MyE28.com

Hey everyone. Today is a bummer of a day. I just completed my manual swap. Was really looking forward to hearing the car run today and maybe even taking it down the road, but the car will not start.

The transmission light on my cluster is illuminated which gives me the impression that it's wanting something from me that I'm not giving it. I have read as much as I can find in this swap, and watched numerous videos and the only thing I have read that would keep the car from starting would be bypassing the neutral safety switch, which I have done. I jumped the wires on pins 2 and 3 on the automatic shifter wiring harness. Details of the swap that might be helpful to anyone willing to help me....

My car: 1988 535is auto
Donor car: 1985 635csi
Transmission being installed: Getrag 265/6.

I don't have reverse lights after the swap either, and I have connected the harness from the 265 to the back up light connector in the console.

Any help would be appreciated. Everything else has gone super smoothly.....but starting the car is pretty important. Thanks everyone

Rob

Well nice list of what you have done but won't start means we need to hear from you what it does when you try to start it

Turn the key and it does nothing
Turn the key and it spins the motor but won't start?

Did you remove the started at all in the process.

Hey thanks for the response. When I turn the key all the cluster lights come on, including the transmission light, but nothing happens. It doesn't try to turn over at all. Starter was not removed during the process and the starter is still connected.

So no starter.
see if the wiring is correct. See of you can jump it at the diagnostic plug.
I guess dive into the ETM and bypass all the auto crap that keeps the starter from getting power when the key is turned.

Great idea. Jumped the starter and the car fired right up. Drove it down the road and it brought a tear to my eye! So the starter is still good. Transmission light being on is what bothers me. Well that and the not starting.

Starting is almost surely the starter relay. IIRC it lives under the kick panel under the steering column. 2 heavy blacks, a small black and a brown/black. Connect the 2 heavy blacks and it should work. Cut off or insulate the small black.

Back up lights. Disconnect the green/white and the Blue/White wires from the A/T harness. Connect the 2 wires going to the back up light switch to them. Doesn't really matter but gn/wt is hot.

What about the clutch switch? Must be either jumpered or correctly installed and adjusted.

Its either that or the AT wiring. The factory autos have a start relay to interrupt the starter which I believe grounds through the AT position switch. This relay can be bypassed or permanently grounded.

turbodan wrote: Mar 30, 2024 4:37 PM What about the clutch switch? Must be either jumpered or correctly installed and adjusted.

You've been around too much new stuff, the clutch switch on E28s is only for the cruise control.

Mike W. wrote: Mar 30, 2024 4:36 PM Starting is almost surely the starter relay. IIRC it lives under the kick panel under the steering column. 2 heavy blacks, a small black and a brown/black. Connect the 2 heavy blacks and it should work. Cut off or insulate the small black.

Back up lights. Disconnect the green/white and the Blue/White wires from the A/T harness. Connect the 2 wires going to the back up light switch to them. Doesn't really matter but gn/wt is hot.

Thanks Mike! I think I have located the relay. So by connecting the heavy blacks you mean leaving the relay in place and jumping them from the back side? Or pulling the heavy blacks out from the their connectors and joining them (which I guess is the same as the jumping method). And then just literally cutting the small black and capping it? Sorry to be redundant but I'm terrified to ruin something.

*Also one of the heavy blacks has a yellow strip....just want to make sure I have the right relay. Everything else about the wires fits the description perfectly

Mike W. wrote: Mar 30, 2024 4:39 PM

turbodan wrote: Mar 30, 2024 4:37 PM What about the clutch switch? Must be either jumpered or correctly installed and adjusted.

You've been around too much new stuff, the clutch switch on E28s is only for the cruise control.

It's probably the first signs of dementia setting in. I'll try to cut back on posting once they put me in memory care...

russellrh72 wrote: Mar 30, 2024 5:08 PM
*Also one of the heavy blacks has a yellow strip....just want to make sure I have the right relay. Everything else about the wires fits the description perfectly

Just jumper them at first, then assuming it works, which it should, then clean it up.

turbodan wrote: Mar 30, 2024 5:14 PM

Mike W. wrote: Mar 30, 2024 4:39 PM

You've been around too much new stuff, the clutch switch on E28s is only for the cruise control.

It's probably the first signs of dementia setting in. I'll try to cut back on posting once they put me in memory care...

Shit, I bet I've got years on you but I'm not going to quit until they pull the keyboard out of my cold, hard, dead, hands. Keep it up! You've forgotten more about turbos than most guys with them ever figure out.

Mike W. wrote: Mar 30, 2024 11:09 PM

russellrh72 wrote: Mar 30, 2024 5:08 PM
*Also one of the heavy blacks has a yellow strip....just want to make sure I have the right relay. Everything else about the wires fits the description perfectly

Just jumper them at first, then assuming it works, which it should, then clean it up.

turbodan wrote: Mar 30, 2024 5:14 PM

It's probably the first signs of dementia setting in. I'll try to cut back on posting once they put me in memory care...

