1987 240 GLT misfiring

HI,
First time posting on here, hope someone out there can help me.
I have a 240 GLT that has just started misfiring(sounds like a rear engined VW at the moment.) I have replaced the rotar arm and the sparkplugs, but still running the same. I'm going to replace the set of leads tomorrow, but somehow I dont think that will fix it. This all started when I was checking for an oil leak and had the engine steam cleaned to see the leak more clearly.
Could it be one of the CI injectors blocking up? The engine is a B230E.
I'd be greatful for any ideas as to what the problem could be.
Cheers.
Just to update: I have replaced full set of leads and engine still sounds like its misfireing. Any ideas?

[morsing]

Does it change with rpms?? When cold or warm??

How to find a dead cylinder: Check RPM. Pull one spark plug wire at a time and note how much RPM drops. If one of them doesn't change much, it's your dead cylinder.

Thanks for that morsing.
There is no difference in rpms. The engine rocks which it wasnt doing before I had this problem.
I was wondering if the auxilliary air valve might be faulty. You can tell I'm clutching at straws now for an answer.
Maybe my only option left is to have Volvo sting me for an engine diganosis to see where the problem is.

The distributor cap is a likely candidate.
Also have a good look at the engine wiring harness insulation especially in areas where it gets very hot. Volvo fitted wiring looms with poor quality insulation for some years and the insulation tends to self destruct leaving bare wires inside the loom. This could cause problems after steam cleaning forced water into the loom.
Hope that is not the problem, but it might well be.
Colin.

Cheers Colin for your info.

I had looked at the distributor cap and it seemed ok, that's why I hadn't replaced it. Afew other people have suggested the same though, so I have now replaced the cap incase there was something I was missing.
Unfortunatley, It hasn't made any difference. Another thought is maybe the timing is out, so I think it might be time to get the engine tuned up. Unless someone knows another reason.
Havent had chance to look at the wiring looms yet.

Hi,
If anyone is still checking this out, I think I've got it sorted.
I managed to find a garage which specialises in Volvos but not at Volvo prices.
The problem seems to be air intake on the injector seals.Apparantly these seals get baked hard because of the heat of the engine.Which then causes them to crack sometimes letting in air.
The problem was resolved by spraying oil on the seals to check for airleaks,this actually softened the seals and things seem to back to normal.I just need to get the engine tuned up now. Possibly in the near future I will have to replace the seals, but at the moment, I think a little spray of oil around the injector seals now and again will be ok.
Apparrantly this is a common problem on 240 injection engines.
Cheers for help and advice
Graham

I had the same problem about a month ago and after checking every-thing as you do it turned out to be the AIR AUX. Valve and I cleaned it and car run ok
TA TA
Highlander

[Andrew (UK)]

The seals are easy to replace, cost about a pound each from Volvo dealers and you could do all 8 (2 per injector) in about half an hour.
Undo the injector holder bolts with a 10mm socket and either the old outer seal will just crumble away as you pull the injector holder out or else you will need to cut it off with a pair of cutters as it will have hardened with age. The inner seal may not even need replacing.
New seals are supposed to be soaked in a little petrol before fitting.
Air leaks here cause loss of performance and fuel economy and can lead to lean running, overhaeating etc.
Do the job properly and enjoy the peace of mind you will get.