Help/Advice needed!

[AdamG]

Hi there,

I’ve been having a problem with my car over the past couple of days. I’ve noticed some Rev hanging during gear changes. This comes a couple of days after putting fresh coolant in my car (it was empty), and now every time I change gear the revs are significantly slower to go down than prior to this. I used to be able to shift fast and drive the car with haste, however now I’m really struggling to build speed. To give some context, on the same day this occurred, I noticed my Speedo has now stopped working. Also, I have a severe rupture on my exhaust at the right angled spot towards the back of the car, and wondered whether this may be playing a part in it. Any advice/help is hugely appreciated, and before typing anything please be aware that I am extremely new to actually working on cars and thus my knowledge is limited.

Thank you in advance,

Adam

[Jay-Kay-Em]

With these cars being a traditional throttle cable, the most common cause for hanging revs between gearchanges is a binding cable.

The easiest answer is simply buy a new cable - but I appreciate that's easier said than done in the world of 480 parts.

I have had mixed results with lubricating cables. I cut a finger off a laytex glove and zip tie the cut finger to the cable outer. I then fill the glove with oil overnight and let it gravity bleed down the cable...



Sometimes they are beyond lubricating because the inner nylon core wears away and the cable frays.

Or its another reason to cause a bind, such as a partially seized throttle butterfly spindle, broken throttle body return spring or even a stray carpet or floor mat!

If it is that, it shouldn't need test driving, it will do it when parked, at idle, just blipping the throttle.

I think the other matters, such as an inoperative speedo and a blowing exhaust are merely coincidence; the speedo being a 480 trait well documented on here.

[AdamG]

Hi!

Thank you for the reply, I had a check of the throttle body and throttle cable today with a more experienced friend of mine and he said they both seem to be in working order. It seems it may not have had coolant in it for some time, and I’m worried that I may have damaged it more than I thought by driving it coolant-less unknowingly!

Adam

[dcwalker]

You should be OK re the coolant - the car should have warned you if it was getting too hot so as long as you haven't ignored any red light warnings on the info centre....

When I see you we will hopefully get to the bottom of all this

David

[jamescarruthers]

Hey Adam,

Check where the accelerator goes through the blukhead in the engine bay. I know two of my early cars have had the sort of guide tube on the cable break up and cause it to stick. I've sort of bodged it with garden hose and tie-wraps to guide it better but on my current car it sometimes still rears its head now and again.

Does your car have a catalytic converter? I ask because if the leak on the exhaust is before the Lambda (oxygen sensor) it will affect the fuelling as it tries to correct itself for what will appear a weak mixture. If you have no Lambda sensor, you are just making noise but not affecting the fuelling.
[edit: you have a Celebration, so it will have a catalytic converter. Some members have had them break up internally and block the exhaust gasses, with the corresponding major lack of power].

P.S. a lot of those faults seem unrelated!

[AdamG]

At first the speedo seems to only want to drop when I’m accelerating more heavily than usual, but after a while just goes altogether! This all starts as soon as my engine has warmed up and as soon as the Rev hanging starts to occur. This is the only reason I believe they must be linked to each other! The car also won’t stall even when in gear. It will happily roll at 400-1000rpm in ANY gear and not stall. Also an absence of noticeable engine braking. Literally none! I could be at 40mph in second, let off the throttle and it just sloooowly cruises back down. Very slowly lol. I’m beyond confused!!

[Alan 480]

It might be the throttle position switch, mine failed and left the revs at 'fast idle' which is not clever in town when dropping down a gear or 'lifting off'

different models have different switching settings.

I think it is a three position switch, mine was filled with oil from the throttle body, cured by drilling a drain hole .. . .

[AdamG]

Car has stalled twice today when decreasing speed for a set of lights or roundabout etc. Worried about it now!

[richard-smyth]

Hello, my 480 stalled a few times when the speedo wasn't working. My understanding is that after going to the speedo the signal goes to the car management and without the signal it gets confused then stalls the car. Seems that speedo issues are usually that the cable on the cluster electronics board needs re-seating or there is a dry joint on the board.
Cheers, Richard.

[dcwalker]

This can be so many things, unfortunately. Throttle Position Sensor faulty or oily; dirty throttle butterfly valve; ICV dirty or faulty; ECU or engine management system related (perhaps not helped by your knackered exhaust); clutch related (thinking about some of your earlier posts); clogged air filter (if so, why?); speedo related (another issue you've mentioned - speed signal goes via speedo to ECU) etc etc...

You're amassing so many problems with this car it's likely that at least some are related. However, it is a 480 so it's always possible they're not, of course.

I think your only answer is a methodical analysis and look at the car and all its issues. I know we're trying to arrange this and hopefully we can manage it sooner rather than later! I'm reluctant in the meantime to throw too many suggestions out there for you.

David