850 power

wilbur · Post by **wilbur** » 07 Feb 2006, 00:18

my 1994 850 5spd. seems to have uneven power under hard acceleration up to about 4 grand , after which it pulls strong and hard, any thoughts on what I should look for ?? Wilbur

Post by **robert213** » 07 Feb 2006, 21:56

Do you have normally aspirated - VIN 55 or turbo'ed VIN 56, 57, 58, 53 engine?

When was the last time you replaced tune-up parts?

Regarding Spark Plugs wires, take ohms reading of old OEM wires and new wires. Readings should be consistant between wires 1 thru 5. Unless you purchased performance wires, readings of new wires should be slightly less than old ones.

Regarding Cap and Rotor, it is desirable to have brass/copper contacts. More and more aftermarket vendors are switching to cheap aluminum. I prefer OEM and NAPA/Echlin http://napaechlin.com/. As long as you have brass/copper contacts, you will be fine. If you have aluminum, return and purchase another brand.

I use NGK plugs in all of my Japanese vehicles. With turbo'ed engines, stay away from expensive platinum, iridum, etc. I can easily go 30K miles with regular BPR6ES-11 and BPR7ES-11 plugs. With NGK, 6 is a hotter plug than 7, -11 is pre-gapped at 1.1mm (.043inch).

Plugs for our normally aspirated engines are:
Bosch Copper FR7DC, NGK BKR6ES or BKR6E (V-power), Autolite 3923, and Champion RC9YC.
and our turbo'ed engines are...
Bosch Copper FR7DC (FR6DC might be too cold), NGK BKR7ES or BKR7E (V-power), Autolite 3922, and Champion RC7YC.

and should be gapped at .028 inch.

wilbur · Post by **wilbur** » 08 Feb 2006, 09:59

non turbo, spark plugs are new volvo brand. age of cap and bug are unknown but appear to be in good in good shape copper and all. I would not think that the plug wires were a problem as the car comes on strong after 4 grand. This is my around town car, were it my highway car I would replace these components as a matter of course. thanks for input

White850Turbo · Post by **White850Turbo** » 08 Feb 2006, 13:18

mileage? Ever done o2 sensors? Reason I ask is that the ECU will go into open loop mode and ignore the input of the o2 sensors after a certain RPM. This is what you may be experiencing.

Post by **vjaneczko** » 27 Mar 2006, 06:43

wilbur wrote:my 1994 850 5spd. seems to have uneven power under hard acceleration up to about 4 grand , after which it pulls strong and hard, any thoughts on what I should look for ?? Wilbur

I had a problem very much like yours - I failed my emissions test because the OBD reported misfires on cyl's 3 and 4. Went to the dealer who changed the cap, wires and plugs. He indicated that the platinum plugs I installed were not reccomended and he put in the coppers. Not sure if that was the single solution, but whatever he did makes it run like a champ - no acceleration hesitation and no 'Check Engine' light.

Life is good.

Post by **MadeInJapan** » 27 Mar 2006, 07:44

Believe it or not the Platinum plugs have been known to cause all kinds of issues. There were even some over on the brickboard claiming that due to the high temp of the plat's, the porcelain part of the plug actually cracked and fell off into their engine causing major damage leading to an engine replacement. If you're running plat's, my suggestion is to replace them with regular copper ones and see how it goes. Of course severe engine damage is highly unlikely, but this in itself was enough to convince me to never use them. On a side note, any of the OEM Volvo plugs recommended for your car seem to be okay. The turbo plugs are copper with plat. tips.