more boost *update

by **808Camry** » Wed Mar 10, 2004 4:36 pm

Doing that is the same thing as wiring the front sensor to read to both ECU inputs. Just without the cost of a fake simulator. Unless both sensors are tripping, in which case I wouldn't recommend doint that.

by **JoeB** » Wed Mar 10, 2004 7:26 pm

I really like what Eric said and it has a lot of technical merit. The knock sensor is similar to a "glass brake" sensor on a home security system. If something else makes a sound that closely simulates the sound of glass braking, it will set off the glass brake detector, setting off the alarm. One way to minimize that is by not having the glass brake detector too sensitive and locating it very close to the window. That way even if something else simulated the sound, it would have to be very close to the window to set it off.

The same principle applies with the knock sensor. You don't want it too sensitive and you want it close to the source. That's probably why we have 2, 1 for each bank. Anyway, if the supercharger is creating the same noise at some point as the knock sensor is listening for, maybe it is tripping it. It is located pretty close which would explain why the rear is a problem.

In this case taking the front and running into both ECU knock sensor inputs should work well. As long as all components are working and fuel delivery is even, monitoring the front bank should be sufficient. I'm not even having a problem with this and I'm going to do it. I think that for whatever reason, some superchargers might more closely simulate the frequency or noise pattern that the knock sensor is listening for. That would explain why some people have much more trouble than others. I've been running 6psi for quite some time and now 7psi and haven't had any trouble. And trust me, I don't baby it

. I NEVER take off from a light worrying if my CEL will come on. And for my disclaimer, I'm not a mechanic, it just sounds right to me... -JoeB

by **cdssolara** » Thu Mar 11, 2004 2:14 am

Error

by **cdssolara** » Thu Mar 11, 2004 2:15 am

Unfortunately for me, I am getting signals from both sensors. Therefore, wiring the inputs to sensor 1 won't work for me. I've been trying to contact people who have tried various options for getting around this problem. I have been advised of at least 2 places to relocate the sensors to, so I might try that. I was also told that some people with MR2 turbos have had similar issues, and that there may be another sensor that will work better. I need to do some more research on this option, as it sounds like the best alternative.

Today, I finally went through a day without setting off the CEL, but I had to baby the car to do it. Yesterday, I set it off 4 times. It's very consistent after being set off. The car immediately goes into limp mode, in which it hesitates somewhat but runs OK up to 3K rpm. At that point it loses power and my A/F ratio goes very rich. After shutting the car down for a few minutes and then starting it up, the CEL will stay on, but the car runs a lot better, although the throttle response is still not that great. After shutting the car down and letting it sit 3 times, it will start up without the CEL staying on. It's happened so often now that I know when the CEL will come on just by how the car feels.

In case anybody was wondering, yes, this is getting very frustrating.

by **808Camry** » Thu Mar 11, 2004 3:56 am

I feel for you, when it sets off it goes off pretty frequently. So I have to stop somewhere and plug in my scanner to clear it. One night it kept on going off and I needed to get up hill, man what a nightmare that was!

by **JoeB** » Thu Mar 11, 2004 6:16 am

Carlo, If you are getting knock from the front, I would worry. I can certainly understand if you are getting false readings from the supercharger on the rear bank but if you really do have knock, I wouldn't just supress the signal by changing to another type or reduce it by moving the sensors. Have you tested the fuel pressure at the rails? It sounds like your problem might be different. How does you WB-O2 meter read? Did you tune it at 11.5-1? I've heard a couple people now say that is where they got the best power and safe tune rather than the normal 12.5-1. -JoeB

by **JoeB** » Thu Mar 11, 2004 6:19 am

I'd like to go ahead and do the mod that Eric described and run the signal from the front knock sensor to both ECU inputs. Has anyone taken pictures of the knock sensors position with the manifold removed from the engine? Does anyone know for sure which sensor is which, bank#1 - bank#2? My guess is that bank#1 would be the front and bank#2 would be the rear but I don't want to guess. TIA -JoeB

by **808Camry** » Thu Mar 11, 2004 11:15 am

If you do the mod I believe you do it at the ECU where the harness plugs into the ECU. I believe if you follow the SAFC II wiring diagram it shows where bank 1 and bank 2 are, but that's just a guess, I'm not sure how accurate that thing is. Anyone here with an electrical wiring manual? Or better yet if Eric can chime in and take a pic of which wire was cut and tapped to where, that would be great!

by **xtychx** » Thu Mar 11, 2004 12:47 pm

Kondo: try the 5psi pulley. I run my car EXTREMELY hard all the time and I have never had my cel trip even once. Its been about 15,000 miles now with that pulley and zero problems.

-xtychx

by **808Camry** » Thu Mar 11, 2004 1:06 pm

Where did you get a 5 PSI from?

by **JoeB** » Thu Mar 11, 2004 1:26 pm

Ron, I understand how to do the wiring at the ECU and believe the wiring diagram to be correct. My question is, which one is bank 1 and which is bank 2? My guess is that bank 1 is the front and bank 2 is the rear but I don't want to guess. Colored pictures would be real nice. :drinking: