ETA head swap questions -won't start, need help

[shawmcbigdis]

I'm currently in the middle of a ghetto head swap on my 86 ETA. Leaving the bottom end totally stock, and slapping all i parts up top (plus a reground 272 cam, bigger injectors and an SSSquid chip). I currently have the new head on the motor, and the wire harness sitting in place, and starting to hook it up. Got to the starter and ran into my first problem.

The starter on the car uses a single bolt terminal for positive, and a single spade terminal for negative. The new wire harness I have has the same positive cable, but then 2 eye bolt type negative wires. How the heck to I connect this to my starter? Do I have to splice the spade connector onto one or both of them? There is a 2nd bolt terminal on the starter that the stock harness didn't connect to. But the eyes on the new wires aren't big enough to fit on the bolt.

Second thing I am worried about. I hear a lot of the how to's say you need to swap the water pump pulley, but some don't mention this. What the truth here? I was planning on keeping my old style complete cooling system, since everything in it is only about a year old and less than 5k miles. So the plan was to re-use everything, and then when its time to replace, convert to the later style cooling system.

Third thing I'm unsure of is sensors. Again, some lists say you have to swap all sensors, some don't. Obviously I need to switch the crank position sensor, and I think its the oil level sensor has a different plug if I'm not mistaking. But aren't all the temp sensors the same? Well the ones that are there, the ETA uses more than the later ones. Again, they are all fairly new in my car, so I would prefer to just keep them.

Last thing is ECU. Again, some say any 1.3 Motronic will work, others say it has to be 173 or whatever. I have a 380 from a think a later model vert. any reason it won't work?

Thanks

[Swanny]

First off, do you have the wiring diagrams? What harness do you have? There were several updates along the production of the cars as engines and body harnesses were changed/improved.

You could probably get away with changing the connections for the starter considering the I starter had a shorter reach due to the smaller bell housing. Can’t just swap starters.

The water pump pulley was updated because they could crack and fuck up your front end and the main concern is getting the proper sized belt depending on which pulley you replace it with. Same with the intermediate shaft pulley.

it’s true that any 1.3 ecu should work, the 173 is just a favorite/reliable

[ForcedFirebird]

The upper spade connector is for the k5/k7 relays. It should be a black wire with a blue stripe. When using a late harness in an early car, that wire needs to be grounded, or your accys won't work - it basically turns off windows, radio etc while cranking to give all available power to starter. If you are lucky and have a late starter, you can just put that wire on the top lug. The black with yellow stripe goes to the bottom lug and energizes the starter motor from key switch.

Cooling systems are the same from eta to iS, you either have early or late.

Water pump pulley is a different diameter to speed the pump up on the eta. You need the front crank pulley, and water pump pulley, or you will need an odd sized belt.
You need all the sensors that match the harness. The eta has a yellow/brown sensor for the cluster, that stays. You need a blue sensor (ECU) from Motronic 1.1/1.3, the AFM, DME, CPS. TPS is the same on both.

You can use any three row m20 DME. There's a list of numbers that match on the spec e30 rules. 153, 525, 173 etc are all plug and play (525 has a speed limiter, they came in automatics).

You will also need injectors, fuel rail, intake mani/TB etc.

Most of this stuff is outlined in the stickies at the top of the sections, just a lot of reading...

[shawmcbigdis]

The upper spade connector is for the k5/k7 relays. It should be a black wire with a blue stripe. When using a late harness in an early car, that wire needs to be grounded, or your accys won't work - it basically turns off windows, radio etc while cranking to give all available power to starter. If you are lucky and have a late starter, you can just put that wire on the top lug. The black with yellow stripe goes to the bottom lug and energizes the starter motor from key switch.

Cooling systems are the same from eta to iS, you either have early or late.

Water pump pulley is a different diameter to speed the pump up on the eta. You need the front crank pulley, and water pump pulley, or you will need an odd sized belt.
You need all the sensors that match the harness. The eta has a yellow/brown sensor for the cluster, that stays. You need a blue sensor (ECU) from Motronic 1.1/1.3, the AFM, DME, CPS. TPS is the same on both.

You can use any three row m20 DME. There's a list of numbers that match on the spec e30 rules. 153, 525, 173 etc are all plug and play (525 has a speed limiter, they came in automatics).

You will also need injectors, fuel rail, intake mani/TB etc.

Most of this stuff is outlined in the stickies at the top of the sections, just a lot of reading...

I had been mainly working of the strictlyeta write up on the head swap. But that is offline now for some reason. I could have sworn on there it said I could use either water pump, and all the temp sensors form the ETA. But I can't confirm that now. I have the whole top end from an 88, head, manifold, TB, fuel system, wire harness, crank pulley, AFM, basically everything I thought I needed. The water pump pulley and sensors are throwing me for a loop.. The ECU is from a different car, I think it was an 89.

so starter and bell housing are original to the car, 86 ETA.

