the DME maybe thinking there is an issues with the bank from either the Knock sensor, or the Oxygen sensor.

Still would be worth to look at live data and pull codes.

[ross1]

The only thing I can think of that is shared by that group of cylinders are bank 1 O2 sensors and the coils ground. I cannot conceive a scenario where the O2s would do this.
The DME will cut fuel after X misfires so if the coils aren't firing it will cut fuel. You may be chasing a red herring with fueling.
I know you said the coil grounds were connected and tight BUT I have seen the coil retaining studs that have been overtightened "repaired" with epoxy. If the stud for your ground was repaired this way the ground may not be there. Easy enough to connect a jumper to know good ground.
A long shot but all I got. Good luck!

[Slippery]

- I checked the grounds with the voltmeter, they work.
- I know all 6 coils produce spark. I checked with a light, see picture below.
- All 6 injectors have 12.7 volts when probing the injector red wire and grounding at the valve cover ground strap. This is while the key is in the on position but the engine is off.
- No voltage across the injector while using the injector ground with the key on and not running. Have to get one of my kids to crank while I do this to see if it it registers then.

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BTW, removing the harness cover was more stressful/difficult than defusing a bomb. Feels like it will break into a thousand pieces.

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Ok, not sure I did this correctly as I was by myself.

- Fuel pump fuse removed.
- All sparkplugs removed.

Probing both the positive and negative at the injector while cranking:

Injector #2: 3.58 volts
Injector #4: 3.70 volts

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Trying to formulate a plan here, this is what I come up with:

1. Remove rail and injectors and place a cup under each of them to confirm that 1-3 are not firing.
2. Remove the valve cover and recheck the timing.

Any other suggestions? I am all ears.

Thanks!

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Pulled the fuel rail to physically check whether the injectors sprayed or not.

#1 No
#2 No
#3 No
#4 Yes!
#5 Yes!
#6 No

So only two injectors are working. Next step, swapping a couple of injectors to see if they are fried or if its the wiring.

Trying to put a few minutes every night into this so that I can hopefully finish it. Today my e46’s alternator took a crap, running out of cars to drive lol.

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Stupid e46 alternator I bought 1.5 years ago and spend extra getting it straight from BMW to avoid these problems died today.

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[Slippery]

Ok, this has been bugging me so much.

I swapped injectors #4 for #1 ... when I installed #4 in the #1 position, it works!

Long story short, injectors 1, 2, 3, and 6 are dead ... how the hell does that happen? Do injectors go bad?

Before I go spending $400 ... would you guys buy these Bosch from Rockauto or get them from BMW for $1k?

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Also, I had forgotten I had this Schwaben tool, it works perfectly. I could cycle each injector independently instead of having to crank. 74200B0E-7F2B-462F-990B-20D5E568BBB0.jpg

[shadowpuck]

yeah, that's the foxwell nt510 - good tool. reasonably good support on the older bmw's too.

i have that same scanner - and about 4 or 5 others....

if you start going down the injector route i don't think its necessary to get them from bmw - i would check out fcp euro, turner, etc. and just see what the pricing is.
i'm always leery of rock auto for anything beyond simple consumables. i've had some friends and neighbors have good experiences thus far with something like this, but, you just never know if what's in the box is actually a bosch part, etc....

although, i suppose that's true from any supplier anymore...

have you tested the injectors to see if their in-spec resistance wise?

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I have not tested the injectors yet. I called my brother and he said he is pretty sure these are high impedance, and he mentioned that they should be around 14-16 ohms.

He said to test a good known one and kind of base it on that number.

I will test them tomorrow.