Shit, I bet I've got years on you but I'm not going to quit until they pull the keyboard out of my cold, hard, dead, hands. Keep it up! You've forgotten more about turbos than most guys with them ever figure out.

Again, sorry to ask for too much explanation, but jumper them from the back of the connector and leave the relay? And do I actually cut the small black wire?

Also, I'm guessing this needs to be done in conjunction with a jumper on pins 2 and 3 on the auto shifter wiring harness which I have already done.

russellrh72 wrote: Mar 31, 2024 12:05 AM
Again, sorry to ask for too much explanation, but jumper them from the back of the connector and leave the relay? And do I actually cut the small black wire?

Also, I'm guessing this needs to be done in conjunction with a jumper on pins 2 and 3 on the auto shifter wiring harness which I have already done.

OK, it doesn't start with the key, right? I would pull the 2 heavy wires off the back of the relay and push them together, they'll kind of slide in together. Turn the key, it should start. Assuming so, do a proper connection by snipping off one of the connectors and using a crimp on male connector, push them together and insulate it. Verify it starts. Then you can either snip off the small black wire or leave it and the relay in place. You don't even need to think about the old A/T connector, it switches ground so it's not like it's going to short anything out. Leave it. Remove it, whatever.

I'm 99.9% sure I'm right, but verify before you cut anything. Verify before you trust some guy on the 'net.

Mike W. wrote: Mar 31, 2024 12:42 AM

russellrh72 wrote: Mar 31, 2024 12:05 AM
Again, sorry to ask for too much explanation, but jumper them from the back of the connector and leave the relay? And do I actually cut the small black wire?

Also, I'm guessing this needs to be done in conjunction with a jumper on pins 2 and 3 on the auto shifter wiring harness which I have already done.

OK, it doesn't start with the key, right? I would pull the 2 heavy wires off the back of the relay and push them together, they'll kind of slide in together. Turn the key, it should start. Assuming so, do a proper connection by snipping off one of the connectors and using a crimp on male connector, push them together and insulate it. Verify it starts. Then you can either snip off the small black wire or leave it and the relay in place. You don't even need to think about the old A/T connector, it switches ground so it's not like it's going to short anything out. Leave it. Remove it, whatever.

I'm 99.9% sure I'm right, but verify before you cut anything. Verify before you trust some guy on the 'net.

I will definitely try that first thing in the AM. I have already removed the wires from pin 2 and 3 in the shifter harness and joined them as I have seen several other posts claiming that's all you have to do to bypass the neutral safety switch that tells the auto the car is not in park. Did that and it didn't work. Again, my transmission light is on in the cluster which I hope is related to this same issue. And to top it all off I realized on the second drive today that the cruise control is no longer working after the swap. Not sure why that would be effected by the swap. Again I have read several articles and watched numerous videos and the only thing I saw mentioned in regard to the cruise is to find the factory jumpered wires under the column and add them to the clutch switch to kill the cruise control.

On the bright side, I have driven the car all day by manually jumping the starter at the diagnostic port and the car is doing great! I would drive it as is all day long over the auto that it was born as, but I sure would like to get it operating as it's supposed to on all fronts. Thanks for all your help as always. Thanks for the help in understanding what to buy when starting this project as well, Mike!

Okay I think I have done this correctly. I pulled the heavy black wires from the back of the relay. I am holding them here but to test I wrapped them together tightly. Still nothing when trying to start the car. I honestly cannot think of anything else that would be confusing my auto car. Nothing happens at all when I turn the key other than dash lights coming on. ARGGGHH

I haven't done a M/T conversion on an E28, but I have on 4 or 5 other BMWs. I never jumped it at the plug by the tranny, I always eliminated the starter relay, which is not to say jumping the plug does or doesn't work, just that it's not the way I've done it. But if you have a A/T light on something is in the wrong place.

Cruise control. The clutch switch bracket is beyond flimsy so made sure it's functioning as it should, including adjustment.

Just saw your update. I'm pressed on time at the moment so don't have time to look at the wiring diagram, but you might have to start checking voltage from the ignition switch, and or jumping 12V to the wire that goes to the starter.

Your car, now updated to a manual transmission wants you to go further with a Start button in the dash somewhere.

Which transmission light is on? I have never seen one illuminated on a manual tranny car.

Blue Shadow wrote: Mar 31, 2024 5:00 PM Your car, now updated to a manual transmission wants you to go further with a Start button in the dash somewhere.

Which transmission light is on? I have never seen one illuminated on a manual tranny car.

