Hessitating with part throttle(warning long story)

[Bass J]

Hi folks ..me again .

Basically had this problem before ...spoke to markey mark and thought the best option was to get a carb that worked overhauled and sent up to me .. so fitted that carb ..took it small runs ..like round small roads etc and it seemed fine.

So i thought ..everything was all well ..took it to Millers to get the carb jetted for 1bar boost. ..before we did that we took it on a run with the wideband ..all was fine till i let t he car settle ..put it into 5th gear and tried to use a wee bit of throttle ..it kept juddering(making the car shake like hell). So we got it back to chris's ..he checked it all ..noticed i hadnt had my throttle cable on properly so was only achieving half throttle. Sorted that ..he sorted some bits and pieces ..cleaned it up a bit ..we took it a run again ..checked the AFR's on boost ..he said it all was fine. It did however pop and bang on overun. Chris then said he aint touching any jets untill it can drive off boost first ..which is what i want first lol.

So we left chris's and he told my mate reco to check and clean a jet on the carb. Then on the way home ..it got worse ..got the point it would only drive on boost .

So my mate reco took the carb down and cleaned all the jets out and the tube bit that lifts out(i dunno what thats called ). Put it back on the car ...it revs up ..but if we keep it at a constant 2-3k (unsure what rev range as we were at the engine bay) it would hessitate/judder ..almost act as if it had a missfire.

What could it be? ... since being at millers house we have changed the fuel filter and changed the fuel pump from a clio 1.2 one to a clio williams pump. and weve cleaned the jets.

I took it a drive the other day and it would cut out at junctions ...but it was fine when it was properly warmed up...but it still hessitated. Its stumped me if im honest ..its a hard one to describe over text .

Cheers

[Adey aka Ewok]

mine judders slightly if i just hold the throttle open, whack it on full chat and you dnt get it, think its the acc pump jet arm that needs resetting, could be worth a try?

[philr5t]

it sounds to me mate if you have checked the fuelling then the problem could be timing or electrics have you tried changing the leads or plugs it may be worth checking where your main king lead is routed as i had a crack in mine and it was arking against a metal bracket in the engine bay and causing the same problem

hope this may help
phil

[Bass J]

reseting the acc pump jet arm? ...ive no idea how to do this..anyone got a guide?

and phil ..they are brand new blue lucas leads from cgb ...i baught new leads and sparkplugs as i was trying to sort out a missfire before ..it seemed to have cured it also.

Cheers for such quick reply's

[Miller]

If reco has cleaned all the bits that i suggested and it is still doing it, its probably the accelerator pump stroke that has been set wrong....... but the thing that gets me is this problems has been their on two different carbs?

If you bring it down i can have another look at everything and this time you could come over nice and earlier so i have some more time.

Since reco has put the carb back together have you taken out the idle jet to clean it a few times? as this always gets blocked when the carb has been off....its only .4 of a mm so is easy to get blocked.

Chris

[Bass J]

i can bring it down earlier if you want . as for the idle jet ...reco cleaned it also ..i didnt touch the carb after that as reco told me not to touch anything .

Just let me know when is best for you? ...im off work at the weekends obviously

[dangerous dave]

i was about to tinker with my carb as i had this problem.....then i decided not to bother and fitted my lovely fresh carb that was rebuilt a while back...problem solved..

keep tinkering and you'll get it, i think one problem might have been the acc pump jet was aimed at the venturi so even with a good squirt it was gonna dribble and run poop..

theres another thread like this that had a few good things to look for, do a little search and try find it

[Bass J]

aye we did notice when using the throttle the fuel would only dribble ..but was fine on idle (it would sray down the carb ..if i remember my mate reco saying ..as he's used to carbs from his sierra's back in the day lol)

[Tony Walker]

If its fine on boost then its probably not an ignition problem as on boost and higher rpms is where its most likely to struggle to build the voltage. it sounds like its running lean on part throttle. If you have tried the carb and another carb, then try a new fuel filter, nice and cheap, and make sure your reference pipe to the fuel pressure regulator is ok, check the regulator too. other than that its gotta be a carb fault. Doubt its the accel jet as thats when you initially press the throttle, when you hold it there steady its not pumping fuel in.

[Bass J]

aye we changed the fuel filter ..yet to check the regulator (with the boost guage)

On that note ...im off to my bed...up for work at half 6 2mora morning ..anymore reply's ill read and reply to them 2mora nite

cheers folks

[Miller]

J just text me and we can sort something out for Saturday morning.....this is not just when its at a steady state, it is when you are trying to maintain a steady (throttle moving slightly) state so you are using the pump jet.

Can you bring me over your spare carb when you come down

[Brigsy]

Id start by cleaning the idle jet, also check for air leaks.

The acc pump arm probably needs adjusting aswell, thats assuming the hesitation is caused by a lean spot at low rpm/off boost. A lot of gtt's do this with the stock 120 main jet. With bigger main jet 130+ they never do it due to overfuelling low down.

[Brigsy]

Also check the diapragm on the pump jet, mine had a pinhole in & leaned the fuelling right off causing a mis-fire.

[Sparkie]

do you run a dumpvalve? if so, check the vacuum side of it isnt leaking. - suck it and see if the d/v opens properly.

also check to see you havent got a duff aei vac advance module - suck that too - should hold a vacuum.

both of these probs will cause popping and banging, stalling etc.

