tb42e caughing on start up...

[huardlc]

hi guys larry here. my tb42e 92 model is cauging on start up.no matter the temp outside. replaced a lot of stuff like dizzy, fuel regulator, checked tps, air flow etc.
i suspect an air leak somewhere cause seems to be running hot and dont need much pressure on the pedal to get it going but when warm, its a dream.
was wonderiong is anyone knows about the cold start up procedute for those engines, like cold enrichment, is there anything that is checkable on start up that might be noticeable. i sent it to a tuner and everything is working...
its like its missing its enrichment'' somehow...i m running out of options..ah ah ah
cheers for your time laz

[Pezzer]

Oxygen sensor?

[huardlc]

hi pezzer yes i checked that too. i know that there is a valve below the plenum chamber on the 42 e that allows air to come in. wonder if the bloody thing is not stuck open. i read elsewhere that owners of tb42e experienced the same problems....

[Parksy]

Good luck getting to that valve. Unless you pull the intake off completely it's basically impossible to get to. But let us know if you do decide to have a crack.
Pull off the aac valve on the back of the plenum and give it a clean with carb cleaner, see if that makes a difference. It has moving parts that control air flow, also turns on fast idle when the ac is switched on. The internals do get dirty and it's not a difficult job so a good starting point.

[huardlc]

yes thanks guys . i ll redo all the basic inspections on it. i let you know if i find something specila cause im not the only one with that sort of problem..of what i read before...

[huardlc]

hi guys. larry here with the gq 4.2 efi caughing. well..been investigating for a while and found few problems..caughing on start up is most of the time an air leak problem..
thats what i found anyway and i think i solved the problem. replaced every nissan spring clamp on all hoses around the plenum chamber with screw clamps..stronger as the rubber had hardenned and not that tight anymore on the pipe..
then removed the ficd where the idle speed screw is...wasnt too dirty but found that the little spring inside- that pushes the by pass valve- was not that tough anymore. teh valve wasnt completely shut on start up, leaving some air passing thru it..just added s ring of rubber in the spring to make it ''wider'' and now she shuts !
the difference is amazing. still have few hoses to do but the problem is solved..caughing means air leak hope that help for everyone who got the same problem..
larry