Completed MPFI convertion issues remain - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

carazy · 02-22-2003, 15:59

Hey all I got my MPFI on this sat and it took me exactly 8 hours from start to finish. Would have been quicker but I spent nearly 3 hours stuffing with the timing (not my forte) to get it to start correctly.
Now if any one out there reading this still has CFI....GOD DAMN WELL CONVERT NOW!!! After the convertion the damn thing boots. Totally differant car and now my rear tyres a bald after 1 day of driving around. Still need's some more mods to be a true beasty (like a twin turbo setup or at least a zoorst in the mean time)
But it still has a small issue.
Drives perfectly smooth when accelorating and idles a little high (900-1000rpm) but when you take your foot off the accelorator in 5th it seams to surge or lurch or something like a JUG-JUG-JUG unless you have some throttle on.
Now the only thing I can think of is that the ISC is staying open hence the nice idle but at the same time this extra air being let through when the TPS reads 0 could be stuffing it up a bit.
Does any one know weather the ISC cloeses at any time?
I havn't wired the old plug to the new ISC sensor yet so this is my next step. Just thought I'd ask.
Now I don't really want to wire plug wire 21 in through the engine loom as I don't want to risk killing it can I simply wire it to where the sensor plug is and skip the rest of the loom?
Cheers all.

Walkinshaw · 02-22-2003, 18:08

Quote:

Originally posted by carazy

I havn't wired the old plug to the new ISC sensor yet so this is my next step. Just thought I'd ask.

Theres your answer

02-22-2003, 19:41

The ISC valve is PWM(pulse width modulated) driven by the EEC to maintain idle speed. It constantly varies to achieve this. If it isn't plugged in you will of course not have any idle control. The ISC valve is shut when it is not plugged in so unless it is jammed open it will not be causing your high idle.
It is likely also one of the reasons you had trouble starting it.

Pete.

Sundeep · 02-23-2003, 00:57

Doug (SPHELL) and I did the conversion on my EA too. We did that ISC wire to the loom thing and it idles at 900-1000rpm still?!? I don't know what that's all about. Maybe it's shorted along the line somewhere. What does that wire do?

Also, we didn't do the fuel pump either and it still idles and fine except for one thing, which I am not sure is related....it jerks when you put it in to gear, the same thing that happens when you let go of the clutch too early kind of thing. What's that all about?

Thanks,

Sundeep

ONE39L · 02-23-2003, 02:14

i get a lurching when im slowing down in any gear as soon as the gas comes off it lurches and surges and its still cpi but i put it down to worn engine mounts the motor does bounce around alot thankfully it hasnt caused much else to stuff up....yet

carazy · 02-23-2003, 02:24

yeah sundeep that's exactly the problem I'm having.
The way I have my ISC wired up is this.
on the CFI ISC plug I have taken wire 21 and attached it to the grey/white wire on the plug to the ISC.
The other three plugs are not attached (on the CFI ISC plug)
Now from looking at the wiring diagram.
wire 21 is the DCM + and 41 (or one of the other 3 on the CFI ISC plug) is the DCM - maybe this is the problem I have to wire up both to get it to work??
I checked the base idle on the car and it didn't stall at all so the timing is ok. But the motor didn't rev up like it is supposed to either.
I then did a diagnostic (constant fault diag) and it released the codes 11, 10, 11 (aka nothing wrong)
but then when I ran an intermitant check ( the one where the motor is running) it gave me error 12 and 13 (ISC valve issue)
now what I don't get is why it's saying that it's not a constant fault but it is intermitant if it's not wired up. Surely if it wasn't connected correctly it would list as a constant fault rather than intermittant?
Hope some one has an answer for this.
What I'm gonna try tomorrow is to connect plug 41 to the red wire on the ISC unit and 21 to the grey one. I'll take the unit off and see if it works at all.
Cheers for the responces so far btw!

02-23-2003, 18:14

Carazy,
Have you used an MPI harness and EEC for your conversion?
It's sounds like no?
One side of the ISC valve is to pin 21 and the other goes to VPWR or injector power(EEC pins 37,57).

Pete.

carazy · 02-23-2003, 18:50

Hey there Pete,
I've got the MPI wiring loom for the injectors and the ECU is from a manual MPI setup but the loom from the ECU to the MPI harnes is the CFI one.
I'll check into the other pins cheers.

carazy · 02-23-2003, 18:58

Right I pulled out the old gregories manual and had a look at the wiring. Found the problem.
I have the Grey/green wire going to my ISC rather than the grey/white one.
That's why it's not working.
I'll wire it up correctly tonight and be a happy man again.
The red wire is wired up ok.
I have differant colours on my plug because it's a EB CFI rather than the EA one.
I was warned about the fact that there was 4 differant types of loom.
Oh well hope fully this will fix it.

Brent79 · 02-23-2003, 22:49

Hey crazy, if u still have problems with the ISC wiring, connect the other side of the ISC (ie, NOT the grey/white) to the canister purge connector thats sitting to the right of the throttle body (red wire) i had to do this on my EB cos i used the CFI looms...

Brent