[Jimmy_GTT]

I'd try to change the AEI. I've seen AEIs which cause such hesitations in a certain range of rpm. (between 2500-3000)

[James5]

I'd try to change the AEI. I've seen AEIs which cause such hesitations in a certain range of rpm. (between 2500-3000)

Everyone seems to be getting the 2500 - 3000rpm hesitation I had the same thing, a few months back I ended up replacing Dizzy cap, Dizzy arm, sparkies, TDC, AEI, FPR, Fuel Pump, Fuel lines, Carb gaskets, another carb, she eventually worked when I played with the dizzy gear ok she is now 180 degrees out but she works fine and I am not going to change the dizzy gear the correct way this will do for me.

[Bass J]

J just text me and we can sort something out for Saturday morning.....this is not just when its at a steady state, it is when you are trying to maintain a steady (throttle moving slightly) state so you are using the pump jet.

Can you bring me over your spare carb when you come down

Its now cutting out when i use any throttle .. i managed to get it to drive on the choke last time it did this .. so ill get it to your hose on saturday tho chris Ill also bring my spare carb for too

Cheers for all the reply's folks ...It will be in the hands of Miller on saturday ..hopefully it will be all good when i leave his .

On the plus side i just got my blue hoses from asi

[Markey Mark (BD)]

I'm wondering if the fuel is bad in the car mate, for it to keep clogging up like this i'm wondering if your tank has got alot of crap in it and its sucking it up.

Its strange as the carb ran sweet on my campus here when i tested it for you.

[Kenobi]

Not carb freeze is it? You lot up there have had some proper frosty nights.

[Bass J]

as for the fuel ...when i had it as a 1.2 ..i always put fuel cleaner through it ..always let the fuel go to almost empty ..so id recon it would be sorta clean .

carb freeze ....ive experienced that before and its worse than what carb freeze was like ..even when it was warm outside.

Just had to try move the car ..it kept cutting out when i tried to use the accelerator pedal ..so i put the choke on and put it in gear and it moved by itself. Chris ..it may look like ill have to pick you up on saturday to work on it here

[Miller]

do you run a dumpvalve? if so, check the vacuum side of it isnt leaking. - suck it and see if the d/v opens properly.

also check to see you havent got a duff aei vac advance module - suck that too - should hold a vacuum.

both of these probs will cause popping and banging, stalling etc.

Sparkie i have tested the aei with the suck test, i did not try the DV but i cannot remember if it has one

[Bass J]

nah it doesnt have a dumpvalve ..just the gtt pipes(and a bit of exhaust which is temp lol) as you can see here -

[Miller]

Chris ..it may look like ill have to pick you up on saturday to work on it here

Try taking the idle jet out (big brass screw on side), split it into the three bits and blow out any crap that you see in the small hole......you should be able to see thought it when you put it up to the light.

Try this at least three times while checking to see if it keeps getting blocked.

If you are still having probs then just pick me up.

[Bass J]

Ok will do ..ill try that 2mora when its light after work ..then ill text you the results.

[5teve L]

Not carb freeze is it? You lot up there have had some proper frosty nights.

Was going to suggest this myself...
If not then it's play with the jets & acc pump settings..

[Miller]

Was going to suggest this myself...
If not then it's play with the jets & acc pump settings..

Def not carb freeze when i was driving it the other week, it was warm even t-shirt weather......10c

[Bass J]

As said in the text chris i tried cleaning out the idle jet a fair few times..ran out of carb cleaner . it started but kept cutting out with any use of the throttle .. so ill come pick you up 2mora at 11ish? ..that cool? (Miller that is ..incase ppl reading say .."who ...me?")

[Miller]

As said in the text chris i tried cleaning out the idle jet a fair few times..ran out of carb cleaner . it started but kept cutting out with any use of the throttle .. so ill come pick you up 2mora at 11ish? ..that cool? (Miller that is ..incase ppl reading say .."who ...me?")

10:30 as per the conversation

[Bass J]

Aye't ..no probs ..hopefully it will be sorted by this time 2mora

[Miller]

Aye't ..no probs ..hopefully it will be sorted by this time 2mora

It had better be sorted before then as i am going out

[Bass J]

Finally have it sorted its taken this long as ive been busy with work lol

we tried all sorts ...in a nutshell it turned out the drivegear was out a fair bit ..causing the missfire .. Chris Aka Miller off here sorted that and fitted my new dis cap aswell ..and it drives spot on now

BIG thanks to chris ...if it wasnt for him id be scrapping the car now .

Had a big grin on my face as i drove it home..its been a long time since ive grinned from ear to ear driving it

[Jimmy_GTT]

I have the same problem with my mate's car.
If I only keep 2000-2500rpm it (part throttle) has a bit hasitating. And I can see that at that moment the AFR leans out from 1,03 to 1,07-1,09. I think 1-1 ignition cycle is missing...
But really everything was changed. From TDC sensor, spark plugs, distributor cap, carb,...
And I have also set up the dizzy gear as it is written here.
Please if you have any good advise what to check, let me know.
Thanks

[jermaine666]

I'm having the same problem with my 5. how do I adjust the drive gear?

[KEV 5 GT]

and me as well

[w35ty]

Been a while since iv messed with the c1j..

But set the engine to TDC can go off the flywheel marking

Take dizzy cap off and the arm shud be facing just before no.1 lead

If not undo the 11mm bolt holding the dizzy to the block look down at the gear and its should be facing straight or maybe slightly to the right around 2clock postion.. If not i used to use a extendable magnet to get the gear out and then put it back in as above

Put dizzy back in and try the arm on should now be facing near enough to where no1 lead goes

Been ages since iv messed but sure thats right off top of my head if anyone else can add to it?

[w35ty]

Found a pic sure thats how it should be or thats 180 out

Been too long!

[michael tierney]

if its 180deg out it wont run at all