Hi I have an 88' 240 glt that my dad bought about ten years ago the car was gold when we got it but then he stopped taking care of it and it began to have problems it has an idle issue and wants to idle fast and sometimes pings my dad put an intercooler on and turned the boost up and it was pushing about 13 psi can anyone tell me what my problem might be and a resolution for the high idle it's been to two shops and neither have done crap so I wanted to take a swing at it myself

 

there were no 240 turbos in 1988.

 

Ok sorry about the year mess up I'll check the year but do you have any idea on what could be the problem

 

well, too much boost without a proper boost controller leads to pinging and excess pinging leads to engine destruction (cracked pistons, burned valves, etc)

idle speed on LH cars is regulated by the ICU/ECU which monitor the engine RPM and modulate the throttle bypass airflow through the idle control valve. any air leaks in the intake path including hoses to said ICV could easily cause erratic idle.

but, a 240 turbo is /old/ and may well predate LH. To make educated guesses, we'd need to know exactly which engine and fuel injection system this uses. afaik, the GLT Turbo were sold 1981-1983 (GLT by itself was not a turbo, it was just Grand Lux Touring, a trim package)... and there was a dealer/field installable intercooler kit for them. But, its also possible your car had the turbo added to it, perhaps a 740T or 760T engine was put in it at a later point in time.

also, virtually ALL volvos from around 1981 until mid 1987 have bad wiring, with biodegradable insulation. if the engine wiring is failing, all bets are off, endless erratic behaviors can surface from short circuits. there are no replacement harnesses available anymore for most of these years.

re: shops, about the ONLY places you'll get satisfaction on a Volvo that old will be a volvo/euro-centric independent shop that has some old mechanics that were around back in the 80s. No generic shop, especially chain places, will be worth a damn for anything except running up big bills.