Help: Idling & cold engine issues - 2007 S281 S/C

[mw98gt]

To start off, my 2007 SC has a 3.4 pulley, FR GT500 hi-flow fuel pump, CAI, GT500 heat exchanger, and FR "Hot Rod" Cams. It also has a custom tune a few weeks ago.

For some reason my idle seems to be getting worse and worse, where it will oscillate before settling. It will be worst when it is cold, and typically be less noticeable once warmed up, but still occasionally surfaces. In addition, when my engine is cold, it seems like my engine doesn't want to work if I give it anything more than 25% throttle. I would never give it much more than 25% when cold, but if I try to out of necessity it feel like the engine wants to quit.

Anyone familiar with such symptoms?

[seelye76]

Have you cleaned your throttle body or checked your spark plugs?

[Char259]

The cold running engine issue is something I share. Seems to be an issue for alot of these modded mustangs. If i start mine up and try to go, she stumbles for a couple seconds, clears her throat and takes off. If I let her idle and warm up, no problem at all

[mw98gt]

When I had it custom tuned a few weeks ago, the tuner pulled the spark plugs and noted they were brand new, clean and never gapped, he gapped them. Havent touched the TB.

I don't recall my 98 gt with a vortech sc stumbling, but at least i am not the only one. It feels like the boost wants to kick in and out as well when cold, probably along same lines, i.e. it clearing its "throat".

[wildhorse]

Could be the Custome tune!!!

I know they had to do mine 3 times to get it right on my 07 GT, The last thing I added was the Cam sound great but had to play around with the tune. I had Idle issues then I had shifting problems then stay running issues.

Hope this helps good luck

[mw98gt]

Originally Posted by wildhorse

Could be the Custome tune!!!

I know they had to do mine 3 times to get it right on my 07 GT, The last thing I added was the Cam sound great but had to play around with the tune. I had Idle issues then I had shifting problems then stay running issues.

Hope this helps good luck

This was the second tune. The tuner said he spent a long time working out the idling problem and then it was good, but it just seems to have degraded over the last two weeks now, although my car has been mainly sitting as I have been out of town, perhaps it just feels neglected.

I guess I am more baffled as to why the car drives so horrid when it is cold, but if this is common for a modified car of the 21st century then i guess there is nothing to worry about. I just recall that my 98 gt with a vortech sc never drove like the 07 saleen did when it was cold.

[Stanghungry]

I can say that the cold start issues are in the tune. When I had my 06 saleen I had the same issue for a brief time during start up no matter if it was 20 degrees out or 100 degrees out. When you start moding these cars crazy things happen........

[Gray is Grey]

Cold engine "driving" issues are normal on modified tunes, but it should idle without any problems. If it is becoming worse as time passes then it sounds like a gettin' dirty issue. Have you taken off your intake tube and checked for oil? Are you running a modified PCV system?

Once you start having idling issues due to being dirty then your plugs will start to foul and should be cleaned with a media blaster.

[redpony]

My previous tune had the same issues and was driving me nuts! Rough when cold and had to wait for it to warm before going. Got a new tune from JDM and all runs great now!

[Seabee]

I have the same problem. Its not something I wanna live with, but I can't do anything right now. I hate it. I give it gas and it struggles and then just takes off after a few seconds. Its the tune Im pretty sure. It ran fine before I blew the engine and got the dyno tune.

[OneQwkStang]

My car ever since the blower install stumbles when I fire it up stone cold. But its good after about 30 seconds. I start the car and watch my wideband, you can see the AFR running rich and gradually lean back to stoichiometric. After that she is good to go....if its real cold its slightly longer.

Tune could be an issue for some of you, however I've heard bone stock Saleen S281 with Saleen Power Flash tune run like this cold.

I come from a carburated Fox body car before, when she was cold it would take a few minutes to warm that beast up....so this is nothing.
Hell sometimes my Chevy Equinox stumbles if I fire it up and drive away stone cold.

[hennie]

Get a proper tune and it will respond as it should, also make sure your injectors are large enough.
I have installed several FR hotrod cams and in all cars it seems they live their own life, they respind different every day depending on wheather etc.. at least so it sounds.
contact JDM, Jim should be able to help you.

