The comprehensive DOHC engine swap thread.

[Mr.SWISS]

So do the vacuum line from the TB and the big hose attach to the booster allong with the intake port? It seems that is the way the e30 B booster hose is setup.

[FredK]

No, the booster just hooks up directly to the intake manifold with a single hose (and check valve).

The throttle body has three ports on the bottom. Two are for the coolant in/out for the throttle body heater, and the one on the far right goes to the electric valve (1 in attached diagram) that is connected to the charcoal canister.

[Mr.SWISS]

No, the booster just hooks up directly to the intake manifold with a single hose (and check valve).

The throttle body has three ports on the bottom. Two are for the coolant in/out for the throttle body heater, and the one on the far right goes to the electric valve (1 in attached diagram) that is connected to the charcoal canister.

Hmm my motor didn't have a hose there I noticed the opening last night when I was swapping the temp sensor.

So do I NEED that electic valve thing or can I jusst hook it up? I didn't see a plug for that around there either.

[FredK]

Not sure if you NEED the electric valve, it's an emissions thing. I'm pretty sure some people delete the charcoal canister altogether. Not sure though.

[Mr.SWISS]

Not sure if you NEED the electric valve, it's an emissions thing. I'm pretty sure some people delete the charcoal canister altogether. Not sure though.

I'm just gonna plug it in. As long as it doesn't idle all weird I won't worry. I did go back to the salvage I got the motor and trans from and look for it but it was no where to be seen.
I got to see this bracket I have read so much about. I thought it was a solid cast peice not stamped steel. Autozone gave me a damn M20 oil pan gasket when I told them 92 325i, so I had to quit early tonight. :(

[trent]

I'm just gonna plug it in. As long as it doesn't idle all weird I won't worry. I did go back to the salvage I got the motor and trans from and look for it but it was no where to be seen.
I got to see this bracket I have read so much about. I thought it was a solid cast peice not stamped steel. Autozone gave me a damn M20 oil pan gasket when I told them 92 325i, so I had to quit early tonight. :(

You should use the check valve, otherwise you will have a vacuum leak, as I doubt your entire vapor system is sealed (most are not due to age).

You should just put a cap over the port on the bottom of the TB and leave the system hanging if you don't have to smog.

[Mr.SWISS]

I went and spent some quality time today and got the motor close to mounted. I got delayed a bit since I noticed the subframe part the mount goes was loose. It looks like the factory weld just gave up and it had some wigggle to it so that had to be taken car of. I did have to remove the A/C belt tensioner to get it to clear the condensor and I still have to take off the forward downpipe. The salvage cut them and I thought it was short enough to clear but it kept hitting the sub frame.
Oh well on to the crappy pics.


Da homie Gabe


Big Hoss welding

The top weld. Will do the bottom after the engine is bolted and we can raise the car.

[Mr.SWISS]

Ok I NEED some info on the wiring, not the C101 but the three eyehole terminals on the harness. I was told one is a ground and the others are hot. Two are right by the ecu plug and one is on the other side.

[FredK]

Yes, there are three terminals on the harness.

1. The fat red cable goes to the main power block.
2. The black cable paired with the diagnostic connector gets connected to the shock tower ground.
3. The remaining thinner black cable goes to the 6mm post where the fusible link (the thin power wire coming from the back of the car).

[Mr.SWISS]

Yes, there are three terminals on the harness.

1. The fat red cable goes to the main power block.
2. The black cable paired with the diagnostic connector gets connected to the shock tower ground.
3. The remaining thinner black cable goes to the 6mm post where the fusible link (the thin power wire coming from the back of the car).

1&2 done. The small black wire looks like a ground to me, I put it on the shock tower with the other one. Was that my mistake? I am waiting to get my CPS in b4 I go back to the shop to mess with it.

[FredK]

1&2 done. The small black wire looks like a ground to me, I put it on the shock tower with the other one. Was that my mistake?

Yes.

Peel the heat shrink back a little bit on the third wire, you should see that the wire inside has red insulation. This is definitely a positive wire. The one paired with the diagnostic connector should have brown insulation. You can peel back the heat shrink on this wire as well, to confirm where it goes.

If you have the engine ground strap connected (goes from engine mount arm to E30 chassis rail, there's a threaded stud near there that's perfect for this), the fuel rail ground (attaches between engine hoist eyelet and head), and coil ground (a ground strap that goes from one of the coils to the valve cover, IIRC), the engine should fire.

[FredK]

Here's a picture from LooN, when he was wiring up the power for his swap.

A is power
B is ground

[Mr.SWISS]

Yes.

Peel the heat shrink back a little bit on the third wire, you should see that the wire inside has red insulation. This is definitely a positive wire. The one paired with the diagnostic connector should have brown insulation. You can peel back the heat shrink on this wire as well, to confirm where it goes.

If you have the engine ground strap connected (goes from engine mount arm to E30 chassis rail, there's a threaded stud near there that's perfect for this), the fuel rail ground (attaches between engine hoist eyelet and head), and coil ground (a ground strap that goes from one of the coils to the valve cover, IIRC), the engine should fire.

Saw that when I was cleaning the bay so I went with it. the two ground straps for the coils are fine, and the one on the engine is cool too. I will go and check this out later today. Thanks for the pic.;)

[Mr.SWISS]

What is the year the single pin coolant sensor came on? I bought one for an 86 eta last night and it is 2 pin.

[BigD]

What is the year the single pin coolant sensor came on? I bought one for an 86 eta last night and it is 2 pin.

You must have bought the blue temp switch (for ecu) instead of the brown temp gauge sender.