156 stalling under slow speeds

Originally Posted by jug

hang on a minute, i've just read the original post for the first time, cutting out when warm is almost always the crank sensor.

Good call.

Ooooh?

"Almost always" sounds positive. Are there any particular signs of wear I can look out for on the sensor? (I somehow doubt it)

If the crank sensor could have gotten extra wearing from a recent cambelt change then that would hit the nail in the head. I'll look up crank sensors here on all the symptoms etc and I'll get back to here.

Thank you very much for you opinion their jug, I greatly appreciate your time in helping me save my own.

And Pud your car makes me dribble its annoying so lol

crank sensor is on opposite side of engine to timing belt, buts its a very common problem.

Originally Posted by StevenJW

And Pud your car makes me dribble its annoying so lol

Cheers Steve

I think Jug might have hit the nail on the head with crank sensor.. Luckily its a cheap part and not a difficult job to replace. I'm pretty sure it doesn't often throw up an error code when it fails either..

Originally Posted by Pud237

I'm pretty sure it doesn't often throw up an error code when it fails either..

yeah its very rare to get any code from a dead crank sensor.

Is there anywhere online where I can get a genuine Alfa crank sensor from, or will I have to go to an Alfa dealer? I checked EB Spares, and the Alfaworkshop, and I'm pretty cert they don't sell them.

I wanted to go genuine Alfa though after hearing from another guy on here that had a non genuine one that was more expensive, and not appropriate.

Great, so today I bought a new Crank sensor today, new rocker cover gasket and new MAF filter.

I bought this all from Motorvogue Alfa in Northampton, and got the original Bosch MAF filter for a very reasonable £65. They cut as a deal there too for the lot too, making the crank sensor £22.20, and gasket £21.37.... Gonna do the work tomorrow so I'll let you know if the stalling all clears up.

P.S Motorvogue also trade on Ebay under the name 581300

is she alive?

ARRGH! I'm just doing it now dodging the showers and all. Its such a pain in the arse for an enthusiastic yet inexperienced car mechanic, as there are nooooooo manuals whatsoever. That ELearn thing is such a waste of time, it doesn't even deserve to be a coaster. I just wish Haynes or somebody made a manual for Alfas!

How on earth am I supposed to get to the sensor without removing the starter motor? lol I see 2 bolts on the top holding on the starter motor, but is that really just it? I don't wanna have to get under my car, as it take a good 1/2 hour of time with our crappy jack with the 156 being so low. And will it be a pain to put back on again? As access to the 2 bolts holding the starter motor on is so limited. Im gonna start having to worry about how much daylight i have left.

http://www.alfaowner.com/Forum/alfa-...nk-sensor.html (HELP ! replacing 156 2.0TS crank sensor)
Simon here apparently managed to replace his without removing the starter motor, but frankly, to believe that, he must have hands as thick as cigarette paper?!

need some encouragement bleeeh this is taking hooours!!!

Ok, so can somebody please point me in right direction.
http://img164.imagevenue.com/loc1030...122_1030lo.jpg
The red circled black object is the starter motor right? And underneath it should lie the crank sensor?

The yellow circled cable goes to another sensor.

And the blue arrow points to another sensor, that I couldn't get in shot.

My problem is, is that from what i've felt under the starter motor, there is no cabling going to a sensor there at all, and NOTHING I can see that looks like my sensor.

Can't see the website - access denied.

Suggest - Find where the existing connector connects into the wiring loom (probably behind the manifold) and then trace the existing cable to the sensor. If you can't find the matching connector then maybe it isn't the right replacement sensor.

Also, these things are really sensitive to even tiny exhaust leaks which give fluctuating back pressure to upset the fuelling and fluctuating readings from the lambda sensor to make it even worse. The whole exhaust should be completely silent except at the back box obviously.

Classic leak places are;

- Leaky weld between each pair of pipes on the manifold
- Same where the 2 pipes join on the front pipe just before the joint
- Flange joint between the manifold and front pipe. Any non flatness or smoothness in the plates means the gasket won't seal properly.

The engine is quite noisy at tickover and small leaks can be really hard to track down without the car on a ramp (blow cigar smoke at the suspect area, spray with water + fairy liquid or hold a tissue near it - ouch ?).

Iv'e been chasing my tail with mine after I had a 2nd hand manifold (£20 ebay) and a cheapo new system and alfa gaskets put on mine. I then ruled the exhaust out of the investigation after it made a big improvement - convinced that the leaky exhaust had been masking the real problem which was yet to be found.

It turns out after new
- plugs
- air filter
- HT leads
- lambda
- MAF
- timing belts - variator OK
- pulley belt
- oil separator valve

- air hoses sealed up
- cleaned throttle body
- cleaned idle actuator and ruled out of enquiries

... hesitation almost gone but it still stutters on a steady throttle at 70-80 in top probably because;

Theres still leaks in the exhaust they are just small and hard to find. It's back in to the garage tommorow to get fixed properly - will report results.

Mine also has big splits in the vertical air intake pipe just above the airbox. Successfully repaired with gaffa/speed tape + tyraps.

my elearn cd is great, it has step by step instuctions and diagrams.

you really need to get under the car imo, it makes life so much easier.

