I have a 99 Si with a custom turbo kit, im using a 255 pump 450 injectors and a VAFC running 9 lbs of boost, now im getting a map code every once in a while and i have to reset the ECU from under the hood. i wanted to know if i could just put a toggle switch on the ECU fuse under the hood so i could just reset it from inside the car...could this be bad for the ECU??? any info will help....thank you...Chris L.

 

Never heard of anyone doing it, but why are you getting a MAP code??

EDIT: Im not farmiliar with a VAFC, but I always thought that they had a built in missing link type thing to keep the MAP from going nuts under boost. Does it always throw a MAP code when it sees boost or is it just intermittent?

 

because the map pressure is going into positive on my VAFC

 

Hrmm.....That should'nt be happening. That VAFC with the stock MAP sensor should be good to 1 bar or so. So it throws a code every time or no?

 

well if i drive it all day it will come on like 2 or 3 times

 

Something is wrong with your VAFC or your wiring. The VAFC should not be allowing the MAP sensor to see boost and go into safe mode. Double check all the wiring and make sure all the connections are soldered and not crimped on.

 

i have triple checked the wiring, all solder joints are good, i think my turbo is just too big and its flowing more air than i can trim(if that makes sence)lol

 

ttt

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turbo90crx &raquo;</TD></TR><TR><TD CLASS="quote">i have triple checked the wiring, all solder joints are good, i think my turbo is just too big and its flowing more air than i can trim(if that makes sence)lol</TD></TR></TABLE>

No it's not making sense to me. As long as you are not over 1 bar, you should have no MAP problems running the VAFC. Don't know how else to help.

 

how does a missing link keep the MAP sensor from seeing boost? just curious.

 

Can't tell you for sure, but I do know that the wire from the MAP sensor is cut and then routed through the missing link *or e-manage in my case* and then is routed back to the ECM.

 

Beware, A'Pexi has the wire colors at the ECU wrong for the VAFC hookup on P28 ECU models (others may be similar). It had me splice a white wire which it said was MAP but in actuality it is 02 signal.

Also, if you are going to install a switch, be sure to also cut the "Back-Up" fuse as well as the primary fuse power.

-zelifcam

 

The MAP sensor wire in my car is either green with a red stripe or the other way around. Can't remember right off the top of my head.

 

Apex`i made a mistake in the wiring diagram. Heres the link to the updated wiring diagram hope this helps http://www.apexi-usa.com/produ...e.pdf

 

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You're correct about Apex-i little mistake in the wiring, BillyHOE. And for that you get a cookie . A friend of mine fiqured out a similar problem with his. Let me get back to you on that. But putting a toggle switch to reset your ECU I wouldn't recommend it. I would first fix the problem that causing your ECU to throw the code.

 

you have the % amount for fuel too low. you prolly have it at around -25 to -30 or something don't ya. That is too low for the stock map sensor. -30 is like the borderline of throwing a CEL .

Goodluck with the toggle switch. It's a really good idea. however i think i'd work on the problem first b4 dealing with the symptoms

 

The MAP sensor is a pressure transducer. It takes pressure (or lack of) and converts it into a voltage. The ECU looks at this voltage and makes a determination about whether it falls within a specified range or not. If it does not, you get a code. The stock MAP sensor can sense up to ~10lbs of boost....but at that boost level, the voltage coming out of the MAP sensor is out of range to the ECU, so you get a code (it starts to become out of range at a voltage that equals atomspheric pressure, or about 2.8v). When you start trimming back with the VAFC, you are in effect making sure that when you hit full boost, the voltage coming from the VAFC IS within range, and thus you get no code.

The missing link is a mechanical device that bleeds off boost so that your MAP sensor sees no boost at all.

So as Del_Slowest has said, your % trim is too high.

And yes, you can wire a toggle switch to reset your ECU from inside the cabin.

 

i have the afc trimmed to like -35 and even -40 in some spots..........

 

is the cookie chocalate chip or oatmeal raisen?

 

this company http://www.racingworks.com/ sells missing link but i dont know what is does or heard anyone using it but the company claims it'll solve your map sensor problems is the vafc wiring doesnt help.