Idle and ECU woes

udubrx7

*This is all regarding a D16A6 engine which was originally automatic and still has the auto throttle body/intake manifold*

I was wondering if any of you ECU gurus know anything about the differences between a PS9 and a PR3 ECU? I know the PS9 is just the autotranny version of the PM6. I'm curious because my car acts much differently depending on which ECU I use.

With the PS9, the car will not idle under 1200rpms with the EACV plugged in unless the idle adjust screw is completely screwed in. I'm assuming this just means I need a new EACV. With the EACV unplugged I have to readjust the idle screw to get the car to run, and I can get it to sit right at 850rpm.

BUT, after readjusting the idle and unplugging the EACV to get 850rpm, the car is SO jerky when I try to hold a steady speed or get on or off the gas quickly, it feels terrible and I can tell it puts terrible stress on the drivetrain. It is also jerky like this when I am using the PR3 ecu. Does this just mean my TPS is probably shot?

So onto the ECU differences... When I run the PR3, I cannot get it to idle under about 1000rpm with the EACV plugged in. I would prefer this since it is a lot lower than I can get with the other ECU, but every time I get off the gas now, it pretends I didn't get off the gas for about a second. So when I shift I have to completely let off the gas about a second before I clutch to make it smooth, FUCKIN WEIRD!

Anybody got any ideas? Do I just need a PM6? Or just a new EACV?

TIA,
Thomas

stampern

Hmm, could be a mixture of things. I actually have a manual pm6 ecu and intake manifold if you are interested. I don't know the exact differences between the intake manifolds if any really. It could be a bad EACV, but I'm also suspecting that it's the ecu. Are you getting any CELs?

udubrx7

Only CEL I'm getting is autotrans lockup solenoid on the PS9 (bc the car is manual now). No codes on the PR3.

I didn't think the EACV was necessary to retain regular driveability, I have seen a lot of Y8's with it just removed and blocked off, but I doubt they were having the jerky/touchy throttle problem that I'm having. To me that part of it really points to the TPS, even though I thought that little dashpot on the throttle body was there only to prevent this kind of problem when you let off the gas abruptly.

So I guess I just need to check the voltage on the TPS and see if it is dead/needs to be adjusted. Then if that's OK I'll start on the EACV. Before anybody asks, yes I have taken it off and cleaned it already, didn't do anything.

skinny

You should be gettig a knock sensor code from the pr3 as it's a ecu for a b16. The timing on the pr3 is different and that's why your idle may be higher. There is a guy in the classifieds selling a a6 ecu you should try and get it and see if that helps

Sikocivic

skinny wrote:

You should be gettig a knock sensor code from the pr3 as it's a ecu for a b16. The timing on the pr3 is different and that's why your idle may be higher. There is a guy in the classifieds selling a a6 ecu you should try and get it and see if that helps

The PR3 ECU is for the OBD0 first gen B16s. They didn't have knock sensors. The timing is going to be way out of wack with that PR3 on a SOHC motor. If I were you I would try a PM6 in there before you start replacing other stuff. 8)

udubrx7

thanks for the input!

skinny

My obd0 b16 swap had a knock sensor and the pr3 had a daughter board specificly for the knock sensor.

udubrx7

The PR3 didn't throw any codes in my car except O2 sensor when I had it in for about 2 days.

skinny

I know some pr3 and pw0 have had the board removed cause people dont like the stock knock sensors. I kept mine cause I had IHE and sometimes cheaped out and ran regular.