Hi all!

First time post here, so please be gentle!!! :)

I have owned a V40 T4 for just over a year now and it has not given me any hassle (except from the turbo oil return seal perishing) until last weekend. Now I have a definate issue driving the car.

What happens is if you try and accellerate hard, it gets to certain points (e.g 5000rpm in 3rd), and then starts juddering, as if there's a retarder kicking in - if I keep the pedal pressed while it does this, the car will after a second or so leap forward as if it's broken through a barrier, but then the same juddering kicks in 500 rpm later - sometimes the engine warning light starts to pulsate on and off, until I back off again and then it goes out after a few seconds.

The car makes no unusual noises, idles normally and in every other respect behaves as it should. It is not losing any fluids, and the engine temp stays normal throughout.

Has anyone experienced similar things to this, or otherwise recognise these symptoms? I haven't started looking at the issue yet, but intend to in the morning (willing car mechanic newbie/novice)

I am going to leave the battery disconnected overnight tonight to reset the ECU and clear any fault codes so I can get a clean set of codes (unless there's an easy way to reset the ECU and put it into learning mode again? (assuming the V40 ECU does that - the 480's ECU does just that, which is why I am going to attempt it))

any help you can shed on this would be appreciated.

Thanks

Gaz

This sounds similar to the fault that I have and is described in quite a few different posts between the V40 / S40 forums. It seems only a T4 thing and I'm told it is a turbo wastegate problem. When this happens the engine management shuts the fuel off and makes the car seem to missfire.
This is how I understand it and don't really know how to cure it.

Hey Paul!

Thanks for your reply - I'll get VADIS installed tonight and look through the tech bulletins to see if anything's mentioned in there - I'll have a gander at the wastegate to see if there's anything obvious going on there too.

Will let you know if it helps - other than that, has anyone else got any more suggestions - after looking at it more, it does seem to happen when the boost tries to come up quickly, so perhaps it is a turbo/wastegate issue... Other ideas are it's a fuelling issue under load, or possibly a throttle position sensor issue... If only I could read the ECU fault codes... Anyone know of a cheap place to get a reader?

Well, I came to actually work on the problem and, wanting to do it right, started at the basics - I noticed my sparks were looking more used than they should from it's last service - so I concluded they didn't change them then. Popped some new ones in, and the car is as good as new.

:) We have had symtoms te same as you have ,
There is no point looking into it because all you get is a load of hassle
and a load of usnessacery work being done
Cheers
Al
:banana:

Sorry read the topic again and rememberd that we took it into the garage and
they said they could not get a reding from the ecu ,
The problam is continuing we just simply can not afford to get another car
cheers
Al

Hi, Browsing the net and saw your post about the T4 engine judder, felt I had to register and add my comments too.

I own an 1997 S40 T4 1.9cd, and it too has the same problem as you discribe! Most noticable when accellerating hard (from about 3500rpm in my case) feels like the engine is being limited of power before surging again with the accerelation you would expect! I have had the car approx 4 years and the problem has got worse over that time. I brought the car from a Volvo dealer (as a used car). While it was still under warranty I took it back and was told that no errors were listed in the Engine management computer so they couldn't find the fault! After taking it back a second time they changed the fuel pump (apparently a few of these have been the cause of faults for other S40 T4 owners).... Didn't help! Problem still the same, so decided to live with the slight hesistation.

I fitted a Turbo gauge temporally to see if pressure was down, but it looks like the turbo is well happy and generating enough boost, hesitation didn't match with swing of the gauge.

Approx 3months ago the problem got extremely bad, same symptoms but 100 times worse, felt like a duff ignition plug so replaced all 4 with a set of platinum Champion plugs. No difference... Admitting defeat I took it to volvo to Diagnose the fault. They changed the plugs for volvo plugs (surprisingly they were cheaper than the after market plugs!) they also cleaned out the throttle body/housing. Amazingly the car felt much better, but still has a slight hesistation at the usual 3500, 4000, 4500 RPM!!!

Don't know if it's the same fault or another muddying the water, but have had occasions when the car has stalled when easing off the throttle. When I've managed to 'catch' the stall the engine idles really lumpy for approx 30 - 45secs before sorting itself out. If you switch off the ignition during the lumpy idle and restart immediately the fault is gone (No CEL or anything!!)

As changing the plugs helped I'm begining to wonder if it's the coils or plug leads at fault... Volvo say a set of leads are £41, and each coil £46 (two required!)

Sorry this may not be of any help, but would really like to know if you solve your problem, or if anyone else out there has similar problems with the S/V40 T4.

Regards
MR SJR

Volvo for life... but hopefully not the problems as well!