V70 petrol jerky acceleration / underpowered

[shezzav70]

Hi, I have a 2005 2.4 petrol v70
Over the last few months I've had issues with jerky acceleration which have been getting worse.
It mainly affects the car going up hill or under load (so when fuel demand is highest I guess)
When going uphill with foot to the floor, when I hit 3k rpm, the acceleration becomes jerky
The car feels underpowered & slow all the time regardless and if there's any kind of load in the car, it maxes out at 70mph on the motorway
No EML on
I've changed fuel filter and swapped out the ETM with a matching one on ebay which didn't make any difference.
Does anyone have any other ideas please?
I got overtaken by an artic on the motorway the other day going up an incline which is not right!
Many thanks

[stuart bowes]

inital thoughts would be firstly do you have a method of reading the proper fault codes not just the basic handheld reader (VIDA ideally)

and second when you say you replaced the ETM with a matching one did you literally just swap the hardware or did you get the programmed in by someone, because it's usually not just a straight swap job

it kinda sounds like you've gone into a limp mode which is very much like what mine did with the ETM fault. im racking my brain trying to think if any orange lights came up and I don't think they did (?)

you could try checking both of the two red fuses in the under-bonnet fusebox top left of the fuseboard as you look from the front, they supply power to the ETM (but presumably if you've now got a 2nd unit in without programming that may make no difference now)

there are of course a number of other possibilities

[shezzav70]

Hi Stuart,
Thanks for your input
I don't have access to vida at all, would you know if I can find anyone local to me that could help with that?
The etm was the matching part number & I'd been told they don't need programming to the car as it's just an actuator?? I swapped back my original part when I realised it made no difference though.
Will have a look at the fuses too

[stuart bowes]

Im not sure if it's like the door buttons, where you can find one exactly the same year / week of manufacture and same part number and then cross your fingers hopefully it works? or maybe that changed over time (mine is 2001) .. but without further input from others I think we should assume it needs programming to work properly (would work, but very lumpy revs etc)

it's not 'just an actuator' it's 2 brush type throttle position sensors which wear out (one at each end and takes an average reading .. unless replaced by the single ended contactless unit which is a common repair) and there's a pcb inside as well with bits on it that can fail

when reading codes if the ETM is faulty one possibility might be a 'comms fail to ETM' fault or something along those lines

generally it was the earlier ETM's 2000-2002 or so that were the issue and they sorted it later on, 2005 might/should be fine ? but who knows

again it could be other things still need to keep an open mind obviously

I'm not sure about code reads you'll probably have to ask if anyone here lives near you? or find an independant volvo specialist who can have a look (and also plot out some sensor readings if necessary to identify the cause)

--

just a couple of the more obvious things though when was the last time sparks and air filter were changed and what's your mileage

[Dippydog]

First thing that struck me was that throttle body possibly needs the Sacer conversion doing on it,then the second thought possibly the throttle position sensor down on the accelerator pedal?

[shezzav70]

Thanks guys
Will try to find someone who can scan for me, not really sure what I'd be looking for but would it be a generic scan & hope it throws out some fault codes or would I need to ask for specific readings to help diagnose?
My car doesn't appear to have a fuel pressure sensor on the rail which is odd, just a shrader valve (see pics)
It's done 110K miles
Spark plugs were done 15 months (15k miles) ago & air filter last week
I did the pcv replacement around 15 months ago too
For the record, who would program the etm Stuart, would that need to be dealer or anyone with vida?
Cheers

[shezzav70]

Is the sacer conversion available in the UK or just in the states?
Will look into the pedal sensor as well, could be a fairly straight forward swap

[Dippydog]

Yes Sacer is available in the UK .Don't have any item numbers to hand but they're available on E-bay,I looked recently in case my phase 1 V70 needed one and cheapest I found was about £67[including postage]and came with fitting instructions.

[stuart bowes]

Volvo diagnostics in tilbury used to do the conversions but they don't any more however they can program in the new unit for you. Now that's probably a bit of a trek for you but if you have a ring around local specialists you may find someone.

As mentioned above you can buy the sacer part online (ebay as with everything else) and fit it yourself without huge difficulty there are guides available. I would start on the original unit and that way if the new sensor fixes the issue programming is not required. But you'll have a spare unit to fall back on

If that is the case and programming is then needed.. the stealership probably won't be interested unless they're selling you a new ETM for about 4-500 quid or something (?)

I believe it is possible to do the programming with the vdash software, that opens up the options to anyone with a dice / mongoose / vcx lead and the relevant know how again you might find someone local

This is again all assuming the fault is with the ETM. I would still try to focus on getting faults read and sensor readings plotted out first to establish real fault otherwise you could be wasting money and effort

First you would check for any volvo fault codes specific to the individual components and if that comes up dry you would use vida and look at the various sensor outputs on a graph while driving the car and see if any of them are flatlining or otherwise acting in unusual ways. Any decent volvo specialist with vida would know how to do that I assume

[stuart bowes]

Is the MAF still original and if so have you tried MAF cleaner and made sure it's connected properly

I don't know off the top of my head if a fault on that would throw an EML but it might be worth checking

And did you check those fuses