HELP!!!! PLEASE

SVTCobra5.0 · Sep 27, 2015

Hello Guy's I have a problem with my 1994 mustang cobra, and I hope someone can help me. Every time I get on the gas pedal it seems like my car want to cut out. Can anyone please help me?

rz5.0 · Sep 27, 2015

What's all l done to it. . When was the last time it had a tune up. When was the last time you changed the fuel filter. Is the check engine light on.

SVTCobra5.0 · Sep 27, 2015

I just gave it a tune up. Plugs, wires, cap and rotor. The fuel filter I do not know when it was last changed I bought the car a couple months ago and I went and put e3's in it and dyno'd it and noticed a miss or cutting out so I then bought the NGK TR6's which was the plugs before I put the e3's in. It still seems to do it though. as far as what's all done to it...list below

~Clayton performance ported GT40 heads and intake, 1.94 swirl polish back cut stainless steel valves

Scorpion 1.6 roller rockers

.650" Comp springs and pushrods

Ford racing F303 cam

75mm trickflow throttle body

75mm C&L mass air and intake

24lb injectors

ZEX 150 shot nitrous

255lph walbro fuel pump

SCT switch chip with 3 tunes (N/A, nitrous and nitrous with race gas)

BBK headers, X-pipe and Mac cat back

Sport line springs, strange 8 way adjustable gas shocks and struts

UMI tubular adjustable control arms upper and lower

BBK sub frame connectors

King cobra clutch

Pro5.0 shifter

RichV · Sep 27, 2015

Not sure if this is your issue, but how is the MAF calibrated to the injectors? And what is the tune? That's where I would start. A Cobra has 24# injectors stock with a stock MAF

Is the miss RPM based? Load based? Just under WOT?

g36 monkey · Sep 27, 2015

thinking it might be too rich RichV ? Sort of sounds like it's dumping fuel. Either way I would assume it has something to do with fuel delivery.

Edit:

I should clarify that to say fuel delivery in some way, IE improperly calibrated tune/MAF so it's dumping fuel or leaning out.

SVTCobra5.0 · Sep 27, 2015

At first it was RPM based seemed to happen around 4000. Now it just seems to do it when I get on the pedal it will also back fire every once in a while when I get in on it. Also when I get in on it you smell fuel like it flooding it self out. My fuel psi gage in under the hood and when it seem to stall down the needle goes up. I have not clue where to start fixing this problem so if you guys can help please

RichV · Sep 27, 2015

I would start with the ECU/tune. Make sure all that is correct before throwing parts at it.

It could be a slew of things, and with the mods, it makes it even tougher to find the cause. The key is wen it started dong this, was it after a particular mod? Or just started doing it. That would help whether the issue was with some change? Or a failure.

SVTCobra5.0 · Sep 27, 2015

When I first got the car it had all the mods already done to it and it was acting up like this. Like I said earlier it started after I changed the spark plugs to the e3's then I went back to the original that was in it and I didn't notice it and thought it was the wires so I put them on there and it still does it. I hooked up a scan tool to it and bank two o2 sensor was bad I replaced both of them. it also had a code which read 511 code I do believe which is the chip that's in it and I read up about it and it said it was normal for it to shoot that code cause it is a chip but there isn't a check engine light on.

rz5.0 · Sep 28, 2015

I allways liked the autolites my self. Dataloging would help you. Did the plugs looked fouled when you pulled them?

Nuttinbutcrumbs · Sep 28, 2015

Scan for codes. Was it running shtty when you test drove it? If no then it's not in the tune, tunes don't change themselves. It's more than likely a failed sensor. Have you played with the "tunes"? Does it make any difference which tune setting you use?
Don't Sext and Drive

Nuttinbutcrumbs · Sep 28, 2015

SVTCobra5.0 said:
When I first got the car it had all the mods already done to it and it was acting up like this. Like I said earlier it started after I changed the spark plugs to the e3's then I went back to the original that was in it and I didn't notice it and thought it was the wires so I put them on there and it still does it. I hooked up a scan tool to it and bank two o2 sensor was bad I replaced both of them. it also had a code which read 511 code I do believe which is the chip that's in it and I read up about it and it said it was normal for it to shoot that code cause it is a chip but there isn't a check engine light on.

Come again? It was acting up when you bought it so you you put the e3's in and it got worse and so you put the originals back in and it seemed to go away but then started acting up ? Have you messed w the "tune" settings? Does it run the same no matter which one? Code 511 is the same as code 11 which means "all clear". What did the plugs look like when you pulled them out? Were they all wet or fouled out? After you test drove it and it was running cruddy what was the sellers explanation as to why? Pull the vac line off of the fpr and see if it's wet... Is there smoke out of the tailpipes? If so what color?

Don't Sext and Drive.

