Engine hesitation issue with MPS6

[DannersAU]

Hey Guys,

There are several threads that i've found that refer to an engine hesitation, but most seem to be during WOT - Mine is different to this so i've posted a new thread.

I recently purchased a MPS6 a couple of months ago and have noticed a hesitation issue when under normal acceleration at around 2-3K revs. I purchased a Cobb AP and have logged what I think is the problem occurring. The log is highlighted in red where this occurs. The car runs slightly lean when coming on boost as AFR's hit the 15's and a small amount of knock is detected. This is not something I can repeat and happens randomly. I need to also state that it is not a WOT problem and happens when just driving around normally. The car seems to lose power for a second or two but if I do the same thing again a minute later its fine.

https://www.dropbox.com/s/yfwqkv96ho...SModified.xlsx

To date i've:

*Replaced and gapped plugs
*Replaced oil and oil filter
*Stretched coil pack springs
*Changed air filter
*Cleaned MAF sensor
*Bought Cobb AP and am running the Stage 1 98 tune
*Done a MAF calibration
*Installed a Grimmspeed boost controller


It doesn't appear to be fuel pump related but next I plan to get the Autotech internals anyway as a precautionary measure

I appreciate any advice you can give as i'm stumped

Dan

[son of eevil]

Injectors need a clean perhaps?
Replaced the fuel filter?

[Rayd]

You seem to have tried everything... Have you checked your ABS sensor? Maybe it's dirty and cutting in ? Happened to a couple other cars I've encountered

[DannersAU]

I was googling like a mofo and found this - Fuel Pressure Dips - Mazdaspeed Forums

I've pulled the sensor and pushed the pins down a little to make better contact. I don't know if its all in my head, but the issue appears to be gone now...

The plug looked perfectly clean when I took it off, so i'm highly doubtful, but after two days the issue doesn't seem to have come back and the car seems smoother.

Thanks for your suggestions regardless... I'll try them if the problem re-appears

Dan

[dazza]

May need to replace the sensor if it continues

[1CMS1]

Has the problem reappeared Dan? I have the exact same problem and have had no luck fixing it. When the hesitation happens I get a DTC stating that my car has a misfire in cylinder 4.....annoying to say the least

[DannersAU]

I think it has. I just installed a Cobb SRI and loaded a different tune that does not have my accelerator pedal smoothing and MAF calibration as part of it, so i'm going to re-do those.

Have you tried all of the other things I mentioned in the first post? I've never had the car throw a code, only felt the slight effects of it

[Jmac]

Has the problem reappeared Dan? I have the exact same problem and have had no luck fixing it. When the hesitation happens I get a DTC stating that my car has a misfire in cylinder 4.....annoying to say the least

Modifications? What have you tried?
-clean maf
-check air filter
-check boost leaks
-check for fouled spark plugs
-try the spring stretch

How are you checking the dtc?

Sent from my S4 while I'm tappin dat' glass.

[1CMS1]

I dont want to jinx it but the problem hasnt come back after I pulled the spark plugs and gave them a good clean up with a wire brush on thursday. I also cleaned the fuel pressure sensor again vigorously which I think may have been the problem all along.

The problem was only happening once everytime I drove it, then it started happening so often during a trip to the point I would get shitty and floor it, resulting in it hesitating really bad and a DTC code.

Jmac I found that my plugs were fouled on thursday hense why I gave them a clean up. I knew the hesitation was caused by a temporary over fueling problem as I had the same type of hesitation on a s14 silvia years ago, and the exhaust tip on the MPS had colected more black soot than most peoples chimneys.

I checked for boost leaks and re-checked all hoses etc, did the spring stretch, Air filter is brand new and the maf was cleaned when I installed the new filter.

My mods atm are a COBB SRI, Hypertech (Used Hypertech to check DTC) and Prosport boostgauge as I havnt had the car long and I'm currently unemployed

[newmaz]

Hey Guys,

There are several threads that i've found that refer to an engine hesitation, but most seem to be during WOT - Mine is different to this so i've posted a new thread.

I recently purchased a MPS6 a couple of months ago and have noticed a hesitation issue when under normal acceleration at around 2-3K revs. I purchased a Cobb AP and have logged what I think is the problem occurring. The log is highlighted in red where this occurs. The car runs slightly lean when coming on boost as AFR's hit the 15's and a small amount of knock is detected. This is not something I can repeat and happens randomly. I need to also state that it is not a WOT problem and happens when just driving around normally. The car seems to lose power for a second or two but if I do the same thing again a minute later its fine.

https://www.dropbox.com/s/yfwqkv96ho...SModified.xlsx

To date i've:

*Replaced and gapped plugs
*Replaced oil and oil filter
*Stretched coil pack springs
*Changed air filter
*Cleaned MAF sensor
*Bought Cobb AP and am running the Stage 1 98 tune
*Done a MAF calibration
*Installed a Grimmspeed boost controller


It doesn't appear to be fuel pump related but next I plan to get the Autotech internals anyway as a precautionary measure

I appreciate any advice you can give as i'm stumped

Dan

How long after you flashed your tune did you take your log? I'm curious because there doesn't appear to be any LTFT present on your log. Have you attempted to cal your MAF?

edit: Sorry just read the last line of what you did lol.

It seems funny you dont have LTFT but maybe someone else can chime in on that.

[DannersAU]

Over the last week i've installed a Cobb SRI and a TIH, installed the appropriate OTS maps from Cobb and the problem seems to be worse! I've re-done my MAF calibration too

Even though my logs don't seem to show any HPFP issues, I do have the new internals and will install on the weekend. To top all of this off my turbo has started smoking as well in traffic... awesome. Starting to wish I didn't buy this silly car.

[SarcasticOne]

Over the last week i've installed a Cobb SRI and a TIH, installed the appropriate OTS maps from Cobb and the problem seems to be worse! I've re-done my MAF calibration too

Even though my logs don't seem to show any HPFP issues, I do have the new internals and will install on the weekend. To top all of this off my turbo has started smoking as well in traffic... awesome. Starting to wish I didn't buy this silly car.

Check spark plugs and post a log
Raise idle to 900-1000 rpm

[MPS400]

How do you raise idle...?

[dazza]

How do you raise idle...?

Raising Idle with Cobb AP - Mazda 6 Forums : Mazda 6 Forum / Mazda Atenza Forum Post #5 ...
GEN 2 tables are slightly different, think they are missing one of the tables but the process is the same

[MPS400]

Ahhhh need an AP for it then.

[Jmac]

Or hypertech

Sent from my S4 while I'm tappin dat' glass.

[Jmac]

Stupid question. Have you reset the Ecu?

Sent from my S4 while I'm tappin dat' glass.

[DannersAU]

Stupid question. Have you reset the Ecu?

Sent from my S4 while I'm tappin dat' glass.

I did during my first round of troubleshooting but haven't since installing the SRI and Turbo Pipe. I'll give it another try.

I do seem to have made some success after reading Abilor's tuning guide and have made some changes to my boost tuning maps and fueling tables. In saying this though, I was using completely OTS maps before this and the problem existed so I feel as though my customisations are only masking the problem.

Abilor's Tooning Guide for Noobs - Mazdaspeed Forums

Raising idle didn't fix my smoky turbo... Bnoon bolt is on it's way and hopefully i'll get the Autotech internals installed this weekend

I found this to be a very interesting read.