M35 Blowing Smoke >4K Rpm, Hesitation Around 4.5-4.75K

[Jetwreck]

^^^ that

[PN-Mad]

The afm drops out timing and dumps fuel at well below the 'head goes through the windscreen'. Lets just agree to disagree, you two are surely more proficient at ...

Think you need to go back and read what I wrote. Never talked about fuel and timing. Simply stated that the afm cut was a little over 5v, not talking about ign or fuel...

Dont get your y fronts in a twist over something I never wrote

Better get back to those toyotas hey bud...

[Dunc]

Yep, looks like fuel.

You may have fouled the plugs. Pull a couple out, and inspect. That little hiss might be the PCV. You'll have to check all lines for splits as well, maybe the boost gauge or controller lines. Might have blown a intake gasket. Just ideas.

Pulled the plugs, all of them looked vastly similar. http://imgur.com/a/2sIZI for a couple of reference shots.

unc, pressure testing the intake is easy, just grab an old tyre valve and a lid or plumbing cap that fits nicely into the rubber pipe, then use a pump/compressor to fill the intake. (you could even do it at the servo) Just checking if the fittings are loose won't tell you if there is a split in a hose somewhere you can't see.

No pump/compressor I get the principle, and I'm convinced Id somehow muck that one up. Im not even sure how I'd cap it I might need to get a local mechanic to have a play with that side of things.

I think the lowest worm drive on the intake is a bit suss though, it tightened to a point and then wont purchase for the next rut (just keeps spinning). Not sure if it was doing that prior to me pulling the plugs. I'd hazard a guess that could be a problem but in theory it isn't something 'new' (it would've been like that for the past 12 months). Perhaps it'd be timely to replace all of those for good measure.

I swapped the plugs and coils between cylinders, so they're all in different locations (Eg plug from 1 is now in 2, its coil is in 3, and so on) and I swear on the my first drive after reassembling I hit over 5k without a drama, but a subsequent run repeated the symptoms I've discussed prior.

[DaveM35]

Dunc,

If it is a leak somewhere in the intake system, the best tool ever for finding it is a smoke machine (leak detector). If you can get access to one and you have a leak it will find it 100%. Unfortunately we're not in the same state otherwise I could help you out more with it.

We've used ours at work to diagnose so many cars that I swear you would either never find the fault or take about a week to do it without that machine.

Also, if you've got any mates nearby with m35s, I'd double check your hissing sound with theirs, I've noticed mine seems to hiss a tiny bit when I listen carefully, it makes me always check the boost gauge tube on inlet for a tight seal, but I'm pretty sure it's just normal intake hiss which usually comes from plenum area or at throttle body cause the air gap is tight at idle.

[Jezboosted]

I usually like to look at a nice gap; but not on spark plugs Is that gap setting normal ?? It looks like it would need a tesla coil to bridge that

PS: I am most likely wrong as i know nothing about these newer volvos.

Pulled the plugs, all of them looked vastly similar. http://imgur.com/a/2sIZI for a couple of reference shots.

[scotty nm35]

Think you need to go back and read what I wrote. Never talked about fuel and timing. Simply stated that the afm cut was a little over 5v, not talking about ign or fuel...

Dont get your y fronts in a twist over something I never wrote

Better get back to those toyotas hey bud...

And I never talked about the hardcut the AFM does... Just that it dumps fuel similar to Dunc's issue. If the AFM is seeing increased airflow due to a leak it will protect the engine

The AFM can most certainly cut at lower voltage than that as it is just a variable, depending which cell of the map it's in, the revs at the time, and the AFM voltage.

I usually like to look at a nice gap; but not on spark plugs Is that gap setting normal ?? It looks like it would need a tesla coil to bridge that

PS: I am most likely wrong as i know nothing about these newer volvos.

No misfire on our coils till well over 3mm spark gap at stock boost.

