Post GT40P swap issues! Hooray!

1996mustangGT · Mar 17, 2012

So here is the combo I installed: GT40P heads, Crane Roller Rockers, Explorer Intake. Car has no EGR (No provisions on gt40p FRPP headers for tube), no smog, and no cats. I do have on of the 'egr resistors/simulators' so I'm /hoping/ that it has nothing to do with the egr. Initial timing is set at 12* advance and I'm running 93 octane.

So here are the two issues I'm having....

1) Every now and then, after idling in place for a bit, or stop and go traffic, the car is bogging out. Like its getting way to much fuel?

and my favorite...

2) After the car has been running and is warm, I can hop in, start it up...and it runs/pulls like a raped ape. Goes crazy. However after driving for a short period (less than 5 minutes) it wont pull as hard...i.e way down on power. Doesnt stumble, just doesnt get up and go.

Any ideas? I am throwing a CEL, but its totally intermitten. It comes and goes, normally while driving. So Im having a hell of a time trying to read it.

CC'S95GT · Mar 17, 2012

the codes will be stored whether or not the CEL is on. What are the codes?
Did you have the car tuned?

rz5.0 · Mar 17, 2012

Egr goes off the elbow the heads have nothing to do with it.. Thats for the smog... I would run the egr.. Check for codes they'll be there...

1996mustangGT · Mar 17, 2012

Ahhh cool deal. Didnt know that it stored the codes. Ill pull them as soon as I get off work.

Thanks for the heads up!

EDIT: no tune yet...trying to figure out where to get a chip from.

mikey94gt · Mar 17, 2012

I bet the ecu is freaking out after a few runs cuz of the new combo. My car did the same. Should run like a top once the computer is tuned.

ttocs · Mar 17, 2012

did you do a base idle reset or get a tune on it afterwards? Do you have any aftermarket gauges on it to see what the temp is? I had an issue once where it was getting too hot and the ECU was pulling timming out to try and help to cool it.

mikey94gt · Mar 17, 2012

Didn't think of that, good idea ttocs

waahehe94 · Mar 17, 2012

Your car sounds like it was doing exactly the same thing that my car was doing last year.When I first started it up it ran fine but after a short drive it would feel like it was down on power.The check engine light would come on intermittently and go then go off while I was driving the car.My car was throwing a code 181 and 189 which are Adaptive Fuel rich limit reached at part throttle, right side and Adaptive Fuel rich limit reached, left side.It turns out my mass air meter was giving a false reading causing my car to think that it was running lean so to try and correct the problem my computer was actually making the car run too rich.I fixed my problem with a new mass air meter, but without knowing what codes you have stored there is no way of knowing if that is your cars problem also.

The best thing that you can do, like stated earlier, is to either pull the codes yourself or go to an auto parts store like Auto Zone and have them hook up their scan tool and pull the codes for you.I know that all of my local parts stores have some really nice scan tools that can pull codes and diagnose problems and they are willing to do it for you for free.

1996mustangGT · Mar 17, 2012

waahehe94 said:
Your car sounds like it was doing exactly the same thing that my car was doing last year.When I first started it up it ran fine but after a short drive it would feel like it was down on power.The check engine light would come on intermittently and go then go off while I was driving the car.My car was throwing a code 181 and 189 which are Adaptive Fuel rich limit reached at part throttle, right side and Adaptive Fuel rich limit reached, left side.It turns out my mass air meter was giving a false reading causing my car to think that it was running lean so to try and correct the problem my computer was actually making the car run too rich.I fixed my problem with a new mass air meter, but without knowing what codes you have stored there is no way of knowing if that is your cars problem also.

The best thing that you can do, like stated earlier, is to either pull the codes yourself or go to an auto parts store like Auto Zone and have them hook up their scan tool and pull the codes for you.I know that all of my local parts stores have some really nice scan tools that can pull codes and diagnose problems and they are willing to do it for you for free.

Thats eerie as hell you just posted that man, I was about to ask what those codes mean lmao. Those are some of the codes I pulled.

