B35 Swap cranking, no running

You should pin out the sensor to your ecu plug.
 
I switched them, but it didn't start. I think I will have to check and see where it goes. Maybe with the handling of the harness, it may have broken.

Thanks for your help, Don, I appreciate it.

Scott C.
 
To be sure on grounds, though, let me list them:

1. Stock battery to fender.
2. Strap from valve cover to firewall.
3. Brown cluster to valve cover.

Engine cranks over fast, battery is fully charged.

Does ECU need to have its own ground?
 
When cranking, is the green On wire voltage supposed to drop to zero as opposed to maintaining 12 volts?

I forgot to post back to this thread. From last week:

1. Car cranks fine. No spark or fuel.
2. CPS seems to test okay. Connects to proper connector.
3. Key on 12V at coil. Cranking 0V to coil.
4. 12V to top terminal on starter with key on. Cranking 10.5V.
5. With positive on coil jumpered with 12V from battery, I get spark and engine will run for 5 seconds.
6. Fuel pumps work when jumpered to battery.
7. When cranking, all guages turn off, including fuel guage and dash lights.
8. Oil light does not go out. I have this connected via a jumper between switch and original wiring. Not connected through Motronic.
9. Engine makes horrible knocking noise. I did not change oil pump, but did change pick-up.

I got frustrated and have been busy, so it has been sitting.

Scott C.
 
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Motronic Tips

Here's some engine wiring diagrams and an ecu pinout for a 179.

http://www.e34.de/tips_tricks/motronic/

Pls. ignore the vanos and Jetronic files; but maybe someone else might need it.

The green wires are hot per the diagram.

I'm more concerned about the knock or noise and oil pressure. Can you elaborate more? Speed, rpm, front, back? Same rod as before maybe?

It might be that the injector firing sequence got crossed?
 
I am concerned about the knock, also. When I switched the oil plan to the B35, I did check the rods by tugging on them and they all seemed fine. I just hooked up my oil pressure light and it seems to have pressure.

Some observations for tonight:
1. When cranking all guages die, including the lights (oil pressure, brake, gen). This goes back to my previous question: When cranking, the green (key on, computer power) should maintain 12V, as well as the black/yellow starter wire?

What I think is happening is that 12v is happening in on, but when cranking, it switches 12V to the start only circuit and bypasses everything else. Hence no guages. I can tell my oil pressure is building by the fact that after I crank it, it takes a little longer for the OP light to come back on.
 
9. Engine makes horrible knocking noise.

Stop now and pull the engine.
I know that sounds rough but even if you get it to run nicely and it has a horrible knock you have gotten nowhere.
 
Yeah, I'm a little frustrated. I have done a few projects in my day, and none have fought me as hard as this one. What should have been a couple of weekends of work has turned into seven months of frustration.

For giggles, though, could someone tell me if my 12V at green should be consistant with the key on and also cranking?
 
When cranking- there must be 12 volts [or"Battery voltage"] at the blue/red wire at the main relay. Also at the red/white wire at the main relay. Also at pin 30 at the main relay AND at the signal wire to the main relay. 4 of the terminals at the main relay should read 12 volts while cranking, 1 wire is a ground
You should read 12volts at all 3 terminals of the coil and BOTH connectors of all the fuel injectors with the key on but NOT when cranking.
Do not worry about which connectors are at which injectors- you won't notice the difference if they are wrong.

I spent hours and hours at junkyards cutting up wiring harnesses from e34's, e32's and e24's. Then there are the early harnesses that use the 150 ecu. Each car is different for 02 sensor relays, lower wiring harness, purge valve wiring, green/violet that should be fuel pump wiring that is oil level wiring instead... and then there the harnesses that are shorted internally between the green, the black and the brown/orange and the brown.

Pull your engine and hand crank it with the oil pan off and the valve cover off- take a picture of the valve timing and install a m30b35 oil pump.
Start over with a new harness that is put together by someone that has made a bunch of them.
 
Good advice, Don, thank you. If memory serves, I believe that I used the B35 oil pump, but changed the pick-up. I don't think I ever pulled it off.
 
I think I figured the no start out...

I should have checked this first, but I think I figured it out. The PO installed a generic keyed ignition switch in the car. He wired it wrong. The green wire is hooked up to the Acc terminal while the Violet is hooked up to the On terminal. This would explain the fact that when I turn the key to on, I get 12V at the ACC and On terminals. When I crank it the power drops off of the green (computer on), but I still get 12V at the Violet and Black.

Cliff notes: When switch is turned to Acc the gauges light up. When switch is turned to on, I get power to gauges and computer. When car is cranked, the 12V that supplies the computer is turned off, yet the engine still cranks. Clear as mud.

Wish me luck, I will switch them tomorrow. It's late and this is barely sensible...

Scott C.
 
Old saying- what doesn't kill you makes you stronger....
 
It was the ignition switch that was the problem. PO reversed start and ACC wiring. When car was turned to start, it got 12V to crank, but shut down 12V to computer. I switched the wires and it fired.

The banging in the motor was the "now becoming infamous" number one rod cap hitting the oil pump bolts. Cut them down and no more interference.

I will post pics later.

Thank you to sfdon and all others who helped!

Scott C.
 
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