HELP STALLING PROBLEM AFTER SC INSTALL!!!! & Hard start!! ARGH!

Ny Mustang Guy · May 28, 2006

*I HAVE A Mildly modded '90 5.0 Engine in my '86* MSD 6al and BTM 24#FMU Just installed my Powerdyne 6lb SC last night.. The car starts fine.. idles fine.. I hada little problem with the temp getting a little hot.. (but put a little more Coolant in the car and so far so good temp wise). I havent really gotten on it yet. The main problem is driving normally.. if i give it some gas and then let off the tach will go down to 500-600rpms.. then jump back up to 900rpms @ idle.... Now when I really get on it and see 1-2lbs of boost and then let off.. it will either do the same thing or turn completely off (Stall out)....

Long story short: driving normally or If I get on it and hit 1-2lbs of boost (THATS ALL I'VE HIT IT UP TO SO FAR)..and then let off the gas, the car will turn off (stall out).. or go down to 500-600rpms.. then jump back up to 900rpms. As if its surging or just turning off?

I have a Greddy type RS Bov mounted by the elbow of the power pipe recirculating back before the SC after the MAF

Ny Mustang Guy · May 28, 2006

Should I just get the o2 harness and get the car tuned right??.. I am at my wits end with trying to figure out the problem.. HELP!!!!

Oh yeah.. I have Boost Gauge which reads Vac @ 10 at idle.

Ny Mustang Guy · May 29, 2006

-TtT-

stang730 · May 29, 2006

when i had the vortech put on my 01 bullitt, they had a surging problem, due to the facr that my car had no fog lights, and too much air was comming through the opening, causing it to surge. Im no expert, but id figure id tell you cause i had the same problem and they had to zip screw a small plate to block off some air. Mabye you have the same kind of problem?

sweet88gt · May 29, 2006

You may have a few small issues and together they are causing the problem at hand. What is the fuel pressure set at and what is the step up ratio for your FMU?? What type of condition is your IAC valve in?? You may be able to raise the idle speed slightly to compensate for the IAC vavle not being able to react quickly to the new demands. That is problably the first thing to try as it helped me the most. I found the high fuel pressure cuased alot of my intial problems.

Ny Mustang Guy · May 29, 2006

Double Post

Ny Mustang Guy · May 29, 2006

- I will look into that being that I put my Filter to run into the fenderwall.

- FMU is set for my 24lbers.. and my FP Pressure is @ 39Psi

My Car is at a friends house.. when I get the chance I will check the condition the IAC is in.

Thanks for the responses

I will try the bringing up of the idle and lowering the pressure.. what was ur pressure at and what did you set it to?

Ny Mustang Guy · May 29, 2006

Where is the IAC Located exactly.. I THINK I have a good idea as to what it is.. Just would like to make sure

troyGT03 · May 29, 2006

are you running speed density or mass air?

ninety15.0 · May 29, 2006

IAC id mounted on the throttle body...its that cylinder on an angle with the sensor clip on the bottom. I would take it off and clean it out...they can get gummed up. Also...10" of vac at idle seems a little low. Mine sits at about 16 and i thought mine was a little low. i wouldt check real hard for a vac leak or perhaps you have something hooked up wrong?

Ny Mustang Guy · May 29, 2006

MASS AIR

I will look into a Vac leak tomorrow.. and get back to you guys asap.

btw is hooking up my vac lines ( MSD BTM, FMU, BOV, Boost Gauge) all to the Vac tree on the firewall bad or is it alright?

Ny Mustang Guy · May 29, 2006

ninety15.0 said:
IAC id mounted on the throttle body...its that cylinder on an angle with the sensor clip on the bottom. I would take it off and clean it out...they can get gummed up.

I will check it out tomorrow.

Don't think i hooked anything up wrong.. Maybe i hooked the FMU up backwards??.. I followed the instructions.. hose on the side goes to the top part of the fuel return line. hose at the bottom of the FMU goes to the bottom of the Fuel return line...

Daggar · May 29, 2006

Ny Mustang Guy said:
MASS AIR

I will look into a Vac leak tomorrow.. and get back to you guys asap.

btw is hooking up my vac lines ( MSD BTM, FMU, BOV, Boost Gauge) all to the Vac tree on the firewall bad or is it alright?

Your FMU should have as much of a direct tap to your manifold as you can get it. Sharing vac from the tree between all of those things is certainly not ideal.

The adjustment on your BOV has the potential to effect a lot of the symptoms you describe:

Only seeing two lbs of boost
Allowing unmetered air into the system if not fully closed can cause a stall.
Venting metered air to atmosphere or bypassing the meter and entering the engine can also cause a stall.

