peter's canadian imola ZHP project

[az3579]

hey botond,

i swapped in the MAF from my coupe (which runs perfectly), and i have no change in behavior - it is still hesitating/bucking around 2500rpm under load in 4/5/6th gear. i guess now i need to start checking for vacuum leaks. also, i have an aFe intake on the sedan, OEM intake on the coupe. i wonder if it's not happy with that?

peter

It's doubtful that the intake is causing this issue, unless, of course, there's a vacuum leak somewhere in that area.
I also doubt it's a DME issue, but you can rule this out by unplugging the battery for a while. I think 15-30 minutes will do the trick. Need someone else to chime in and verify this, but because our cars are so electronically "involved", it's definitely a worthy troubleshooting step. The DME itself hasn't changed, so a DME won't just one day decide to make the car buck...

This sounds like a potential fuel pump issue as well, though there may be another issue due to the codes that were read. One thing that can affect both banks 1+2 is a vacuum leak; check the lower intake boot for cracks (might as well check the upper one as well). This is a very common issue.

[slater]

It's doubtful that the intake is causing this issue, unless, of course, there's a vacuum leak somewhere in that area.
I also doubt it's a DME issue, but you can rule this out by unplugging the battery for a while. I think 15-30 minutes will do the trick. Need someone else to chime in and verify this, but because our cars are so electronically "involved", it's definitely a worthy troubleshooting step. The DME itself hasn't changed, so a DME won't just one day decide to make the car buck...

This sounds like a potential fuel pump issue as well, though there may be another issue due to the codes that were read. One thing that can affect both banks 1+2 is a vacuum leak; check the lower intake boot for cracks (might as well check the upper one as well). This is a very common issue.

thanks. i just replaced the upper and lower boots with new OE boots about 2 months ago. i am going to check all other vacuum connections, especially near the CCV (replacing it with a catch can shortly), and the fuel filter (replacing that shortly as well).

hoping it's not a fuel pump.

peter

[az3579]

hoping it's not a fuel pump.

I would actually hope it's that simple, because if it isn't, then you're stuck with trying to find the source of the problem.

In my case, my fuel pump was making my car run like total crap, so I pulled over in a rest stop and swapped it with the new fuel pump I was carrying around for a few months (you know, just in case ).

[ELCID86]

agreed. f/p is an easy fix if it is in fact the root cause.

[az3579]

agreed. f/p is an easy fix if it is in fact the root cause.

Ultimately, a proper diagnosis is key. If you're unsure, have a shop diagnose it.


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[slater]

new pads up front (did rotors 2 months ago), new rotors and pads out back. fixed a seized RR parking brake adjuster, it works as it should now.

next up: OFHG/VANOS/VCG/CCV fun, along with OEM M3 engine mounts and UUC trans mounts.

then: rear subframe bushings (poly), poly RTABs as well, plus new CSB and giubo. fun fun. and some paintwork.

peter

[ELCID86]

new pads up front (did rotors 2 months ago), new rotors and pads out back. fixed a seized RR parking brake adjuster, it works as it should now.

next up: OFHG/VANOS/VCG/CCV fun, along with OEM M3 engine mounts and UUC trans mounts.

then: rear subframe bushings (poly), poly RTABs as well, plus new CSB and giubo. fun fun. and some paintwork.

peter

you go girl!

[slater]

you go girl!

ha!

if you could see my previous car history, this kind of list would be expected. i'm a "i like my car to be 100%" kinda guy. especially because my wife and kids spend more time in it than i do.

peter

[johnrando]

Nice

[az3579]

new pads up front (did rotors 2 months ago), new rotors and pads out back. fixed a seized RR parking brake adjuster, it works as it should now.

next up: OFHG/VANOS/VCG/CCV fun, along with OEM M3 engine mounts and UUC trans mounts.

then: rear subframe bushings (poly), poly RTABs as well, plus new CSB and giubo. fun fun. and some paintwork.

peter

I think you'll like the M3 mounts! I put them in mine. It took a little while to get used to the fact that my car didn't feel quite as refined anymore, but now that I'm used to it, I love the slight vibration you get. It's not obnoxious at all; it's just enough to make you feel like the car actually has a soul. lol

Also good call on the poly RTABs. I have them and zero complaints.