V70 T5 -07 28.000km - Jerky Acceleration Uphill
 

Hello!

I’ve been having this issue for quite some time now so I give it another go and see if anyone knows the solution.

My V70 T5 can sometimes have a sudden drop in idle, mostly when I do a quick stop at an intersection. The idle can drop to 3-400 RPM before getting stable at 6-700 again. This only happens sometimes but it keeps happening, warm or cold.

Also, the car can become a bit jerky in the acceleration. If I do a big sudden acceleration (not pedal to the metal) but kinda, the car can be a little bit jerky. Not a lot but you can really feel it in the entire car, this mainly happens if I accelerate uphill. The steeper the hill, the more of the jerky you can feel.

I’ve done ALOT to try to solve this but nothing has helped…I’m out of ideas. My last resort is that my turbo is going bad, but I can’t find a thread that has those symptoms when a turbo is going bad, and it’s expensive to change “just because”.

What I’ve done so far:

1: Tested for vacuum leakage with both smoke and LPG, no result.
2: Replaced the fuel pump and tank fitting.
3: Replaced the fuel filter.
4: Replaced the air filter.
5: Replaced the air mass sensor incl. housing.
6: Replaced all ignition coils.
7: Replaced all spark plugs.
8: Replaced all fuel injection valves.
9: Replaced the fuel pressure sensor.
10: Replaced solenoid valve (turbo).
11: Replaced evap valve.
12: Replaced the entire crankcase ventilation.
13: Replaced the manifold-intake-gasket.
14: Replaced the throttle body.

What else is there to replace?

/Toby

This really sounds like a slipping clutch if manual and also slipping clutches or torque converter if auto. But also the idle is also problematic that you may have a vacuum leak, if there is a vacuum leak it can throw the air fuel mixture in disarray and also cause similar symptoms I guess.

That is what I thought too, 'mcfe'. But 'Skillern's car has only done 28,000 Kilometers. That's around 17,000 miles, an incredibly low mileage for the onset of transmission problems I would have thought - I've done 10 times that in previous Volvos without issue.

I would also concur regarding the possibility of induction leak(s), but again, the O.P. seems to already have addressed many of the probable causes of such a leak.

Unfortunately I can't add much to your answer above, but I would be most interested in learning of the cause and solution when it is found - as I am sure it will be.

Regards, John.

Is there any way to test the clutch? It is a high HK car with 325+ HK so previous owners most likely has done some hard acceleration and slipped on the clutch etc.

And do you know a good way to test for vacuum leaks? I’ve tried smoke by pushing smoke in the air filter, with the filter and LMM removed ofc. Also by using flammable gas around the fittings but no luck so far.

What would you suggest me to do?

There is a tiny bit of oil in the plastic pipe from the turbo so the turbo is obviously used but I don’t know if that tiny bit of oil can mean the entire turbo is bad and if my symptoms is because of a bad turbo.

EDIT!: So sorry, i typed the wrong number in the title. The car has gone 280.000 KM. I typed how we type in sweden but forgot to convert from swedish mile to km.

Thanks that you typed!

EDIT!: So sorry, i typed the wrong number in the title. The car has gone 280.000 KM. I typed how we type in sweden but forgot to convert from swedish mile to km.

Thank you. Thinking about it I've had the same misunderstanding when I've been in Sweden. Ten Kilometers = One Swedish mile = 6.25 English miles.

I still convert my fuel consumption from MPG to l/100km when comparing notes with my Swedish friends. Somehow your method makes more sense - the greater the value, the more fuel used. :regular_smile:

Coming back to your car, if it has indeed done 175,000 miles it could well be a transmission related issue as 'mcfe' suggests, particularly if it has been abused or neglected in the past. Do you know the history of your car? How long have you owned it? Is it a manual or automatic - if auto, changing the ATF may be helpful if it hasn't been done recently, maybe smells burnt and / or is brown in colour.

Regards, John.

Hey!

I’ve used it for about 2-3 years, done a lot of maintenance on it, like to change stuff and have that new stuff feeling :)

I’ve driven it for about 30000 KM, no knowledge of how past owners have driven it but it is a past owner who tuned the car, mostly software but also a sport cat on the exhaust and the exhaust itself, but nothing much, mainly stock.

It’s a 6-speed manual car, the gearbox is a M66, engine code is B5244T5.

Can the clutch also be a symptom about the sudden drops in idles? Or is that more towards like vacuum leakage? When it comes to the idle, the biggest improvement came after I cleaned the old throttle body. But it came back like 50%, after that I changed a lot without success and lately a new throttle body, still nothing.

I also have no fault codes at all in the car related to anything close to this problem.

I do not think any past owners has changed the clutch before. I’ve changed the gear oil twice, 1 for maintenance and 1 after I changed the seals for the driveshafts.

It’s a front wheel driven car also, that might be logical but I’m saying it just in case :D

It is a long time since I had any dealings with a manual car, we have only had automatics for about 30 years now.

BUT, in the 'old days', you could get a good idea of the condition of your clutch as follows:

Where does it 'bite'? Generally speaking, the higher the better. If it is very low down on the pedal it would indicate that it is nearing the end of its life.

Does it judder on take off? Oil contamination from a leaking seal can cause this, or the flywheel and / or plate may have become distorted through excessive heat.

To test for slip, set the handbrake hard on, engage *first* gear and, with the engine at a fast tick over, gradually release the clutch. The car should stall cleanly; any 'slippage' should be immediately apparent.

You've had the car for about 20,000 miles, so 150,000 were in other's hands. Much will depend on how they have treated it. You say that it is 300+ HK (thats BHP to us) a lot of power for the clutch to transmit. Has it been uprated, or is it standard? This is a common issue on ex-police cars, which while well serviced tend to be worked hard.

Has the problem always been there, or has it got worse in the time that you have had the car? I'm not familliar with the model, is your clutch cable operated, or hydraulic. Clutch cables can stretch (and break!), hydraulic fluid can degrade over time. If hydraulic, does the clutch need bleeding or the fluid changing?

I don't think a bad clutch would adversely affect idling, but others may know differently. I think you have probably done all that you can on the induction side, so I would tend to agree with 'mcfe' that the clutch / transmission may be at the root of your problems.

That's about the limit of my knowledge I'm afraid, but I hope that you can soon get to the bottom of it. Keep us posted on your progress.

Regards, John.

It’s a hydraulic clutch what I know of, working on the same fluid as the breaking fluid. I’ve bled the breaking system before but idk if that also does something to the clutch, but I haven’t bled that before either way.

I haven’t felt something weird under normal driving, only when I put pressure on the car by accelerating fast and especially in uphill, but it doesn’t always happen. But also, I don’t always do hard acceleration.

I’ve felt this from start since I bought the car, same with the idle problem. Though the idle problem wasn’t as bad in the beginning as it has become over time.

I’ll do some more research about the clutch, if that has anything to do with it.

When it comes to the idle part, do you have anymore suggestions about how I can test for this? None of the things I’ve tried has worked, that ofc might be good but if there is a leakage and I can’t find it..not so good. Maybe I should ask a mechanic with the proper tools to do that. I’ve done it with smoke and gas.

All the hydraulic clutches that I have ever been involved with have been entirely separate from the brakes. They may have used the same fluid, but they were a completely independent circuit with their own master cylinder. Bleeding the system was however done along the same lines as with the brakes.

I think that if I had already done all that you have on the induction side without success, I would also be seeking advice. I'm sure that someone with more knowledge / experience than myself and able to help further will be along shortly.

Regards, John.