All codes were: 172, 176, 181, 191, 223. And I though 221, but there is no 221.....so I'm going to start with cleaning the MAF and new o2 sensors and see where that gets me.

waahehe94 · Mar 17, 2012

Before you go out and buy new parts like new O2 sensors I would do a search on the internet to see how other people fixed those codes that you have.Your O2 sensors might not have anything wrong with them because they are still giving out good information and doing what they're supposed to do.You have one code saying that your right bank is lean at part throttle and another code saying that your left bank is rich at idle and that the computer is at its most adaptive limit trying to correct the problems.

I've never had any luck cleaning a mass air sensor because when mine went bad, it just plain went bad and wasn't dirty.When a mass air meter starts to go bad it can cause the computer all kinds of fits because it is sending out false information about the incoming air without the computer knowing it.Here's a decent article on how the mass air meter works and what it does.
http://www.cnlperformance.com/MAF_info1.html

rz5.0 · Mar 17, 2012

I have a spare stock 95gt maf if you need it...

Mrstangerbanger · Mar 17, 2012

Call Willy at Dirty Dirty Racing .com and what ever you do dont get a garbage SCT chip ... ( SCT chips are not the problem its the people programing them )

He is amazing with tuning mustangs and will send you a chip that will fix your cars problem for sure ... He will adjust part throttle and WOT through the tune and give you more timing so your car will run better then it ever has trust me ..

Also check your cars grounds make sure you have one that is from the engine to the frame and one from the battery to the frame??

The problem is going to be the computer after learning how these computers work with Binary edition tuning software you have to change a lot of shit to make these H/C/I set ups work and run good ..

The Chip is only 179 dollars shipped

http://www.dirtydirtyracing.com/

ttocs · Mar 17, 2012

to say that a chip will fix everything is a little premature in my book. Way to early in the process to start throwing parts that cost that much....

rz5.0 · Mar 17, 2012

^^^I agree with both you guys.. A tune will help and will bring all the performance out of the engine.. But you have to get all the bugs out of it first.. The car should run pretty close to normal with only a head and intake swap... start with the lil things check for vac leaks clean maf.. If the o2 havent been replace in a while it wount hurt to replace.. Clean maf or try a diffrent one..

Mrstangerbanger · Mar 17, 2012

ttocs said:
to say that a chip will fix everything is a little premature in my book. Way to early in the process to start throwing parts that cost that much....

Trust me bro if you knew how much shit needs to be adjusted you would never say that.. No matter what he needs a tune and he needs to adjust air/fuel at idle, part throttle and WOT and thats not taking account all the other shit that needs to be changed ..

I get what your saying and I would say the same thing you would if I was not learning all about are cars computers ...

1) Every now and then, after idling in place for a bit, or stop and go traffic, the car is bogging out. Like its getting way to much fuel?

Sounds like a tune problem!!!!!

Were is the cars timing at ?

Also were is the fuel pressure at ?

1996mustangGT · Mar 18, 2012

Cleaned the MAF last night with some C&C cleaner, runs like a champ now lol. Pulls like a sombich. Still throwing a CEL, so once this hangover decides to leave me alone I'll run out there and pull the new ones. I'll probably end up replacing the o2 sensors at some point for the hell of it....they're the OEM ones with 85K on them. Probably wouldnt hurt either way.

Thanks for the link to that chip! I'll take a look and give him a shout!

mikey94gt · Mar 18, 2012

Cool man, glad you got it sorted.

waahehe94 · Mar 18, 2012

Don't forget to unhook your battery for a few minutes so that your computer will erase the old codes that it has stored.After that I would drive it for a few miles to see if throws any new codes and then if it does pull them and see what they are.

A cheap way to gain some power if you haven't done it yet would be to install an adjustable fuel pressure regulator so that you can change your fuel pressure and then try advancing your timing a little.If you go with a custom tune be sure and talk with your tuner about the timing curve that they program into the tune at full throttle and part throttle as well as at what throttle position percent the program switches from part throttle to full throttle curves.Back in 1998 I bought an SVO Extender for my Mustang and am still running it today without any problems.It lets me adjust my RPM limit and A/F ratio as well as changes other things in the factory program.Back in 1998 I was running 13.90's on the motor before the Extender and 13.70's on the motor after I installed the Extender.