[Solved] M52 Swap in an Early Model, Crank no Start

[Chilezen]

Hey, I'm back again..

I have a question about the wiring regarding the C104 connector in my Early Model '87. I think it's related to my car cranking but not starting. The engine & harness is a '98 Z3. Keeping it OBD2 emissions compliant. Only the EWS was removed from the ECU.

I checked to see that I have spark (took the coil off and shocked myself)
I have fuel in the rail (I pushed the schrader valve at the front of the rail and it squirted out)
The fuel injectors ARE NOT firing (I pulled up the rail with the injectors, put a towel down, cranked, and towel is still dry)
Most wires are connected, except for the ones shown below.



I sent the harness to be modified by sweet3 who did a great job labeling all the connectors, so that portion was a breeze. But I'm unsure about where these 4 go.
The wires are labeled, Vehicle Speed Signal, Fuel Rate Signal, A/C Signal, & Engine Speed Signal.
I'm guessing my injectors aren't firing because the Engine Speed isn't hooked up. The question is, should it be connected to one of those wires on the C104?

https://www.r3vlimited.com/board/for...52/207715-c104
This post is conflicting, I do but don't need it connected. Can anyone provide some clarity for an early model wiring, please?

Other than that, I've been digging for answers and this is all I've found. If these is another culprit for the injectors not firing, I'd like to hear suggestions. The crank and cam sensors are brand new Genuine BMW parts.
The OBD2 port is not hooked up, that's another one I haven't been able to figure out yet. There's been a lot going on..
Thank you!

[Chilezen]

I looked at this thread, it's not totally relevant to me since it's OBD1, but,

per the suggestions, I have my 12V constant power distribution block hooked up correctly, and I do hear the hum of the ICV.
The DME isn't bolted to the bracket, but I did take a jumper cable and connected the exterior of the box to a ground. That did not help.
His solution was to use another ECU. I would need to find someone local who has a swapped car with EWS removed.

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I looked at this thread, and it's unresolved. Fudge.

But, per the suggestions, the fuel pump seems to be fine since there's fuel in the rail.
I haven't tried spraying starter fluid in the engine yet. I will go to the store when I can soon.

I have the stock 3/2 valve hooked up correctly. Here's a photo I took of the car when I grabbed the part:


Just so I know that the fuel filter is on the "bottom" side. After the 3/2 valve, the supply goes to the back of the M52 rail (unlike the M50 rail).
Even if the fuel lines were backwards, the injectors should at least leak gas, which none are.

So the easiest next step is spraying starting fluid to confirm I can get combustion.

It also suggests, make sure the fuel pump relay is activating. With the relay socket labeled 1-9, Pin 6 will be constant +12v. Pin 8 will be switched +12v. If the relay is not activating, double check those 2 wires.
If the fuel pump IS activating, the only other possibility would be the fuel pressure regulator and/or the Cam/Crank sensors. The Cam/Crank sensors should throw a CEL code.
I'll try that after.

I do wonder if the EWS was actually deleted successfully.

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I looked at this thread, and he described a problem just like mine, and he found an answer. However, I already have my FPR hooked up correctly. So that's out.

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And this one, but again, my FPR is hooked up.

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If I connected a scanner, can the scanner tell me if the EWS is disabled? What else would cause the injectors to not fire?

[moatilliatta]

I would use a fuel pressure gauge to confirm you have proper fuel pressure.

I've seen partly bad crank sensors give sloppy signal to the coils, but no pulse width to injectors.

[Chilezen]

Three updates:

I rented a noide light kit and fuel pressure tester.

1. First test was easy: the light did illuminate during cranking! So there is signal going to the injector.

2. Next I wanted to test fuel pressure. But the kit didn't have a fitting for a BMW rail. It did have an option to tee inline, so I could put it between the 3/2 valve and the rail. But I didn't want to, so I tried the third option.

3. I grabbed jumper cables and alligator clips to test for the clicking of the injector. Nothing happened. I mean it sparked a little, but no click. I tried the next 3 injectors, all nothing, no clicks.

I rummaged through my parts bin and found an extra set of pink injectors. I did the same test, power and ground to the injector terminals. It clicked!

So there's my problem it seems...

Which is really strange. I sent out that set of injectors to be cleaned/tested. They came back labeled, clean, and with new seals and caps. And I assumed they were operational when they were being cleaned? So somewhere between there and now, they must have gotten fried. I tested 4 of the 6, and they're not clicking, so I want to find out if I fried them, or if the cleaning service fried them...

Either way, I'm going to transfer the new seals onto the spare set, then plug those in and start the car. Hopefully.

How unusual.

[TobyB]

Did they sit for a long time after being cleaned?
At least one cleaning place cautions to use them as soon
as you get them back, as the cleaning/testing solution
can gum up the injector.
(??? but whatever)

Next step is to check them for flow- because they may
not make an audible click but still flow fuel. I have some random
plumbing bits and a spare Volvo external pump
I use for things like this- takes only a few minutes,
confirms that they at least flow OK and have similar spray patterns.

The noid light should blink on and off- usually, mostly off with a quick flash 'on'
as the injector has a short pulse width at starting.


Having wrestled with a misbehaving no- start E46, I found it very useful to have
live data from the DME as I was troubleshooting- the DME will tell you what
it's seeing, and what it's not seeing in real time.

hth
t

[Chilezen]

Did they sit for a long time after being cleaned?

Yes, they sat for about 3 months as I got the rest of the things prepped/installed. That is the leading theory for the issue. Happily, the shop that did the work (it was Sssquid Tuning, great guy I've been speaking with) said he'll take a look at them for me.

Yes, the noide light behaved like that.

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I put an extra set of injectors in,

AND SHE FIRED RIGHT UP!

Revs nicely, idles fine. I still have a laundry list of other work to do before driving her, but this is a great leap of progress.

[crownedplatypus]

Is the fuel rate signal for the mpg gauge? And what does ALC do? My car seems fine without them

[Chilezen]

Is the fuel rate signal for the mpg gauge? And what does ALC do? My car seems fine without them

Yeah I think so, but I don't know for sure.

ALC?