850 1994 Auto sedan engine miss under load

buster850 · Post by **buster850** » 06 Jan 2023, 16:24

Hi every one and thank you for helping.
I have a 1994 850 auto sedan which had a new fuel pump and filter installed 10,000km ago, new NGK (triple pronged) plugs 10,00km
ago. it ran fine for a few months then I got an occasional miss under load that has gotten worse each long (600km ) trip until yesterdays trip it is now a constant missfire/lag at all times in all gears and I only just limped home.

I just checked the codes but only a 1:1:4 came up on port A1, I was expecting something to come up on A2 fuel port but nothing.

The car had only done 120,000KM from new.

I read on a forum that triple pronged spark plugs may cause problems and I should only use standard single contact coppers supplied by volvo, any comments on this?

Im suspicous of the $120 after market pump so Im about to go flog the pump top with a hammer to see if it "jogs" it.

Any input greatly appreciated.

Regards, Buster

Post by **misha** » 06 Jan 2023, 16:51

Port A6?

https://www.matthewsvolvosite.com/read-codes-volvo-850/

A1 1-1-4 should be sorted out.
It's program selector open or short circuit to supply.

I just saw that your car is '94 850 GLE.
GLE in EU is 10v car...should be in AUS too.
Is it 2.0 or 2.5?

454cid · Post by **454cid** » 06 Jan 2023, 20:02

Are the cap and rotor in good shape?

buster850 · Post by **buster850** » 07 Jan 2023, 00:56

Hi every one who offered help , today i spent 6 hours with a multi meter and took the time to check the coil, the spark plugs, the crank sensor and the ignition leads. Thank fully I found the problem but it was very hard to spot. Just a pin head dark brown hole in the blue plastic that clips to the spark plug, obviously it was shorting to the block causing weak spark at the plug hence that plug did look darker due to a richer burn from less spark. As a quick diagnostic I wrapped electrical tape around the affected spot and turned the key to find it ran smooth as silk.
I will order new leads as they are the originals from 1994 ! Anyway I am no mechanic, in fact I dislike working on vehicle but by patience and perseverence I got a positive outcome this time.

To answer the other question, the rotor and cap are original 120,000km but Ill keep that in the back of my mind, many thanks to those who responded.

Misha, as for the code I will need to get further information on exactly what slector etc its refering to so Thank you too.

Kind regards Buster.

Post by **abscate** » 07 Jan 2023, 02:07

Replace the cap rotor and wires as budget allows, Buster. At least clean the brass parts until they are shiny. Use Bougicord for the wires , the other brands cause problems.

Three prong Bosch or Volvo plugs for non turbo cars , single prong ones for turbos

Post by **misha** » 07 Jan 2023, 04:02

Is it 10v or 20v?
Ignition cables are not interchangeable between these two engines.

About transmission codes...it could be PNP switch or S,E & W switch on center console.

454cid · Post by **454cid** » 07 Jan 2023, 10:01

misha wrote: ↑07 Jan 2023, 04:02 Is it 10v or 20v?
Ignition cables are not interchangeable between these two engines.

I found this out the hard way. I was sent the wrong ones. The ends that fit the plugs on the 10v wires are taller.

buster850 · Post by **buster850** » 07 Jan 2023, 20:20

I have to find out if my 850 is 10v or 20v before ordering new leads.
Does anyone know an Australian supplier of Bougicords leads ? Cheers.

Post by **misha** » 08 Jan 2023, 03:21

If it says DOHC on valve cover...it is 10v.

20v cars have 20v on valve cover.

Is it 2.0 or 2.5?

Post by **abscate** » 08 Jan 2023, 03:38

misha wrote: ↑08 Jan 2023, 03:21 If it says DOHC on valve cover...it is 10v.

20v cars have 20v on valve cover.

Is it 2.0 or 2.5?

Buster found his sticker confirming it is a 10V engine in another thread, misha. Take care of those Huskies for us...