Suggestions for troubleshooting:

Split up your vacuum devices. Too many devices on one skinny port or line can make them all act stupid.

Install a .050 orifice inline with your boost gauge (not required but often helps in say 5 out of 10 circumstances)

Close off that BOV valve with the adjustment. Adjust it so that it doesn't open at all but be very nice to it when you do this. Then begine slowly tuning that BOV towards "more open" as you get into it.

I read your statement about how your BOV is hooked up but can't say that I understood it well. I'm assuming that you've got it hooked up in such a way that metered air is being recirculated back into the manifold.

91lxttrim · May 29, 2006

I just installed my T-trim this weekend and I thought the directions weren't very clear about FMU fuel lines. It says to remove the return line at the lower right side of the block, but the fittings aren't right to do that.

I had to leave both chrome parts of the fuel lines, just disconnected the return line at the manifold and connected the corresponding line from the fmu to the end coming from the FPR and then the other line coming from fmu back to chrome portion of return line to tank.

confusing... here's a pic...

btw, HOLY CRAP!!!! It freakin kicks a$$!! I have some pretty hard tires on there now and it just smokes 'em. I'm also blowing alot of black smoke when I hammer it. Stock injectors- could it be FMU setting too?

86bluecobra · May 30, 2006

Black smoke usally tells us that we are running rich.

Ny Mustang Guy · May 30, 2006

Daggar said:
Your FMU should have as much of a direct tap to your manifold as you can get it. Sharing vac from the tree between all of those things is certainly not ideal.

The adjustment on your BOV has the potential to effect a lot of the symptoms you describe:

Only seeing two lbs of boost
Allowing unmetered air into the system if not fully closed can cause a stall.
Venting metered air to atmosphere or bypassing the meter and entering the engine can also cause a stall.

Suggestions for troubleshooting:

Split up your vacuum devices. Too many devices on one skinny port or line can make them all act stupid.

Install a .050 orifice inline with your boost gauge (not required but often helps in say 5 out of 10 circumstances)

Close off that BOV valve with the adjustment. Adjust it so that it doesn't open at all but be very nice to it when you do this. Then begine slowly tuning that BOV towards "more open" as you get into it.

I read your statement about how your BOV is hooked up but can't say that I understood it well. I'm assuming that you've got it hooked up in such a way that metered air is being recirculated back into the manifold.

how exactly do you adjust the BOV.. I know there is a nut up top that you can loosen.. but how do you exactly adjust it?.. My BOV was never blowing off to begin with btw...

Can you please tell me where exactly I can hook up my Vac's because this is confusing me as to the spots that I can hook my Vac up to. THANKS FOR ALL THE RESPONSES

Ny Mustang Guy · May 30, 2006

86bluecobra said:
Black smoke usally tells us that we are running rich.

Cant tell if im blowing black smoke being that the car is dumped.. and I havent had a friend look behind me yet.. It smells like gas when i step on it and also i am not runnin a o2 sensor harness..

Ny Mustang Guy · May 30, 2006

91lxttrim said:
I just installed my T-trim this weekend and I thought the directions weren't very clear about FMU fuel lines. It says to remove the return line at the lower right side of the block, but the fittings aren't right to do that.

I had to leave both chrome parts of the fuel lines, just disconnected the return line at the manifold and connected the corresponding line from the fmu to the end coming from the FPR and then the other line coming from fmu back to chrome portion of return line to tank.

confusing... here's a pic...

btw, HOLY CRAP!!!! It freakin kicks a$$!! I have some pretty hard tires on there now and it just smokes 'em. I'm also blowing alot of black smoke when I hammer it. Stock injectors- could it be FMU setting too?

Hmm.. which line of the FMU is going where is my question. theres one line going off the bottom and one line going off the side

Daggar · May 30, 2006

Ny Mustang Guy said:
how exactly do you adjust the BOV.. I know there is a nut up top that you can loosen.. but how do you exactly adjust it?.. My BOV was never blowing off to begin with btw...

Can you please tell me where exactly I can hook up my Vac's because this is confusing me as to the spots that I can hook my Vac up to. THANKS FOR ALL THE RESPONSES

Search online for a set of instructions for your particular BOV. I'd hate to stab a "guess" and have you end up worse off than you are.

As for your Vac lines... look up under your intake for a fresh source for your vac operated devices. You want to get as far away from that brake booster as poosible. That thing is pretty high volume and doesn't play well with others.

Ny Mustang Guy · May 30, 2006

i have 2 in the back of the intake that are capped off.. guess i will try those

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