enging missing a beat, i think

Jun 6th, 2004, 09:54

Dear all,
I have a bit of a problem with engine running, please would you know of any idea why my engine in running unevenly when idle and revving at a constant rev.

When idling, you can see, the rev counter is fluttering up and down gently between 720 RPM and 850 RPM it’s not stable. its sounds like its missing a beat every other second, you can hear “pumm pumm sounds out of the exhaust and also when you rev the engine at a constant rev you still can see and hear the engine is still not running evenly like missing a beat every second or so.

I have serviced the car, cleaned the throttle body out, check spark plugs, new distributor cap and rotary arm and breather pips.

Many thanks
Harvey

Jun 6th, 2004, 10:19

http://pic7.picturetrail.com/VOL188/...8/23744414.jpg

Model, Year, Engine Type ??????????????????????

There are some very knowledgeable people on this forumn but as far as I know they are not psychic.

Colin.

1990 740SE B200E/M47, remote C/Locking.

Jun 6th, 2004, 10:33

Dear Colin.
Sorry, my specs on the car are:

Volvo 940 GLE 2.3i
Estate
Non-turbo
Unleaded fuel
5 speed
Catalzer
H Reg (1990)
8 valve
188k on the clock

Jun 6th, 2004, 18:04

http://pic7.picturetrail.com/VOL188/...8/23744414.jpg

My first thought is an air leak into the induction system, into one particular cylinder, possibly manifold gasket or injector seals.
(the problem is happening at times of high vacuum)

You can isolate it to a particular cylinder by removing the plug leads one at a time until you find the one that makes the least difference.

Also you say you have changed the dist. cap and rotor but if the plug leads are fairly old they may well need replacing as well.

There are many other (more complicated) possibilities but the above should be checked first.

If you don`t find the problem post again.

Colin.

1990 740SE B200E/M47, remote C/Locking.

Jun 7th, 2004, 12:05

A few years ago I had a similar problem on a 1961 960 Estate (2.3 HPT). It was the engine speed sensor lead going to the rear of the engine somewhere (accessible by my local Volvo service manager reaching down the rear of the engine bay and repositioning the lead to stop it earthing as damaged insulation allowed the lead to touch metal). The lead was temporarily taped then later changed.
Hope that's of some use.

Stuart

Peter Milnes · Jun 7th, 2004, 20:59

Didn't know they made them in 1961 }( I know, you typo'd :P !!

All the best, Peter

Jun 8th, 2004, 08:49

'Tis true -1991. You know what they say "Most car accidents are caused by the nut holding the wheel ....."

PEGE63 · Jun 10th, 2004, 12:41

Hi Harvey,
I have similar symptoms to yours and have tried various things, even dropped it off to Volvo last week for a check-up and nothing is showing up. I was advised to leave it and live with it.
You can change half the engine without finding the fault in the end so why bother....

Jun 6th, 2004, 09:54	#1
jamielee1425 Guest Location:	enging missing a beat, i think Dear all, I have a bit of a problem with engine running, please would you know of any idea why my engine in running unevenly when idle and revving at a constant rev. When idling, you can see, the rev counter is fluttering up and down gently between 720 RPM and 850 RPM it’s not stable. its sounds like its missing a beat every other second, you can hear “pumm pumm sounds out of the exhaust and also when you rev the engine at a constant rev you still can see and hear the engine is still not running evenly like missing a beat every second or so. I have serviced the car, cleaned the throttle body out, check spark plugs, new distributor cap and rotary arm and breather pips. Many thanks Harvey

Jun 6th, 2004, 10:19	#2
Colin Shepherd Guest Location:	RE: enging missing a beat, i think http://pic7.picturetrail.com/VOL188/...8/23744414.jpg Model, Year, Engine Type ?????????????????????? There are some very knowledgeable people on this forumn but as far as I know they are not psychic. Colin. 1990 740SE B200E/M47, remote C/Locking.

Jun 6th, 2004, 10:33	#3
jamielee1425 Guest Location:	RE: enging missing a beat, i think Dear Colin. Sorry, my specs on the car are: Volvo 940 GLE 2.3i Estate Non-turbo Unleaded fuel 5 speed Catalzer H Reg (1990) 8 valve 188k on the clock

Jun 6th, 2004, 18:04	#4
Colin Shepherd Guest Location:	RE: enging missing a beat, i think http://pic7.picturetrail.com/VOL188/...8/23744414.jpg My first thought is an air leak into the induction system, into one particular cylinder, possibly manifold gasket or injector seals. (the problem is happening at times of high vacuum) You can isolate it to a particular cylinder by removing the plug leads one at a time until you find the one that makes the least difference. Also you say you have changed the dist. cap and rotor but if the plug leads are fairly old they may well need replacing as well. There are many other (more complicated) possibilities but the above should be checked first. If you don`t find the problem post again. Colin. 1990 740SE B200E/M47, remote C/Locking.

Jun 7th, 2004, 12:05	#5
langport Guest Location:	RE: enging missing a beat, i think A few years ago I had a similar problem on a 1961 960 Estate (2.3 HPT). It was the engine speed sensor lead going to the rear of the engine somewhere (accessible by my local Volvo service manager reaching down the rear of the engine bay and repositioning the lead to stop it earthing as damaged insulation allowed the lead to touch metal). The lead was temporarily taped then later changed. Hope that's of some use. Stuart

Jun 7th, 2004, 20:59	#6
Peter Milnes Premier Member Last Online: Apr 10th, 2014 00:01 Join Date: Feb 2002 Location: Tonyrefail	RE: enging missing a beat, i think Didn't know they made them in 1961 }( I know, you typo'd :P !! All the best, Peter

Jun 8th, 2004, 08:49	#7
langport Guest Location:	RE: enging missing a beat, i think 'Tis true -1991. You know what they say "Most car accidents are caused by the nut holding the wheel ....."

Jun 10th, 2004, 12:41	#8
PEGE63 Master Member Last Online: Mar 18th, 2023 11:23 Join Date: Dec 2002 Location: Stenungsund	RE: enging missing a beat, i think Hi Harvey, I have similar symptoms to yours and have tried various things, even dropped it off to Volvo last week for a check-up and nothing is showing up. I was advised to leave it and live with it. You can change half the engine without finding the fault in the end so why bother....

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