Missing under load

v8mick · Jul 12th, 2015, 20:42

Had a slight miss that slowly developed into a major one, last week. I thought it was arcing under the plug cover so I removed that and sprayed wd, and it kept on running, ,miraculously seemed to get better for a while. So I turned my attention to the fuel filter, cracked it , I thought! Today on a 40 mile trip, its started to act up again! Its had new plugs, and leads, dist cap and rotor, and it only seems to miss when under load, it can rev freely when stood. It always starts. Any ideas? Cos Im beginning to run out! Btw no lights up on dash, its a 96 850 10v. Thanks in advance

DSK · Jul 12th, 2015, 22:13

Out of curiosity, what brand parts did you for the ignition items? Missing under load is usually suspect of ignition items.

Austin160 · Jul 12th, 2015, 22:23

I think the key question here is whether the problem occurred after the ignition parts were renewed, or if the parts were renewed to try to solve the problem.
As has been mentioned, ignition components branded with once loved brand names may no longer be guaranteed not to give problems when fitted as replacement parts.

v8mick · Jul 13th, 2015, 00:06

I think that may have partially answered my question, as other than the spark plugs (bosch) the parts were sauced cheaply off ebay. But having said that, the problem, would appear to be fuel related--breaking down under load etc?

Austin160 · Jul 13th, 2015, 07:59

You still are not telling us Mick. Problem occurred since fitting the parts, or if the parts were fitted to try to solve a prior problem? If it were mine I would not look at anything else until that side of the debate is clear.

960kg · Jul 13th, 2015, 09:20

It does look as though you will have to replace the aftermarket parts with Volvo Genuine parts one at a time until the problem goes!....start with Volvo Bosch plugs for your model and NOT just Bosch as they are different heat ranges...

v8mick · Jul 13th, 2015, 12:30

As I remember I stated chasing a bit of a flat spot and because it hadnt had a service for sometime I decided to renew the ignition components. Im going to first change the new graphite plug leads for the old originals.

Lets put it this way, I will find the problem because I like the car too much!

Ive also got the use of a 328i e46, but I always take the Volvo, cos shes far more comfortable.

DSK · Jul 13th, 2015, 14:10

From experience and I'm sure others will agree, that Volvo's are fussy when it comes to critical engine components. Using uncertified and approved parts will not cut it with these cars.

I would firstly replace the ignition items with genuine Volvo ones.

Contact FRF Volvo for a price or take a look on partsforvolvoonline. IIRC for the S70R the OEM genuine leads from the latter were about £48.... can't see why anyone would buy aftermarket at that price.

(Fwiw my S70R when I bought it ran poorly in terms of flat performance and shockingly insane fuel consumption - spent about £120 on plugs, leads, cap, rotor, filters etc from Volvo and guess what - the difference was night and day. Some of the items removed were non OEM plugs, filters and most probably some average spec oil).

Then hopefully that may cure your issue all together as you say, the car hadn't been serviced for some time so chances are the original items OEM or aftermarket had degraded with age/use and needed to be replaced.

v8mick · Jul 15th, 2015, 14:12

I put my "old" spark plug leads back on--and low and behold shes purring like a kitten again, so the "new" ebay leads were just crap!! A lesson learned, thanks chaps.

Austin160 · Jul 15th, 2015, 20:03

It's strange that many of us felt that until a few years ago, we were doing the right thing by our cars to maintain them on the basis of preventive maintenance - in other words you changed components before they gave problems.
Now, the quality of some replacement parts appears to be of such variable quality that you run a fair risk of introducing problems which you didn't have before!
Funny old world - governed by a quest to buy at the lowest price on on line auction site?

Jul 12th, 2015, 20:42	#1
v8mick New Member Last Online: Feb 27th, 2018 12:38 Join Date: Oct 2014 Location: Derby	Missing under load Had a slight miss that slowly developed into a major one, last week. I thought it was arcing under the plug cover so I removed that and sprayed wd, and it kept on running, ,miraculously seemed to get better for a while. So I turned my attention to the fuel filter, cracked it , I thought! Today on a 40 mile trip, its started to act up again! Its had new plugs, and leads, dist cap and rotor, and it only seems to miss when under load, it can rev freely when stood. It always starts. Any ideas? Cos Im beginning to run out! Btw no lights up on dash, its a 96 850 10v. Thanks in advance

