'86 240 wagon

Hi , My engine is skipping and sometimes hesitates on taking off from a dead stop. I replaced the distributor cover and rotor and it seemed to run better for a few days. But now is doing it again. I want to check the fuel injectors and wonder - can you take one out at a time and watch it spray? And then there's the electronics - if not the distributor then what would cause skipping and how can that be checked?
Thanks

 

the electronics are generally dead nuts reliable on these cars, with the possible exception of one early LH EFI controller, I think they were the 'pink label' ones, but when they fail, the car is completely dead.

commonest cause of bad idle is a gummed up throttle body and/or idle air controller.

stumbling can be a sign of poor fuel pressure, clogged injectors. air leaks around injectors can cause crummy idle. have you checked the spark plugs? the color of the plugs can tell you if the engine is running lean or rich.

 

Thanks for your reply. I did check the sparks and they all look good; replaced the rotor and cap; still stumbling. It seems to get frozen in idle once in a while when trying to accelerate from a dead stop-like the gas just isn't going down the tube.
In an earlier communication, you thought my wiring harness could be that biodegradable kind with all the broken insulation that you have showed in a photo but my wires don't look like that - just a couple with totally burned off insulation that was probably a short from a previous owner.

 

You MAY have a failing main fuel pump. Check the fuel pressure--I know, hard to do while driving but it's probably low based on what you describe.

 

I replaced the pump about two years ago. But it is sounding different. How do you check the pressure? Thanks!

 

You have to hook up a fuel pressure tester to the Schrader valve at the fuel rail. Borrow one from a parts store like AutoZone.

 

Great. thanks.

 

an 86 might not have said shraeder valve, and instead require putting a T adapter between the fuel line and the fuel rail.

 

Did you replace the main pump or the in-tank pump? The best way to fry a new main pump is to have a non-working in-tank pump. The change in sound may indicate a failed in-tank pump.

Check out this site. It walks you through checking both pumps.

In the Tank - 240 Volvo Tank Pump and Sender

 

Thanks. Last I knew both pumps were working. I''ll check the link.

 

Pierce - In an earlier diagnostic you suspected my '86 wiring harness might be all cracked up. I denied any such thing on MY Volvo BUT I didn't know where the wire harness began and sure enough it's all cracked up. I suspect this may be the problem. but I'll keep this latest - above - info in mind in case it's a fuel problem. thanks!

 

yeah, bad harness means all kinda problems. AFAIK, Volvo no longer stocks these.

however, Dave Barton has a supply of aftermarket harnesses!
Dave's Volvo Engine Wire Harness Page

note there's two harnesses, the 'main' one for the fuel injection and stuff, and a seperate ignition harness, he has both...

 

******I replaced the main pump. But it was prescient of you to zero in on fuel pumps concerning my stumbling engine. I think you nailed it. When the engine is missing the pump is louder - when operating well - quieter. I looked at the link and am going to try and run each pump separately. Thank You Very Much!!!