When you say "yellow/brown sensor for cluster and blue sensor (ECU)" what/where are you talking about?

As for pulleys, I'm not worried about mine cracking, because it was replaced last year with everything else in the cooling system. But is the i crank pulley a different size than the e crank pulley, therefore my belts (or any belt really) wont fit with the i crank and e water pump pulleys?

[shawmcbigdis]

OK, so I just went out and checked the pulleys, and the crank pulley from the i motor is way smaller than the one from the e motor. So I will def need a new water pump pulley. My question is, why the heck is that pulley so freaking expensive? $130 for a stupid stamped steel pulley, that's crazy. So is it jsut the crank and water pump pulleys that are different? The alternator is also on that belt, is it the same?

[ForcedFirebird]

I probably have a pulley at the shop I can sell you. Lots of those BMW-specific items are getting expensive. Check out the late model metal cooling pipe that runs behind the pump.

The pumps are the same from eta to iS, it's just early style that has the pill shaped expansion tank that uses a hose from the pump to expansion. The late uses a single outlet water pump, and a tee shaped hose on the driver side to integrate the expansion with the heater core routing.

The Motronic 1.1 and later uses a blue water temp sensor. It plugs in the injector harness, blue 2 pol Bosch connector (like the injectors). The eta has just the brown sensor on that leg of the wire harness. The eta used another two pol spade connector on the t-stat housing for the idle control box, that wire lead will be missing on the iS harness, instead you will have a brown (or yellowish faded) connector that goes to the brown sensor (one pol sensor for the cluster).

The iS crank pulley has the reluctor teeth on them, and that's needed for the CPS that mounts to the front of the b25. The eta has two crank sensors and are located in the bell housing.

This will all make sense as you start removing and replacing items.

[ForcedFirebird]

Also, since you have an 86 (my first e30 was too, wahoo), pay mind to pin #20 on the c101. Depending on how late model your harness is, that may be a ground, or power, so you will fry the harness on the first key on....

[shawmcbigdis]

I think I understand (and have) all the temp sensors. Working on getting the correct water pump pulley. Once I have that I should be able to install the water pump and then get the timing belt on. Then once I have all the wiring verified put on the intake manifold and plug everything in.

So for the starter wires. can I splice the spade connector onto one of the negative wires, and then bore out the eye on the other wire and connect it to the second terminal on the starter, or should I connect it to a body ground or something like that?

Now this bit about pin 20 on C101, this is the first I've heard this, and it freaks me out. So the car is an April 86 build, wire harness if from an 88, and I think the ECU is from an 89 (maybe 90). So I assume this will be mismatched? How do I fix it?, heck how do I even test it without turning anything on?

[ForcedFirebird]

If your starter has two small lugs, then the black/yellow wire goes to the bottom and black/blue goes to the top. If you happen to have a really early original starter (they all come with two lugs now) then you won't have the top terminal. The early models had a spade on the black/yellow, the late models have an 8mm nut and eyelet on top, 10mm on bottom. If your stater is really early and only has one spade on the bottom, then, yes, you will need to ground the black/blue for power windows etc to work.

To check pin #20, use a small pick or flat screwdriver and carefully peel the rubber boot back to expose the wires in the connectors on both the body side, and engine side. If there's a red wire in one, and a brown in the other, then they shouldn't be powered up when connected. Some harnesses have #20 empty, some use it for ABS relay ground, and other use it for airbag power.

Check the diagrams from both cars here: http://wedophones.com/BMWManualsLead.htm

Since you have a late model harness, you will also need to wire the tach, eco gauge and CODE in the glove box. A 1987 iS harness would be a direct fit for you, but it doesn't take much to adapt the late harness as it has the three wire plug next to the ECU (yellow/black/green). The 88+ harnesses used the c101 for those signals.

[shawmcbigdis]

If your starter has two small lugs, then the black/yellow wire goes to the bottom and black/blue goes to the top. If you happen to have a really early original starter (they all come with two lugs now) then you won't have the top terminal. The early models had a spade on the black/yellow, the late models have an 8mm nut and eyelet on top, 10mm on bottom. If your stater is really early and only has one spade on the bottom, then, yes, you will need to ground the black/blue for power windows etc to work.

To check pin #20, use a small pick or flat screwdriver and carefully peel the rubber boot back to expose the wires in the connectors on both the body side, and engine side. If there's a red wire in one, and a brown in the other, then they shouldn't be powered up when connected. Some harnesses have #20 empty, some use it for ABS relay ground, and other use it for airbag power.

