MyE28.com

Posted: **Oct 22, 2024 9:24 PM**

I have gotten a good distance into this project and then ran into this problem and can't figure it out. When I turn the key the power comes on but does not crank. No sound for the fuel pump. Currently need to flush the fuel lines, I have heard of people jumping the fuel pump to test if its the fuel pump itself or something else, I have no idea how to do that.

I checked the fuses and they all seem good, replaced some that were missing and nothing. Fuse for the fuel pump is good too.

I have bypassed the neutral safety switch, at least I think I have

I cut the wires from the two prongs at the top right

Then wired them together. I had it spliced together more neatly till I pulled them apart to clean them and try again to no avail

I followed this diagram made by Dave Kan

This should work right? Or should I try to connect these to ground c200? Looking at the diagram for the wiring, that could bypass the neutral safety switch as well.

Posted: **Oct 23, 2024 7:36 AM**

I'll let others chime in on the wiring,
it's been too long since I've done a swap.

My guess would be that your fuel system components are in the same condition they were in prior to beginning the project.

Did you mess with the starter wiring?

Posted: **Oct 23, 2024 9:05 AM**

The neutral safety switch bypass should work, but I'd check the Kan diagram against the actual wiring diagram for your year/model, as stuff can vary. Personally, I just deleted the TCU and all of the transmission wiring harness, then connected the large black/yellow connectors at the base of the column together.

You'll need to create a WOT ground, which I did by wiring the ECU WOT wire that ran to the TCU to the kickdown switch. Otherwise, you need to use a different engine harness and throttle switch.

BTW, twisting wires as you have is a hack job. Please get proper terminals, connectors, and tools.

Posted: **Oct 23, 2024 3:17 PM**

1st 5er wrote: Oct 23, 2024 7:36 AM I'll let others chime in on the wiring,
it's been too long since I've done a swap.

My guess would be that your fuel system components are in the same condition they were in prior to beginning the project.

Did you mess with the starter wiring?

Yes, but could this effect the fuel pump not priming when I turn the key?

Posted: **Oct 23, 2024 3:30 PM**

Shawn D. wrote: Oct 23, 2024 9:05 AM The neutral safety switch bypass should work, but I'd check the Kan diagram against the actual wiring diagram for your year/model, as stuff can vary. Personally, I just deleted the TCU and all of the transmission wiring harness, then connected the large black/yellow connectors at the base of the column together.

You'll need to create a WOT ground, which I did by wiring the ECU WOT wire that ran to the TCU to the kickdown switch. Otherwise, you need to use a different engine harness and throttle switch.

BTW, twisting wires as you have is a hack job. Please get proper terminals, connectors, and tools.

I'll have to look again at the wiring diagrams, the image I gave is the only one I could find but it doesn't say which color they are

Also I'm still ignorant to a good amount. I'll need to do research on somethings you mentioned. Specifically the WOT

Also as I said, I had it done properly but second guessed myself so I undid it, re did it poorly after cleaning the wires. I'm going to make sure it's clean so in the future I don't hate myself

Posted: **Oct 23, 2024 5:03 PM**

Reconnect the automatic transmission lever switch with the cables as they were originally (I suppose the rest of the connector is still there??) and test the start. If it turns on, you have a problem with the connection of the new bypass, but if not, the problem is something else....

Posted: **Oct 23, 2024 5:09 PM**

Did you remove the wiring from the starter? There are two tabs that the spade terminaled wire can attach to and one is labeled Not Used in the diagram the other one goes to the start system.

Posted: **Oct 23, 2024 6:54 PM**

Shawn D. wrote: Oct 23, 2024 9:05 AM The neutral safety switch bypass should work, but I'd check the Kan diagram against the actual wiring diagram for your year/model, as stuff can vary. Personally, I just deleted the TCU and all of the transmission wiring harness, then connected the large black/yellow connectors at the base of the column together.

So I started removing the transmission wiring. Where exactly are the large black yellow connectors? The ones that connect to the start relay or c200?

Posted: **Oct 23, 2024 7:06 PM**

Aldo525 wrote: Oct 23, 2024 5:03 PM Reconnect the automatic transmission lever switch with the cables as they were originally (I suppose the rest of the connector is still there??) and test the start. If it turns on, you have a problem with the connection of the new bypass, but if not, the problem is something else....

Did that and nothing happened. Guess the issue is elsewhere then

Posted: **Oct 23, 2024 7:07 PM**

Blue Shadow wrote: Oct 23, 2024 5:09 PM Did you remove the wiring from the starter? There are two tabs that the spade terminaled wire can attach to and one is labeled Not Used in the diagram the other one goes to the start system.

I had not separated the wiring as I didn't need to fully remove the starter to remove the automatic transmission

Posted: **Oct 23, 2024 8:13 PM**

NVM, SHES CRANKING NOW. LETS GOOOOOO

Big thanks to Shawn for getting me on the right track! I connected the yellow black wire connector, that originally connects to the start relay, to c200

Big thanks everyone!

Posted: **Oct 23, 2024 8:20 PM**

Fuel pump is still not priming. What's the main cause for an issue like this? The 16anp fuse? A fuse relay? Or the pump?

Posted: **Oct 23, 2024 9:48 PM**

Notelect wrote: Oct 23, 2024 8:20 PM Fuel pump is still not priming. What's the main cause for an issue like this? The 16anp fuse? A fuse relay? Or the pump?

No too all of the above. Try design. With the possible exception of the 88 super e's, E28s don't use a prime function for the fuel pump. It's not supposed to prime. Where on the wiring diagram do you see a prime function?