Hennie

[OneQwkStang]

Originally Posted by hennie

Get a proper tune and it will respond as it should, also make sure your injectors are large enough.
I have installed several FR hotrod cams and in all cars it seems they live their own life, they respind different every day depending on wheather etc.. at least so it sounds.
contact JDM, Jim should be able to help you.

Hennie

I know a car tuned by JDM, it runs rough when cold too.

[hennie]

It should be possible to correct this in the tune.

Hennie

[wildhorse]

Please let us know what fixed the issue.

[purevnm]

Originally Posted by wildhorse

Could be the Custome tune!!!

I know they had to do mine 3 times to get it right on my 07 GT, The last thing I added was the Cam sound great but had to play around with the tune. I had Idle issues then I had shifting problems then stay running issues.

Hope this helps good luck

Not to hijack this thread but you have a pic of my car in you sig...http://mustangattitude.com/cgi-bin/s.../2006_00023_07

[ubnhad]

Take the throttle body off and clean it. There is a video on Breenspeeds web site on how to do this correctly. My friend had this same promblem on his car. I cleaned it for him and it fixed it. I couldnt believe it.

[mw98gt]

Originally Posted by ubnhad

Take the throttle body off and clean it. There is a video on Breenspeeds web site on how to do this correctly. My friend had this same promblem on his car. I cleaned it for him and it fixed it. I couldnt believe it.

I will definitely try that and the MAF cleaning this weekend when back in town. Just watched the videos and went to amazon, read great reviews on the two CRC products, and then purchased them. Thanks for pointing this out, and I will provide everyone my feedback this weekend, very excited to give it a go.

Will this effect the custom tune or will the computer "work it out"?

[ubnhad]

It doesnt have anything to do with the tune. You should be fine.

[mw98gt]

The MAF was clean but the TB definitely had some gunk on it. After a good cleaning there is a noticeable difference. There is still some hesitation when cold, but other than that the throttle response is much better as is the idling. Thank you all for the tip!

[07SaleenSC]

I have the same issue when cold. Car stumbles, like someone said above, like it wants to clear its throat. Most noticeable when cold but it sometimes does it when up to temp. Coming home from work car started the stumbling thing for a block or so. Rev'd it up and it seemed to clear. Also on the highway at 2000 rpms or below, even warm, it does not want to go, hesitates. Then it takes off.

Car was upgraded by Saleen with smaller pulley and their Saleen tune when it was still new. No aftermarket tune and it only started doing this about a year ago. Upgrade by Saleen was years ago. Problem is getting worse. Throttle body is new, plugs are new, supercharger just rebuilt, MAP is clean. I'm thinking bad MAP, bad upstream O2s, clogged Cat, or bad air temp sensor (where ever that is). Anyone else have any thoughts? IT IS NOT THE TUNE!!!

[Jason @ 281m]

Originally Posted by 07SaleenSC

I have the same issue when cold. Car stumbles, like someone said above, like it wants to clear its throat. Most noticeable when cold but it sometimes does it when up to temp. Coming home from work car started the stumbling thing for a block or so. Rev'd it up and it seemed to clear. Also on the highway at 2000 rpms or below, even warm, it does not want to go, hesitates. Then it takes off.

Car was upgraded by Saleen with smaller pulley and their Saleen tune when it was still new. No aftermarket tune and it only started doing this about a year ago. Upgrade by Saleen was years ago. Problem is getting worse. Throttle body is new, plugs are new, supercharger just rebuilt, MAP is clean. I'm thinking bad MAP, bad upstream O2s, clogged Cat, or bad air temp sensor (where ever that is). Anyone else have any thoughts? IT IS NOT THE TUNE!!!

How many miles on the car? How do you drive it; grocery getting, playin once in a while or racing every POS that trys?

[07SaleenSC]

Jason, this is George from Denver. You just rebuilt my supercharger and replaced throttle body. Car is an 07 with 40,000 miles. It has been acting funny for about a year maybe longer. As you know it is my everyday driver. I don't beat on it. Temps are normal. Even the supercharger temp came down after purging system and putting in more water as you suggested.

