3200 surging / hesitation

[Dodge]

Hi all.

At motorway / A road speed, at constant throttle and constant speed my 3200 has a slight hesitation / surging feeling. When accelerating or decelerating it's not there. It's only subtle and doesn't affect the speed of the car, but annoying on a long journey. Otherwise the throttle is fine.

Has anyone else had this issue? We've changed the lambda sensors which didn't cure it so I'm wondering whether it's an early sign of a throttle body issue.

Any help / suggestions appreciated. Cheers

Andrew

 

[davy83]

Could be a bunch of things unfortunately. it might be throttle body, could be pedal sensor too. does it idle ok? only notice this problem at cruise? does it matter what speed you are going? could be knock sensors or O2 sensors, both of these can cause some instability at constant throttle.

 

[Dodge]

It idles okay, a little erratic when cold, but no severe jumping in engine speed, when warm it's fairly level.

It's only noticeable at a cruise and generally between 60 and 70 mph

 

[Contigo]

Surging is phonic rings. Get them checked out.

 

[CatmanV2]

Or just a misfire.

C

 

[allandwf]

My guess is the throttle body, worn where it sits at the majority of time. Although, as others have said, it could be a few things.

 

[Dodge]

Thanks for the replies guys. It doesn't feel like a misfire as it only happens at high constant speed and not when accelerating or at low constant speed. It's an odd pulsing

 

[conaero]

Check the turbo actuator arms, they seize and cause this issue.

 

[Dodge]

As its due a service soon, I'll get those things checked out and hope it's something simple! Appreciate your help, thanks

 

[Contigo]

My car had exactly this even with new throttle body and Davy's pedal pot, as i have said it was like a surging pendulum effect as if the brakes were being applied very slightly at cruising speed in top gears around 60-80mph. I had it diagnosed as Phonic Ring issues by Emblem but sold the car a few months after, Talking to the new owner he say it is still there and he thinks it is a gearbox issue (manual car) but I struggle to see that.

Phonic rings is where I would start.

 

[Rex B]

phonic rings interesting, I used to experience a very slight variance of speed at around 70 on motorways when you are applying just a slight throttle, don't have the problem at the moment but did have a rusty phonic ring changed so who knows and miles at emblem know more than us, I also have had throttle body and pedal changed.

Rex B
Manual 3200

 

[RW3200]

My car had exactly this even with new throttle body and Davy's pedal pot, as i have said it was like a surging pendulum effect as if the brakes were being applied very slightly at cruising speed in top gears around 60-80mph. I had it diagnosed as Phonic Ring issues by Emblem but sold the car a few months after, Talking to the new owner he say it is still there and he thinks it is a gearbox issue (manual car) but I struggle to see that.

Phonic rings is where I would start.

Could it possibly be a faulty crank position sensor in that case? I'm sure I've read of similar problems on other cars.

 

[davy83]

i thought the phonic rings only came into use when the brakes are applied? or does it apply the brakes to stop skidding, so if it thinks your wheel is locking up it applies brakes? seems wrong way to me? if its a stability regulation thing then it would be applying brakes to one side? so it would pull as well? Crank sensor is a good call, they don't last long. it might be causing very subtle problems and not noticeable unless you are trying to hold constant speed.

 

[alfatwo]

i thought the phonic rings only came into use when the brakes are applied? or does it apply the brakes to stop skidding, so if it thinks your wheel is locking up it applies brakes? seems wrong way to me? if its a stability regulation thing then it would be applying brakes to one side? so it would pull as well? Crank sensor is a good call, they don't last long. it might be causing very subtle problems and not noticeable unless you are trying to hold constant speed.

That's what I thought Davy...what's the ABS braking ECU got to do with the engine management system's in normal running.... not in sport mode

Dave

 

[Rex B]

Phonic rings surely also control the ASR system which has the ability to cut injection and ignition, I am not saying this is the problem but if Emblem are saying that it could cause this problem then there must be a link in the systems, let's be honest Emblem have a lot of knowledge of these cars.

Rex B
Manual 3200

 

[alfatwo]

Phonic rings surely also control the ASR system which has the ability to cut injection and ignition, I am not saying this is the problem but if Emblem are saying that it could cause this problem then there must be a link in the systems, let's be honest Emblem have a lot of knowledge of these cars.

Rex B
Manual 3200

The ASR system according to the hand book only works when you manually switch to Sport mode..

In normal driving all that stuff is disengaged!

Dave

 

[Rex B]

The ASR on my 3200 works on normal and sport mode , it cuts in ealier in normal mode and allows more slip in sports mode, you must have experienced this unless year 2000 cars were different to year 2001.

Rex B
Manual 3200 year 2000

 

[Tompelli]

Can confirm Rex B's statement 2002 3200gta, ASR cuts in on normal mode with excessive loud pedal usage & noticeably going over humps where one or more wheels not in contact with the road

 

[davy83]

yes the workshop manual tells you the ASR works in both modes its just less aggressive in sport mode. So i can only assume that faulty phonic rings make the ASR controller think there is a problem and it starts touching the brakes to stabilise the car, causing surging. makes sense. so yes check your phonic rings!!!

 

[Contigo]

Exactly that Davy, if faulty it is like someone is ever so slightly dabbing the brakes which is exactly what mine did and what the OPs does!