cams causing miss help please!

[joshmartin]

I assume its the cams... anyways this is my first post i baught a 98 gt about a month ago.... only mods i know of is preety radical cams in the car it doesnt thrash like a race car but has a preety heavy lope to it... it has exhaust , gears and thats all i know of... i baught a sct sf for the car also but on to the problem at hand!!!!

the car idles fine at startup and everything but while im driving the car and when i come to a stop the car stumbles really hard to where it nearly dies then revs back up to around 1200rpms or above then again nearly dies then back to around 1200rpms then it smooths out like it is supposed too....

Ive been told this is the cams surging but im not sure , its not very consistant... at times it does this bad to where the car actually dies when i come to a stop then others it just stumbles once....

any ideas guys? the car has 90k miles on it and as i stated the only known mods are cams , gears and exhaust.... this issue happened before the sct install and continued after the tune....

:snow_laugh:
thanks again guys and look forward to keeping in touch this is my new little project car

 

[MustangMatt96GT]

Try cleaning the IAC and replaceing the TPS

 

[joshmartin]

ok ill try that , any other ideas?

 

[MustangMatt96GT]

Do you know what cams are in there?

 

[joshmartin]

not sure ill go take a quick video of under the hood and the sound of it... i know visually u cant tell what cams are in it lol just maybe someone will spot something else done to the car lol

like i say its not race car nasty but it sounds preety mean

 

[MustangMatt96GT]

K

 

[joshmartin]

http://videos.streetfire.net/video/67da72c2-9558-48b7-b0fe-9a0d011f9719.htm

the car just has a xpipe with raven brand mufflers on it from best i can tell.... you can hear it lope twords end of vid once i take camera to back of car... but it doesnt even give it justice... it sounds preety mean.... the car has stock plug wires stock air filter and all lol i cant understand for the life of me why someone would go threw the trouble of installing cams and nothing else is changed... unless the guy stripped the other mods off before the sale.... i baught it off a small lot and they got it out of north carolina...

 

[joshmartin]

also if your wonderin why i got no tips out the back lol i cant for the life of me get them to line up evenly out the back of the car lol so i unbolted it right after the rear end.... you could hear it alot more if it came out the back but gives it a nice deep tone under the car :santa_afro:

 

[MustangMatt96GT]

I would say that those are very mild cams, maybe a Comp 262 if that. anway, I would clean your IAC and Replace your TPS. Those would be my only guesses.

BTW you have the best color ever. And welcome to the site, why dont you stay a while.

 

[joshmartin]

like i say the camera doesnt give it justice at all... ill try doing what ya said and see if that works....

yeah im a fan of the color.... just tryin to decide what path i want to go with this car.... its my first mustang build , tho all my friends got mustangs, from 331 , 347 strokers to just bolt on 2 valves.... only time will tell

 

[nyuk98gt]

joshmartin:

I can tell you that your car is suffering from "drivability issues" and these can be cured with a good tune. There are a lot of parameters that can be tweaked for cams but your tuner will focus on the 'dashpot' function and the 'dashpot decay rate'. If this is the only issue you have, then a good tuner will be able to get you fixed up pretty quickly. What your tuner needs is a decent datalog of the problem. So, if you can hook up your XCal to the old laptop and collect data when the car stumbles at idle, your tuner should be able to nail the tune. If no data is available, it may take a couple of e-mails back and forth to get it just right. Or, you can just get Advantage from SCT and sort it out yourself. I have to say that Advantage can be addicting and a whole pile of fun because you can get your car to run exactly as you like it (for better or worse, lol).

HTH,

Chris :xmassign:

 

[joshmartin]

yeah im just gonna ditch the sct and get a chip and get a custom dyno tune after i start modding the piss out of it.... ill just deal with the little stumble until then and no more then i drive it or plan on drivin it i can deal with it

its a sct sf so i dont think it has to many capabilitys does it?

 

[black_96gt]

Do a visual check of your vacuum lines and hoses... could be something very basic as well.

 

[GThang98]

You need a dyno tune... that's what my car did when i installed my comp cams 262's it would die every time at a light and it would idle surge..

 

[joshmartin]

thanks guys im gonna chip it and dyno tune it but ima do some more mods first, i just baught a upper plenium , 75mm tb, cold air and 90mm mass air flow housing .... found me a set of pi heads off a local for 400 bucks for the heads and intake...

 

[nyuk98gt]

joshmartin:

I suggest that you keep the XCal and your tuner can load it with a custom tune for your mods. This can be done as you add mods to the car. Most tuners are quite flexible about updating their initial tune and the price will be a nominal charge. You will get enormous satisfaction out of tuning your own car, too, if you opt for SCT's Advantage (Pro Racer) software. A good tune will make the most out of all of the physical mods.

[parental lecture tone] Even with PI heads, the cams require some tuning (more air is needed at idle because of reduced vacuum [reduced vacuum = less negative gauge pressure]) so you might consider getting that stalling thing fixed. You don't mention whether the car has a stick or auto but, either way, a stalled engine when you don't want it may have some unpleasant consequences. [/parental lecture tone] :snow_laugh:

Anyway, enjoy the modding!

Chris

 

[joshmartin]

i dont got the xcal i got a SF i dont think you can do that much with just a SF... correct me if im wrong

 

[nyuk98gt]

joshmartin:

You can convert the SF to a 'custom flash tuner' (but it's a one-way operation!!). Your tuner can do this for you, too. Take a peek at sctflash.com and find the forums under Support. You will see a bunch of reputable tuners post there and offer very good advice.

The XCal and a custom tune (and even the Advantage software) cost a few bucks, just like any other modification. I usually suggest to people to get one early in the modding process. But, because it is an "invisible" mod, it's hard to spend the dough compared to a new throttle body or a catback!

Enjoy the modding and plan wisely. There is nothing worse than spending money on the same mod twice (trust me).

Chris

 

[joshmartin]

so the dyno shop can convert the sf into a custom hand held like a xcal? thanks again for the help :xmassign:

 

[joshmartin]

wow i may of fixxed this issue today, we installed the c&l upper plenium and cold air and 75mm bbk tb and the car missed like crazy so i got the hand held out did a little tweeking and turned up the idle nutreul rpms and it seems to of fixxed the issue :santa_grin: