331 issues

88Saleen · May 24th, 2011, 08:31 PM

Hey guys im working on a 1995 5.0. It has 30lb injectors with matching MAF. I have gotten almost all the bugs worked out of it except a few. When driving normaly and coming to a stock light you press the clutch in and the RPM's hang up around 2k for about 5-10 seconds and then drops to idle. The other problem is in second gear it feels like it misses about 2000-2500. Sometimes its higher in the RPM range than that also. I thought it might have been running out of fuel so i put a adjustable fuel pressure regulator and gauge and set the pressure to 45psi without vacuum line hooked up. I know that is kind of high but i wanted to start high. It still misses the way it did with the stock regulator.

Things i can think could be the issue with the missing problem.
1. Fuel pump (it is stock)
2. Tune (it has stock tune, but i figured it would at least run alright)

As for the idle i may just try and get a new TPS. If i do get a new TPS do i need to set the voltage with the procedure in the sticky?

Thanks for the help guys

ryanw · May 24th, 2011, 08:41 PM

you have a 331 stroker ? and a stock fuel pump ?

FastStang91Lx · May 24th, 2011, 08:44 PM

Make sure your starting point is lower than 1 volt and like over 4.5 at full throttle. Fogged306 knows his electronic shit pretty well, and he said the .95-.98 is just a myth. I still do it anyway, but that's cuz it's easy and although it may not help, it certainly doesn't hurt. Without checking the full sweep of the TPS with a meter, you may just be pissing money away. The one on there might be good. Probe the wires and slowly open the throttle and watch the voltage. If it's a steady sweep, you are good. If it's erratic, junk.

88Saleen · May 24th, 2011, 08:47 PM

Ryan, its not my car. I didn't build the car. I am just trying to get all the buggs worked out, there has been quite the list. I will be getting a walbro 255lph. Faststang, i will check that the voltage is right like you said and then i will do the resistance sweep also to make sure its steady. what else do you think the hanging RPM thing could be?

FastStang91Lx · May 24th, 2011, 09:02 PM

I know someone on here had it happening, but I can't remember what the outcome was.

I have the memory of an 80 year old with alzheimers.

fogged306 · May 24th, 2011, 10:42 PM

Have you checked for codes? Read the plugs? I agree, I would definitely get a bigger pump in there before anything, it might not be your miss, but it needs to be done regardless.

Hey Scott, this is actually a really good read about the TPS voltage. stang&2birds in that thread makes a lot of sense out of it. EECTuning.org • View topic - Why TP voltage does not matter

FastStang91Lx · May 24th, 2011, 11:08 PM

I didn't make it that far.... that shit's WAY above my head. I'm a dyno tuning kind of guy, lololololololololol.

fogged306 · May 24th, 2011, 11:13 PM

Hah, don't pay attention to the screenshot in the first post. Thats beyond me at the moment too. But the RATCH functions explained pretty plainly makes a lot of sense. Trust me, it's not as technical is it looks.

FastStang91Lx · May 24th, 2011, 11:20 PM

Hell, I haven't even looked at modifying the outputs for the Abaco meter yet either, I just ran it as was. But didn't have a wideband either, so really would have been pointless... nothing to compare it to. I'll finish reading that later - promise

69fastback · May 25th, 2011, 01:30 PM

Have you checked for vacuum leaks?

88Saleen · May 26th, 2011, 06:03 PM

There are no vacuum leaks. I reset the base idle and i am putting a 255 walbro in it and i hope that fixes the problem. i see the fuel pressure needs to be set to 35-45psi. Got that off alldata. What do you guys suggest fuel pressure be set at?

kmedeiros88 · May 26th, 2011, 06:28 PM

39 psi

fogged306 · May 26th, 2011, 08:02 PM

Originally Posted by kmedeiros88

39 psi

with the vacuum line off the regulator. 39 PSI is the target for the EEC at WOT. When you go WOT, there's no vacuum in the manifold so the FPR is at it's max PSI, which is why you pull the vac line off and set it. If you're within a couple PSI you're fine.

88Saleen · May 26th, 2011, 08:35 PM

Ok thanks, yeah i know how to set it. I was just wondering what you guys thought. If i still get this miss im going to try and bump it up a little and see if the miss feeling goes away. 30lb injectors should be enough to fuel this build i think. thanks for the input guys

May 24th, 2011, 08:31 PM	#1
88Saleen Enthusiast 1988 Mustang Join Date: Apr 2008 Location: Grand Blanc, Michigan Posts: 832 iTrader: 0 reviews	331 issues Hey guys im working on a 1995 5.0. It has 30lb injectors with matching MAF. I have gotten almost all the bugs worked out of it except a few. When driving normaly and coming to a stock light you press the clutch in and the RPM's hang up around 2k for about 5-10 seconds and then drops to idle. The other problem is in second gear it feels like it misses about 2000-2500. Sometimes its higher in the RPM range than that also. I thought it might have been running out of fuel so i put a adjustable fuel pressure regulator and gauge and set the pressure to 45psi without vacuum line hooked up. I know that is kind of high but i wanted to start high. It still misses the way it did with the stock regulator. Things i can think could be the issue with the missing problem. 1. Fuel pump (it is stock) 2. Tune (it has stock tune, but i figured it would at least run alright) As for the idle i may just try and get a new TPS. If i do get a new TPS do i need to set the voltage with the procedure in the sticky? Thanks for the help guys __________________ 1988 vert - still in progress 2004 F250

May 24th, 2011, 08:41 PM	#2
ryanw I Post Entirely Way Too Much 1991 Ford Mustang GT Join Date: May 2007 Location: San Diego, California Posts: 6,063 iTrader: 0 reviews	you have a 331 stroker ? and a stock fuel pump ? __________________ DART 331ci stroker, AFR 185 heads, Trick Flow R intake, Accufab 70mm tb, 75mm pro m Maf, 30lb injectors, jba headers, 2 1/2" x pipe flowmaster super 10 mufflers, 255 fuel pump, 3:27 gears