Never had a start button car but I can imagine that it is life changing for sure!! Probably even more so than lane changing technology!!

The car is starting!! Now I just need need to sort the cruise control, and the reverse lighting.

Picture of the transmission light staying on

russellrh72 wrote: Apr 02, 2024 11:58 AM

The car is starting!! Now I just need need to sort the cruise control, and the reverse lighting.

Picture of the transmission light staying on

So what was it on not starting?

And oh, that transmission light. I forgot yours would be the later EH electronic tranny, which I believe that is the light for when it's not happy. You might have to unplug the tranny ECU or maybe just the bulb depending on what it's part of. I was thinking it was the P light or one of those.

Start buttons solve a surprising number of ID10-T problems with people bringing cars in for repair that there is nothing wrong with. The manufacturers now provide a large, easy to press button that ordinary, salt of the Earth people can successfully operate.

turbodan wrote: Apr 02, 2024 1:15 PM Start buttons solve a surprising number of ID10-T problems with people bringing cars in for repair that there is nothing wrong with. The manufacturers now provide a large, easy to press button that ordinary, salt of the Earth people can successfully operate.

While I haven't had any problems with them on the rental cars I've had, I don't like them. Not at all. Not that I've heard of problems, but I see no advantage to them and lots of stuff to potentially go wrong.

turbodan wrote: Apr 02, 2024 1:15 PM ordinary, salt of the Earth people.

gadget73 wrote: Apr 03, 2024 9:04 AM

turbodan wrote: Apr 02, 2024 1:15 PM ordinary, salt of the Earth people.

That's exactly what I was thinking of when I wrote that.

Mike W. wrote: Apr 02, 2024 1:33 PM

turbodan wrote: Apr 02, 2024 1:15 PM Start buttons solve a surprising number of ID10-T problems with people bringing cars in for repair that there is nothing wrong with. The manufacturers now provide a large, easy to press button that ordinary, salt of the Earth people can successfully operate.

While I haven't had any problems with them on the rental cars I've had, I don't like them. Not at all. Not that I've heard of problems, but I see no advantage to them and lots of stuff to potentially go wrong.

I agree. More complexity, unnecessarily in my opinion. Honda for example had a lot more problems with the start buttons than they ever did with the conventional switch. For people who are too dumb to successfully, consistently start their cars with a conventional ignition though, it's better. Might be more reliable overall for someone who rides the starter every time they start the engine, holding it against the ring gear even after the engine has started. It's the kind of thing that makes me cringe every time I hear it, like people clicking the gas nozzles 37 times trying to top off when they fill up their tank.

I kinda figured you were thinking of that Blazing Saddles scene.

My truck has a standard key, but the PCM seems to sit between it and the starter. I can just bump it in "crank" and it will crank until it starts. Doesn't take long but the starter is definitely engaged longer than the switch is in the crank position.

Everything else is very dumb in that department. The key switch operates the starter or starter relay, and when I let go the starter does too.

So, I am about to undertake this swap on an 87 535is. I have some questions specific to the electronic controlled automatic transmission.

The electronic controlled autos have different connections for the idle and full throttle inputs into the Motronic brain. For idle, there is an idle position switch. For full throttle, the input comes from the tranny electronic control unit. I’m thinking I need to hunt down a throttle switch like the ones unsed on manual cars to obtain these inputs. Can anyone who has done this confirm this for me?

The Motronic brain, for both manual and automatic transmissions, has a “transmission position” connection on pin 28. With a manual, this pin is grounded directly. With both earlier automatic and 87/88 electronic control automatic transmission, this pin is grounded in both park and neutral thru the automatic transmission selector. I think this is what russelrh72 was doing when he jumped pins 2 and 3 in the automatic transmission selector nine pin connector. I’m planning to do this.

In addition, the Motronic brain for the elctronic control automatic transmissions has at pin 10 a “shift input” connection from the transmission control unit. I’m guessing this may be part of the automatic kick down circuit. So, I’m planning to pull the transmission control unit and leave this connection open. Is there a problem with this?

Further to the original questions about cruise control, here is what I think needs to be done to get the cruise to work.

- The blue/brown wire connected to pin 3 of the cruise brain needs to be grounded. Best to use ground location G200 under the dash.

- The switch on the clutch pedal needs to be wired into the cruise control circuit so that depressing the clutch shuts off the cruise control. The brake light switch is wired using a green/red wire to connector 9 on the cruise control brain. This clutch pedal switch needs to be wired into this circuit in series. There is a video out there that indicates a connector exists under the dash that is jumpered that can be used for this.

With some help (Thanks Chris), I found the answer to the question I posted above. Best to switch to the manual throttle position sensor. See here:

https://www.mye28.com/viewtopic.php?t=142838