Something is seriously wrong!! - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

AUII_Forte · 10-11-2004, 05:53

Just a quick question regarding my recent MPFI conversion.......

Is it wrong that the car runs heaps better with the CFI ECU than what it does with the MPFI ECU??? LOL!!! I can confirm that a CFI ECU will run MPFI, not exactly 100%, but it runs. In my case the car actually idles and revs pretty responsively, but the ECU seems to cut fuel for a second or so every now and then. If the car is idling it'll just die, but if held at 3000rpm it'll nearly stall, then pick itself up again. It doesn't seem random, the frequency is pretty consistant.

For those of you that didn't read the other thread, the car hesitates really badly throughout the rev range, misses eratically and occasionally backfires out the inlet. As well as having a pretty bad idle. I changed the injectors over and it made no difference and today I bought new plugs, leads, dizzy cap and rotor. I haven't installed them as yet because I don't think they are the problem, they are far from new, but the engine ran smoothly with the CFI setup.

I think it's fairly safe to assume I have a dodgy ECU! The timing is staying static at about 30+ deg BTDC and isn't advancing or retarding at all. If i twist the dizzy back to 10 deg BTDC the bloody thing won't run. I'm sure the balancer hasn't moved because it was running spot on 10 deg BTDC with the CFI setup and it was running fine. I spliced into the appropriate wire for the ISC so the idle should be fine, I have no vacuum leaks and I have changed the fuel pump over to the MPFI one. Does anyone have a 3spd MPFI ECU that they are willing to donate or sell very cheaply???

Apart from the ECU what could the problem be???

Rmyers · 10-11-2004, 10:25

Maybe check the fuel pump?? Could be dodge. From what i've read, the ecu's are one of the most reliable things in the car, so i'd be looking at other things that could cause these symptoms rather than blame the ECU straight away. But you could be right, and if so, then your best bet is to find someone willing to even lend you their ecu for a day or so to see if it solves the problem...

EA-XR6 · 10-11-2004, 15:15

I'm having my car looked at today.
It could be a wiring problem related to PIP and i'm having my car looked at today because my injectors are staying open for too long.
Ill let you know how it goes

AUII_Forte · 10-11-2004, 15:41

The thing that sort of gives it away is the timing is staying static. I started it with the CFI pump before I put the MPFI one in and it was doing exactly the same thing. I don't know how it can be wiring related....the only thing I had to wire in was the ISC. Does anything need to be done with the dizzy wiring???

EA-XR6 · 10-11-2004, 17:05

Can you take your plugs out?
Tell me if they are all carboned up..and put the new ones in as well.
And see if they carbon up

NZ · 10-11-2004, 17:10

It might be running in Limp Home mode (aka LOS Limited Operation Stratagy)

In Limphome mode you will get:

Ignition timing fixed at 10 degrees BTDC
Canister purgeis locked out
Injector pulseis fixed - MPI 4.5ms, EFI 4.0ms and all injectors fire on every PIP signal
MPI ISC duty cycle is 75%
EFI the ISC DC motor remainsa at whatever pointit was at when the failure occured

This give a very rich engine charachterised by black smoke from the exhaust

Sundeep · 10-11-2004, 21:18

Ahhh yeah....sounds to me like the fuel pump is knackered. Had the same problems running a CFI fuel pump in my EA after MPI. It would get pressure, run good and then the pressure would die down and it'd start running like a mother, and when revved it'd back fire or die in the arse. You could feel the power dying out as the pressure went down.

Sundeep

AUII_Forte · 10-12-2004, 01:02

Ok, latest update:

Got a 3spd MPFI ECU from the wreckers and plugged it in. Car runs fine, idles pretty well (still need to set the base idle) and seems pretty responsive, BUT i'm still not getting any timing advance! Whats the go?

As I understand it, as revs increase the timing advances as needed, but it's not even fluctuating at all, just stuck rock solid in the one spot. According to the balancer it's sitting at like 30-40 deg BTDC and if I back it off to the IGN mark, the car just becomes a complete dog, won't idle, backfires etc. I suppose the balancer may have slipped, but it still doesn't explain the static timing. I put the car in self test mode and the timing was in the exact same spot and the only code the ECU spat out was 12, which is something to do with the ISC-DCM. I don't get it at all!!!

AUII_Forte · 10-12-2004, 02:58

Anyone??????

AUII_Forte · 10-12-2004, 20:58

Come on guys! Someone has to know. I've fiddled round with everything and I can't seem to find why the timing is staying static. For all I know it could be supposed to be static until the car is in gear or something.