dave1986

Hi everyone, I have finished my engine swap in my 1986 Rx7. It was a n/a 13b, I swapped in a complete drive train from a 1986 tII right hand drive donor car. I kept the original n/a engine harness(thanks misterstyx69). everything went very well with all the info from this club, I have engine spitting and sputtering when the turbo spools up, I dont know anything about the boost sensor wiring or if it is the problem, any advice would be appreciated.

misterstyx69

iTrader: (142)

Dave..you need the N318 boost sensor at the strut tower location.
the APS is a the inside of the passenger kick panel and can be a N326.
Where are you again.?..Courtice?

dave1986

Is the n318 boost sensor on the donor car or do I have to buy one, I am going back to the garage right now to see what the APS number is but it came with the donor car. Is the APS the same as the ECU inside of the passenger kick panel? I am in Brighton, Ontario, 1 hour east of Toronto.

dave1986

the ECU or APS number on the passenger side kick panel is N319

dave1986

on the original n/a engine wiring harness that is hooked up to my turbo engine, there is no plug for the turbo boost pressure control solenoid valve, what do I do?

misterstyx69

iTrader: (142)

The APS connector is on the N/A car harness that goes through the passenger firewall.
I never changed mine(kept it N326) on the Swap so it is good to go if it is there on the car when you hook up the harness.
Boost Sensor solenoid valve.I didn't use one.
I hooked a boost controller in between the wastegate and the turbo inlet nipple.You can use a manual controller,.They work just fine.
Make sure that your Turbo is not going to give you boost creep if it is an S4 you may want to port the wastgate.(look that up..long explanation)
I just went S5 Turbo.

dave1986

i would prefer a computer controlled boost controller if possible for better driveability. Can I take the parts I need from the donor car or do I need to buy anything/

misterstyx69

iTrader: (142)

your setup will work fine even without a boost controller.It's just assurance that is best to have.Personally I don't trust these engines to not have some sort of control.
The parts?.you can get off any donor car..S4 anyways.

dave1986

thanks, I will look into an aftermarket boost controller.

dave1986

I hooked up the n318 boost controller on the strut tower but no change, the engine still spit and sputtered when the turbo tried to spool up. I changed the ECU to the N326 but again no change. I would like to try the simplist set up to get this to work, what ever it is. You mentioned a manual boost controller between the wastegate and the turbo inlet nipple, is that it, or is there some electrical wiring involved? Once I get the basics working I will like to try some modifications. Thanks

satch

iTrader: (1)

See if this makes any sense.

https://www.rx7club.com/2nd-generati...ensor-1046741/

dave1986

Thanks for the link, I definetely have some wiring problems, the engine idles good and has good bottom end torque before the turbo tries to spool up. I know it will work well when the bugs are out. I heard you were a wiring wizard, thanks again and I will let you know how I made out.

misterstyx69

iTrader: (142)

Manual boost controller just fools the wastegate on pressure that the turbo is putting out and when it is supposed to open.
Picture a water faucet...Turn it on you get good flow out the tap.
Now,If you increase that water flow you get MORE water,right?
Well stick a hole in the pipe to let the water out before it gets to the tap.You are gonna have to flow MORE water(increased Boost) to get the same amount of water to come out of the tap..The excess water flowing out Before the Tap is essentially what the Boost controller is doing.Bleeding Boost off to the wastegate so it stays closed longer.

dave1986

I found the X15 connector by the ECU. I cut the Black wire with the white stripe on the EM side.
Both sides of the connector was the same color wire - Black/ white.
No change the turbo starts to spool up then spit and sputters.
I only wanted to make one change at a time so I did not cut the BrB wire yet.
I feel like I am shooting in the dark.
Can I do a diagnostic check myself and if yes how?
Thanks.

satch

iTrader: (1)

You would know if you had a problem w/the Boost Sensor by measuring the voltage at the sensor on the four wires. If the Br/R wire had 12 volts w/key to on then you know that would cause a driveability problem. This should be simple to do.

satch

iTrader: (1)

When looking at X-15 and X-16 you need to make sure you don't have them confused for starters. Also, you need to recognize that there could be more than one B/W wire in the connector you are working on. If you were trying to cut a wire that mated B/W to Br/R then you obviously cut the wrong wire. If you were trying to address another issue then that is a different circumstance, but you need to identify which problem specifically you were trying to address when cutting a B/W wire.

dave1986

I will check voltage at the boost sensor with the key on. What should it read?
I used the diagrams for the connectors, x15 had 13 pins available, x16 had 15 pins available.
the arrow on the x15 connector(BrR) pointed to the BW wire, that is the one I cut, (EM) side.

satch

iTrader: (1)

From one of your previous posts: I found the X15 connector by the ECU. I cut the Black wire with the white stripe on the EM side.
Both sides of the connector was the same color wire - Black/ white.

So this is a bit confusing. And the Br/R wire at the sensor would read about 2.5 volts or so.

dave1986

the voltage at the boost sensor is 2.7 vdc

dave1986

not a boost sensor problem?

satch

iTrader: (1)

Did you look at the link within the link provided? It has the following info.

The following about X-15 and X-16:

The (BrR) is coming from the boost sensor and mating with a BW wire that is going to the Meter fuse. Bad.

The (YW) is coming from the water temp sensor and mating with a ...well no wire. Not good if you want a water temp signal.

The (GB) is from the auxillary fan temp sensor and is mating with ....well no wire. No harm done if you have no aux fan.

The (BrB) is a gnd wire going to every sensor in the engine bay and is mating with a WB wire that goes to the alt relay in the CPU. Not good again since it’s putting a gnd on that relay all the time when it should not.

That’s just looking at the X-15 plug and JUST the EM half of that plug (the EM is the harness that changed the F did not).

As for the X-16:

The (LgB) is from a pwr steering switch (memory here) and is mating with a YB (forget what YB does in life. Still, it’s not right.

Then theres a (W) wire mating with a GB. Not compatible at all.

Then the (Lg knock sensor output going to .....no wire at all. Wheeeee!

That’s all I care to input on this topic. A little digging will give you the answers. This is just series four , NOT series five which is easier.

dave1986

yes, I looked at the link in the link.
water temp problem solved.
no aux fan.
I didnt do anything with the BrB wire yet.
I didnt do anything with the X16 connector wires yet
I cut the wire from the power steering at the ECU so timing would not be retarded when I turned the steering.
I am going back to the garage with my manuals to check as many individual sensors and components as I can before cooking dinner for the faimily.
I you can think of any thing, I will try it to, Thanks, check back in a couple of hours.

satch

iTrader: (1)

Did you install the Fuel Pump & Relay Resistor that is used on turbos?

dave1986

I installed a new walbro 255 fuel pump.
I dont know what the relay resistor is, please explain it to me.
Thanks

satch

iTrader: (1)

It boosts the voltage to the fuel pump when you step on the throttle to accelerate quickly. It ends up supplying more fuel to the engine under heavy load. W/o it it 'might' cause the engine to gasp when under heavy load. If the engine can smoothly accelerate while the throttle is slowly pressed but falters otherwise then keep this in mind. The wiring diagram for the turbo fuel pump will show this item.

You also might want to check for a boost leak.