Rough idle after warm up. Hrmm...

[waters17]

ANOTHER UPDATE!

I kept noticing some throttle hesitation/lag, which I attribute to the DBW, but it seems to be getting worse. Really frickin' annoying when shifting. This prompted me to run another DIS diagnostic. Seems I'm right back to where I started.

Here's my collection of DIS screenshots from today.

Faults: The electrical ones seem to be hit or miss, depending on the day I run the scan. INPA only shows one for 140 Output Thermostat Map cooling.
DIS_v44-2017-07-28-20-57-15.png


DIS_v44-2017-07-28-21-00-36.png

Onto the tests. The first test was a nominal/actual value comparison test (as clearly stated below)
DIS_v44-2017-07-28-21-03-30.png

These results suggested I run some more tests.
DIS_v44-2017-07-28-21-04-09.png
DIS_v44-2017-07-28-21-04-23.png

So I did.... Continued on next post

[waters17]

DIS_v44-2017-07-28-21-06-17.png

DIS_v44-2017-07-28-21-10-03.png

DIS_v44-2017-07-28-21-10-14.png

DIS_v44-2017-07-28-21-10-30.png

DIS_v44-2017-07-28-21-10-39.png

[waters17]

DIS_v44-2017-07-28-21-11-02.png

DIS_v44-2017-07-28-21-11-28.png


That's it for the tests. Previously I had a tank vent valve issue, but ever since in re-timed it, that issue has gone.

Quick recap of things (related) that have been replaced on the car. Everything has been done in less than 35k miles and maybe 1.5 years.
Vacuum lines. -items 9, 11, and 12
CCV & gasket
Intake manifold gaskets (twice)
Throttle body (VDO) & gasket
O2 sensors (front)


Things I have NOT changed yet, but may be contributing to the issue.
MAF
O2 sensors (rear)

I just can't figure out where this vacuum leak could be coming from.


They probably both need replaced, but I'm wondering if I should swap the rear O2 sensors to see if one of them is bad?

[jicaino]

Do you know how well your exhaust is sealing?
I'd replace MAF if yours hasn't been replaced and you know that for fact.
I wouldn't think that rear O2 sensors are the culprit here.

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[jicaino]

Also are you on the original TU manifold or you've replaced it? Sometimes with older manifolds when warpage becomes an issue, you need to trim the sleeve that rides in the rubber spacers or they will bottom out on the heads before the rubber can press the manifold enough for the gaskets to seal

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[waters17]

Are you suggesting the exhaust manifold could be leaking? How do I even go about checking? That truly seems like a nightmare.

I imagine the intake manifold is the original one that came with the car. I never even thought about warping. When I replaced the gaskets recently, the old gaskets did look squished pretty evenly. I've also added washers to the intake manifold bolts allowing me to tighten them down further.

Per your suggestion, I ordered a new MAF. It'll be here on Saturday. I'll also be installing new spark plugs too.

Should I reset my adaptations after installing the new MAF?

[jicaino]

It never hurts to reset adaptations when chasing ghosts.

Yes the exhaust manifolds (or one of them, or just half of a side on each bank) could be leaking throwing off the O2 sensor reading and causing issues. way to check would be having a helper closing your exhaust tailpipe and hearing/feeling for leaks (best if done from under the car and with a very bright light source as an aid to detect exhaust fume leaks)

If you had to add washers maybe the intake manifold is somewhat warped. Adding washers only makes it worse since the main issue with sealing warped manifolds is that the grommet rides on the outside, allowing the center tube to bottom out metal on metal while the top hasn't compressed/seated the rubber grommed all the way down onto the manifold recess. I will look in my pictures and in my notes, I recall having read something online about this, maybe on a brit site, and it explained what you should do to seal minorly warped manifolds. Google "intake vaccuum leak BMW M60 M62"

[waters17]

I might try to check the exhaust for leaks this weekend. I need some bright lights though.

Now, I didn't really have to add the washers. It was just another one of those shots in the dark.
Here's the Brit site I got the info from:
http://www.meeknet.co.uk/e31/BMW_E31...d_Leak_Fix.htm

[jicaino]

I might try to check the exhaust for leaks this weekend. I need some bright lights though.

Now, I didn't really have to add the washers. It was just another one of those shots in the dark.
Here's the Brit site I got the info from:
http://www.meeknet.co.uk/e31/BMW_E31...d_Leak_Fix.htm

That's good info. If you added washers like that then its good.

