SpeedracerRX7

Ok I have tried posting this before but the moderator moved it to PFC forum and I got no responses so please don't move this one.

Pictured here is my dyno and from the consensus it seems that it must be a wastegate duty cycle problem. This being the case, which way should I adjust my duty cycle to alleviate the problem. Should I replace the solenoid or is this the signal it is being sent. Please give me some help because it is really making the car vibrate on the top end. It is also very annoying knowing that the car is capable of running smoother and isn't currently. I haven't had the car running at 100% in over a year and if I could solve this problem at least I would be at 98% or so. Thanks for all you help and time.

PraxRX7

I saw a similar reading in my Tourque levels on my turbo II, it had something to do with retarded ignition timings(timing for RPMS and Torque were being read from the Spark Plug wires)...but they didn't effect the HP curve

Are you still running the Twin-Turbo system? It almost looks like when your second turbo comes on your power and torque start fluxing. That could only be a wastegate malfunction if it was opening and closing spiratically and opening to much???

It looks like somthing more though...wish I knew 3rd gens a little better. (something buggy with the second turbo / how the wastegate is handling it). It could also be something to do with your ECU/fuel computer isn't getting the right signals and is giving a spirattic fuel supply....

Dunno if that helps or not...might want to get it checked out at a shop (if you can find a good one).

SpeedracerRX7

Ok I am still running on the stock twins. The signal for the ignition was taken from one of the spark plug wires. Before I put it on the dyno I though that I was getting breakup due to ignition but looking at the graph it makes me think that it has something to do with boost. I just don't know where to go and look for the problem or for that matter how to.

Are there any other opinions out there.

SpeedracerRX7

One last chance before I go nuts. I may even go crazing and trade this damn thing in for a Grand Sport Corvette if your aren't careful. Somebody please talk me down. (I hate people who just write bump)

es

Does the boost stay consistant or is it bouncing to?

SpeedracerRX7

The boost seems to bounce just a hair on my boost guage but of course that is could be about 2 psi from looking at my guage. This is one reason I think that it has something to do with the wastegate.

Beast From The East

Dude, it's definitely your wastegate/boost control venting and shutting, venting and shutting. Since you posted on the PFC board I'm assuming you have the PFC, so what are your boost control settings for primary and secondary (duty), both for setting 1 and 2?

Either the settings are wrong or one of your solenoids is freaking out.

I've gotta go off-line now, but we can look at it in the morning.

Beast

SpeedracerRX7

Thank you so much for your interest. I do have the PFC. I have never adjusted the boost settings from what they were when I first got the computer. If I were to even start messing with it without professional support I know the motor would pop. This is why I haven't tried anything to date. Do you think that trying a new solenoid is the first thing that I should try or should I give the duty cycles a go?

Want2race

I had that problem

turned out to be spark plugs and wires ( I think it was the wires)

SpeedracerRX7

I thought that it might be ignition related at first but after looking at the dyno I ruled that out becuase the power loss seemed to be cyliclical and not peaky like most ignition breakups. If you notice it seems to have a consistant wave patern to it and this is why I think it must be boost related.

Beast From The East

Let's look at your duty cycles first - if they are ok, then you will need to test the solenoid.

How old are the solenoids? The get heat baked and will fail regularly.

There's a guy named Asraf Farrag on the Big List who is the resident guru on boost control issues. If you are a member of the Big List, you should give him a shout. He's very knowledgable and pleasant to boot.

Please publish your duty cycle settings for boost, as well as what setting you are at (option 1 or 2 on boost).

Beast

SpeedracerRX7

Ok here we go:
1 PR .80 @ 56%
SC .70 @ 64%

2 PR .90 @ 62%
SC .80 @ 70%

I always run the car on setting 1 but I was going to try 2 the day of the dyno until I saw the chart. I wasn't sure I would have enough fuel to run it after seeing this one as well. I thought that I was running on the edge with a peak of about a 12 AFR.

I have never heard of the "Big List" before but is sounds interesting. Let me know where I can find it if I can.

As far as age of the solenoid is concerened, all I can tell you is that I have changed the two solenoids out once before searching for a problem but that was with another set of used ones. This tells me that they are at least 8 years old so that very well could be the problem. Thanks for all your help and let me know what I could do to test that solenoid. I am sure it requires a volt meter or a jumper cable from a live source but I wouldn't exactly know what to do with it. I would say that the solenoid has to be working partially in order to keep me from overboosting as well as underboosting. Can it partially fail?

Beast From The East

OK, your settings are stock and should be fine. You have another issue, either your solenoids, or collapsing hoses, or your wastegate diaphram itself is cracked. You'll have to figure it out by process of elimination.

To test the solenoids you will need a 12v power source and a volt meter.

The best person I can recommend to help you is Ashraf Farrag - aka The Boost Dr. Here is his email:

afarrag@triad.rr.com

He's on the Big List and knows the system better than anyone I know besides my own mechanic.

The big list is the old rx7 listserv. You can ask the email admin on the process for joining. His email is:

owner-rx7-digest@world.std.com

Good luck.

Beast