ChrisRX8PR

Here is my questions:

Will a leak on a runner between the LIM and the UIM cause the car to misfire or appear to do so?

I was weary of a seating surface on the new UIM I fabricated for my engine because it seemed to seat a little less nicer than the other two surfaces and I used some gasket paper to make gaskets for the UIM/LIM joint because the stock UIM/LIM uses special deep O-ring type gaskets and I couldn't reuse these.

Today I was driving at or under 0psi of boost (so I know it isn't a broken engine) and all of a sudden after about 5min from leaving the house I felt like something went and the engine started sounding like it does when it has a coil unplugged, or an injector not working right or maybe even a cracked apex seal(although I know it isn't that) ....I could hear some kind of intermittent hissing coming from the engine so I am assuming its a vacuum leak.

I want to know whether the leak itself will cause misfire/lumpy running or whether there is a possibility that a piece of gasket got sucked into the engine(I was at vacuum when it happened) and maybe got lodged in an apex seal or a side seal or something of the sort and that is causing the misfire.

Attached find a pic of the UIM in question with a circle around the one area I was weary about. My car has a Microtech LT10s so it doesn't run on MAF even though it has one.

All help is appreciated, thanks in advance.

Best regards,

Chris

arghx

iTrader: (3)

The first thing to do is see if it is in fact leaking there. Any leak will show up if you pressure test the system. you can build or buy a pressure tester like the one at www.boostpro.net/prodtester.html (universal tester at the bottom, you don't even need a gauge installed). then just use a 4" --> 3" reducer coupler to attach it to the turbo.

I just bought that one in the link, but to make the tester yourself I think you can just use a 3" PVC cap and tap it 1/2 NPT and install a male air compressor fitting. Bolt everything up like the car is running. Remove the air filter and install the pressure tester on the compressor inlet using clamps, then attach the air compressor hose to the tester. gradually increase the pressure on the air compressor regulator starting at 0psi and moving up, until a few psi boost register on the gauge in the car. Feel around for air escaping at the suspect mating surface. spray it with some slightly soapy water to verify there are no bubbles.

One more question... do you retain the SSV and auxiliary port motor for that Renesis setup?

ChrisRX8PR

I actually already determined that it was leaking. First the boost gauge was reading way less vacuum than usual and it was also fluctuating a little at idle showing variation as the port drew air in. I also left the car running and opened the hood and I could tell the hissing was coming from there. When I get home I will do the "stethoscope" test with a piece of 3/8" hose to my ear just to verify that it is only leaking there.

About the setup...I Have the SSV fully open all the time (just like a REW engine has all four ports open if you replace the throttle body w an aftermarket one) and this poses no issues. The APV I had open all the time for a while and it is still that way, it kills the bottom end of the engine(I don't really mind too much) but I am working on a controller for that motor that I can adjust the RPM it always opens at. I don't want it running off the stock ECU because it has like 6-7 variables that need to be met for it to open and this makes tuning a PITA no to mention that it will not allow it to open when it thinks you lost traction(like when on a dyno with the front wheels not moving).


Anybody have input regarding whether the leak can cause a "misfire" kind of lumpiness?

Thanks,

Chris

arghx

iTrader: (3)

if your boost gauge is reading less vacuum so is your EMS, and any problem with the vacuum reading can make the car run worse. What do your logs say? Is it running in different cells? This is an Interceptor-X right, basically Microtech wired in somehow in parallel with the stock ECU?

I thought the APV motor needed a duty signal. That's what the 2009's use at least, according to the service highlights document from Mazda.

ChrisRX8PR

I did not have logs for the drive. I am hoping that is what it is though....

I do have an Int-X but its still a stand alone microtech...it just leaves certain things connected to the stock ECU to keep it happy so the power steering and the A/c, TCS/DSC etc still work...oh, and it controls the throttle body because it is Drive by wire. I am hoping I can pull the intake mani off and see an obvious piece of gasket missing...and then just remount it with better sealing...and it goes away...

The APV has 5wire plug. it works like a servo that has the "control chip" external to it....this means that 3 of the 5 connections are for the position/duty cycle control...the other two are the + & - of the motor (the actual test mazda recommends to check whether the APV motor is working consists of sending power to these two terminals to ensure the motor is turning). So if you make a controller that can shut off when it reaches either end you can control the motor in the APV through those two wires.

Chris