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Have a Au XR6 falcon ute and trying to figure out whats doing with it. Its using like 22L/100km and can actually see it puff out black smoke when free reving it.

It runs ok with an intermittent roughness like its trying to stall on me and a few times has cut out completely on me while driving, usually as I come to a stop at a traffic lights it will get rought and the revs come down to 400-500rpm. 90% of the time she'll run perfect though.

This weekend I removed the manifold and found the intake manifold flooded with what looks like fuel, so ive installed new injectors and tightened all intake manifold bolts and resealed the plenum. Took it for a drive and still doing the intermittent wanting to stall and coughing black smoke, no engine warning lights on and will idle perfect most of the time. so got me stumped.

Have read the falcon forums and I think people on here might have more knowledge.

Just looking for sensible idea's, suggestions and not smart ass comments. Apart from this issue its a good vehicle, dual fuel and just got a paint job.

post-70965-0-24759700-1398591205_thumb.jpg

Edited by AngryRB

I have a second shitbox falcon same model so I can try swapping sensors but a few mechanics said if theres no engine warning lights on then the sensors should be fine

would a blocked cat cause rich fuel mixture?

Edited by AngryRB

tomorrow Im gonna take it to exhaust shop and have the cat and front muffler replaced with a straight thru pipe, then replace the coolant temp sensor, 02 and map sensor with the other falcons that runs

perfect..

thanks for the help so far ..

Edited by AngryRB

Try an ecu reset. Disconnect the battery, hold your foot on the brake for 30 seconds, reconnect battery. If it's getting stuck on the cold map this should probably fix it. If not then hunt elsewhere.

The 4l doesn't have a maf. You've already replaced the inj so I'd check the reg. you're about 13l too rich, that's a lot for a few dud sensors.

this is correct, it has a map sensor which a vacuum leak will cause the car to run rich

It's a maP sensor not a maF sensor so it measures vacuum in the inlet manifold, the more you open the throttle (more load) the less vacuum is in the manifold.

So if you have a vacuum leak the maP sensor believes there is more load on the engine and injects more fuel

MAF= Mass Air Flow

MAP Manifold Absolute Pressure

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