I've just had a mate around asking me to take a look at his car as it's not running right.

It seems to be "hunting" and when revving it, plumes of black smoke is coming from the exhaust, you would think it was a diesel. If you just apply a little bit of revs and lift off it almost stalls.

It was mot'd 3 weeks ago and has only done 25 mile since and he says it starts off with white smoke first thing, then it turns to black smoke.

I know this is mainly for fiat coupes, but I also know there are some knowledgable folk on here that may be able to help.

What engine?

3ltr v6

Wondered where this post vanished too.

Is the engine misfiring on idle?
Timing belt,coolant temp sensor and airflow meter all fit the profile as well as coil pack or injector.
Could be any of them tbh

Or maybe someone's put diesel in It by accident .

It does seem to be misfiring which made me think coil pack or timing.

I know its had a new block fitted and has stood for about a year until 4 weeks ago when he took it for an mot, but he says it was running fine until last week.

Temp gauge reaches 90ish then fans kick in, could temp sensor still be faulty?

Is there a managment light on at present?

Thats normal temp like the coop. It actually means the thermostat is working often like coop they fail and stay open and temp is at 50-70 which is wrong.

Although it can knacker the maf you can try cleaning it with carb cleaner by spraying it. Whatever you do don't touch or brush it though. If you need a new only only buy real ones Alternative Autos stock them.

You can test run a car with a disconnected maf and the idle will be lumpy but it can run better and be more free reving without one if the maf is totally knackered(i believe the computer detects there is no maf so runs on a default map). The management light on the dash board will show red though while its disconnected. It won't harm the car for a quick test run.

There is a throttle reset procedure using the keys which you can google, if you do it inccorectly it can cause v6s to not rev freely. As it stood so long i imagine he recharge the battery and might have reved it when its been fired up for the first time, this is part of the procedure and might have caused a problem.

Old petrol can could be the cause too, petrol only last 3 months or so and then its well past its best.

Inspect the plugs or change them

...if its not any of these simple things you will have to start thinking about getting the injectors checked and/or the engine compression tested. Then think about cambelt/belts changed.(the complete job on a v6 is a big one, some specialists quote cheap with just the belt but look into it.)

Nope, no management light on.

It did have old fuel in and he replaced it with half a tank of fresh fuel and got 25 miles out of it, which even for a v6, seems a lot to me for half a tank.

The way I can describe it is if you put your hand over the air box on the coupe and the revs drop.

The car revs no problem but massive clouds of black smoke, and when you lift off the smoke clears but it ticks over rough.

At first, my initial thought was perhaps the timing belt had jumped a tooth or a dud coil pack.

I'll get him to start with the easiest and cheapest first and go through a process of elimination, starting with disconnecting the maf, then plugs and coil packs.

Is the coil packs the same as the coupe ones?

Just text my mate and he says he had a jump start and that's when his problem started, so thinking ecu/throttle reset might be the problem according to alfa website.

I will post results when I find out the outcome.

Thanks for the help guys really appreciate it

I am not sure about the packs.

They way it sounds is that he must have charged the battery and it was fine then he needed a jump start after it failed again then he then had the problems....

If the battery is on its last legs it can cause running problems, i have heard about this a few times on Alfas GTVs. The battery being in the back has some issues due to the way Alfa wired it, one common being that the rear screen wire can over heat and melt various things one being the whole car...there is a mod to fix this though.

Also he could have fried something when it was jumpstarted.

If it was bump started that can finish off a dieing cat as well which would account for the smoke and the rough idle i think.

When you get sorted post up always interest to hear, good luck

Tom.

edit PS. forgot to say check the induction pipework for splits especially if its been sat for ages it will effect the runing/air/fuelling, these perish lots and there are loads Alfa v6 with modified induction pipework for this reason.

If he jumped it, chances are the ECU is spiked.
Or the battery is poor

Check the engine intake pipe. They split and cause an air leck.

Thought I'd update this as I've just had word back from my mate saying the ecu/throttle reset did make it run a bit better and he has had a diagnostic done on the engine and it's showing a fault on 4 cylinders and air flow sensor.

He also changed the filter back to his old one as the new one he fitted didn't seem to fit correctly and says it's running much better. Just waiting for a new maf and coil packs coming and then we'll see how that works out.

Yea the wrong/badly fitting air filter is a common problem on v6's (i put this in buying guide in a post on here for someone) the miss-fitting air filter has probably wrecked his maf so he should be ok when new one is fitted. Make sure he buys a proper one not a cheap Chinese copy!

After that is fitted get him to do another throttle reset.