moosestang

These cars switch to closed loop so fast, that I wouldn't think it would matter that much.

Eolson, how new is the battery? When my battery started to go, after only 3 years, it was causing some weird stumble on startup, but it was limited to startup.

I wouldn't take it to a ford dealer. They will just start throwing parts at it.

eolson

157dB and moosestang, Thank you again.

157dB - Thank you so much for your detailed post, I am printing everything out so far you have sent. The original JDM tune was used as a open base tune, was run and studied on the Dyno, and then was adjusted by MRT to idealize parameters for timing and A/F. I know they felt the JDM tune was running lean, but that's because there is still possible issues with the MRT H-Pipe that had been put in, it relocates an oxygen sensor, and they were all replaced, but the car did pull lean codes after the H-pipe and JBA shorty headers were put in on the old tried and true JDM tunes. So JDM wrote the open base tune, and MRT adjusted it for the cars new dynamics with the H-pipe and headers. Makes sense. But this custom tune pulled a too fat code after 85miles, and so I was left not knowing if it was still an oxygen sensor design issue with the new H-pipe, or if MRT was just tuning too conservatively and accepted to rich of an A/F, which the car was OK with for a bit, but not for long.

Being sick of it all, I drove errands only on that tune, and would re-boot it every 75 miles, and it drove fine with no issues. Then about three weeks later I noticed the start up roughness, and the cold acceleration hesitation, but it was mild, and went away as soon as the car started warming up, 2-3 minutes from ignition.

That was were I was in August, when I went to Livernois with the engine code situation, and they replaced the spark plugs, changed my injectors from 39# to 60#, and put in a more robust 90mm MAF, so that they were comfortable with a lower duty cycle average for those parts. They also checked all related air intake parts, and changed all the 0/2 sensors in the H-pipe too make sure. Then they wrote from scratch the current 10lb tune I'm on, but i saved the MRT tunes on my scanner as well. Livernois could not solve nor did they suggest any other solution to the obvious start up issue as I mentioned in the original post. They had my car for two months, and other than checking the boost bypass valve system(which was working properly) they didn't offer me anything else, and said it was the nature of the beast. Their tune is still running fine so far, but I'll see if it pulls a code, if it does, I'm getting rid of the MRT H-pipe and gong back to the stock on and it's normal 0/2 sensor design.

mossestang - I still have the stock throttle body, and as I mentioned the plugs and injectors are new, and I know Livernois didn't go any further with testing the spark. I am printing all your posts out.

My battery is original, and that is a good suggestion going into winter, do you have a good suggestion for our cars?? Otherwise I am stuck only presenting these possibilities for another round with my car. I don't trust these shops anymore to ensure that my car is working properly before they give it back to me. I've spent the money, been very patient, and always willing to go the distance to solve problems. But they are not. It's sad and dishonest that these suggestions were not offered by these shops and acted upon. I have to really call around with these suggestions from all of you, and really get someone honest that is willing to look at the whole picture here in the Detroit area. I can't drive my car down to Brendspeed, my wife is not going to put up with any bull from these people, so I'll call Donny Walsh from Walsh Motorsports, he builds race engines, and was very honest about changes to the car, and would not release my car or others without problems being explained to the client and solved before they left the shop.

Any more suggestion and advice would be greatly appreciated. Thank you , Erik

VistaBlue

I would imagine JDM and/or Livernois didn't suggest a vast amount of these possibilities to you, due to them not being the problem. Here on this forum, we are all just taking stabs in the dark. It's very possible these companies have already ruled out a lot of these possibilities and just didn't relay it to you, or didn't feel the need to look into specific areas, as they may not suit your car. As they have been working on / tuning your ride, they are obviously more in sync with your specific situation than any of us on the forum are.

I say get it back down to the shop, and don't pick it up until it's fixed.. You paid for a custom tune. Any respectable tuner will get to the root of the problem.

hammeron

based on what i've read here and on the other forums where this is also
a thread, i'm leaning towards a mechanical not a tune related problem.

i do hope the car gets fixed so you can enjoy it again, but i think this may
be a slow, expensive process. a significant amount of resources is going to
go towards the labor of a shop playing with the car and trying to duplicate the complaint.

eolson

Thanks Vista Blue and hammeron.

Vista Blue. I do agree that the tuner and staff at Livernois would have most likely discussed all the reasonable mechanical or electrical possibilities. My point is that they seemed to have the position that it was a boost and SC related issue. They were very clear that it wouldn't be their tune, as they have done many for 05-10's and have all the transfer protocols down( plus the problem was already present previously), they were also very specific about their approach and reasoning that it might be a boost bypass valve issue, which it was not. Once it did not turn out to be that, they basically took the approach that it was in the nature or a quirk of having FI. They did not verbally indicate to me that there could be 2-3 or 4 basic mechanical or electrical issues that needed to be explored, and they know I wanted it resolved. That's were the frustration lies.

hammeron, since the issue is specific to cold start up, cold idle and cold acceleration hesitation, I am inclined to also think it is mechanical, and because it is about being cold start up through 2-3 minutes into warm up only, that should eliminate enough other possibilities for Livernois or others to continue taking reasonable systematic steps to investigate.

The good news is that the new Livernois tune is running very well so far, and the start up cold issue, if I warm up the car for an extra minute, as well as drive normally with gradual normal traffic acceleration for the first two minutes, the car is totally normal beyond this. I'm just hoping the issue it stays at this level, and does not get worse.

Thank you again for the input, Erik

jiga

Mine does this on startup as well, I get the hesitation on normal acceleration if I don't let the vehicle warm up for about a minute or so. Once it warms up she runs fine.

My car is an automatic, the hesitation feels like a new person driving a stick. I'm thinking it is the fuel pump.

loots06

Wow, I think I'm having the same issue. I have to let my car warm up. If I don't then I end up throwing codes for a MAP sensor which our cars do not have. I plan on getting a new tune in the near future.

jiga

I thought it might have been the fuel pump due to issues before I had my tune.
Read a couple other threads on this at another site and am actually thinking it is due to O2 sensor heater http://forums.themustangsource.com/f...n-cold-444680/

eolson

Thanks jiga, and everyone else. That thread link was very helpful. It sounds like many people have the exact same issue as i do, and it doesn't seem obvious how to solve it.

My car starts up reasonably, but without the same "varrruuuum" as it did. It used to kick right on and stabalize to 1250rpm then go down to 750rpm as it wamed up. It kinda does it now, but it slips down and crawls back up between these rpm's a little, and bucks for the first minute of driving unless I'm very even and gradual on the gas. Then it's fine when 1/2 way to fully warm on the dash gauge.

The Livernois tune is still A-OK. Andy did call from Livernois and made it clear that we could continue the process of elimination in the winter, but as logic dictates, the shop only gets the jump on one cold start a day in the morning, and then after the engine is warmed up from testing and running, it is many hours before the shop can recreate the rough start condition with a stone cold engine. So I'm organizing all these posts and will continue printing out the new info to make an organized list. Thank you again everyone. Erik

loots06

Thanks for the link. Good to know.