He-he-hesitating

[Juice]

Yesterday I may or may not have been chasing an Audi S4 up an on ramp, but what definitely happened was the car hesitated under power when going up hill. At first I didn't conclude that it was up hill, but I tried reproducing it a few times after it happened, and it didn't happen again until another up hill area. I'll see if I can reproduce it on video, but until then, dafuq?

Thanks in advance. :)

[Juice]

To start off, I'm probably going to replace the fuel filter. Cheap fix if that's it, and it could probably use it anyway. I can't find my log book since I moved, so I don't know when it was done last.

[mike P71]

I had very similar simptoms recently and it turned out to be a coil. The first thing I would do is change the fuel filter then ck the coils. Good luck

[RF Overlord]

It only happens going uphill? Sounds like a fuel delivery issue...

[fastblackmerc]

Definitely change the fuel filter.

[03sport007]

If its fuel related be careful under boost. Do you have a wideband?

[Juice]

If its fuel related be careful under boost. Do you have a wideband?

I don't. :(

It's on the list though.

[justbob]

I don't. :(

It's on the list though.
Keep playing with that fire and it will be a new block on the list as well... It is your engines LIFELINE.

[Juice]

I figured as much. I don't drive it hard that often, so it wasn't high up on the list of priorities.

Would this one do the trick?

http://www.amazon.com/AEM-30-4100-UEGO-Controller-Gauge/dp/B000CFQM4G/ref=pd_sim_auto_1

[03sport007]

I figured as much. I don't drive it hard that often, so it wasn't high up on the list of priorities.

Would this one do the trick?

http://www.amazon.com/AEM-30-4100-UEGO-Controller-Gauge/dp/B000CFQM4G/ref=pd_sim_auto_1

I think that's one I have. Have you done any data-logging? Does it happen every time you go up a hill or just sometimes? Still running the stock fuel pump?

http://i1084.photobucket.com/albums/j414/03sport007/photo-34.jpg

[Juice]

That was the first time it happened, so the car is parked until I figure out what's up. I bought a fuel filter, but I haven't put it in yet.

I haven't done any data logging, I don't know how. The two times I got it to do it were both up hill and under medium to heavy power, it didn't do it just cruising.

Stock pump with a bap.

[03sport007]

I'm no expert so take what I have to say with a grain of salt:

I find it hard to believe that the gravity of going up a hill is putting enough extra stress on the fuel system(Pump or Filter) that your loosing enough pressure that the motor starts to hesitate. If that's true I would think you've been on the raged edge for awhile. How many miles on the pump and filter?

I'd really like to see what your FP duty cycle, Fuel Pressure and A/F is doing.

Do you have a SCT Tuner? If so you its pretty easy to Data-log.

[Juice]

I'm pretty sure it's the stock pump, so 83k. I don't know about the fuel filter, like I said in my post I don't know where my log book is, so I don't know the last time it was replaced.

I have an SCT tuner, I'll check that out tomorrow. I'm going to replace the fuel filter first though. I'd prefer not to drive it too much if there is some other issue.

[Blackened300a]

I'm no expert so take what I have to say with a grain of salt:

I find it hard to believe that the gravity of going up a hill is putting enough extra stress on the fuel system(Pump or Filter) that your loosing enough pressure that the motor starts to hesitate. If that's true I would think you've been on the raged edge for awhile.

Agreed. I think it's coil related since they can be finicky and start breaking up under a load. Even just one coil can cause a huge hesititation.

[Juice]

Alright, thanks. This coil concept is foreign to me, so I'll do a little digging.

I tried to data log the fuel pump today and hit a bump, so that's on hold til I fix my screw up. I did change the fuel filter though, so if nothing else, that's one thing eliminated.

[03sport007]

The good thing is fuel filter, pump and coils are all prett easy to do. Good luck and keep us posted.

[Juice]

I did a little digging (I didn't even really understand what the coils did/were). I kind of want to invest in a multi-meter so I can test them, but they may just need replacing anyway.

The more I read about coils, I feel like that might not be my issue. It happened only twice, and happened under heavy load. I feel like that is more of a fuel delivery issue than anything.

