Car not starting, need help

[Ashkanar]

So I'm working on my new to me 1988 325 and I'm running into some issues, I'm hoping one of you on the hive mind will be able to help.

So to start, I wasn't getting spark so looking through the forums I replaced the crank position sensor (ohm reading was almost double the limits). Next I tracked the spark from the plug back to the coil, with the coil not sparking and the ohm readings be on the edge of acceptable I replaced that as well. Now the car gets spark but still doesn't start. Using starting fluid it will sputter like it wants to start.

Then I moved onto the fuel system. I found a couple leaky fuel lines (the rubber ones) so I replaced those as well. Fuel pump fuse is good and the relay works. If I manually ground the relay it clicks on and the fuel pump starts running. I traced the ground line (br/gr iirc) back to pin 3 on the ecu wire harness to make sure the line isn't broken. But when turning the key on it doesn't kick the pump on or prime the system.

Another weird thing it's doing. When the key in on the "ON" position it buzzes like the headlights are on regardless if the door is open or not and the speedo shows around 60 mph. When I manually ground the fuel pump relay the buzzing stops and the speedo returns to normal.

I'm not sure where to go from here, Anyone have any ideas?

Side note: I have a second ECU for it and nothing changes between the two ECU's.

[DBShiznit]

I’d check to see if all your grounds are good. If you have a bad ground it could be causing the issue. I’m not sure where all the grounds are located though


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[Ashkanar]

OK so update. I checked all the grounds for the MCU and they all tested good. I changed the crap ass battery (plus charger) out that came with the car for a good yellow top and that fixed the speedo problem and the weird buzzing it did.

So now I'm down to just a "normal non-start" problems. When using starter fluid is will sputter once then nothing. When trying to test the coil we get a couple sparks then nothing. I can't help but think its related to the fuel pump not kicking on somehow. The fuel pump relay works when manually grounded to kick on the fuel pump, so the MCU isn't telling the fuel pump to turn on. The CPS ohm readings at the MCU are ~580 ohm which is within the acceptable limits (540 +-10%).

Its driving me nuts not knowing why the MCU isn't kicking on the fuel pump. Any other ideas?

[E30Garage]

Make sure the intake hose is tightly connected to the ICV idle control valve. If needed clean the ICV as well.

[superj]

the sensors in the trans are not swapped? the two next to each other in the bell housing. since the plugs are the same and the sensors are the same, sometimes people unplug them and then plug them in to the wrong plug

[Ashkanar]

Being an '88 there's only one cps at the front of the engine. That being said, where the cps plugs in there is another plug right next to it. Tried swapping them to no avail. The icv is clean and tight...

Being an auto is there anything that would stop the car from starting like a park/neutral switch? I do find it odd that the car will let me take it out of park and into gear without applying the brake first...

[Ashkanar]

Another fun thing i noticed is the main relay was hot (at least hotter then the fuel pump/o2 sensor relays). Used the old fashion pocky test light to test for hot wires. With the key out of the vehicle the main relay was live. I was under the impression that should only activate when the key is switched to the on position, so that's a thing....

[superj]

the lock for the shift lever is in the handle and plastic so its broken easily. mine is the same way. I can't help on the main relay, I never noticed if mine is hot or not. I am not sure if there is a neutral safety switch, I guess see if realoem shows one but, I think there is because I vaguely remember mine not trying to start while in drive or reverse.

[Ashkanar]

So found the neutral safety switch and jumped the leads similar to what people who do a auto->manual swap, you know to try and see if thats why it won't start. I hear what sounds like a relay under the driver side dash click on when its jumped. Looking at the wire diagram for these cars there shouldn't be anything between the switch to the computer? guess I'll start by following to that relay and/or the signal from the neutral safety switch is making it to the computer.

[Ashkanar]

well the relay im hearing is the starter relay and there is continuity from the harness to the computer so i say the neutral safety switch is working just fine. Seems like im running out of things to test besides it being the computer itself -_-

[superj]

so it cranks and no spark, still? and you have good grounds on the engine?

[Ashkanar]

Correct, it cranks but no spark or fuel pump kicking on. That would lead me to think its the CPS but its been replaced with a new one and continuity to the computer checks good.