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156 2.5 V6 stalling cut out misfire

8K views 29 replies 11 participants last post by  selimgencoglu 
#1 ·
Hi people,

I need your expertise again please.....

I have a problem with my 156 2.5 V6 2000 W reg. :confused:

Once the engine has warmed up it stalls when pulling up at lights etc, when you dip the clutch the revs go so low it cuts out, sometimes it catches itself and brings back to idle. Also my temp gauge does not work. I have changed the temp sensor, lamda sensor, charged the battery, cleaned the throttle body, changed the air filter, put new spark plugs in, drained and put new coolant in, the maf was changed just before purchase a few months ago and seems to work as when pipe removed car stalls. I now have alfadiag but am unsure what to be looking for to determine the problem, old skool diy not new school you see. It has a slight rough feel when reving so might be misfiring slightly? Would appreciate any advice as its starting to do my head and pocket in.

Cheers

Danny :thumbs:
 
#13 ·
I own a 1998 156 2.5 v6, and I have the same idle problem. I don't think it is the split on the corrugated rubber pipe. If there is such leak, then the idle has to be higher that usual..because there is more air getting into the mixture...

I have cleaned my throttle body several times. I have had my MAF and lambda sensors replaced with genuine BOSCH parts...I've had my spark plugs replaced with NGK ones. I fitted new air filter. Oil and filter change done... But still have this erratic idle problem. I am sick of it. Sometimes the engine stalls in a parking lot..sometimes at a speed bump.. It is becoming really dangerous.

I suspect the culpit is the small stepper motor on the side of the throttle body.
Does anybody know if I could get only a new stepper motor without buying whole throttle body..?

All the best.
 
#7 ·
Actually in my own experience my car drives awfully and won't even idle a lot of the time with the MAF unplugged. But then mine has a 3.0 in it with Dastek engine management running a lot of ignition advance so its not exactly the best test car for things like unplugging MAFs etc.
 
#15 ·
Like I said, if there are any splits, this will cause a higher idle. I don't have any high idle..
When i first start the engine, the idle goes up to 1.100 and 1.200 then gradually drops to 800-900 range. I slow down for a speed bump..and release the clutch to go in neutral gear, and then the car stalls...
 
#18 ·
I think I am gonna buy another throttle body (second hand) and see if it solves the problem. I feel the stepper motor causes the problem. No matter how much I clean the throttle.. this problem starts again in a week or so.
 
#20 ·
Pud237...

what if there are no leaks, splits on the plastic pipe..? What would I do next..?
 
#26 ·
hey Pud237...
I did a throttle reset (90 sec sequence), and now my idle is worst. I tested the car. WHenever I slow down for a speed bump and release clutch....or at the red light I wait...the idle starts getting higher and higher gradually..until it hits 1200 -1300 rpms...
Strange..very strange. I disconnected the battery.. I will re-reset the throttle..when I get home. I don't want to take all inlet maıfolds and the plastic pipe apart all by myself...I am gonna stop by my alfa service, and let him disassemble the whole thing. Good thing is that we become friends and also he owns a 1998 2.5 v6 too..he does not charge me for such things..

Sometimes I miss the good old days with wire controlled throttles...
Thanks for the inputs. I will let you guys know.
 
#28 ·
I don't think the culprit is knock sensor. I will check the throttle potentiometer with Examiner, and the connector to the ECU under passenger foot well. Then I will clean the throttle body and re-reset it. While doing that, I might as well check the idle actuator. As far as I know, once you clean the throttle body, no matter how many times you reset it, it takes some time for the ECU to re-adapt and re-learn my driving habits..
So time is the cure I guess. I love my Alfa anyways..
 
#29 ·
Ok.. just discovered that when I cold start the car, it won't idle properly..it cuts out as soon as I wanted to go.. I push throttle pedal smoothly to keep idle at 1.200 at red light..If I drop the pedal, the car stalls.. Anyway..if the temp gauge read 50 and over..There is no stalling at all... Funny..?
Then when I stop at a red light, the car idles very smoothly..
Why...???

Any suggestions...?
 
#30 ·
Guys,
I have fixed the idle and stalling problem by replacing the throttle body and the dodgy connections between the throttle body and the ECU which sits under the passenger foot well.

Rock solid idle...!!!
Try the reset, if it does not help you..than change your idle actuator and check for dodgy connections..(depending on your car.. 2.0 TS or v6)
http://www.alfaowner.com/Forum/alfa-147-156-and-gt/55388-156-wonky-idle-the-fix.html - (156 wonky idle - THE FIX !!!!)

If it is a v6, which is the case here.. then upon resetting the throttle body..drive for 200 miles, let the engine adapt your driving..If you notice that the problem arises again..then it is time for a throttle body replacament..

I know it is not that hard to clean the throttle body..but somehow the bloody mechanism is so ginger..Cleaning works for couple times..than it is time for a throttle body replacement.
So take extra precautions while cleaning that up. Do not under any circumstances touch the flap.. Spray the carb cleaner..and use pressurized air to dry it.

Cheers to all.

--
Selim
 
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