Jul 12th, 2015, 22:13	#2
DSK C70 T5 Last Online: Mar 23rd, 2022 21:00 Join Date: Sep 2006 Location: Midlands	Out of curiosity, what brand parts did you for the ignition items? Missing under load is usually suspect of ignition items. __________________ 2000 C70 T5 GT Coupe 1998 S70R / 1995 Toyota Supra Twin Turbo 2007 Mercedes CLS 320 CDI / 2011 Mercedes S350 Bluetec 2007 Suzuki GSXR-1000

Jul 12th, 2015, 22:23	#3
Austin160 Master Member Last Online: Oct 29th, 2021 13:42 Join Date: Oct 2013 Location: Cardiff	Missing under load. I think the key question here is whether the problem occurred after the ignition parts were renewed, or if the parts were renewed to try to solve the problem. As has been mentioned, ignition components branded with once loved brand names may no longer be guaranteed not to give problems when fitted as replacement parts.

Jul 13th, 2015, 07:59	#5
Austin160 Master Member Last Online: Oct 29th, 2021 13:42 Join Date: Oct 2013 Location: Cardiff	Missing under load. You still are not telling us Mick. Problem occurred since fitting the parts, or if the parts were fitted to try to solve a prior problem? If it were mine I would not look at anything else until that side of the debate is clear.

Jul 13th, 2015, 09:20	#6
960kg Premier Member Last Online: Dec 28th, 2022 12:25 Join Date: Jun 2009 Location: Mercville	It does look as though you will have to replace the aftermarket parts with Volvo Genuine parts one at a time until the problem goes!....start with Volvo Bosch plugs for your model and NOT just Bosch as they are different heat ranges... __________________ Mercedes C320CDI Sport Estate 3 litre V6 7 Gear Auto Remap 290bhp 628Nm torque @ 1600revs 45.1mpg

Jul 13th, 2015, 00:06	#4
v8mick New Member Last Online: Feb 27th, 2018 12:38 Join Date: Oct 2014 Location: Derby	I think that may have partially answered my question, as other than the spark plugs (bosch) the parts were sauced cheaply off ebay. But having said that, the problem, would appear to be fuel related--breaking down under load etc?

Jul 13th, 2015, 12:30	#7
v8mick New Member Last Online: Feb 27th, 2018 12:38 Join Date: Oct 2014 Location: Derby	As I remember I stated chasing a bit of a flat spot and because it hadnt had a service for sometime I decided to renew the ignition components. Im going to first change the new graphite plug leads for the old originals. Lets put it this way, I will find the problem because I like the car too much! Ive also got the use of a 328i e46, but I always take the Volvo, cos shes far more comfortable.

Jul 13th, 2015, 14:10	#8
DSK C70 T5 Last Online: Mar 23rd, 2022 21:00 Join Date: Sep 2006 Location: Midlands	From experience and I'm sure others will agree, that Volvo's are fussy when it comes to critical engine components. Using uncertified and approved parts will not cut it with these cars. I would firstly replace the ignition items with genuine Volvo ones. Contact FRF Volvo for a price or take a look on partsforvolvoonline. IIRC for the S70R the OEM genuine leads from the latter were about £48.... can't see why anyone would buy aftermarket at that price. (Fwiw my S70R when I bought it ran poorly in terms of flat performance and shockingly insane fuel consumption - spent about £120 on plugs, leads, cap, rotor, filters etc from Volvo and guess what - the difference was night and day. Some of the items removed were non OEM plugs, filters and most probably some average spec oil). Then hopefully that may cure your issue all together as you say, the car hadn't been serviced for some time so chances are the original items OEM or aftermarket had degraded with age/use and needed to be replaced. __________________ 2000 C70 T5 GT Coupe 1998 S70R / 1995 Toyota Supra Twin Turbo 2007 Mercedes CLS 320 CDI / 2011 Mercedes S350 Bluetec 2007 Suzuki GSXR-1000 Last edited by DSK; Jul 13th, 2015 at 14:33.

Jul 15th, 2015, 14:12	#9
v8mick New Member Last Online: Feb 27th, 2018 12:38 Join Date: Oct 2014 Location: Derby	I put my "old" spark plug leads back on--and low and behold shes purring like a kitten again, so the "new" ebay leads were just crap!! A lesson learned, thanks chaps.

Jul 15th, 2015, 20:03	#10
Austin160 Master Member Last Online: Oct 29th, 2021 13:42 Join Date: Oct 2013 Location: Cardiff	Missing under load. It's strange that many of us felt that until a few years ago, we were doing the right thing by our cars to maintain them on the basis of preventive maintenance - in other words you changed components before they gave problems. Now, the quality of some replacement parts appears to be of such variable quality that you run a fair risk of introducing problems which you didn't have before! Funny old world - governed by a quest to buy at the lowest price on on line auction site?

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