When it first started acting up it only did it for a short distance when I started it in the morning. Over time it seems to have gotten worse. There is no check engine light either. The last CEL I told you about was due to a crack in Saleen catch can thing. That's been fixed and I've added catch cans to both sides now.

Problem appears only at low RPMs. Seems fine above 3000 so I'm thinking its not the cats.

[Jason @ 281m]

Originally Posted by 07SaleenSC

Jason, this is George from Denver. You just rebuilt my supercharger and replaced throttle body. Car is an 07 with 40,000 miles. It has been acting funny for about a year maybe longer. As you know it is my everyday driver. I don't beat on it. Temps are normal. Even the supercharger temp came down after purging system and putting in more water as you suggested.

When it first started acting up it only did it for a short distance when I started it in the morning. Over time it seems to have gotten worse. There is no check engine light either. The last CEL I told you about was due to a crack in Saleen catch can thing. That's been fixed and I've added catch cans to both sides now.

Problem appears only at low RPMs. Seems fine above 3000 so I'm thinking its not the cats.

Can you get 100 Unleaded Octane up there?

[07SaleenSC]

I don't know of any place that sells 100 octane. Would octane booster work?

[Jason @ 281m]

Originally Posted by 07SaleenSC

I don't know of any place that sells 100 octane. Would octane booster work?

No, and please never use that stuff. Give me a call tomorrow and we'll try to strategize. Do a google search and see if you can locate some 100 octane locally.

[mikebna]

Originally Posted by 07SaleenSC

I don't know of any place that sells 100 octane. Would octane booster work?

As mentioned by Jason, Octane Booster is a horrible solution and is not recommended to use in our cars. I tried it, even though everyone was against using it and it produced a lot of negative results.

Best solution-good spark plugs, make sure MAF is cleaned with correct cleaner, correctly tuned with AF ratio for your available highest octane rated fuel in your area. I ditched the good ol Saleen tune a few years ago and have had no more problems like that. Mine runs great on 91 Octane, just completed a 3600mi road trip to Seattle and back with hardly and problems.

[07SaleenSC]

An update on my problem. Car ran poorly continuously all day. Put 100 octane in it but it was running so crappy that I couldn't run it hard as Jason had suggested. Had the Mass Air Flow sensor replaced as well as the battery today. Still ran crappy. Finally threw a code on the way home P0303 = misfire cylinder 3. Also has a P0303 pending. Tried a new coil on plug on cylinder 3, no luck. Plug looks ok. No vacuum leaks as far as I can find. Connected real time data acquisition system but nothing obvious. All O2s seem to respond (ie the voltages change and appear consistent with the opposite side). I think I am beginning to hate this car.

[07SaleenSC]

Disconnected battery, put headlight switch on, let sit for 30 minutes. Reconnected, started car, let run for several minutes, didn't touch any controls. Took for a ride and it is better. Could be cured. We'll see tomorrow when I get more time to run it.

[07SaleenSC]

Car is like a totally new car. If you are having the issue described here follow the procedure as outlined in post 29.

[Jason @ 281m]

Originally Posted by 07SaleenSC

Car is like a totally new car. If you are having the issue described here follow the procedure as outlined in post 29.

Your welcome!

[mw98gt]

Originally Posted by 07SaleenSC

Disconnected battery, put headlight switch on, let sit for 30 minutes. Reconnected, started car, let run for several minutes, didn't touch any controls. Took for a ride and it is better. Could be cured. We'll see tomorrow when I get more time to run it.

I understand the disconnecting the battery part, but what does turning the headlight switch on have to do with it?

Did it take care of the cold engine issues as well? My car has been running pretty good since cleaning the TB, but still can be a bit rough when cold.

Originally Posted by 07SaleenSC

Jason, this is George from Denver. You just rebuilt my supercharger and replaced throttle body. Car is an 07 with 40,000 miles. It has been acting funny for about a year maybe longer. As you know it is my everyday driver. I don't beat on it. Temps are normal. Even the supercharger temp came down after purging system and putting in more water as you suggested.

When it first started acting up it only did it for a short distance when I started it in the morning. Over time it seems to have gotten worse. There is no check engine light either. The last CEL I told you about was due to a crack in Saleen catch can thing. That's been fixed and I've added catch cans to both sides now.

