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240 84 Turbo won't idle

B

BenBlue&Betty

New member
Joined
Nov 20, 2012
Location
Tulsa OK (for now)
Acquired an 84GLT TURBO from others who'd apparently dogged it, without regular maintenance. At this point, I've replaced rotting K-jet harness, done tune-up, etc etc.

After SEVERAL attempts, I get it to stay running... But ONLY by pushing accelerator to keep it at about 1800 RPM. Foot off gas... dies. Now, I've followed procedures to check constant idle system... All (power,throttle switch, temp sender, air valve) check out.

So, following service procedures, I tried another CIS computer. No improvement. Two baffling responses: while shorting wires to CIS computer to imitate cold engine, it high idles... But not at the prescribed 1600-2400 RPM, but at 3000-3500! Also, once... After doing that, I plugged the connectors back into computer and the car actually ran & drove PERFECTLY... For about two hours, then went right back to dying. :-(

Any one shed light on this weirdness?
 
Micro switch? Make sure it's working properly. Make sure the throttle body is real nice and clean. Auxiliary air valve plugged in and working properly? Also, make sure the air flow sensor plate and control plunger are clean and move without binding.
 
Appreciate your input, stephensgill. Micro switch working and adjusted with test light, and not one but TWO aux air valves checked, installed & tried... But I DO need to check & clean throttle body and that sensor plate & plunger may also be suspect...
 
my kjet was infected with vacuum/boost leaks. charge pipes would come loose, crankcase vent was loose, vacuum lines would slide off, and i found my injector seals were toast(one wasn't even seated properly from the factory). i prolly could have saved it by removing the crankcase vent from the turbo inlet(too much oil in the intake and stuff kept coming apart when hot and under boost) - unmetered air = too little fuel = only idle with extra throttle input. at least that's what i ran into

could be base fuel pressure? maybe? i know nothing about that, but i know others say it's important :p
 
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Yea, fuel pressure is the most important with k-jet. But if the car runs well but just won't idle, I would think fuel pressur is good? Not sure about that though. Making a fuel pressure tester guage is not that hard at all. Bad injector seals will definitely cause trouble...
 
It actually runs WELL on highway, boosts well and all... but have to drive with one foot on gas and one on brake to get that far! It just baffles me why it ran perfectly, idle and all, for a few hours... then back to crap!
Another strange thing, for a while, it seemed to run ok intermittently after it died and i restarted... as though something electrical was being reset.
Have to get a new main fuel pump for it anyway, as the old one was a small aftermarket weenie pump... and the line from the pump to the accumulator is kinda shredded. Anyone have a decent used pump & banjo connector line to unload (just so i can continue testing and diagnosis for now?) I know that's another thread in another place, but... just askin anyway...
 
Have you checked for vacuum leaks?
What's a tune up for you? Did you replace the intake gasket and the TB gasket? O2 sensor? All 8 injector seals? How are the 5 fuel injectors flowing?
 
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