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Discussion Starter #1
I have gone from OBDI to OBDII to be able to better control fuel with a piggy back.

I am having a problem of running too rich, and no matter how lean I make the piggy back, it won't lean out. It is almost like a voltage clamp or something where as the ECU won't allow the voltatage to drop enough. I don't know though.

I am getting an error though, CPS error which I assume is the crank angle sensor. Anyone have any issues with this?
 

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Hardtopper
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Why in the world would you go from OBD1 to OBD2? Are you sure this is not a TT?
 

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What kind of piggyback you got in your car? I'am obdII right now and just boght the map ecu II to be able 2 control my o2 sensors since obdII ecu keeps adjusting my a/f back 2 14.7..so my prob is like the other way. JDM NA-T
 

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feeding your habit
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Why did you go OBD2? OBD2 is a pain in the ass because you have to force it to open loop control or it self tunes out your fuel trims. I'm not saying it cannot be done - there are ways (o2 foolers, split sec black boxes, removing the water temp sensor input to the ecu) but most people go OBD1 from OBD2 not the otherway.

The ECU (OBD2 or OBD1) doesn't care what you have for injectors.

Please keep us updated on your status.
 

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Registered
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274 Posts
Why did you go OBD2? OBD2 is a pain in the ass because you have to force it to open loop control or it self tunes out your fuel trims. I'm not saying it cannot be done - there are ways (o2 foolers, split sec black boxes, removing the water temp sensor input to the ecu) but most people go OBD1 from OBD2 not the otherway.

The ECU (OBD2 or OBD1) doesn't care what you have for injectors.

Please keep us updated on your status.
I guess the only thing on obdI is
Quote:
Originally Posted by 96sc3
really? only 440cc? how come GTE guys can run 800cc+?

NA cars are Karman Vortex, not MAF. Karman Vortex is completely different (frequency based not voltage) and you cannot run 50% larger injectors. Apples to oranges.

Thanks,

JH
__________________
a quote from PHR
 

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Discussion Starter #7
I have come to the realization that NA ECU's CANNOT control 780cc injectors. Doesn't matter if it is MAF or KV.

This is my hypothesis:

Reason is due to a voltage/frequency clamp. These cars will idle with no AFM/MAF at all. The only way this can be done, is that the ECU must only allow a certain low voltage/frequency, otherwise it would not be able to run with ZERO signal. Once you go to a certain size injector, you cannot get the ECU to pull back anough fuel.

This would probably also be the same with the TT ECU, but you can probably run up to 1200cc injectors.

NA=320ccx2=640cc
TT=550ccx2=1100cc

I could be wrong, but it makes perfect sense to me.

Looks like I will be going stand alone.
 
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