Enviado desde mi SM-N920G mediante Tapatalk

[Reggieleemorton]

I'm having the same issue after doing a timing chain replacement, Sluggish idle that goes away above 2000rpm.
hesitation and stalls in first gear and reverse.

[Reggieleemorton]

I found the leak I had previously associated with the CCV. When I removed the Oil filler cap with engine running there was an increase in hissing from the Hose that exits underneath driverside cabin air cleaner. This hose does an S bend and connects to a Y fitting located near the CCV. On closer inspection I discover a big cut in middle of S bend, when I stretched this hole the engine immediately lost rpms. I don't know what this hose does, but think its for the Brake booster. will replace soon

[waters17]

I found the leak I had previously associated with the CCV. When I removed the Oil filler cap with engine running there was an increase in hissing from the Hose that exits underneath driverside cabin air cleaner. This hose does an S bend and connects to a Y fitting located near the CCV. On closer inspection I discover a big cut in middle of S bend, when I stretched this hole the engine immediately lost rpms. I don't know what this hose does, but think its for the Brake booster. will replace soon

Lucky! I think the hose you're talking about is called a jet pump or something. I might replace mine too. May as well just blast the whole car with the cash cannon.


I replaced my spark plugs and the MAF yesterday. Overall, it feels a little smoother and responsive, but the issue is still there. My helper went out of town for a few days, so I couldn't try the exhaust test.

[JimLev]

Philly posted about doing this same thing a few years ago.
He used wave washers.

[jicaino]

Have you guys checked on your brake booster? that hose you describe provides filtered vaccuum to the booster. If the hose's cracked or the checkvalve is clogged open it's like hell breaks loose on your idle. You have to remove the driver's side cabin filter case. Another vacuum leaks sources are the plugged cap on the CCV cover ("back of the manifold cover") often overlooked, there's a little rubber plug on the passenger's side of the CCV cover. Most new CCVs comes without the plug. If you failed to replace it (you or whoever replaced the CCV) you'll never get a decent idle.

Another mandatory test for crappy idling engines is a dry compression test. Persistent idle failures can be pinned on cracked rings, or more generically, ring sealing issues (CCV failing to operate correctly on account of vaccuum leaks counts as rings sealing poorly)

Don't freak out, not saying your engines have cracked rings or such, just suggesting what tests I'd do if my engine had such issues.

So, "to do list" includes

A ) checking brake booster vac lines and checkvalve
B ) checking CCV cover for proper vac ports connections and for that little pesky plug installed (it should have the same diameter as a vac line)
C ) checking the idle checkvalve, filter and solenoid vac lines routing under the acoustic cover (top engine cover)
D ) if your idle's particulary crappy when cold and then improves, check on the SAP and its connections
E ) if you have to take out the clutchfan for some reason, it would be wise to check the crossover tube for the SAP. Cracked O-rings, stripped threads at the clamping bolts on the ends, leaky gasket or poorly tightened SAP valve results in exhaust leaks that throws O2 readings off particulary at idle (without the car moving) because no negative pressure differential behind the car means less "scavenging" and low engine rotation coupled to that means the exhaust fumes kind of "hesitates" where's the exit.
F) let your tank get low on fuel, load it with new premium fuel and take her for a spin @high RPM's if you can't pound her good to go fast. Cruise at your legal speeds selecting a gear that would take your engine between 4 and 5k rpm. Sometimes long periods of driving below 3000 rpm coupled with just weekend driving and extended periods of time between fresh fuel is in the tank results in all sorts of misbehaving that goes away as soon as you pin her down hard, good and frequently. Not to be a chauvinist pig, but's like wives. If they're yapping to much and giving you a hard time with minor nuances is entirely your fault...

[gmak]

Lucky! I think the hose you're talking about is called a jet pump or something. I might replace mine too. May as well just blast the whole car with the cash cannon.


I replaced my spark plugs and the MAF yesterday. Overall, it feels a little smoother and responsive, but the issue is still there. My helper went out of town for a few days, so I couldn't try the exhaust test.

Sucking Jet Pump.

[Reggieleemorton]

After patching the cut with electrical tape the engine was a little more stable but it still has a slight hesitation on 1st gear and idle. I don't believe the cut was the underlying issue of the sluggishness and hesitation however the engine is a bit more responsive. There still exist a hidden issue with this engine and I still feel its operating at only 85%. I ordered a new booster hose but the search continues.

