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Discussion Starter #1 (Edited)
Sorry this is so so long. But please read because I put a lot into it and I need the board's intelligent input!

I picked my car up today from having a week's worth of service to replace a long list of items (listed below). Upon driving home I noticed quite a difference in exhaust note. It was much deeper and throatier, and I could really hear the rhythm of the engine, like it sounds if you roll your r's. In the end, this may have seemed so different because I had been driving a Kia Rio rental all week (easter egg on wheels :grrrr:).

Trouble started once I got fast enough to get into 4th gear. At low rpm there is a lot of stuttering and between 3k-4k when gas pedal depressed it feels like there is no power being supplied by the engine. Just a minimal increase in acceleration, not the pull I am used to. So i started to get concerned. At one or two instances, right at 3k rpm the exhaust note dropped really deep for about one second and came back. That freaked me out a lot. I pulled over at a gas station to pull any fault codes (listed below). I then reset the codes.

After getting back on the road, everything seemed better. Exhaust sounded normal again, car pulled fine, I was happy :). Then I got to 4th gear and all the same problems remained. So I thought for a second, what had been done that could affect engine performance? Two things, cleaned throttle bodies which were very dirty as I was told, and installation of the Dinan big MAF housings. That's where I realized this could all be because of the larger MAF housings. I figured I would need a tune, and was going to get that done from Evolve when I get their headers. I had no idea it could make this much difference though! I read the fault codes when I got home too, after another 30-45 minutes of driving.

Question: Can the larger MAF housings be the issue I am having in 4th gear? 1st-3rd seem ok. If so, any real issue in running without modified software for a few weeks? I currently have the standard Alpha-N tune.

Also, please feel free to comment on the below figures for compression and leak testing, as well as on the pictures of my spark plugs.

Parts replaced

Water Pump, W/P pulley, T-stat, both Temp Sensors, belts, CPS x4, TPS x2, O2 sensors x4, Oil Change, cleaned TBs, Spark Plugs, Fuel Breather Valve, SAS cut-off valve, cleaned SAS tube of carbon buildup, all vacuum lines/hoses/o-rings related to these items and fuel pressure regulator, o-rings and gaskets for the heat exchanger, Dinan MAF housings, oh and the dipstick o-rings for good measure! ;)

Codes pulled after initial drive
- 1b 69 AA 6b 4E 78 77 E6 08 b2 b3 68 (I was getting 69 b2 b3 before the service)
Codes pulled after reset and drive- 1b 08 68 (much smaller list whew)

Code References
69 - Engine Coolant Temp, Plausibility (most likely resolved from t-stat change)
AA - Secondary Air System, Flow Too Low (hopefully fixed from valve replacement and tube clean out)
6b - Control Unit Self-Test, Pre Drive Check of Drive-by-wire System (no idea what this is??)
4E - Coolant Temp Sensor (hopefully just from replacing both sensors)
78 - Throttle Position Sensors, Cross Check (hopefully just from TPS replacement)
77 - Throttle Position Sensor 2 (same as above)
E6 - Drive-by-wire, Throttle Position Failure (same as above)
08 - NOT IN THE MANUAL ? (this one came back and worries me) :sad1: Could be "Intake CPS Cyl #5-8" in table 18
b2 - Catalyst System Efficiency Cyl #1-3 (these from before service, hopefully fixed)
b3 - Catalyst System Efficiency Cyl #4-6 (see above)
68 - NOT IN THE MANUAL ? (this one also worries me, it came back too) :sad1: I'll have to check and make sure this wasn't a "b8"

Results from Compression and Leak Testing

I was told that these are very good numbers, leak testing was 0% for all cylinders.
#1 - 218
#2 - 215
#3 - 220
#4 - 220
#5 - 216
#6 - 222
#7 - 218
#8 - 217

Spark Plugs (HIGH RES)
How do these look to everyone? I think these have about 30k miles on them.
 

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Maybe the DME is taking a little time to adapt to the larger MAF's. It could be a fuel filter/pump issue.
 
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Discussion Starter #3
Maybe the DME is taking a little time to adapt to the larger MAF's. It could be a fuel filter/pump issue.
Thanks, I did notice a slight improvement by the time I got home (hour drive from shop). So I will continue to drive and see if things improve.
 

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They look a bit oily? Mine were less black just looked sort of dusty and brown...I am no spark plug whisperer though...
 

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Drew,

Really disappointed and sorry to see you are having this kind of grief after all the hard work you put
into your research prior to this shop visit.

Plugs 4, 6 and 8 do exhibit signs of running cold (#4 especially), while #3 is running at elevated temp.
I would suggest either flow-testing the #3 injector (or just replacing it and then testing it afterwards).
I believe this should be rectified as soon as possible.

Your compression test values are excellent, so that's good news.

Again, my priority would be resolving the #3 cylinder high temp. You know my email address, so don't
hesitate to contact me.

Regards,
Alan
 

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Thanks, I did notice a slight improvement by the time I got home (hour drive from shop). So I will continue to drive and see if things improve.
When I added the bigger MAF housings, I let it idle about 90 seconds. After some fluctuating idle, I didn't have any stumble. Perhaps I was lucky. But without changing the tune, you won't see any power gains. I tested on the dyno, no change, although the car sounded better!

