Another E30 M30 Swap Thread, this time with an 84 318i

[the imitator]

always, wont be starting without video.

[ThatOneEuroE30]

Wait so why are you finishing this if your gonna do a n54 swap?

[the imitator]

Not a happy camper... and it has to be on my end of things
I have strong turn over, but the classic no fuel symptom upon checking the lines, But jumping the fuel relay yields fuel pumping successfully through the line, so the pump and filter are good, which means its back from the relay.. which is ecu,crank, (maybe main relay too?)

My crank positioning sensor is known working, but for giggles I tried one off a different m30

My 179 ECU is also known work, with a reputable chip, but I switched one out for a stock also known working unit.

I took the main relay and fuel relay out of a different e30 and tried those and no dice.

I switched around the crank positioning sensor with the VR sensor connections Many times to reassure I was reversing the connectors.

Grounds are tight on driver side and strut tower. There's one from the valve cover to the battery tray as well.

Coolant temp sensor is brand new

Lines are hooked up right

The only thing I can think of is the fuel rate output in the c103 since it's an 84 but would that cause a no start? I was under the impression it goes to the cluster .. no where can I find an actual picture or diagram of the c103 using google, r3v etc.

ill continue research on my end, didn't do any resistance testing assuming it was my mistake, and the back up parts and mine were in known working order.

Let me know if any of you successful candidates have any suggestions.

[Mr. Burns]

Go over this thread...
I was helping a buddy of mine diagnose the same issue with his M20 but with a wire tuck

Lots of good pointers in here

http://www.r3vlimited.com/board/showthread.php?t=327501

[the imitator]

I'll have to see if u have a functioning obc, but 84 to 89.. I'll just have to look.

[ThatOneEuroE30]

Which harness are you using? I had a b35 harness and had to hardwire the main relay to the battery once I did that I got fuel and power.

[the imitator]

This harness came off of a running m30b35 swap on the same motor... its an extended m20 harness though.

Hmm interesting though..

[glnr13]

The only thing I can think of is the fuel rate output in the c103 since it's an 84 but would that cause a no start? I was under the impression it goes to the cluster .. no where can I find an actual picture or diagram of the c103 using google, r3v etc.

can't be that, the ECU and motor don't rely on those inputs to run. I ran without connecting those for 2 months.

This harness came off of a running m30b35 swap on the same motor... its an extended m20 harness though.

Hmm interesting though..

how is the engine harness connected to your chassis harness? adapter? spliced connector?

[the imitator]

Spliced with pins using a c101 just like a stock harness, nothing janky, I check my pins briefly and everything seemed to have matched.

[glnr13]

hmm, baffling

[the imitator]

Ya, everything points the finger back at me and operator error. Once I get the car at the place I call home, ill go over things one at time. Glnr, I may PM you and go over things with you via pics.

[glnr13]

Word. I'm going to have limited info since I'm going out of town tomorrow. But I'll do my best since I have some documentation on my Google Drive.

[G-Man the Visionary]

Did you get it fingered out?

[kronus]

do you have a chart of the splices you made? m30b35 needs like 6 wires connected to run, i can get info for you

[the imitator]

hey sorry guys for the lack of updates here. Still chasing a No spark and No fuel here.

I wrote the pin numbers and colors down side by side and then labeled based off of schematics from multiple sources to make sure I had the wires Identified correctly. The late model harness wasn't hard to find, but I DO have different colored wires on the Early model side then what you would normally see for an 84-85 318i.

early model (fusebox/engine side)-------------- Late model (ecu/harness side

1 - Blue - Alternator---------------------1 - Blue - Alternator
4 - Brown/Purple - Coolant temp-------4 - Brown/purple - Coolant temp
5 - Brown/Black - Oil pressure----------5 - brown/green - oil pressure
6 - green/yellow - fuse 9----------------6 - Green/white - Fuse 9 & 27
7 - One Green - Start input--------------7 - Two Greens - Start input
11 - Blue/white - Diagnostic------------11 - White/green - diagnostic
13 - Purple/red - Fuel Pump------------13 - 2 Green/purples - Fuel pump
18- yellow/black - Starter--------------18 - Black/yellow - Starter


I used Jlevie's trouble shooting post here

http://www.r3vlimited.com/board/showpost.php?p=2618091&postcount=2

Everything checks outs as far as wiring goes now, I have the switched power hooked up to pin 27, pin 18 receives a constant 12v with key off, switched, and during crank.

• Resistance is in spec on 2 crank different sensors, and I've tried both.
• Continuity to both main relay and fuel relay from the dme read zeros
• Main relay gets power in off position.
• 2,14,19,24 are grounded on dme
• power is at coil
• thin wire going from battery block to fusebox is hooked up
• Coolant temp sensor is brand new
• I can jump the fuel relay terminals and get fuel pumping nicely out the other end and yes its connected correctly.

Before I go suspecting a crank sensor, relays or the ECU I want to question myself.

Jlevie says the following:
"Power to pin 18 is from the main relay and there should be power to the
injectors and fuel pump relay."

I get power on pin 86 & 30 of main relay and pin 18 of dme with key off; But the way I routed the 12V constant might be questionable.

I grabbed 12V from a convenient wire coming from the glovebox area, The wire stays active with key off, key on, and during crank. I simply took this wire and T spliced it into the the red wire leading to pin 18 on the dme plug. so the way pin 18 is receiving constant 12v isnt through the main relay, its through a splice; That splice is AFTER the relay.

Lastly: I tried bridging main relay terminals 30 and 87 and still, no start, no fuel.


"Bridge the DME relay by connecting pin 30 to both pins 87. This is to see if power to both the ECU and the Fuel Pump relay has been lost. If the car starts once bridged, it confirms battery power is getting to Pin 30, and that both 87 circuits are working (power to ECU and Fuel pump relay). It doesn't test the circuit that latches the DME relay, which therefore needs to be tested before condemning the relay."

Since I didn't get a Start here I stopped and took a breath and haven't touched it since yesterday which was just to make sure I was reading everything correctly. and no being a goofball.

I tested the main and fuel relays with a 9 volt battery and the gates function, but I didn't test continuity or anything else, so I think tomorrow I may get a generic relay from napa and see what happens... Unless you find error somewhere else.

EDIT: its 3am, I apologize if something doesn't add up here, mechanically, mentally, sensibly.. etc. let me know if you need clarification.