Very minor issue but I'm stumped

Post by **jblackburn** » 15 Dec 2011, 23:07

Don't happen to have the climate control on defrost?

My car is low on a charge and when left on defrost, the compressor cuts in and out and causes a slight RPM fluctuation like that.

Post by **JRL** » 16 Dec 2011, 06:32

jimmy57 wrote:Does it have the shallow sump angle gear and no vibration damper fitted?
I am unsure of that detail on 99's. I can't recall when the deep sump appeared and damper was omitted.
I have the same cyclic throbbing on my 98 that is shallow sump and has the stud head bolts for the damper to bolt to but no damper. I have done all three mounts which made everything else better but actual brought this on. Or maybe the new mounts took away the other harsher stuff and let this be felt.

No idea

rspi wrote:I was thinking that maybe your knock sensors were tweeking the timing. Toss some octane boost in it or run some 93 for a tank or two and see if it changes.

Techron AND Seafoam, no change

jblackburn wrote:Don't happen to have the climate control on defrost?

My car is low on a charge and when left on defrost, the compressor cuts in and out and causes a slight RPM fluctuation like that.

l always run the AC manually, so no

Post by **erikv11** » 16 Dec 2011, 09:10

JRL wrote:
jimmy57 wrote:Does it have the shallow sump angle gear and no vibration damper fitted?
I am unsure of that detail on 99's. I can't recall when the deep sump appeared and damper was omitted.
I have the same cyclic throbbing on my 98 that is shallow sump and has the stud head bolts for the damper to bolt to but no damper. I have done all three mounts which made everything else better but actual brought this on. Or maybe the new mounts took away the other harsher stuff and let this be felt.
No idea

Well are you going to check?? You have our interest now ...

JRL wrote:
jblackburn wrote:Don't happen to have the climate control on defrost?

My car is low on a charge and when left on defrost, the compressor cuts in and out and causes a slight RPM fluctuation like that.
l always run the AC manually, so no

How you use the AC is not relevant to his post - he asked if the defrost is on. We all know you are expert in these cars, but still your response suggests you are not aware of this: If the dial is set to defrost, then the climate control will turn on the AC if/as it determines AC cooling is needed (for condensation purposes, yes even when it is cold).

Post by **E Showell** » 16 Dec 2011, 09:23

I have the same issue on my '98 V70 5 spd FWD.

Post by **anjill182** » 16 Dec 2011, 19:07

My 98 XC used to stutter occasionally at idle, almost like it skipped a beat or misfired. It ended up being the computer. Hope you solve your issue.

Post by **JRL** » 16 Dec 2011, 20:33

Of course it's not on defrost, I really don't think I needed to clarify that

Post by **E Showell** » 17 Dec 2011, 19:10

Anjill182 -- what did you do to address the computer issue?

Post by **burnout8488** » 18 Dec 2011, 02:23

Mine will do this too, as if something is turning on. Check to see if the fan or compressor are engaging, regardless of what the ECC is set to.

Does it do it when the engine is cold AND hot?

Post by **anjill182** » 18 Dec 2011, 06:38

Swapped it out with a JY unit. Problem solved.

Post by **matthew1** » 18 Dec 2011, 08:12

Everyone: I deleted some posts. Please stay on-topic and don't be afraid to start new topics if it's warranted.

JRL: no need to be prickly. They're just trying to help. You're frustrated... with your experience with the P80 this must keep you up at night.