As to plugs,most look a little too dark. The first set, reading left to right, #3 looks good, right color. Dark is either running rich or a touch of oil seeping in. I can't see how good the electrodes look. But fresh plugs should help.

As to codes, "b"'s and "6"'s are easy to interchange. On the codes that "don't exist", try substituting one for the other and see if it makes a difference.

Throaty engine and lack of power is often exhaust CPS. I know you changed all 4, but shutting the car off and restarting to clear it means it is electrical and not mechanical. So I would look for an exhaust CPS code. Could be VANO's but less likely from what you described.

Regards,
Jerry
 
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Discussion Starter #7
Alan, the car has been running cold most of the year. I noticed immediately today that the car is warming up to proper temps. Before this service, I was barely getting over 70C and oil was not getting passed the first dot. Now water temp is at the 12 oclock position and oil temp is well passed the first dot. This could be why some plugs show signs of running cold.

It is interesting that you two disagree on #3. Either way, #3 looks the cleanest, #1 #2 #5 #7 at the next level of coloration, and #4 #6 #8 are the darkest.

I am still just concerned about the stuttering and loss of power that I get in 4th gear. Does tuning software provision for different values in each gear? Could my Alpha-N tune not be playing nice in 4th gear with the larger MAF housings? Or could the problems be from some other item that was replaced?

A lot of things were replaced, including a lot of sensors and items important to the performance of the engine. So I will try to log some more road time and see if the car adapts and settles down. This is most likely the first time the CPS, TPS, and O2 sensors have been changed.
 

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Discussion Starter #8 (Edited)

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So could one of my intake CPS have been installed incorrectly?
That is the first thing that I thought of when you described your symptoms, Drew. They are classic symptoms of a bad CPS. Since you just had yours replaced, perhaps they were installed incorrectly or were bad from the factory? I recognize that both of those things are unlikely, but your symptoms are dead on with a bad CPS diagnosis.

--Peter
 

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Discussion Starter #11

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Not a software issue,mate!

Have also had already new cps that were faulty.Your issues sound very much like Vanos or fuel!

Check the wiring on the CPS and also check the O2 sensor wiring.Would not be the first time that they are connected wrong!Vaccum leak is another possibility!

I changed from stock air boxes back and forth with my intake tubes and Sal as well.We were running at that time the same tune you have,no issues at all!

Were the throttle bodies removed for cleaning?
Were the adaptation values reset?
 

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Discussion Starter #13
Not a software issue,mate!

Have also had already new cps that were faulty.Your issues sound very much like Vanos or fuel!

Check the wiring on the CPS and also check the O2 sensor wiring.Would not be the first time that they are connected wrong!Vaccum leak is another possibility!

I changed from stock air boxes back and forth with my intake tubes and Sal as well.We were running at that time the same tune you have,no issues at all!

Were the throttle bodies removed for cleaning?
Were the adaptation values reset?
Thanks Raikku. I was having no issues before this service! Argh. I am hoping this is just related to one of the newly installed CPS sensors.

Throttle bodies should not have been removed for cleaning. And I doubt the adaptation values were reset.

This is such a bummer
 

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Discussion Starter #17 (Edited)
If the ECU has been over written you will have air mass sensor 1 and 2 as a fault code as you run MAFless.

The Dinan tubes cannot cause these faults so look away from that.
Excellent point. My MAFs are still disconnected and no MAF codes are coming up. Scratch that off the list.

I just went for another test drive, reset the codes, and the same two came back: 08 and b8. Now I was beginning to get some VANOS rattle before this service and the car was still running fine. The rattle does sound a little worse, but I don't see how this service could have expedited any new performance issues.

Raikku, if O2 sensor wires were installed wrong, wouldn't there be an O2 sensor related code?

I think the problem resides with the two codes I am getting, which others have resolved with the replacement of the Intake CPS Cyl #5-8. However, I believe a VANOS test is also warranted at this time.

Is there an easy way for me to personally check the CPS sensor wires? I know others have replaced that sensor in an hour or so, but that involved going under the car to remove a bracket. I'm just wondering if I could wiggle it around and just make sure it is seated securely.
 

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Check the wiring of the CPS for sure,mate!
Also do me a favor and remove the solenoid cover from this bank.Check if one of the solenoides is further pushed out than the others and report back.

The O2 sensors take time until they throw errors,as the ECU only detects the issue with the LTFT!
 

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Discussion Starter #20
Check the wiring of the CPS for sure,mate!
Also do me a favor and remove the solenoid cover from this bank.Check if one of the solenoides is further pushed out than the others and report back.

The O2 sensors take time until they throw errors,as the ECU only detects the issue with the LTFT!
I'm going to reach back to the driver side intake CPS tomorrow and make sure it is connected firmly. I'm not sure I'll have the ability to pull it all the way out or anything. I'm crossing my fingers it is unplugged or something.. :crying:

If I have time, and the above doesn't fix anything, I will take the cover off the VANOS. Cyl #5-8 is the driver side right? And all I have to do is remove the MAF housing and related tubing and then use 6mm allen wrench on the cover?
 
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