A couple of technical questions.

[Drew]

I have a 854 T5 manual with a RICA 304 remap. It was serviced 3k miles ago [oil/filter/air filter] and has had 5 new plugs. I have a couple of issues. This is my first manual T5 [my last auto didn't have any issues] so could be a characteristic of the manual gearbox.

Surging:
When the car is cold in the morning, I am very gentle with the throttle, so feather the pedal so not to put load on the car, and often let the rev's rise to around 3500 before changing gear. On my way up the rev range [the boost doesn't go beyond 12 o'clock] the car appears to give a bit, then take a bit away, then gives a bit back and so on. It gets more prominent beyond 3000 rpm. This also happens when warm, but only over 3k rpm. When I bury the pedal I get lots of boost and a smooth, but relentless, acceleration with no surging. The colour of my old plugs suggested a perfect mixture.

Is it my top mount?
Picture this; you are in traffic doing 1000-1100 rpm in 2nd gear going down hill - the car is is feels like it is hunting a little. It sort of rocks as if i were slowly tapping the pedal???

Another example is if you accelerate hard lets say between corners being aggressive on and off the power, 2nd gear again, flat to the floor then lift at lets say 5k rpm, it jolts - again feels like a movement of the engine/transmission or something.

I know these explanations may be confusing - does anyone know what I am talking about - lol?

[bb54]

hi mate, ive had this gentle surging for 18 months, (auto) box.
ive changed untold sensors and valves etc and never cured it.
i live with it as it doesnt seem to cause any issues.

if any/all engine mounts are worn it will allow the engine to rock/twist under full load and will return under lift off, yes.
just have good look at them for any splits or degrading.

wayne

[Jod T5]

Originally Posted by Drew

Surging:
When the car is cold in the morning, I am very gentle with the throttle, so feather the pedal so not to put load on the car, and often let the rev's rise to around 3500 before changing gear. On my way up the rev range [the boost doesn't go beyond 12 o'clock] the car appears to give a bit, then take a bit away, then gives a bit back and so on. It gets more prominent beyond 3000 rpm. This also happens when warm, but only over 3k rpm. When I bury the pedal I get lots of boost and a smooth, but relentless, acceleration with no surging. The colour of my old plugs suggested a perfect mixture.

sounds to me like you have a inlet manifold air leak...check the elbow on the o/s of the manifold which goes to the pcv ...this may well be allowing unmetered air into the system....i would also check all the other vaccum hoses too....
i found this very useful diagram of the vaccum system which may be of help...
http://www.matthewsvolvosite.com/cha...pic.php?t=6941

Originally Posted by Drew

I

Is it my top mount?
Picture this; you are in traffic doing 1000-1100 rpm in 2nd gear going down hill - the car is is feels like it is hunting a little. It sort of rocks as if i were slowly tapping the pedal???

Another example is if you accelerate hard lets say between corners being aggressive on and off the power, 2nd gear again, flat to the floor then lift at lets say 5k rpm, it jolts - again feels like a movement of the engine/transmission or something.

i would change the top mount for a polyflex one from pfv http://www.partsforvolvosonline.com/...oducts_id=3806
this definately stiffened up any gearbox movement i had...i will soon be replacing the lower mounts as a matter of course im sure replacement will not do any harm....

cheers
jod

[Drew]

Thanks to the both of you for your help.

I have realised that my car looks slightly different under the bonnet to those diagrams?

like this:



Is this Pedro's car?

[Pedro Fandango]

Hi Drew, yes thats my car (BT)

when you say it looks like mine do you mean its got the big intercooler pipe going over the top of the engine instead of going round the block?

[Drew]

Originally Posted by Pedro Fandango

Hi Drew, yes that's my car (BT)

when you say it looks like mine do you mean its got the big intercooler pipe going over the top of the engine instead of going round the block?

Yeah - it has the early reverse i/c piping

[Pedro Fandango]

Originally Posted by Drew

Yeah - it has the early reverse i/c piping

nice one, it was only early 1994 cars that had that so guess someones had a tweak with your car

[Drew]

Originally Posted by Pedro Fandango

nice one, it was only early 1994 cars that had that so guess someones had a tweak with your car

That would suprise me as it has the early back lights too. I think the car must have sat in the showroom for a while before being registered?

[Jod T5]

Originally Posted by Drew

ive said it before and i will say it again that is one fab looking engine bay....
cheers
jod

[Pedro Fandango]

Originally Posted by jod t5

ive said it before and i will say it again that is one fab looking engine bay....

thanks Jod, but i'm afraid thats an old pic.

looks like this now

gone from 2 batteries under the bonnet to none now lol, & the wood will be replaced with carbon fibre sheet eventually