May 24th, 2011, 08:44 PM	#3
FastStang91Lx I Post Entirely Way Too Much 1991 Mustang LX 5.0 Join Date: Jan 2010 Location: Minnesota Posts: 5,572 iTrader: 2 reviews	Make sure your starting point is lower than 1 volt and like over 4.5 at full throttle. Fogged306 knows his electronic shit pretty well, and he said the .95-.98 is just a myth. I still do it anyway, but that's cuz it's easy and although it may not help, it certainly doesn't hurt. Without checking the full sweep of the TPS with a meter, you may just be pissing money away. The one on there might be good. Probe the wires and slowly open the throttle and watch the voltage. If it's a steady sweep, you are good. If it's erratic, junk. __________________ Point made in less than a few hours with minimal response. http://www.moddedmustangs.com/forums...ml#post4465184

May 24th, 2011, 08:47 PM	#4
88Saleen Enthusiast 1988 Mustang Join Date: Apr 2008 Location: Grand Blanc, Michigan Posts: 832 iTrader: 0 reviews	Ryan, its not my car. I didn't build the car. I am just trying to get all the buggs worked out, there has been quite the list. I will be getting a walbro 255lph. Faststang, i will check that the voltage is right like you said and then i will do the resistance sweep also to make sure its steady. what else do you think the hanging RPM thing could be? __________________ 1988 vert - still in progress 2004 F250

May 24th, 2011, 09:02 PM	#5
FastStang91Lx I Post Entirely Way Too Much 1991 Mustang LX 5.0 Join Date: Jan 2010 Location: Minnesota Posts: 5,572 iTrader: 2 reviews	I know someone on here had it happening, but I can't remember what the outcome was. I have the memory of an 80 year old with alzheimers. __________________ Point made in less than a few hours with minimal response. http://www.moddedmustangs.com/forums...ml#post4465184

May 24th, 2011, 10:42 PM	#6
fogged306 MM Fanatic 89 GT Join Date: Apr 2007 Location: NY Posts: 4,875 iTrader: 2 reviews	Have you checked for codes? Read the plugs? I agree, I would definitely get a bigger pump in there before anything, it might not be your miss, but it needs to be done regardless. Hey Scott, this is actually a really good read about the TPS voltage. stang&2birds in that thread makes a lot of sense out of it. EECTuning.org • View topic - Why TP voltage does not matter

May 24th, 2011, 11:08 PM	#7
FastStang91Lx I Post Entirely Way Too Much 1991 Mustang LX 5.0 Join Date: Jan 2010 Location: Minnesota Posts: 5,572 iTrader: 2 reviews	I didn't make it that far.... that shit's WAY above my head. I'm a dyno tuning kind of guy, lololololololololol. __________________ Point made in less than a few hours with minimal response. http://www.moddedmustangs.com/forums...ml#post4465184

May 24th, 2011, 11:13 PM	#8
fogged306 MM Fanatic 89 GT Join Date: Apr 2007 Location: NY Posts: 4,875 iTrader: 2 reviews	Hah, don't pay attention to the screenshot in the first post. Thats beyond me at the moment too. But the RATCH functions explained pretty plainly makes a lot of sense. Trust me, it's not as technical is it looks.

May 24th, 2011, 11:20 PM	#9
FastStang91Lx I Post Entirely Way Too Much 1991 Mustang LX 5.0 Join Date: Jan 2010 Location: Minnesota Posts: 5,572 iTrader: 2 reviews	Hell, I haven't even looked at modifying the outputs for the Abaco meter yet either, I just ran it as was. But didn't have a wideband either, so really would have been pointless... nothing to compare it to. I'll finish reading that later - promise __________________ Point made in less than a few hours with minimal response. http://www.moddedmustangs.com/forums...ml#post4465184

May 25th, 2011, 01:30 PM	#10
69fastback Premium Member 1969 Mustang Mach 1 6.824@101.61 Join Date: Aug 2006 Location: Oklahoma jackass, get to driving Posts: 5,565 iTrader: 0 reviews	Have you checked for vacuum leaks? __________________ ./___ _ ____ ___ \. ( ]]] _ _ O _ _ [[[ ) \_ o _ _____ _ o _/ \|___\| ......... \|___\| http://www.youtube.com/watch?v=HyYU3...e_gdata_player

May 26th, 2011, 06:03 PM	#11
88Saleen Enthusiast 1988 Mustang Join Date: Apr 2008 Location: Grand Blanc, Michigan Posts: 832 iTrader: 0 reviews	There are no vacuum leaks. I reset the base idle and i am putting a 255 walbro in it and i hope that fixes the problem. i see the fuel pressure needs to be set to 35-45psi. Got that off alldata. What do you guys suggest fuel pressure be set at? __________________ 1988 vert - still in progress 2004 F250

May 26th, 2011, 06:28 PM	#12
kmedeiros88 Regular 89 Mustang LX Hatch Join Date: Feb 2011 Location: Fall River, MA Posts: 324 iTrader: 0 reviews	39 psi

May 26th, 2011, 08:35 PM	#14
88Saleen Enthusiast 1988 Mustang Join Date: Apr 2008 Location: Grand Blanc, Michigan Posts: 832 iTrader: 0 reviews	Ok thanks, yeah i know how to set it. I was just wondering what you guys thought. If i still get this miss im going to try and bump it up a little and see if the miss feeling goes away. 30lb injectors should be enough to fuel this build i think. thanks for the input guys __________________ 1988 vert - still in progress 2004 F250

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