2.8i throttle sticking?

[Dansta]

Hi folks.

Driving after my 2.8's winter slumber, it seems like the throttle is staying open on overrun ie does not coast slow down when I lift off throttle. Also engine is battling against braking. If I depress the clutch revs stay 2500-3000 ish either at speed or stop.

If I blip the throttle, the revs drop whether stationary or coasting. If I am stationary and hold revs high they drop to normal when I release throttle.

Throttle body does not seem to be sticking and opens and closes freely.

I'm still figuring out MFI (I'm used to EFI) and I would value any thoughts anyone has please. Thanks.

[Peter-S]

Having you checked that the cable itself moves freely within the outer casing?

[Dansta]

Thanks, it seems to be moving ok.

[MattMe]

I'm by no means an expert, but until someone else with more knowledge comes along (which they undoubtedly will), here's my thoughts:

If the throttle body appears be opening and closing, and the cable not sticking the other things that could cause the engine to rev would be fuel mixture.
Perhaps something else is sticking like the central plunger in the metering head, or the sensor plate in the airbox is sticking, causing the plunger to stay open?
Should be a fairly simple check - you could have it all apart and back together in an hour. There can't be that much that could cause this issue I wound't have thought, and giving a good pray of carb cleaner over the plates and arm won't be a bad thing to do anyway.

It may be something to do with a vacuum on the system somewhere, but that's not something I know much about I'm afraid.

Good luck and let us know how you get on.

[Bug]

Whoa!
Before you dive in too deep try this...
Next time it happens, put your foot under the throttle pedal and pull it up.
If it slows down then it's a nice simple fault in the linkage somewhere

[Dansta]

Thanks MattMe and Bug.

Good thought about the pedal. I'll try that. It would be nice for it to be simple like that. I've got a CO analyser so I'll check that too. Thanks!

[MattMe]

Whoa!
Before you dive in too deep try this...
Next time it happens, put your foot under the throttle pedal and pull it up.
If it slows down then it's a nice simple fault in the linkage somewhere

Yeah, that sounds an easier thing to try first!

See, I told you someone else would be along soon enough!

From what you'd posted already I got the impression you were happy the throttle cable, linkage and throttle body were operating as expected. But if not definitely that's the first place to start before going down the route of anything I've said.

[Dansta]

Finally found the problem. The cable was being squashed slightly between the the bonnet deadening material and the strut brace. Thats why it always seemed OK when stationary but also why it didn't seem like the cable was sticking. Re routed below the strut brace and problem solved.

[pbar]

Credit to you for coming back and offering the solution. Many don't!

[Andrew 2.8i]

Finally found the problem. The cable was being squashed slightly between the the bonnet deadening material and the strut brace.

Hi,
A nice easy fix, and something for others to watch out for.

Andrew.

[D366Y]

Finally found the problem. The cable was being squashed slightly between the the bonnet deadening material and the strut brace.

Hi,
A nice easy fix, and something for others to watch out for.

Andrew.

Mine has just started doing this yesterday - was interesting as I tried to slow down for a rounabout and the bloody thing just sped me towards it even faster.
I don't have sound deadening on mine though so is it likely to be a connection at the pedal/carb end I need to look at?

Thanks

[Bug]

Finally found the problem. The cable was being squashed slightly between the the bonnet deadening material and the strut brace.

Hi,
A nice easy fix, and something for others to watch out for.

Andrew.

Mine has just started doing this yesterday - was interesting as I tried to slow down for a rounabout and the bloody thing just sped me towards it even faster.
I don't have sound deadening on mine though so is it likely to be a connection at the pedal/carb end I need to look at?

Thanks

Good luck finding the carb on a 2.8i (assuming that is what you have?)
Often the culprit (on the 2.8i) is a build up of crud on the sliding quadrant on top of the throttle body (you will have one of those )
A good spray of WD40 and a brushing off may well be all it needs, before you go any further.
I assume you've tried the old foot under the pedal, pull it up, trick?

EDIT: Oh hang on, looking at your details, not sure it is a 2.8i you have after all?

[D366Y]

Good luck finding the carb on a 2.8i (assuming that is what you have?)
Often the culprit (on the 2.8i) is a build up of crud on the sliding quadrant on top of the throttle body (you will have one of those )
A good spray of WD40 and a brushing off may well be all it needs, before you go any further.
I assume you've tried the old foot under the pedal, pull it up, trick?

EDIT: Oh hang on, looking at your details, not sure it is a 2.8i you have after all?

haha yes sorry I should have been more clear!
This is on the 1.6, have a 32/36 on it currently

Putting my foot under the pedal and pulling it back up does work, which is what makes me think there is something wrong with the cable or connectors but I don't know where the best place to start would be??

[pbar]

I tried to slow down for a rounabout and the bloody thing just sped me towards it even faster.

That's just the power of the Pinto engine.

[Mc Tool]

I tried to slow down for a rounabout and the bloody thing just sped me towards it even faster.

That's just the power of the Pinto engine.

Oh gawd , dont you start

[Mc Tool]

Good luck finding the carb on a 2.8i (assuming that is what you have?)
Often the culprit (on the 2.8i) is a build up of crud on the sliding quadrant on top of the throttle body (you will have one of those )
A good spray of WD40 and a brushing off may well be all it needs, before you go any further.
I assume you've tried the old foot under the pedal, pull it up, trick?

EDIT: Oh hang on, looking at your details, not sure it is a 2.8i you have after all?

haha yes sorry I should have been more clear!
This is on the 1.6, have a 32/36 on it currently

Putting my foot under the pedal and pulling it back up does work, which is what makes me think there is something wrong with the cable or connectors but I don't know where the best place to start would be??

Nothing gives your sphincter a workout like a stuck throttle, not good getting cramp there . Remove the cable from the carb and the throttle pedal(dont have to take it off the car at this stage ) and then move the inner back and forth to check for snagging . Sometimes the inner cable frays inside the outer sleeve , usually at a bend , ....where you cant see it . Also make sure the carpet isn't fouling the pedal.......wouldnt be the 1st time thats happened

[Mr B]

Mine has just started doing this yesterday - was interesting as I tried to slow down for a rounabout and the bloody thing just sped me towards it even faster.
I don't have sound deadening on mine though so is it likely to be a connection at the pedal/carb end I need to look at?

Thanks
[/quote]

Inner cable possibly fraying and snagging inside the outer sheath?

Had this happen about a year or so ago, it frayed in the small section between the pedal and where the inner cable enters the outer sheath at the firewall, the only symptom was the idle speed getting hung up, sadly it snapped when I was jestured too gun the car by a couple of people who see me coming up the road, 3litre Essex with Sportex pipes- sounds lovely well it did until the cable snapped, luckily I was already just passed them when it happened, I just turned up the idle speed as much as possible then had to drive the car up the A13 in East London at just over 20 mph, total nightmare

[pbar]

Also make sure the carpet isn't fouling the pedal.......wouldnt be the 1st time thats happened

That's a good shout. I've had similar on a campervan, although the pedal is hinged from the floor on that, but the floor matting interfered with the pedal and caused it to rev high when braking/changing gear.

[D366Y]

Thanks for the replies guys, will go and check tonight that it's not the carpet, and if it isn't I guess I'll just buy a new cable?

Cheers

[D366Y]

Wasn't stuck on the carpet at all, but cleaned up the throttle linkages and the sort around the carb with some WD40 and a toothbrush and so far it's all working as it should (so far!)