[jicaino]

After patching the cut with electrical tape the engine was a little more stable but it still has a slight hesitation on 1st gear and idle. I don't believe the cut was the underlying issue of the sluggishness and hesitation however the engine is a bit more responsive. There still exist a hidden issue with this engine and I still feel its operating at only 85%. I ordered a new booster hose but the search continues.

How many times did you spin it when timing it?

[Reggieleemorton]

I timed the engine 4 times and hand-turned 5 times after each timing, on the last timing I replaced the cam blocks and vanos blocks to verify. I did need to turn the passenger side cams to reinstall cam blocks but this is normal, plus the blocks were not seated correctly on the heads and tended to move whenever I made the final torque for exhaust and intake cams. After reflection Im realizing that I was very sloppy so I will retime tomorrow.

Prep for tomorrows retiming

1. On inspecting my timing kit Im noticing play with the vans gigs for the driver side, the bolt that holds the pieces together was not tight. This could be the main cause of the timing being slightly off. Ive replaced all Vanos gig bolts and applied locktite.
2. When I install the cam blocks i will either tape or fashion a piece of metal to prevent the block from moving during final torque of exhaust and intake, any movement will not be tolerated!
3. Received new MAF and will install tomorrow
4. Received new Vanos seals/ washers but I don't really understand how to preform this job, its still up in the air for tomorrow.

[Reggieleemorton]

Finished retiming the engine and it does feel a little different but the rough idle and low power below 2000rpm is still present. Upon mounting the vanos gig to bank5/8 the pin was 1/2 the vanos hole advanced, bank1/4 was dead on. Both intake cams and vanos continuity were done and torqued, I didn't touch either exhaust cam. After torqued then hand turned for 5 rotations and replaced all gigs, everything lined up perfectly. Fired up engine and immediately I recognized the same rough idle. I can't stand this shit!

Will be ordering the GAS Vanos gigs tomorrow! you get what you pay for, lesson learned.

[jicaino]

I think you're turning it too many times with no checking and correcting in between. The whole idea behind turning it over and over is to correct/ensure timing is dead on AFTER each whole turn by hand. Take into account that one crankshaft turn will equal 2 camshafts turns.

1. Time it
2. Spin it half a turn (one camshaft revolution) CCW then spin it turn and a half (3 camshafts revolutions) on the CW direction. This is for eliminating chain slack from the equation. Time it (correct VANOS actuators/position, etc).
3. Repeat #2 x3

[waters17]

Will be ordering the GAS Vanos gigs tomorrow! you get what you pay for, lesson learned.

What are gigs? Jigs? Are you talking about the timing tools?

Were you using the EWK ebay/amazon tools? btw, the GAS tools are so nice to use.

[Reggieleemorton]

I will be ordering the GAS jigs for vanos because I don't think the problem is leak associated. I believe the my cheap ebay vanos tools are the issue.

[waters17]

I hope it works out for you. I went through the same thing with the ebay tools, but I didn't really check my work, so I can't officially blame them. Even after I timed my car with the gas tools, I'm still with the rough idle.

[Reggieleemorton]

Jcaino, I will was under the impression that cycling the engine was done solely to ensure no crash of valves. I made sure no slack was present between both Intalke cams and U glide. And I always tighten the chain tensioner more than nessary to ensure no slack. I still must buy new vanos Jig because bank5/8 jig still has a lot of play even though it has a replaced bolt. More than 4 mm of play, I think treads are stripped. Will try your way next timing.

[Reggieleemorton]

Received the CCV replacement and the MAF today and discovered the old CCV was larger than the new CCV. The old CCV was in very good shape and didn't have cuts or holes. The new MAF is also different from the replacement with a circular connection. This is the pitfalls of buying EBay parts, some salers purposely false advertise. This is my third incorrect item I've received from EBay. Be warned.

On a positive note when I reinstalled the old CCV, I heard loud hissing and rough idle from the CCV area. So I continued pressing the unit back in place until it locked back into its grove. Once it settled the hissing stopped and the engine immediately changed its rough idle and started a normal idle. It doesn't have the hesitation in throttle anymore. So apparently Ive fixed the problem and the issue has gone! I wish i knew what i did, will drive test after traffic settles.