Erratic idle

[mraldonnelly]

Evening all,

Posting here and on the VOC forum so apologies if you're seeing double.

I have a weird problem with my '99 V70 T5.

When idling the revs fluctuate. They generally don't go higher than they should (900 - 1,000rpm) but they do drop. It's weird, almost as if they are bouncing off 700rpm, returning to 900 - 1,000rpm then dropping and bouncing again.

Originally I thought it was the climate control cutting in and out because it didn't happen all the time. However, further investigation revealed that it did it when the climate is off too. I then thought it could be because she was due a service but she still does it even though I've had her serviced.

So, any thoughts? Keith at North West Trading (Volvo specialist) said it could be the throttle housing needing cleaning.

OK, this is the first ME7 fly by wire I've owned and I haven't got a clue where things are (I was a bit surprised a while back when I popped the bonnet and couldn't see any HT leads - further investigation revealed a coil on the top of each plug - what's that all about???).

So, where do I find the throttle housing, body or whatever else it's called? How do I remove it? What do I use to clean it (brake cleaner?) and is there anything I should be wary of like damaging a fragile sensor?

Thanks in advance for your help.

Regards

Andy

[SaffronC70]

Hey guy

You have to remove the intake pipe to the ETM (electronic throttle module).

This it the plastic pipe that comes from the top of the intercooler directly onto the ETM.

It is held on the ETM with a jubilee clip, which can be reached by bending your arm backwards! after removing the airbox intake pipe.

Just use some intake cleaner and spray some up into the ETM. Carefully use some cloth to give it a rub about.

Hope this gives you some direction !

Chris

[SaffronC70]

Forgot to mention, mine has had three ETMs, three MAFs, three sets of sparks, numerous attempts to find air leaks, swapped about coils . . . . .

I still get an uneven idle 5 times out of 10.

Chris

[mraldonnelly]

Hi Chris,

How's things going? Been spending more money on further mods I see. Will you ever stop?

Thanks for the reply. I'll have a look at that tomorrow. I'm a bot wary of the ETM as I believe they're a bit prone to failure and replacement is ££££££££!

You sure having a little rummage about inside isn't going to do any harm?

Regards

Andy

[SaffronC70]

Well, I took mine completely off to clean (only 4 bolts) but i won't recommend this as it's not necessary.

It costs about £400 to get it replaced (Volvo covered the cost of the second ETM I had) - it had the same problem after the new ETM, so Volvo replaced it under parts warranty - now I'm on the third ETM and still have the idle problem

Just got two new lambda probes as well, no help idle wise, but boy does the performance improve !

I'm after a custom map for mine now, just saving the pennies.

Chris

[d14vd_h]

hope this relates to the newer models but my 940 had that problem and its the idle air control valve. basically it just needs located and the little shutter cleaned with carburator cleaner easy job for diy, let me know if u need more details.

[SaffronC70]

thanks for the hint - the newer models have one throttle butterfly on a stepper motor.

I wish for the good time of the idle control valve !

Chris

[d14vd_h]

ah bummer - theres my one piece of mechanical knowledge went to waste.
i do enjoy the relative simplicity of the older engine been a good 'teacher' for me

[Vikingxl]

When mine did this i was told it was either the maf or etm it turned out to be the etm unfortunatly

[Oly]

I had a 99 s70 t5 with me7. it had exactly the same problem. didn't need to replace anything, just took it to volvo workshop in chesterfield and they cleaned the throttle housing for 15 quid. totally sorted it.

[danthet5man]

hey ! out of interest have you got engine management light on? Mine is on an had the etm diagnosed . Cheers Dan

[mraldonnelly]

Hi Dan,

Nope, no engine management light on.

Right, think I've found it now. Is it down by the turbo?

If Volvo will clean it for fifteen quid then I might just take it in to them. I'll give 'em a call tomorrow. It just seems too damn fiddly to get my hands down behind the engine.

If they quote any more than fifteen quid then I'll do it myself.

Thanks for all the replies folks.

Regards

Andy

[JUDGENINJA]

Have you got the same little pipe connector just left of the huge intake (wobbly may have a piccy of this) that is a common thing to degrade due to the high temps and lack of free flowing air. Costs about £1.82 and is quite easy to fit..
It caused my Lambda Light to come on after Bruntingthorpe track day but more noticably the idle was extremely rough..once fitted machine purred again...

[SaffronC70]

The throttle behind the engine ! lol - I think I missed something.

I'm gonna have a looksee for that pipe.

Chris