hoping someone here could help cure a T25 small turbo escort cossie that's not feeling well. its has a strange "fuel cut" under heavy throttle/boost. it feels like fuel momentarily cuts out when accelerating hard, but goes back to normal when you lift off the throttle. also, i have a fluctuating idle for about 30 seconds when the engine's cold (goes up to bout 1500, then almost stalls, then goes back to 1500). and finally, the car when at normal temp on occasion won't start until the engine is cold. battery is good, starter is normal, and fuel pump is working. somehow fuel isn't reaching the engine.

i've replaced the spark plugs, fuel pump, map sensor, air flow meter and still the problems persist. any input would be appreciated.

 

Not too sure about the small turbo engine, but in general think terms, have you tried replacing the Idle Control Valve. This should stop hunting for idle at cold.

As for the cutting out, what sort of fuel levels are you running. Low fuel levels in the tank can sometimes cause a misfire under acceleration. Might also be worth checking the fuel pick up in the tank is ok and hasn't moved. (Big job as this is tank out).

Other suggestions are blocked fuel injectors or old fuel filter not letting full flow rate to the injectors.

 

I had the same problem on my T25 cossy, when I bought it and it bacame worse when I put a HYBRID turbo on it. Ispoke to loads of ''experts'' on the subject and they all kept saying fuel starvation etc, bad tank design, but in the end I figured it out for myself.
The car used to do it under load, but not all the time.
Basically the brain can calculate so fast that it hit's overboost, before it even gets there. Answer remove boost limiter and turn up the boost. I had this done and now the car is excellent. Mine mucks around in a similar way at idle from cold, but I don't know what it is. I just suffer it for a few minutes.

 

Mine used to mess about and be erratic on idle when cold - only happened after I had new lambda sensor fitted. Was fine before that

 

Stupid question....Have you replaced the fuel filter?

 

actually i forgot to list that. yes, that was replaced. the mechanic found a "kink" in the fuel line inside the tank and thinks that may be part of the cause. but he's still working on it.

 

Hi, I've got the same problem on my T25 only when I connect the pipes on the overboost sensor...if the sensor is off ev.thing ok. try to put on NGK sparks

 

Overboost sensor? The MAP sensor senses overboost and you can't run without that connected.

 

a recent finding in this puzzle was that after replacing the MAP sensor, i started running 100 octane petrol in the car and the fuel cut problem seemed to go away. until that time, i was running 91 octane as that's usually all we've got here in sunny california. i'm guessing the original computer is rated to run on 95 and higher so it wasn't liking the crappy american fuel.

 

Jesus i dont think my lawn mower would run on 91 oct lol, if ya have to use it try putting some octane boost in that should help.
Cheers steve

 

maybe one of the coils is letting go ?