Engine: T5: Surging acceleration / vacuum advice.

[deathrider311271]

Originally Posted by 7 Seat Sports Car

cheers simon,

Is that internal or external diameter or is it just ordered as 5mm silicone hose. How many metres of this stuff would i require. 4 of the small and 3 of the large?

I bought a Scantool Obdlink to look at live PID readings and all i detected was +7% long term fuel trim (by-product of lean condition). Everything else either didn't make sense or was something that could be taken for granted.

I pass my local Volvo dealer everyday and they have been good for me in the past and apparently the techs in there are good too. Will get proper plugs and start there.

Drew

i just ordered 5mm and 7mm, im assuming thats internal, and yes 4 meters and 3 meters, i ordered 3+3 and it was a bit too tight for my liking.

[7 Seat Sports Car]

Cheers fella.

Looks like i'll be freezin my baws off outside this weekend. Deep joy!

[7 Seat Sports Car]

Popped into local stealership and got some new spark plugs. Fitted and still no joy. I think that kinda isolates the ignition side of things. Just 2 more sides of the 'Fire Triangle' to go. Fuel and air!

New hoses on their way to me so hopefully get somewhere soon.

[960kg]

Originally Posted by 7 Seat Sports Car

Popped into local stealership and got some new spark plugs. Fitted and still no joy. I think that kinda isolates the ignition side of things. Just 2 more sides of the 'Fire Triangle' to go. Fuel and air!

New hoses on their way to me so hopefully get somewhere soon.

Do you not realise that the coil`s and also ignition leads and plug caps are part of the ignition?? You have nowhere finished with the ignition side of things yet as you don`t mention replacing these!
On a high miler these could of broken down!
The ignition is the heart of any engine even if you have an air leak it will still fire properly the AFR`s will just be at the weaker end! The air leak would have to be that bad to effect the full boost performance and you would hear the leak as well.

Have you any cracks on the tube part of the plug caps, if so put some insulating tape around the crack to see if it makes a difference as the spark earths out on the block and gives a weaker spark for the plug. If it stops the mis fire then replace the faulty cap and lead.

I would look at the vacuum pipes last, you can`t just fit the cheap bit`s if they are not the problem.

[deathrider311271]

Originally Posted by 960kg

Do you not realise that the coil`s and also ignition leads and plug caps are part of the ignition?? You have nowhere finished with the ignition side of things yet as you don`t mention replacing these!
On a high miler these could of broken down!
The ignition is the heart of any engine even if you have an air leak it will still fire properly the AFR`s will just be at the weaker end! The air leak would have to be that bad to effect the full boost performance and you would hear the leak as well.

Have you any cracks on the tube part of the plug caps, if so put some insulating tape around the crack to see if it makes a difference as the spark earths out on the block and gives a weaker spark for the plug. If it stops the mis fire then replace the faulty cap and lead.

I would look at the vacuum pipes last, you can`t just fit the cheap bit`s if they are not the problem.

His car is ME7 model so doesnt have them

[JamesV70R]

Of course it has coils Simon! Ignition leads too - the Coils need power from somewhere remember. What it doesn't have is a distributor.

Doesn't take much to pinch and damage one of the many wires running under the cover when you put it on.

[960kg]

Originally Posted by deathrider311271

His car is ME7 model so doesnt have them

[7 Seat Sports Car]

I'm sure i already mentioned that i've installed 5 new coil packs within the last 12 months. As the previous set looked original i'm guessing they are fairly resilient so I should, in theory, be able to eliminate them as a source of my problem. The LT leads leading up to them have most of the corrugated conduit broken away from brittleness and the wires underneath look ok.

I've had the head off and replaced all 10 exhaust valves and all the engine loom looked decent enough when exposed to that level of maintenace. I don't remember anything looking out of place. Some of the LT leads were trapped under the coils plastic cover when i got the car but i'm not that stupid to trap them myself.

As for just doing cheap stuff first, i'm only doing little stuff that may or may not do anything to cure a fault but that would, none the less, benefit the car due to its vintage. I would class this all as preventative maintenance just like premature replacement of timing belts. They will fail in time and cause no end of trouble when they do. Doth one agree.

As i said before, the engine feels and goes smooth for the vast majority of the time but has this niggly stutter with wide open throttle. I don't want it to be a tired turbo or bypass valve but am fully prepared to replace it if required. I just want to know that the major component I change has been correctly diagnosed and for that i am asking for any thoughts and ideas as i have been unsuccessful in finding any threads on my exact scenario.

Many thanks for everyones input thus far.

Oh, silicone hose is here so will have that fitted imminently.

[960kg]

Sorry, my bad , you did mention coils but i lost it in between other words! and of course anything even cheap will only benefit the motor.

""My high miler T5 has developed a hesitation during hard and wide open throttle acceleration. It feels like the engine goes then holds back then back to normal and so on. It seems to settle a bit above 4k rpm but not always symptom free.""


A "hesitation" or mis-fire is not the same as "holding back" on WOT so which do you think it more is like?

Holding back at 4k can even be fuel pump!
Have you cleaned the fuel pump filter in the tank?

It won`t be O2 sensor as it goes open loop when WOT.

Have you read for any error codes?

What mileage is it at?

Are the plug gaps at 0.7mm?

[deathrider311271]

could it possibly be a sticky actuator???