i was looking at 1300cc.com and looked at the rewire part and at the bottom there is a little drawing. could i just fallow that and it pretty much says everything or does it leave out some little details? i read over and over already but pictures make more sense. also i was just wondering what everybody would do first. get a avc-r or a safc. because im gonna be upgrading alot here soon and just wanted to know which one you would get first

 

 

Wow! Great diagram, thanks!

This applies to both S4 and S5s?

 

the wire harness for the resistor in my car arent the same color, and also is there a way to test it to make sure its working without my car being on because it currently doesnt run and i am doing this. need help pretty much

 

anybody

 

those colors are for S4 only

 

Sorry, was editing ...
I saw my mistake 10 sec after posting
Too Tired.

 

c = blue red as well

 

ok..

 

thank you

 

I went go to do the re-wire tonight and had a surprise.

On the relay/resistor plug, the D slot is empty. No pin.

She's an s4 NA.

Do I carry on with the procedure as described, or is there a different version for me?

 

there is no relay resistor on the N/A they are constant 12v. all you need to do is run a power wire to the back and use a relay off the stock wire.

but there is really no reason to rewire an N/A

 

So if I was to anything, I might as well replace the fuel pump wire entirely (like with a heavier guage) and not bother with a relay?

My 7 isn't acting up, but I figured doing this wouldn't hurt. At least, that's what I thought until discovering that the mod is TII only.

 

You still need a relay.

 

Gonna bring this back up.

I am doing a TII conversion to my 88 GTU.
Do I need to rewire like this or anything?

From the above posts I am guessing the NA's system doesn't have the fuel voltage bump down?

Will the S4 TII ECU throw any codes or anything because it won't have the extra stuff?

 

The Turbo ECU will run the engine rich most of the time if you don't use the dropping resistor.

 

***The Turbo ECU will run the engine rich most of the time if you don't use the dropping resistor.***

I don't run rich all the time. I've a TurboII in a non-turbo. Using a TurboII fuel pump with the standard non-turbo wiring. Also using a TechEdge wideband in the car. I also use a TechEDge in the other car, a standard 87 TurboII. Neither car runs rich. I just passed emissions testing this month with both cars, if that's independent proof.

This line of thought about how going from 9 to 12/13 volts will cause a car to run rich is bugging me. I'm gonna put a fuel pressure gauge in the fuel line this weekend and look at the fuel pressure with 9v and with 12/13volts. I don't figure to see squat in the difference. Nor do I expect to see a difference in the afr reading.

Someone define RICH for me verses NORMAL.

 

I bet you do.

We know changing the voltage changes the flow, but pressure and flow are inextricably linked. You can't change one without the other changing.

 

Define *RICH* Surely that fpr has the ability to regulate the very small rise in flow.

 

On th engine bay side it looks like you have A+B & E+F conecting to each other.... is that the idea? or is that just how you made the drawing look?

-Robert

 

no, that's the idea. don't think too much about it, just do it. it works.

and when the fuel pump goes from 9 volts to 12 volts, the flow almost doubles. the way i figure it, the stock FPR isn't large enough to return the unused fuel when the pump is at 12v. which will cause an increase in fuel pressure and running rich when not under load. when i do the parallel fuel rail mod and implement a good FPR, i'll get rid of the resistor/relay and just run the pump at 12v all the time.

 

Okay, thanks for the input. I have mine rewired now... but I did it long ago, and I did it my way before i knew about the relay and all the diograms. I don't think my way is very "safe" I am pretty sure it will not cut off by the AFM, and I think i am running 12V all the time... I am going to do the above rewire tommorow, it will make me feel better inside I picked up the relay and **** today.

 

Richer than before.
The FPR cannot respond to upstream changes in flow/pressure. It is a simple mechanical device that responds only to manifold vacuum.

 

AHHHHHHH Fudge. Damned simple fpr done me in. So here goes the confession:

At idle the alternator is putting out 13.96 volts

AT idle the fuel pump shows 10.11 volts and the AFR is 12.9-13.0 (consistant over a three minute period).

I pulled the pin 3D out of the ECU.

Same idle: the pump now shows 12.61volts and the AFR is (choke, choke, cough, cough) 12.7-12.8 (consistent over a five minute period {hoping the pressure would drop in the fuel rail every minute}).

That was on the stock 87TurboII. I saw no need to look at the 87conversion car that has no resistor and is wired stock, nor did I put a pressure gauge in line with the fuel rail (the numbers convinced me).

I just decided to look at the conversion car: the alternator shows 14.64volts at idle (series five alternator) and the pump
shows 13.96 at idle. The afr is at 13.0, most likely due to my setting the variable resistor at that when setting the idle. Both cars seem to idle best around 13.0afr vs anything else.

Heck, I've forgotten what this thread is all about now.

But...being the hard head I am......I see no reason to add a resistor on a converted car i.e. non-turbo to turbo. A 86-88 has a variable resistor that has a dandy little screw that I can turn and make that 13.0 turn into a 14.7 in a heartbeat (talking idle here and only idle).

And for what its worth...stock turbo cars with mild modifications run PIG RICH at full boost and 10psi on a cold day in Texas. Talking 10.5afr.

 

Thing is, the fuel pump spends most of it's time at low voltage. The variable resistor can only change idle mixture, and you need to be boosting hard to get the ECU to switch to high pump voltage, so for probably more than 95% of the engine's running time, it's going to be running richer than it should be. It's basically fuel, power and efficiency you're throwing away. It may not be a large percentage, but if you're going to all the hassle of converting from NA to Turbo and using the Turbo ECU as you should, then correctly wiring up the resistor/relay seems like a tiny amount of extra work.