Originally Posted by StevenJW

Ok, so can somebody please point me in right direction.
http://img164.imagevenue.com/loc1030...122_1030lo.jpg
The red circled black object is the starter motor right? And underneath it should lie the crank sensor?

the pic is far too small to see anything, its smaller than my thumb.

aah ****y, thats weird why that happened. It was HUGE, maybe imagevenue resized it.

Oh well, well i completed the work today. I replaced the MAF filter, and the crank sensor. The thing is, now when i go to key the car, they injector light flashes, and the relay in the bonnet near the battery clicks. Is that blown? Its such an arse, as now I can't move it at all! Thanks for your replies though.

It sure was nice working through the rain, lying in puddles, and getting drips in my eye. still love my alfa though

Is the fuel pump priming when you turn the key?

Erm, how do you mean "priming" when the ignition is on 3/4 way, the injector light with flash, and click at the relay.

It just sounds like it needs to "catch"

Pud's suggestion about crank sensor would be right if the car is hard to start again when warm. If it stalls when warm and restarts OK, I'd probably say it isn't the crank sensor.

On cable-throttle cars the idle actuator on the side of the throttle body can alter the idle. I've reset the actuator with AlfaDiag a few times when the idle starts to fluctuate and this has always solved it. Even just the simple throttle reset (90 secs on/off) has often made a difference for a while.

The actuator problem shows up in two ways from my experiences:

1) on low throttle in traffic, the car lurches (kangaroos) as the throttle is being altered by the actuator

2) if you hold the throttle so the engine runs at around 2500rpm, it will climb and drop again as the actuator affects it. At first I though this was me and put a block of wood under the throttle ... proving it was the car. This is the engine speed used on the MOT to test emissions ... and this can and will often cause it to fail ... my problem a couple of years back.

But I am starting to think my lambda may have something to do with it as well. When I've looked at the various manufacturers websites, what sticks out is that the correct Bosch lambda is rated at 8 ohms but the NTK fitted to my car is only 4 ohms. It's highly likely that universal sensors are also only 4 ... but I've never been able to prove it and have steered clear of these anyway. I'm not an electrical engineer but that says to me, the NTK is wrong for the car. As most of my idle problems seem to be when the engine is warm and on reasonable low revs, I'm looking to replace my lambda with a Bosch one when funds permit ...

When I started to experience my original problems it wasn't helped that the "oil separator valve" between the crank and intake manifold was faulty (i.e. missing). Replacing that bought the idle back to a reasonable level ( without it was 1400rpm!). But then the lambda showed up as faulty on the MOT (hence quick NTK replacement). It was now the fluctuating idle started to manifest itself ... so it has always been difficult to diagnose. But it was only when I started to use AlfaDiag, that I managed to get the idle back under control.

It's been fine now for 2-3 years, only now starting to occur again. A lambda sensor has a limited life, this is why I think it's the NTK unit. Only when I've got the car running on the proper Bosch can I look into the other aspects ... and as the car is due an MOT in late-June, I shall be looking to replace that lambda shortly.


Other owners have had problems with the NTK lambdas: but in their cases, it usually affected MPG. Mine's not bad at around 25-26 but it's been better ... so I'm wondering if this is the sign I'm looking for ...


One final thing: my battery is now about 4 years old and starting to struggle starting the car first thing in teh morning ... could this be another factor? The battery was fairly new when the problems originally started so I discounted that. Don't forget my car's a manual with a cable-throttle.

ah lol, I disconnected the earth cable that connected up to the throttle body, that's why it wasn't starting. What a cooicidence how it showed up my MAF as faulty though? Right.... test run tonight guys!!! Cross your fingers!

(I can't while driving, its hard enough to grip a wooden steering wheel with any kind of moisture in the air)

And thanks for all that gazza, that's really interesting. I can definitely look back at that and get some really good holes to scope out any future problems. I too went for a generic Lambda sensor, but mine has barely done 100 miles, so I expect it to be ok unless faulty from the beginning. That AlfaDiag also seems like a little shining beacon of happiness for you lol as it really is quite flexible in its uses to scope and solve problems.

....... It still stalls....

The fact that the new MAF filter gave me a new v-max of 130mph is of small consideration as, as soon as I come from a slow speed into a stop, it stalls. It just ruins the whole experience you know of driving?

I'm at the end of my tether guys, I can actually say I hate my Alfa today..... sad day...

I'm £170 down, 3 days erased from my life/72hrs I could have spent have sex, and I'm still at square one.

I'm gonna check the spark plugs tomorrow now.
(And please don't have a go saying "it should have been the first thing you should have tried" as I mentioned it from my first post)

I don't see why it would be the spark plugs though, as the replaced HT leads fixed my misfiring problems. If the sparky's were failing intermittently then I would have experienced a misfire at speed, but I haven't? So....

Just to recap then guys, my car has had:

New MAF filter
New Lambda sensor (non original)
New HT leads
And a Diagnostic

And the car seems to have developed a passion for oil too...

Oh an RT, my car does have small exhaust leak in the back box, but nothing along the rest of the exhaust from the manifold on, so I kinda doubt that small hole makes this whole problem.

Sorry for not reading back through the whole thread, but have you had it on an examiner/AlfaDiag yet?