Problem appears only at low RPMs. Seems fine above 3000 so I'm thinking its not the cats.

I wonder if I should purge my intercooler and add more water as well. My car has an upgraded GT500 heat exchanger (Part AFCO-80280NDP) and a 10lb pulley, but it seems to run quite hot. I know I live in Florida, but a lot of times my IAT gauge is around 150. After going at highway speeds in cruise for a while it will drop down to 110-120 range, but city driving it is 150-175, is this normal for my setup?

[seethrough]

Turning on the headlights with the battery disconnected will drain any residual energy out of the engine control system. It basically does a restart on it and forces it back to it's raw program so it has to relearn again. The same thing is possible if you remove both battery cables and hold them together for 15 seconds (make sure this is done AFTER both cables are removed from the battery).

[seethrough]

I dont know if it is required on our cars but on my Dodge truck they recommend that after you reset the engine control system that you should open and close the throttle completely several times so that the TPS can learn it's range.

[fungirl]

So will doing this battery/headlight thing erase my custom tune? I'm having similar issues that started a few months after some upgrades: SC vacuum line upgrade kit, 3.6 SC pulley, CAI, GT500 fuel pump, 80# inj, custom tune. But now it's getting much worse.

This all started a year ago. I didn't notice it at idle while it was warming up. But as soon as I took off, it would sputter for the first several blocks and then be fine. I've been ignoring it because it seemed harmless to just let it warm up longer & drive to clear it out. Plus it didn't happen every day.

Well 2 weeks ago it started getting progressively worse. In the middle of a hot day, drove across town & parked for 45 minutes. Afterwards, car barely started & ran super rough at idle (like not getting enough fuel). It seemed similar to before but much worse, so I tried driving to clear it out. Only made it a block then it died and wouldn't restart. Sat there for 30 minutes, then it started right up like nothing had happened. A week later same thing happened again. A few days after that, it stalled while I was driving. I had been driving for 1/2 hour & was at a stop sign. It died when I started to take off, sputtered extremely when I restarted it, then wouldn't start at all for a couple minutes. It ran fine for a few days then stalled while I was sitting at idle in a drive through (embarrassing). That's 4 incidents in the last 2 weeks.

So I've gone from mildly running rough after a cold start; to stalling/dying while driving away from a stop sign (then not starting for a few minutes); to stalling/dying while sitting at idle (& not starting for a few minutes).

[Kendog]

Reseting the computer does not erase the data that is already encoded on it. It just erases the data that has been collected during driving. Modern car computers are very much like your home computer. They record real time informaiton about the sensors and conditions your car is in and uses those to make decisions about how to manage the cars engine. Sometimes since they store data about your car in real time they can get confused or corrupted and need a reboot which is essentially what your doing by disconnecting the battery and grounding out the system.

Also, in terms of your poor idle and cold start issues is can be your tune sure but it can also be one of the sensors going bad intermitenly. Many times when a car warms up the bad sensor will behave better. It can be a Throttle Position Sensor or more commonly a Crank Shaft Sensor. Even a small intermittent error on your TPS can cause you idle to do weird things. Sometimes you will get a code but often you will not. If you perform the reset, clean your intake, check your plugs and clean your fuel injectors (20-30K miles) you might look at your sensors next. If you just had the engine tuned I would take it back to who ever tuned it and have them check the tune and the sensors on your vehicle for issues. Sometimes the vehicle can have issues after a tune because one or more of the parameters during the tune could be way off. Like the humidity was really high or low or the temperature was really high or low while they tuned it but not after.

Ken

[fungirl]

This weekend, I'm taking it back to the place that tuned it. I'll tell them about all these suggestions. Hope it works. Thanks everyone!

[Jason @ 281m]

Originally Posted by fungirl

This weekend, I'm taking it back to the place that tuned it. I'll tell them about all these suggestions. Hope it works. Thanks everyone!

I would limit the driving in this car until you get it figured out.

[fungirl]

Originally Posted by Jason @ 281m

I would limit the driving in this car until you get it figured out.

Easier said than done! I drive it about 70 miles every day. Found a loaner car for next week. Maybe I can get it early.

[Kendog]

That us great advice Jason! Should have mentioned that!