CC'S95GT · Sep 28, 2015

I agree with the others. sounds like you need a dyno tune and not a crappy mail order tune either..
But here are some things to look for too. Clean the MAF especially if you have a K/N oil type of filter, replace the fuel filter and PCV vlv (and the screen under the PCV).
Change the plugs to the good and cheap copper autolites. The 5.0's don't typically like the exotic plugs.
good luck

SVTCobra5.0 · Sep 28, 2015

The car was running good before I went and put new plugs in it. (the e3's) so I thought that was the problem so I went back to the ones that were in it. The plugs weren't wet or fouled the just looked a like they were running a little hot, like a light brownish color. I could take a picture of one of them and post it if I can post pictures on here.

Nuttinbutcrumbs- when I put the new ones in it did not run shitty, then one day it decided to. which senor would go bad? I changed both o2 sensors. and gave her a tune up. And far as the tune there are 3 different settings 1,2,3 the first is just 93 octane, the second one is 93 octane with nitrous, and the third is race fuel with nitrous. It was running fine when I bought it just figured to put new plugs in it, how could you go wrong there. but anyway wen I put them in I took it to school and thew it on the dyno and noticed it was breaking up, I do have a video of it and you can tell in the video but its fant.

CC'S95GT- I did take the MAF off and cleaned it, didn't seem to do much after that.

SVTCobra5.0 · Sep 28, 2015

What should my Fuel pressure regulator read? How many PSI?

Nuttinbutcrumbs · Sep 29, 2015

SVTCobra5.0 said:
What should my Fuel pressure regulator read? How many PSI?

Do you have a stock regulator? If you pull the vacuum line off the FPR, the fuel pressure at the schraeder valve should be 39psi.

Don't Sext and Drive.

Nuttinbutcrumbs · Sep 29, 2015

How's the idle? Unplug the maf after its warmed up when it's idling, if the idle gets so bad that it tries to die, then more than likely it's good. I've had two MAF's go bad on me and both were after I oiled a k&n filter. Cleaning the maf didn't help so I had to buy another. One of the MAF's had 300k miles on jt without a hiccup prior to the oil. Did you oil the filter recently? I've heard rumors that c&l are junky but unless you got oil on it I doubt it'd just crap out on you like that.
Pull the vac line off of the fpr and see if it's wet.
Are your plug wires arcing anywhere?
How does it act when you're cruising? Does it get hotter quicker and kinda "buck n chug"? If so could be ect.
Get some autolites, gap em correctly and go from there.
Don't Sext and Drive.

SVTCobra5.0 · Sep 29, 2015

It is not the stock FPR. I'm pretty sure its an Aeromotive. The gage on top reads 30 psi when it is started and idling. I don't know what it should say but someone told me ford usually is like 35-50 psi. I may not be getting enough pressure and could be running like shit cause of it. That why I just asked.

The plugs, wires, cap and rotor is all brand new. Everything is MSD and the gap of the plugs are are .038. I read a forum that they should be anywhere between .050-.054 and I think that's a little to much to be honest. Plus everything being MSD I also heard the should be gapped at .035.

And what do you mean about oil the filter that cold air intake filter?

when I'm cruising it seems like there is a slight sputter or miss but as soon I would get on it is when It starts real bad. and I also known it seems to do it when it is at operating temperature instead cold start up.

rz5.0 · Sep 30, 2015

I'd gap a lil bigger.. 35 if you are boosted but not n\a using the right heat range.. Msd is not the best.

Sent from my LGLS996 using Tapatalk

Nuttinbutcrumbs · Sep 30, 2015

SVTCobra5.0 said:
It is not the stock FPR. I'm pretty sure its an Aeromotive. The gage on top reads 30 psi when it is started and idling. I don't know what it should say but someone told me ford usually is like 35-50 psi. I may not be getting enough pressure and could be running like shit cause of it. That why I just asked.

The plugs, wires, cap and rotor is all brand new. Everything is MSD and the gap of the plugs are are .038. I read a forum that they should be anywhere between .050-.054 and I think that's a little to much to be honest. Plus everything being MSD I also heard the should be gapped at .035.

And what do you mean about oil the filter that cold air intake filter?

when I'm cruising it seems like there is a slight sputter or miss but as soon I would get on it is when It starts real bad. and I also known it seems to do it when it is at operating temperature instead cold start up.

The pressure should be 39-41 psi KOEO and KOER in the 35+ psi range when measured at the fuel rail. Is it an adjustable regulator? The stock one isn't but those pressure levels are what you're looking for. An easy way to check if your FPR has gone bad is to take the vac line off of the top and see if it's wet, if so its bad.
Let me start over with the air filter oil. Earlier when we were talking about bad/dirty MAF's I was saying that in my experience the #1 killer of the maf is the oil that you spray on a reusable air filter such as a k&n etc that is found on a cai. If you didn't oil the filter recently the maf is probably ok. MAF's will generally work for quite awhile unless they get oily. Unplug it while the motors running and see what happens. If it runs worse than it's working. When you test drove it did you go full throttle? How'd it run? Scan for codes one more time.
Don't Sext and Drive.

RichV · Sep 30, 2015

You fuel pressure at 30psi is normal if you didn't unplug the vac line to it. But you want to take the reading with the line off. Should be 39psi.

Also, you sure you got the firing order correct after the plugs?