setting carb up

[Thundercat]

Well right puzzled, spent half of Wednesday setting carb up with afr gauge. Thought I had cracked it, when for a drive and was awesome, on boost afr was in 12, idle at 14 and off boost 14+. On me way back from drive backed off boost and suddenly afr going off scale to lean, had to keep revving it to get home.
Thursday stripped garb completely and cleaned every hole. Problem is now want idle smooth unless idle set at low 13s and now boost afr in the 11s and feeling flat.
All gaskets new, also car sounds erratic at idle and confirmed on afr gauge.
Anyone got any ideas please.

[BluntyR5GTT]

boost in 11s is pretty sound really fella, safer than being in the 12s etc and gives you a tad of room to adjust.

what spec is your carb? what boost are you running etc

[BluntyR5GTT]

just as a heads up i run the following

t28/t2.63 @ 23psi

125 main
130 2nd stage
0.9 2nd stage
2mm needle
standard venturi

i see around 11.4 - 11.9 on full boost in all gears, off boost is 13-14

[Thundercat]

Running a t25 at 0.8 bar, carb been put back to 120 main, 125 a/c, 1st stage untouched, 2nd stage now at 1.2mm. Did run fine until fault, afr jumping about a lot know and hesitation when coming on boost. Goes lean before boost brings afr rich again.
Was expecting more adjustments to carb when setting up but was fine with just 2nd stage adjustment.

[BluntyR5GTT]

personally id say try a smaller a/c maybe a 100 ? see what that does. iv certainly fount alot out about tuning engines since owing the 5gtt

[Thundercat]

Will try that Sunday mate, other option is to try another carb and see if afr settles. Also to check if carb idles more smoothly.

[BluntyR5GTT]

has the carb been fully rebuilt has i had the hesitation on boost a while back when i was running 19psi, we rebuilt carb and it sorted that problem out

[Thundercat]

Stripped carb completely down, only parts not removed were butterfly spindle and emulsion tube. Didn't realise emulsion tube was removal till I rechecked service article.

[Wade]

New poster! (less than 10 posts)

hopefully you'll get it sorted mate and figure out all out and show me how to do mine when I need one :p

[Markey Mark (BD)]

It sounds to me that the carb has small bit of dirt in there somewhere mate, take the idle jet out and the enrichment body off and give them a good clean out

[Thundercat]

First thing in the morning, full strip down again. Fingers crossed this time.

[Thundercat]

Well good news, car idles solid know and afr are stable. Couldn't find any dirt in carb buy found that bottom part to middle section were not sealing. Had to flat the lower side of middle section with emery paper on a plate. It was evident that where the carb is bolted down it had warped. Hopefully after a run out it will prove fixed with no other adjustments required. Also changed a/c to 1mm so be interested in changes.

[Thundercat]

Happy to say car is running good, idles solid. Afrs go a little rich before turbo kicks in, will live with that. Only issue now is when coming off boost and using engine to slow car down the afr goes quite lean. This is evident with odd puffs of white smoke. Any ideas welcome on how to richen the off boost deceleration. Thanks.

[Nad-5GTT]

Happy to say car is running good, idles solid. Afrs go a little rich before turbo kicks in, will live with that. Only issue now is when coming off boost and using engine to slow car down the afr goes quite lean. This is evident with odd puffs of white smoke. Any ideas welcome on how to richen the off boost deceleration. Thanks.

Its no help to you but id be interested in an answer for this to as i noticed my Afrs went lean on overrun friday other than that everything was fine.