[Meikol02]

Hey Fungirl, the 80# injectors are really oversized for your power level/other mods. The larger injectors can make it more difficult to tune for idle as well (according to my tuner). 60# injectors aren't even needed until you get smaller than a 3.2 pulley or so. Just a thought.

[06281E]

Originally Posted by Meikol02

Hey Fungirl, the 80# injectors are really oversized for your power level/other mods. The larger injectors can make it more difficult to tune for idle as well (according to my tuner). 60# injectors aren't even needed until you get smaller than a 3.2 pulley or so. Just a thought.

Yeah that's right! 60lb injectors can put down 700rwhp! I would not run 80lb injectors and whoever put them in was not thinking about your car being a daily driver. I would throw in a set of the Saleen 39lb injectors and that should help out your idle issues and tuning..

[fungirl]

Interesting. I think the way they explained it to me is that the 80# injectors are flow matched so they will work for my low HP now. Then I would be able to keep them when I have the motor rebuilt someday (to be faster). Hmmm...we'll see how it all works out when I take it back this weekend.

[06281E]

Originally Posted by fungirl

Interesting. I think the way they explained it to me is that the 80# injectors are flow matched so they will work for my low HP now. Then I would be able to keep them when I have the motor rebuilt someday (to be faster). Hmmm...we'll see how it all works out when I take it back this weekend.

That's some good shop B.S. right there.. Any set of injectors can be flow matched. It just means that they are bench flowed and tested to be within a small tolerance of each other in regards to flow so that you get an even flow out of them. The issue is that you are pouring in a lot more fuel in idle than you would on a 39lb injector and that would cause all sorts of hesitations, bogging, stumbling, etc.. You can also foul your spark plugs if you are getting too much fuel in idle but that could be sorted out with a tune. I would find another shop before anything else..

[Jason @ 281m]

Originally Posted by 06281E

That's some good shop B.S. right there.. Any set of injectors can be flow matched. It just means that they are bench flowed and tested to be within a small tolerance of each other in regards to flow so that you get an even flow out of them. The issue is that you are pouring in a lot more fuel in idle than you would on a 39lb injector and that would cause all sorts of hesitations, bogging, stumbling, etc.. You can also foul your spark plugs if you are getting too much fuel in idle but that could be sorted out with a tune. I would find another shop before anything else..

Oren,

I agree! I never recomend using a larger injector then thats actually needed.

[fungirl]

Originally Posted by 06281E

That's some good shop B.S. right there.. Any set of injectors can be flow matched. It just means that they are bench flowed and tested to be within a small tolerance of each other in regards to flow so that you get an even flow out of them. The issue is that you are pouring in a lot more fuel in idle than you would on a 39lb injector and that would cause all sorts of hesitations, bogging, stumbling, etc.. You can also foul your spark plugs if you are getting too much fuel in idle but that could be sorted out with a tune. I would find another shop before anything else..

I don't think they were trying to BS me. I think I just totally misunderstood the flow matched thing. They said the 80# would work fine with my car's setup now, so I assume they sorted it out with the tune. Other than the occasional, slight cold start issues, I didn't have any problems for over a year.
Well, I'll see how it works out this weekend when I take it back. They're a good shop so I definitely want to give them a chance to sort out my issues.

[Kendog]

Okay I am curious to know if they were able to fix your car and what the problem ended up being?

[fungirl]

Originally Posted by Kendog

Okay I am curious to know if they were able to fix your car and what the problem ended up being?

They're really busy and I'm not sure if they've had a chance to look at it yet. Dropped it off on Sat so I didn't have to take a day off work. They're hoping it happens when they drive it, so they can witness the issue. Plus they'll check the obvious stuff. I'll post again when I hear back.

[Kendog]

Hey girl it has been a week and have not heard anything... How is it going with your car?

[fungirl]

Going to pick it up tomorrow. He ended up replacing the crankshaft sensor and alternator (another long story). The crankshaft sensor is susceptible to heat. Since it has cooled down quite a bit, that's probably why it hasn't acted up in the last few weeks. If the issues start up again, he will assume it's getting too much fuel and adjust the tune.

Off to work, so I'll explain the alternator issue later :)