960 reluctant to rev over 3000 rpm

tomatoes4all · Post by **tomatoes4all** » 25 Aug 2011, 04:01

Hi all,
My 1992 960 with 1995 engine, 250,000 km/155,000 miles has some minor issues that I can not seem to fix.
Running rich, poor milage( poorer than usual I should say) on lpg as well as petrol. A poor idle and reluctance to rev over 3000 rpm started while on lpg, so I had the lpg system adjusted. The technician was unable to get all 6 injectors to "balance" properly, because the engine would not run perfectly on petrol either. I have looked over his shoulder while adjusting the injectors and the engine management system and indeed, not running well. He suggested to replace the MAF, as it was dying. The goal is now to get it perfect while running on petrol and then go back to get the lpg system running well.
I have checked the old MAF (thank you Bill!) and purchased another one, which checked out OK, 3.2 Ohms. engine idles very nicely with the "new"MAF, very clean air inlet, air filter is clean, no vacuum leaks as far as I can tell. Sparkplugs are only 5 months old. My car idles well, but hesitates slightly when accelerating from a stop, uses too much petrol compared to a few weeks ago, but does not want to rev higher than 3000 rpm, unless I really put the boot in so to speak. When accelerating firmly the car sometimes "hangs up", i.e. does not shift up into a higher gear and does not want to rev any faster either. The front grill of the Kenworth gets closer and closer as I try to merge onto the freeway.... Where is that 204 hp from a few months ago? Can anyone shine a light on this problem for me?
Thank you, best regards, Erik.

Post by **precopster** » 25 Aug 2011, 06:23

Hi Erik, sounds like it's time for a compression check. Are you losing coolant?

Do this with a warm engine first, then squirt some oil in and see if compression rises. You should get over 190psi.

Because the engine runs badly on both LPG and fuel I'm not going to suggest checking fuel pressures. Another possibility is failing coil packs.

If oil fails to raise the compression you may have a badly seated valve(s)

Have you moved to Sydney yet?

Alpha Bill · Post by **Alpha Bill** » 25 Aug 2011, 20:00

You did not state whether your car has the Aisin automatic transmission. If it does, your current problem could be with the transmission, not the engine. I took my 1997 960 to the best transmission mechanic I know and now the car revs right up to 6000 rpm; and down shifts "right now" upon pedal depression. Also, if your transmission has the "Winter", Economy" & "Speed" buttons, those might not be operating properly.
Alpha Bill

Post by **jimmy57** » 25 Aug 2011, 21:25

Has anyone checked for the catalytic converter being stopped up? If no catalyst is fitted to that year AUS models then muffler or front pipe blockage.

Post by **phils94850** » 26 Aug 2011, 01:50

have you checked the fuel pressure ??

tomatoes4all · Post by **tomatoes4all** » 26 Aug 2011, 04:23

Thanks all for your hints. I will get the transmission checked by a transmission mechanic, but fluid level is good and fluid is clean, nice and red. Catalytic converter was changed about a month ago with a used unit, which was checked before installation. I would check fuel pressure if I would know how to do this. Could you tell me how to, please?
Precopster: I will also do a compression check, after removing all the lpg injectors, they are right on top of the inlet manifold and the valve cover, looks like a better part of the day. I have a single meter, as in one cylinder at a time. From some of the instructions on this site I get the impression that most measure all cylinders at once?
I have moved for work to the central coast, about 90 minutes north of Sydney, but fly back to Adelaide every 2 weeks for 3 days to see my bride and children. We will all move here early october; till that time I have extra time to get my car back in good shape.. Best regards, Erik.

tomatoes4all · Post by **tomatoes4all** » 02 Nov 2011, 04:26

Hi all, just an update. The culprit was a faulty ignition module! Had this replaced at the Volvo specialist, as I was by now taking random stabs at this problem. Took them 20 minutes to diagnose and the same time to replace. Took the car home today and all is good now, smooth and strong acceleration, will red line when asked and transmission shift smooth as well! Love driving "Thomas the tank" again!
Thanks for all your suggestions and help, dear Volvo community!! Best regards, Erik.

Post by **billofdurham** » 02 Nov 2011, 13:38

Thank you for the update.

Bill.

Post by **dcarlson12** » 02 Nov 2011, 15:09

Erik,
Just interested to know how they diagnosed the faulty ignition module? Did they use special equipment or ???

tomatoes4all · Post by **tomatoes4all** » 06 Nov 2011, 01:56

Hi dcarlson12,

I understand they used the process of elimination, ended up with the ignition module, removed it, tested it and came up with "dead" readings. I am happy the problem is fixed now, it just got too dangerous to merge on the motorway or even crossing an intersection. I never knew if I would get acceleration or not.
By the way: Surrey, BC? I lived in Maple Ridge and Pitt Meadows for 10 years. Small world, eh?
Best regards, Erik.