M50NV: injectors not firing? Not starting

[Nick_S]

:Check last post for update:

So I finally got to the point of trying to start my car. Took my time and to the best of my knowledge is wired correctly, however since it's not starting I assume something is wrong. Any input or suggestions are GREATLY appreciated.

engine is from a 92 NV 325i. Engine harness from the same car but I did need to re attach a few connections. Harness adapter from Nando. 402 DME supposedly from a running car. Starter engages fine and turns the car over no problem. Checked crank sensor is at 509ohm, all engine grounds read fine, main relay checks tested fine. Injectors are grounded to the front of the engine on the lift hook. Pulled the fuel feed line and cranked and def was pushing gas. The car had no fuel delivery issues prior to pulling the M42 a month or so ago. Sprayed some carb cleaner into the intake and it started right up for about 4 seconds and died so it seems to be getting spark. I won't be able to get back to the car till the weekend so I'm trying to gather as much info as I can before I dive further into trouble shooting.

Thanks
Nick

[berlow94]

Is it an early model e30? Could be that your positive displacement pump is running but not the high pressure boost pump.

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[Nick_S]

Is it an early model e30? Could be that your positive displacement pump is running but not the high pressure boost pump.

Sent from my Nexus 5 using Tapatalk

Apologies for not clarifying in my post, it's a 91 318is.

[e30rapidic]

did the cam/crank sensors get plugged in wrong on the harness? its easy to do.

[Nick_S]

They will be the first thing I'm checking. I suspect I have my fuel lines backwards which I'm hoping is the only issue.

[blunttech]

Do you have a node light to check if injectors are firing?? they are dirt cheap at the auto store. Ive done the fuel line reversed thing a couple times. you feel so dumb afterwards. But mine would idle with the lines reversed but die when you touched the throttle.. I suspect I had a faulty FPR

[Nick_S]

I'm sure my buddy has one somewhere in his shop. If not ill go buy one. If the injectors aren't firing, how would I possibly diagnose the issue? I'm learning a lot with this swap but there is still a ton I don't know.

[m735is]

From what I've gathered in my recent no start issue- the cam sensor tells the injectors when to fire. Since yours starts with starting fluid, you're in the right direction. Are the injectors powered up with 12V with the key in the run postion? I just took the wire cover off of the injector run and checked there with a meter. I have not found a way to test the cam sensor though.
Do you have a fuel gauge to check the actual pressure going to the rail?

Freshly charged battery, dry chambers and clean plugs if cranking a while?

[e30austin]

Check for tight battery connections, secured engine harness grounds (including DME grounded to body, which is required on E36 harness) and ensure that the cam and crank sensors weren't reversed.

[Nick_S]

From what I've gathered in my recent no start issue- the cam sensor tells the injectors when to fire. Since yours starts with starting fluid, you're in the right direction. Are the injectors powered up with 12V with the key in the run postion? I just took the wire cover off of the injector run and checked there with a meter. I have not found a way to test the cam sensor though.
Do you have a fuel gauge to check the actual pressure going to the rail?

Freshly charged battery, dry chambers and clean plugs if cranking a while?

I haven't got a chance to check. I ran out of time last weekend and since the weather isn't playing nice, I won't be able to get it back in the garage this weekend . I'll pull the harness cover and check in there, why I didn't think to do that I have no idea. I'm sure my dude has a fuel pressure gauge somewhere. Battery was good before the tear down and was hooked to a jump pack while cranking, plugs were brand new and I'm not honestly sure the last time this engine ran so who knows. Hopefully late next week I'll get up there. Supposed to a high of 2 on Tuesday so I'll have to wait for a bit nicer weather.:cockbloc:

Check for tight battery connections, secured engine harness grounds (including DME grounded to body, which is required on E36 harness) and ensure that the cam and crank sensors weren't reversed.

The ground for the DME, is it outside of the glovebox or right near the DME? I know the harness had a ground wire right near the diagnostic plug but I'm not sure if that was what you're referring to.

Thanks guys!

[Nick_S]

Bump, hoping for a little more help. Made it back up to the shop today.
After switching fuel lines and double checking the Crank and cam sensors were correctly hooked up, I put the booster pack on the battery and tried cranking again...still nothing. So I'm at a bit of a wall, I can confirm the following..
-fuel pressure seems strong (hose at fuel rail blasted me in the face when I removed it to check for fuel delivery)
-CPS tested at 505ohm which is in spec (it is the one that came on the motor, should replace anyways?)
-ICV is humming with key to 'ON'
-fuel pump isn't priming but runs with the relay jumped
-will fire if carb cleaner sprayed into intake so seems to be getting spark

All of this leads to me think the injectors aren't firing. Now the cause of this I'm not sure of obviously. The DME was supposed to be good but I can't verify. We tested the main relay last time and it checked out. I switched the other relays around for other ones with no different results. While cranking it will occasionally sputter like one cylinder tried to fire and have a faint smell of burnt fuel (open headers still). We checked all the important grounds last time and they were good. Hooked up to the booster pack so it's a strong 12v constant power. So with my limited but learning knowledge I'm leaning to believe that I either need a cam sensor or I have a fried DME.

[NickL]

Try a new cps nick. On an e36 I had my cps ohmed out fine but it ohmed out between the wrong pins on the connector. Tried a new one and the car fired right up.

[Nick_S]

Try a new cps nick. On an e36 I had my cps ohmed out fine but it ohmed out between the wrong pins on the connector. Tried a new one and the car fired right up.

I've got one in my parts stash that came with my E34. The part numbers cross reference but I seem to remember reading they are different between Vanos and NV. I'd like to give this a try before spending $100 on a new one. Also have another DME on the way just in case. I really wish the car wasn't an hour away. Would make trouble shooting alot easier.

[m735is]

Cranks sensors will swap. Cam sensors will not.
I swapped a cranks sensor from my 92 NV e36 motor to my 95 525 Vanos. Fit fine and fired right up.
Cam sensors are indeed different.

[Nick_S]

Cranks sensors will swap. Cam sensors will not.
I swapped a cranks sensor from my 92 NV e36 motor to my 95 525 Vanos. Fit fine and fired right up.
Cam sensors are indeed different.

Ahh I had them mixed. Thanks for the clarification!