164 3.0 v6 24v poor throttle response!

Help! I started up my 164 super today after its been sitting dormant for a good 6 months hoping to get her mot'd and back on the road.

It started fine but when giving it any more than part throttle it seemed like it was misfiring and is very reluctant to rev above 2.5k with occasional backfiring.
Its also running hot and producing foul smelling sulpher exhaust fumes and I can't work out what the problem is.

I took the air flow meter out and cleaned it but it made no difference

Any one else experienced anything like this?

I can honestly say from this JUST happening to me this past week... best bet is your fuel pump went out. I replaced mine and fired right up... then the relays went out oh alfa electrics! Yeah but it may be a pain to get it out but that would be my best guess, also see how much fuel pressure you have.

Hi Alfissimo,I have a funny feeling its fuel related but with an electrical fault associated with the fuel system rather than the fuel pump itself.
When I first started it there was some loud clicking noises from the front of the engine bay (timing belt side) and there is a single lone relay there but couldn't tell if the relay was the cause of the noise or not.
The car starts and idles ok if a little bit lumpy and fumey but when you press the throttle it revs to around 2.5k then just will not go any higher and if you keep trying the engine just dies.

It feels like its being starved of fuel but I dont know although the fuel pump could be an option but I got the the feeling it would either work fine or not work at all.

I'll try checking some fuses to see if that shows up anything.

Originally Posted by Jamiegtv

Hi Alfissimo,I have a funny feeling its fuel related but with an electrical fault associated with the fuel system rather than the fuel pump itself.
When I first started it there was some loud clicking noises from the front of the engine bay (timing belt side) and there is a single lone relay there but couldn't tell if the relay was the cause of the noise or not.
The car starts and idles ok if a little bit lumpy and fumey but when you press the throttle it revs to around 2.5k then just will not go any higher and if you keep trying the engine just dies.

It feels like its being starved of fuel but I dont know although the fuel pump could be an option but I got the the feeling it would either work fine or not work at all.

I'll try checking some fuses to see if that shows up anything.

I would confirm timing first. Also make sure all connections are free of corrosion, modules on airbox are clean and have the correct grease on them to work properly. Also check for any vacuum leaks, especially the main air hose, very carefully. A hairline crack can cause this issue.

I have a suspicion that it may be timing related or vacuum leak..


Try those things and get back with us.

BTW, nice name AlfissimoUSA

Jason

Make sure that the fuel pressure regulator's not stuck either!

Well,I had a look again this evening and fiddled around with various things but still no joy.
I removed the relays and fuses associated with the fuel pump and cleaned the contact areas but still the same problem.

I couldn't see any vacuum leaks but I'll have a better look tomorrow and check the air flow meter with a multimeter.

The fuel pressure regulator,I never thought about that I'll look into that as well

But alfa's,you've gotta love em,that loud clicking noise that I mentioned earlier was the air conditioning clutch working for the first time since I bought the car 4 years ago!
So although the engines not running worth a damn at least the aircons working

Originally Posted by Jamiegtv

Well,I had a look again this evening and fiddled around with various things but still no joy.
I removed the relays and fuses associated with the fuel pump and cleaned the contact areas but still the same problem.

I couldn't see any vacuum leaks but I'll have a better look tomorrow and check the air flow meter with a multimeter.

The fuel pressure regulator,I never thought about that I'll look into that as well

But alfa's,you've gotta love em,that loud clicking noise that I mentioned earlier was the air conditioning clutch working for the first time since I bought the car 4 years ago!
So although the engines not running worth a damn at least the aircons working

Also while your at it, check crank angle sensors and cam angle sensor. Might as well change fuel filter as well just to do some easy things.

Had another go tonight,checked the airflow meter with a multimeter and it seems ok but suspicion is now falling on the throttle switch.

I disconnected the plug to the throttle switch and the idle speed increased but apart from that made no difference to the running of the engine with the initial problem still there.
I also checked it with a multimeter and couldn't match the results printed in the book.

Until I can source another throttle switch it looks like I'm stuck.

Can you be sure that the timing is correct?

I can't be sure the timing is correct but unless a component associated with the timing has failed since I last started it 6 months ago,I can't see what could've changed,crank sensor maybe?

I noticed last night that it's slightly better when the engine is cold.

I've had a brainwave though,I'll disconnect the throttle switch on my alfa 75 and see what happens, although its jetronic rather than motronic it'll be interesting to see.

Originally Posted by Jamiegtv

I can't be sure the timing is correct but unless a component associated with the timing has failed since I last started it 6 months ago,I can't see what could've changed,crank sensor maybe?

It could have happened when starting up, I guess. Maybe the belt's loosened over the period of non use and jumped a tooth when starting. I'm no mechanic by any means, but I've gone through this rigmarole twice and both times it was the belt having jumped a tooth.

I hope it isn't mind, and it's worth checking everything else out. I just would have thought you might have a warning if it's something the ECU requires to work.

Well,it looks like im beaten on this one for the time being until I can get some time off and spend a good 3 or 4 days getting it properly sorted out.

I disconnected the throttle switch on my alfa 75 and it made no difference to the running of it so I doubt thats what the problem is on my 164.

I'll order a new fuel filter and timing belt and maybe a lambda sensor as well and see if that helps.

I'm beginning to wonder if the spark plugs are maybe fouled up with it sitting so long.

