I cleaned the throttle body in an '86 244 dl with throttle body cleaner and a tooth brush and rags. I removed it first, covered the sensor box with plastic, cleaned the inside well but not perfectly, re-attached it with out a new gasket (trying hard to conserve the old one). Fired her up a couple hours later, noticed unsteady exhaust output, and took her for a spin. She stalls hard starting in first gear, once going she continues to stall in the rest of the gears but not as bad, terrible loss of power. What did i do wrong? Oh and originally the TB was not all that dirty.

 

my 1st guess is, you have some marginal vacuum hoses in the vicinity of the throttle body, or some sketchy old electrical wiring got disturbed. 86 is, I believe, in the range of the 'biodegradable' harnesses where they had switched plastics to something less toxic, and early years of that tended to get brittle and crack with age.

there's no 'sensor box' on the throttle body of a LH car, just a microswitch to detect when the throttle is fully closed so the idle regulator circuit can activate.

 

Hmm.... Are throttle bodies on the LH cars generally safe to clean? The sensor switch can it be damaged with toothbrushes and TB cleaner? Thanks -not sensor switch, microswitch

 

i can't say I've had to clean any of mine.... I did have to clean the TB on a 1991 Mercedes 300E 2.6, but taht car is a KE-Jet... the crankcase vent on those spews a lot of crap into the air path, and the throttle body was nastily gummed up.

 

well maybe the TB is nice and efficient in the LH jetronic. I'm affraid to touch the car at this point.. The vaccum hoses look okay, the wires to the TB electronics aren't visibly deteriorated. Maybe junk blew threw to the intake valves or something..... Anybody know if the TB (sensor) is extra sensitive in someway? Or know how it works? Or if gummy tar may have settled into TB plate arm that runs to the (sensor) after spraying/brushing around it? Can't afford a mechanic right now.... rrrrg

 

Thanks pierce for trying to help me out. It was the mass airflow sensor, unplugged it earlier for an air filter replacement and didn't get it latched in. Those are important, lol -but hey the 240 will actually drive with out one. Cheers pierce

 

well, the engine will START without the MAF plugged in, but it will be running in limp-home mode, as it has no idea how hard you're stepping on the gas, it has no way of knowing how much fuel to put in ... the MAF tells the fuel injection exactly how much air you're sucking in, so it knows how much fuel to add for a stochastic mixture.

on LH2.4 cars at least, if you ran with the MAF unplugged you probably got a 'check engine' light, and even if you didn't, you should read the diagnostic codes and reset them. simple procedure, doesn't require any tools, here...

Engine and OBD Diagnostic Codes

read codes and reset in BOTH socket 2 (EFI) and 6 (ignition).

LH2.2 cars don't have any codes as such, and should just reset when you plug the MAF back in and drive. don't ever unplug/plug the MAF in when the ignition is switched on, only do this with the engine shut off.


oh, 1986, thats a LH2.2 system. so the LH2.4 codes don't apply. no diagnostic reader.

 

Apparently '86 is too old for that cool little test box, don't see one on mine (2.2 LH). Here's a youtube address for a demonstration of that box in case you'd like to use it as another reference for somebody: Volvo 240 Self Diagnostic Tests - YouTube

 

i'd much rather read about something than watch some idiot droning on in a video. just the way my brain is wired.

and yes, the diagnostic box is only on LH2.4 cars, 1988 or 89 and newer (1990 or 1991 for turbos, I think). There *ARE* some diag codes on a LH2.2 system, but you need to rig up some kind of LED test light and the codes aren't very useful, there's only a half dozen of them.