Intermittent idle problem....

[Cpagec]

Hi everyone.

I've got an intermittent issue with my rocco that I'm hoping you can help with.

She's a 1.8 with a weber carb and the problem is with intermittent idle/stalling problems.
Its been going on for a few months now and it's once she's up to temp with the choke in, about 3 in 10 times when I come to a stop and put the clutch down the revs will drop to 200-300 or even stall completely sometimes. I can pick the revs up with the accelerator (getting better at left foot braking!) and once I rev the engine a few times it will idle happily at 1000 again. The only other symptom I have noticed is if I'm going downhill for example, with the car in gear, the car will judder as if its stalling. and if I put the clutch down at that point it will be at that low 200rpm level again.

My suspicions so far are either a vacuum problem or a fuel issue, but the latter seems unlikely as I can increase the revs with the accelerator? I got the weber carb cleaned and tuned since this happened, but it hasn't helped.

Any suggestions greatly appreciated. Also if anyone knows a decent garage in Bristol for future work that'd be good.

Cheers
Cp

[Nate]

Buy yourself a tin of carb cleaner from your local motor factor (halfords do it, but expensive without a trade card) and then, with the engine idling, spray it round the vacuum pipes and around the base of the carb. If you have a vacuum leak, the sound of the engine will change when you spray cleaner over it.

[jond]

i seem to have a similar problem,ive has loads of running issues with mine at first it kept losing power when driving and cutting out also lots of kangerooing i was advised to check in the tank by lifting the back seat and removing the sender unit then look inside the tank to see if there is rust debris from a dodgy filler neck blocking the fuel take up when running mine looked quite clean next i checked the base of the carb the new rubber gasket has a split as i had forced the airfilter down to fit the clip without realising the weber carb is 10mm higher i bought a new gasket(again) and fitted an adaptor so the gasket was not under stress when the airfilter was fitted then checked the carb bolts were on nice and tight (one nut had wound down the bolt so it was not tightening properly ) once all bolts were nice and tight the car ran alot better i then spent 50 quid having it tuned and it ran great for 100 miles then the revs droped when idling to 300rpm then it cut out i find if i drive the car at first its ok then when i park up leave it 10 mins then re start it does this for 10 mins or so i have fitted a clear fuel filter and can see fuel getting through and a 0.6mm fuel restrictor i think its the carb perhaps its worn or maybe a dodgy choke though i am unsure how to check ,it also has a small oil leak from the head gasket though i cant think why that would cause a problem i have thought about selling as i need a reliable car but i am getting attatched to it as when running it drives great and it gets loads of attention from other people , hope you get your car sorted and keep me posted on anything you find out

[Cpagec]

I know what you mean about getting attached.. Wasn't planning on having mine for too long, but can't imagine getting rid of it now!
Sorry for not replying sooner, been away and then the the girlfriends car broke so mine naturally had to come 2nd! Because of this not much to report, only that I got some carb cleaner and sprayed all around the base of the carb and around the vacuum pipes, but didnt notice any change to the idle. I will try again when the engine is hot though (fire extinguisher on standby) as this is when the problem seems to manifest itself. I also changed the fuel filters so to hopefully spot any rust debris being caught, but havnt looked in the tank yet. Will report back soon.

[james butler]

common fault is the rubber pipe that connects the servo pipe to manifold splitting which opens up and closes with revs.
sounds like the right symptoms.

[Dutch GT]

The mrs' 'rococo was doing the same but all the time. I tried a number of things then gave in and took it to a garage. Turned out that it just needed opening and cleaning. Haven't picked it up yet though so will see tomorrow. It's a pierburg too and I should have guessed from having to clean the idle jet a couple of times (that didn't work). Think all the gunk got disturbed when I replaced the rubber carb mount.

You said you had it cleaned, but how well? I'm no expert by the way, far from it.

Good luck.

[GT Matt]

She's a 1.8 with a weber carb and the problem is with intermittent idle/stalling problems.
Its been going on for a few months now and it's once she's up to temp with the choke in, about 3 in 10 times when I come to a stop and put the clutch down the revs will drop to 200-300 or even stall completely sometimes. I can pick the revs up with the accelerator (getting better at left foot braking!) and once I rev the engine a few times it will idle happily at 1000 again. The only other symptom I have noticed is if I'm going downhill for example, with the car in gear, the car will judder as if its stalling. and if I put the clutch down at that point it will be at that low 200rpm level again.

I've seen this quite a few times now with vehicles with Weber carbs fitted. Tool me a long time to diagnose but turned out to be a sticking needle valve in the carb itself. Tried several attempts to clean but only cure was to fit a repair kit with all new gaskets and valve. Kit only cost £22 but transformed it. Have since also transformed several other ageing Weber's too.

Matt

[M4tty69]

Ah brilliant, was just about to start a thread about the same problem!

[Cpagec]

Hi everyone.
Finally my car is sorted! I had it looked at by 2 mechanics in Bristol, each of them couldnt diagnose an air leak and said it was a random problem within the carb. Both garages cleaned & tuned the carb. one suggested Probably play in the throttle linkage that runs through the body if the carb sucking in air. On they're advice I've bought another identical 32/34 dmtl and had it fitted this avo. Et voila. Sorted! No more jerking around holding constant speed, no more idle problems.
Do kinda wish I'd tried the repair kit first.. Could've saved me a couple of hundred! But sod it, just glad it's fixed!
I don't know if I'll ever find out the exact cause, but I have no idea who fitted the first one so anything could've happened.

All the best everyone, and if anyone wants the old carb and try a repair kit on it I'll be happy to do a deal.. I can at least confirm its bloody clean inside :)