[Dunc]

I finally got access to a workshop and compressor - but we couldn't find any leaks under pressure, we replaced some pipes and worm drives for good measure though - it's all nice and tight now but the problem persists.

Monitoring the Informeter whilst driving the car under load it looks like when the AFM starts to max out, and presumably then the ECU starts listening to the MAP sensor, is when it has a fit. It seems like a protection mode, so the next theory we had was whether the MAP sensor is miss reading badly. Unfortunately the Informeter doesn't pick that up for display

Any other ideas?

[scotty nm35]

What happens if you drop the boost?

[Dunc]

What happens if you drop the boost?

Irrespective of the fact that I don't have an boost controller, its not making anywhere near enough pressure to open the wastegate of its own accord - how else could I drop the boost?

[scotty nm35]

The actuator is only 7 psi, unless you have one of mine, in which case you would need to drop the spring.

Have you changed the plugs since taking those shots?

I can send over another AFM if you like, or simply swap it with another one off a known working Stagea?

Might be time to think about a tune if all that fails...

[Dunc]

The actuator is only 7 psi, unless you have one of mine, in which case you would need to drop the spring.

Have you changed the plugs since taking those shots?

I can send over another AFM if you like, or simply swap it with another one off a known working Stagea?

Might be time to think about a tune if all that fails...

I dont think Im even getting up to 7psi, but thats just at best guess.

I did change the plugs after taking those photos.

Might see if Ryan wants to play 'swap the part and see what happens' with his M35; I'd be fairly surprised if your after market AFM was causing this problem - which existed with the same symptoms on an OEM one. Particularly as its at the upper end of its range. You don't think the MAP sensor could be at fault then?

[scotty nm35]

I wouldn't rule out the map sensor, I just don't think it is used for tuning on the engine. It's easy enough to swap and try it though. On the C34 you could just disconnect the hose to the map sensor...

Can you list the mods you have currently? What turbo are you running again?

Shame I can't stick the consult on it, is it coming up with any codes?

[Dunc]

No codes, that'd be a dream at this point!

Engine/exhaust mods are:

Hdi fmic

Plenum spacer

Dolphin hard intake

High flowed turbo (GCG, one of the older ones)

Decat dump pipe

IMPUL ecu (I have swapped in the OEM to check that too)

[Dunc]

The actuator is only 7 psi, unless you have one of mine, in which case you would need to drop the spring.

Just tried running it off wastegate pressure; same black smoke.

[scotty nm35]

What plugs are you running?

It seems very unusual, perhaps the o2 sensor is playing up? I can't think of much else it could be.

Is the rear cat blocked perhaps?

[Dunc]

What plugs are you running?

It seems very unusual, perhaps the o2 sensor is playing up? I can't think of much else it could be.

Is the rear cat blocked perhaps?

Plugs are LFR6AIX-11

I did change the O2 sensor shortly after buying the car (4 years, 30k km's max; it wasn't presenting with any particular issues at the time - wish I'd kept that one as a spare now!

Haven't dropped the exhaust to check the rear cat, hadn't really crossed my mind

[Dunc]

Ryan was kind enough to lend me his time and let me play 'swap the sensors' last night to see if we could instigate any changes.. and we did! With his AFM! It still blew some black smoke under high load but I was able to rev out past 5k, but the car also had hesitation after the gear change before it got going again. So I'm not really sure what this means

[scotty nm35]

Means you have modded the car enough that it is running into areas of the map where the ecu isn't comfortable, and you need a tune to address it.

[Dunc]

Means you have modded the car enough that it is running into areas of the map where the ecu isn't comfortable, and you need a tune to address it.

But I haven't done any mods recently?

[Dunc]

I've been systematically replacing hoses and clamps, finally found the culprit. The hose connecting the FMIC back towards the turbo split on top, several people had visually inspected it and felt it - we all assumed that was fine. It wasn't. Heat, pressure and time - what a glorious combination.

Scotty had a spare, so now its all sorted. Im back in business!