Posted: **Oct 24, 2024 9:41 PM**

Not even the 88 primes the pump when you turn the key on. It starts pumping when the engine starts cranking.

Posted: **Oct 25, 2024 6:40 AM**

Just as a comment, when you refer to this "priming" you are talking about the pump running for half or a second in key position 2 before starting??...Euro 518i K Jet and 525i L Jet do it when the car has been stopped for several days. It doesn't do it from one day to the next, but if it is stopped for many days, when you connect pos2, the pump is activated before starting....maybe just on K and L Jet, not in Motronic...

Posted: **Oct 25, 2024 1:13 PM**

Aldo525 wrote: Oct 25, 2024 6:40 AM Just as a comment, when you refer to this "priming" you are talking about the pump running for half or a second in key position 2 before starting??...Euro 518i K Jet and 525i L Jet do it when the car has been stopped for several days. It doesn't do it from one day to the next, but if it is stopped for many days, when you connect pos2, the pump is activated before starting....maybe just on K and L Jet, not in Motronic...

Yes, US K jet cars, the E21 320i did have a prime function. K jet kind of runs off fuel pressure so it's a much bigger deal than on L jet or Motronic.

Posted: **Nov 01, 2024 5:30 PM**

Sorry guess I was thinking it did

I did try jumping pins 87 and 30 on the fuel pump relay and it did start pumping fuel. Was able to flush out the fuel lines.

However I switched the main relay and fuel relay and nothing changed, didn't start and no fuel pumped but this time the radiator came on.

I am going to buy a replacement for the fuel relay and hope it's just that.

Posted: **Nov 01, 2024 6:02 PM**

Main and fuel pump relays are different. The main relay is unique on the car and if the right one isn't in there you will get a no start. It's also slightly troublesome, in close to 1M miles on BMWs I've replaced 3 relays and 2 of them were E28 main relays.

If the correct relay isn't in the main relay spot you will have a no start condition. Period.

Posted: **Nov 10, 2024 2:44 PM**

So I got the new relay, plugged her in, and she cranks but still no start. I cleaned the connectors on both the main and pump relays and both connectors where they insert, same result. Swapped them, same result

Fuel pump is not engaging with the new relay, BUT when I jump those two pins then the fuel pump runs fine.

Anyone have any ideas?

Posted: **Nov 18, 2024 12:15 PM**

Have you revisited your reference sensors?

My first 5 speed swap I pinched a reference sensor wire in-between the bellhousing and block.
Took a while to figure that one out.

Posted: **Nov 21, 2024 7:42 PM**

1st 5er wrote: Nov 18, 2024 12:15 PM Have you revisited your reference sensors?

My first 5 speed swap I pinched a reference sensor wire in-between the bellhousing and block.
Took a while to figure that one out.

I removed those as the transmission I installed doesn't have anywhere to plug them into the transmission. Are those needed or can they be bypassed?

Posted: **Nov 21, 2024 7:58 PM**

I'm using a manual transmission from a 325i

Posted: **Nov 22, 2024 3:03 AM**

Notelect wrote: Nov 21, 2024 7:42 PM
1st 5er wrote: Nov 18, 2024 12:15 PM Have you revisited your reference sensors?

My first 5 speed swap I pinched a reference sensor wire in-between the bellhousing and block.
Took a while to figure that one out.
I removed those as the transmission I installed doesn't have anywhere to plug them into the transmission. Are those needed or can they be bypassed?

Sorry for the sarcasm, but those are essential to it's operation, you can't just remove parts and expect it to work. Without them the ECU doesn't know where TDC is or how often it should be sparking or anything. One sensor gives a signal as to when TDC is, the other counts flywheel teeth so the ECU knows when to spark and how often to inject fuel. Slightly later cars than E28s, except I think 88 super E's, use different sensors, a different crank dampener, a different ECU so they read all the stuff the bellhousing sensors do off the front of the engine. But it's a complete system, you can't just use parts of it and have it work. You would need the crank dampener with the teeth, the bracket and sensor for it, the ECU, a different wiring harness and more. It will probably be easier and cheaper to buy the correct tranny and put it in than try to adapt what you have. If the bosses are there on the tranny it might be possible to drill for them in the 325i tranny, but I've never heard of anyone doing that.

Posted: **Nov 22, 2024 11:55 AM**

Mike W. wrote: Nov 22, 2024 3:03 AM
Notelect wrote: Nov 21, 2024 7:42 PM

I removed those as the transmission I installed doesn't have anywhere to plug them into the transmission. Are those needed or can they be bypassed?
Sorry for the sarcasm, but those are essential to it's operation, you can't just remove parts and expect it to work. Without them the ECU doesn't know where TDC is or how often it should be sparking or anything. One sensor gives a signal as to when TDC is, the other counts flywheel teeth so the ECU knows when to spark and how often to inject fuel. Slightly later cars than E28s, except I think 88 super E's, use different sensors, a different crank dampener, a different ECU so they read all the stuff the bellhousing sensors do off the front of the engine. But it's a complete system, you can't just use parts of it and have it work. You would need the crank dampener with the teeth, the bracket and sensor for it, the ECU, a different wiring harness and more. It will probably be easier and cheaper to buy the correct tranny and put it in than try to adapt what you have. If the bosses are there on the tranny it might be possible to drill for them in the 325i tranny, but I've never heard of anyone doing that.

No worries on the sarcasm

The bosses are there, I may just get them drilled. Been looking at different transmissions and it might be cheaper to just drill the holes.

Those holes go all the way through, correct?

Posted: **Nov 22, 2024 12:17 PM**

Notelect wrote: Nov 22, 2024 11:55 AM
Those holes go all the way through, correct?

Yes they do.

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