[quote="nebbian"]Hi,
Yesterday afternoon my stock 1.8 started really hesitating when I give it more than 10% throttle. It was so bad that I stalled it three times before finally being able to pull out into the traffic.
When cold, the problem isn't apparent, but steadily gets worse as the engine warms up. You can stall the engine in neutral just by giving it 50% throttle in the right rev range (2000 - 2500 rpm). One of the engine tuners at work thinks that it's going really lean at that throttle position. This hesitation happens in all cylinders, and sometimes backfires. The spark is certainly still there, and looks to be happening at the right spot (I checked it with a timing light). Distributor cap and rotor look fine.
That morning I was running REALLY low on fuel, so put half a tank in, perhaps it's the crap that floats on top of the fuel that got sucked into the fuel system?
Initially I thought it was the throttle position sensor, but I checked that and it appears fine.
I've filled up the rest of the tank with Optimax (high octane unleaded), put in Wynns spitfire injector cleaner, taken the battery cable off and hit the brake pedal for 30 seconds, and changed the coolant just for kicks. None of this helped.
When I disconnect the engine temperature sensor the engine goes into some form of 'limp home' mode, idles at 1600 rpm, the mixture gets richer, and the problem is much diminished, allowing me to drive around reasonably normally. But the idle is very high, not really all that good.
I checked the temperature sensor and it looks OK to me (350 ohms).
Any ideas?? I'm really scratching my head here.
Someone at work suggested making the computer flash some codes at me, does anyone know which pins to bridge to make the computer tell me what it thinks is happening?
Thanks for any ideas,
Ben[/quote]
You can check if the idle is correct by warming up the engine to operating temperature then bridging two contacts in the diagnostic box. Bridge GRD(ground) and TEN, then adjust the idle screw till ticking over at 700-750 rpm. This will re-map your mixture perfectly.
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, but whatever the case it's all better now. I did leave it for 5 days because of work commitments, and wasn't looking forward to trying to fix the damn thing... but it looks like it fixed itself!