Hello All,

Patient is my '90 744GL w/223k. When first started every morning it will rev to 1200 rpm or so and stumble, frequently dies but will usually restart and run OK, however it never idles really cleanly and is quite noisy.

I have replaced the plugs/wires/cap/rotor and cleaned the throttle body but the problem persists.

I leave the serious wrenching on my car to a friend who is a fine mechanic but has little experience of Volvo's, he is convinced the problem is a vacuum leak of some sort but can't find it. The narrow hose from the flame trap housing to the inlet manifold had a crack in it but changing it didn't do anything either.
The other hoses look OK but are there any "usual suspects" I should check more carefully?

The return tube beneath the flame trap looks oily and nasty however I can't see how I can access this without taking most of the car apart... The trap itself is clear and the car has no leaks or oil consumption issues.

As alluded to in the title, the car refused to start after lunch today & would turn over but showed no sign of starting. I came back about 3hrs later and it started OK which only served to annoy me as I have no idea why it chose today.

I would be grateful for any suggestions where to start on this one...

Thanks for listening.

Matthew

As noted, first look for a vacuum leak:
-intake manifold gasket
-air intake hose tears
-cracks in vacuum hoses
-leaks at flame trap
-bad throttle body gasket

Poor warm restarts are usually a relay or rpm sensor problem.

Sure sounds like it could be a vacuum leak, though I doubt that would keep you from starting. You can use propane, or even carb cleaner to help find a vacuum leak.

Look in the FAQ under features above for Crank Position Sensor http://brickboard.com/FAQ/700-900/EngineSensors.htm#Crank_Postition_Sensor
and then the link in that to other intermittent start problems.

Sounds like the crank position sensor could possibly be your issue and I think both LH 2.4 and Regina systems have one. Which EFI system do you have ?
--
Andy in St. Paul, '91 745 Regina 198K mi, '89 244 142K, '87 245 RIP

the little fitting that goes into the intake might be clogged, it was on mine!!!
89 740 wagon, take a small piece of wire and try to put it into the brass fitting
and see if it will go thru if not i put mine in a drill and spun the wire around in the fitting and cleaned it out.

a definite change in idle after no more hunting etc. but i still have warm start issues it starts up fine in the morning but after i have to hold the throttle at 750 rpm for a min or so or it will stall....will try throttle body clean next???

use a needlenose to get at the small curved tube ftrap to breather box i stood infront of car put right hand under intake and used fingertips to reposition tube on breather fitting...used clotheshanger to clean it out, use nnose to pull tube straight up thru 3 and 4 have to move a few things around etc.

Thanks for the reply. My car has Regina.