I really dont think its the cam timing though as it starts and runs perfectly at idle and up to about 2.5k rpm, after which it seems to misfire and fluff,but I could be wrong.Must investigate further.

Originally Posted by Jamiegtv

I really dont think its the cam timing though as it starts and runs perfectly at idle and up to about 2.5k rpm, after which it seems to misfire and fluff,but I could be wrong.Must investigate further.

You may be right. On mine when the timing's been out, the idle has been wonky and it's only okay past 4k rpm.

May be cause its been stood so long it could be damp coils Why dont you try at the spark Take out the front plugs give them a good clean same with the coils dry them and try again and see if there is any improvement

Hi,

hate to say it but agree it could be the cam timing. Am in the process of replacing the belt on my 1995 164 as something made contact with the belt, thankfully without snapping it but caused it to jump a tooth - on the rear bank, of course. Runs a bit better when cold but generally a bit lumpy. The rear inlet cam jumped forward a tooth but tooth jumping can also cause it rev poorly - had a cam out by 2 or 3 teeth on my X1/9 once (Fiat made a batch with the timing mark in the wrong place!) and it just would not rev beyond 5000rpm - instead of the usual whizz round to 8000rpm (into the red but pretty indestructable engines those).
Definitely try everything else first though - changing the belt is a bit of a dog.

Hang on a mo.... could it just be expired fuel? why not drain it and re-fill with new clean fuel..

I'm kinda with B.N. and Richard on this one; mine had a very similar problem... turned out it had jumped a tooth on the rear bank!
Not uncommon apparently.

Right! I'm away to remove the rocker covers to check the cam timing and It'll be a good time to fit the cloverleaf intake runners I bought last year in the process

I'll report back to let you know what the outcome is.

Originally Posted by Jamiegtv

Right! I'm away to remove the rocker covers to check the cam timing and It'll be a good time to fit the cloverleaf intake runners I bought last year in the process

A mod well worth doing BTW. Only problem is you get used to them after a couple of weeks.

Removed the rocker covers and the cam timings fine on all four cams so unless the belt slipped around the crank pulley the cam timings ok.
Thats a relief at least because it is four years since I changed it but there was a big chunk out of the back of the belt though,don't know what could have happened there.

So I will order a new timing belt tomorrow along with a fuel filter but I'll leave the lambda sensor for the timing being,I just saw the price of them

Alfaholik, thats a good point about draining the fuel,the reserve lights on anyway so I'll do that before I fit the new filter.Does petrol go off after a while?

B.N,How do you mean you you only get used to the intake runners after a couple of weeks?

Richard 111,another exxie owner do you still have it?my x19 is keeping my alfa 75 company in my garage,funny you should mention that about the cam timing because mine wasn't running as I felt it should be and discovered the mark on the pulley was 2 or 3 teeth out from TDC,after I lined them up it ran much better but I never had the chance to try it on the road as mot had ran out.Looks like the last owner must have thought he had one of the bad pulleys.

Hi Jamie

Yup, Petrol does not last forever.... and if your tank is low it is more likely that and nasty deposits will have been forced through the fuel system too... i wouldnt waste any more money until the Fuel system has been drained and filled with a decent tank full of 99RON from Tesco..

PS cant believe you had x19's too.. i have had loads over the years.. sold my latest one a 1976 1300 serie special to a chap called graham in Aberdeen... he drove it there all the way from south wales...

Good luck mate...

I'm with Alfaholik with the idea of fuel that has aged.

I had a generator, on a carb, which had sat for about 4 months, which wouldn't start. Opened the carb bowl up, and the fuel had started to turn syrupy, and in places had gelified into icky flammable blobs.

I was surprised it had gone so far in 4 months, so six months is definetly in territory for going gloopy.

I believe it is to do with the additivies to the octane, either reacting with each other, or with the octane itself, causing polymeristation, i.e. the 8 carbon chain octane starts becoming 10,12,14,16 etc carbons. As the number of carbons on the chain increase, the more solid the result.

This is why some people claim a difference in fuel quality in favour of the cheap supermarket stuff. It may not have so many "trick" additives as the BP or Shell, or as much Octane (97 RON rather than 98), but the freshness from the high turnover at supermarket petrol stations off sets it "lower quality". It would be difiicult to prove this, as atmospheric affects can have as much influence (cold wet air Vs Hot dry air), but enough anecdotal evidence is about for there to be something in it.

I would consider flushing the fuel system with clean fuel, and maybe even go to the expense of having your injectors ultrasonically cleaned, or at least checked. They have very fine holes through which the fuel flows, which would clog very easily, even at the very high fuel rail pressures.

Originally Posted by Jamiegtv

Removed the rocker covers and the cam timings fine on all four cams so unless the belt slipped around the crank pulley the cam timings ok.
Thats a relief at least because it is four years since I changed it but there was a big chunk out of the back of the belt though,don't know what could have happened there.

So I will order a new timing belt tomorrow along with a fuel filter but I'll leave the lambda sensor for the timing being,I just saw the price of them

Alfaholik, thats a good point about draining the fuel,the reserve lights on anyway so I'll do that before I fit the new filter.Does petrol go off after a while?

B.N,How do you mean you you only get used to the intake runners after a couple of weeks?

Richard 111,another exxie owner do you still have it?my x19 is keeping my alfa 75 company in my garage,funny you should mention that about the cam timing because mine wasn't running as I felt it should be and discovered the mark on