I accidentally deleted my tune when updating my tuner so I could read the data log. I'm waiting to hear back from Jerry at Trilogy on getting the tune again. You're all welcome to punch me in the nuts for doing that. So it might be a while before I can get the data log info, or even drive the car to test the new fuel filter for that matter.

[Mr. Man]

What is a reasonable life expectancy of the COP's?

[RF Overlord]

160,000 miles on Phoebe and only replaced one so far.

[Juice]

A little update. I found my log book, and the fuel filter was replaced at 66k miles, so it had 17k on the one I replaced.

[Juice]

Another little update: Car isn't running yet (no tune), but I blew the old filter (teehee) and it was very restricted compared to the new one.

[Juice]

Alright, I ran a data log of the fuel pump duty cycle, but I have no idea what the hell I'm looking at. Is there a way I can post it so everyone can see?

[SNOOT]

Use the control print screen and paste the image into some place you can save it.. Maybe when we meet up next weekend we can exchange notes on logging information. I have tried a couple times but there are so many things you can pick from its confusing to me.

[03sport007]

Alright, I ran a data log of the fuel pump duty cycle, but I have no idea what the hell I'm looking at. Is there a way I can post it so everyone can see?


My understanding is 0=off and 100percent means the pump is maxed out.

If you see anything close to 100 percent then you've got issues

I'm usually in the 30-40 percent range and a little over 60 at WOT

What it's reading?

[JoeBoomz]

For the duty cycle, you want to see values between 0 and 0.5. Then multiply by 2 to get your percentage duty cycle.

If your logs have values above 0.5, these are error conditions reported by the FPDM. For example, when you have the ignition on but do not start the car, the duty cycle will be 0.75 indicating the system is primed and ready for the motor to start.

If you want help reading your datalogs, I just posted a guide here that might help: http://www.mercurymarauder.net/forums/showthread.php?goto=newpost&t=80544

[Juice]

For the duty cycle, you want to see values between 0 and 0.5. Then multiply by 2 to get your percentage duty cycle.

If your logs have values above 0.5, these are error conditions reported by the FPDM. For example, when you have the ignition on but do not start the car, the duty cycle will be 0.75 indicating the system is primed and ready for the motor to start.

If you want help reading your datalogs, I just posted a guide here that might help: http://www.mercurymarauder.net/forums/showthread.php?goto=newpost&t=80544

Thanks for the link. My version of LiveLink is different, so I couldn't really follow along. Also, for mine, when the pump is off it reads 0.

Here's a screenshot of the data log I took:

http://img.photobucket.com/albums/v624/JonesSoda/sct-1.jpg

[JoeBoomz]

You are running Gen 2 which isn't (to my knowledge) publicly released, or at least isn't bug-free yet. It would be best spending your valuable time datalogging with a tool that you know is as accurate as possible!

I highly recommend using LiveLink 6.5, you can download it from http://sctflash.com/LiveLink.php

[JoeBoomz]

You are running Gen 2 which isn't (to my knowledge) publicly released, or at least isn't bug-free yet. It would be best spending your valuable time datalogging with a tool that you know is as accurate as possible!

I highly recommend using LiveLink 6.5, you can download it from http://sctflash.com/LiveLink.php


I did some digging and educated myself a bit more about LiveLink Gen2. This was the first time I've heard of it. Good luck finding it on their site today, they seem to have pulled it down.
http://images.ioncross.com/mercurymarauder.net/06-24-2012-DataloggingAndAnalyzing/Gen2.PNG

Here is a download link for those who want to try it:
http://sctflash.com/software/LiveLink_GenII.exe

Gen2 has the addition of Histograms which is the same thing I accomplish in my LiveLink post using Excel (http://www.mercurymarauder.net/forum...ewpost&t=80544 (http://www.mercurymarauder.net/forums/showthread.php?goto=newpost&t=80544))

Once SCT gets Gen2 compatible with all vehicles and tuners and makes it consistently available to the public, I look forward to working with it, then I can stop using my klunky Excel solution!