Check the diagrams from both cars here: http://wedophones.com/BMWManualsLead.htm

Since you have a late model harness, you will also need to wire the tach, eco gauge and CODE in the glove box. A 1987 iS harness would be a direct fit for you, but it doesn't take much to adapt the late harness as it has the three wire plug next to the ECU (yellow/black/green). The 88+ harnesses used the c101 for those signals.

My starter has 2 lugs, and the spade on the bottom. I'll have to double check the wire colors on both harnesses after work.

I'll dig into the C101 after work also, and see what I have on each side.

As for the tach wires, I think I have that done, I tapped the black from the 3 pin gauge connector to the black wire in the main harness, and the yellow into the white/black wire on the harness. Which supposedly goes to the right pins on the ECU. Forgot where that article was, but I found it somewhere. I only changed the tach, not the whole cluster, so I don't have to do anything about the fuel or temp gauges from what I understand. I could wire up the check engine light if I want to, but I'll do that at some later point.

[shawmcbigdis]

OK, so here is what my starter wiring looks like;

Old harness has just the large red wire with the eyelet, and a smaller black/yellow with female spade,




The starter looks like this, one large bolt that the red old red wire attached to, a smaller bolt terminal that nothing from the wire harness attached to, and the male spade at the bottom;



The new wire harness has a large red wire that can connect to the large bolt terminal on the starter, but then 2 all black wires with small eyelets on them, that don't fit anywhere;


Actually in the pic, the red is already connected to the starter. The two blacks that I'm not sure what to do with are in my hand.


As for pin 20, I think I lucked out. On my body side harness the pin is not wired (ditto on the old engine side harness). It is wired on the new engine side harness, but that shouldn't matter since there is nothing on the body side for it to connect to correct? Because of that I didn't even bother to pull off the boot to check if it was positive or ground, since its not connected to anything.

So right now, my big concern is what to do with the starter?

[ForcedFirebird]

I can't see the pics. The black/yellow and black/blue have a all black second sheath over them. Gotta pull that back and see the actual wire color. The early cars used a spade connector, late used eyelets.

Here you go: https://www.r3vlimited.com/board/for...ter-wires-look

[shawmcbigdis]

I can't see the pics. The black/yellow and black/blue have a all black second sheath over them. Gotta pull that back and see the actual wire color. The early cars used a spade connector, late used eyelets.

Here you go: https://www.r3vlimited.com/board/for...ter-wires-look

I don't think that thread is relevant, since it is about an M50 swap. So I assume they are using an M50 wire harness, and starter.

I'm using my old ETA starter, and an M20b25 wire harness.

So my starter has a large bolt terminal on the right and a small bolt terminal on the left, and a male spade terminal on both top and bottom. My old Harness had a red cable that connected to the large bolt terminal and a black/yellow cable that connected to the bottom spade.

The new harness from the 88 "i" has branch with a large red cable with an eyelet on it, and a black/yellow cable with a smaller eyelet. Then there is also a black/green cable with an eyelet that comes out of the harness, in the same spot as the other 2, but is not bound together with the red and black/yellow.

So I assume I have to connect the black/yellow to the spade terminal (any issue with soldering the spade terminal on there? I know you aren't supposed to splice ABS sensors because of impedance issues, anything like that here?), but what about the black/green?

[ForcedFirebird]

Swap or not, it's the same starter motor and wiring ;), the m42 is wired this way (as well as m52, m54 etc). The odd ball is the pre-facelift e30's, they used only the starter engagement lug. I used that thread to give you a visual.

Your starter is the same as the one in the pics in that thread, but you have the early style spades. I wouldn't suggest soldering, just use quality crimp connectors/pliers and snip/strip/crimp just like the factory did. If you notice, the only place BMW used solder is on circuit boards, never on wiring.

It's the black/green, excuse my mistake. Often when typing, it's from memory. :/ Correct, that black/green needs to go to the top lug.

[shawmcbigdis]

Swap or not, it's the same starter motor and wiring ;), the m42 is wired this way (as well as m52, m54 etc). The odd ball is the pre-facelift e30's, they used only the starter engagement lug. I used that thread to give you a visual.

Your starter is the same as the one in the pics in that thread, but you have the early style spades. I wouldn't suggest soldering, just use quality crimp connectors/pliers and snip/strip/crimp just like the factory did. If you notice, the only place BMW used solder is on circuit boards, never on wiring.

It's the black/green, excuse my mistake. Often when typing, it's from memory. :/ Correct, that black/green needs to go to the top lug.

OK, crimp on a spade connector, no problem. Wait, top lug or bottom lug? I could have sworn I unplugged it from the bottom lug.

What about the black/yellow wire, where does that go?