Need Help! Car wont start after Carb Conversion...long

91FrankinStang

New Member
May 15, 2005
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Did a Carb & T5 conversion on my '91GT. Installed an MSD 6A w/ blaster 2 Coil, '85 GT dizzy, performer 289 intake, brand new Holley 600 Carb, Holley Blue pump w/ Mallory Bypass Regulator.. Removed computer, harness & smog..

What is happening is I am getting popping/backfiring from the exhaust, AND the carb.. The carb spits fuel, like its flooding real bad.. When I remove the aircleaner, there is a nice cloud of gas that comes up.. But no flames have come up from the carb.. And every once in awhile i get backfire from the exhaust..

To set timing, i removed #1 spark plug, had someone bump over the motor till it blew my finger out of the spark plug hole.. Check the mark on the balancer and its close to BTDC.. I turn the motor by hand to 10* BTDC. lift dizzy enough to turn rotor till it drops in with the rotor pointing to the #1 spark plug.. Snug dizzy, reinstall spacer & cap.. Verify correct firing order and it is counter clockwise..

To my knowledge & experience, it should start at that point.. ITs cranking and it sounds like it wants to start, but it just doesnt.. But its close..

Now, to the fuel system.. Originally, I had the regulator that came with the blue pump. i never installed a fuel pressure guage b/c for that reg., the pressure is preset.. Now, I had to switch to the bypass b/c the holley reg was no good for a return style system.

But, being I have no fuel pressure guage ,I dont know what my pressure is and if it is too much.. I think it is getting too much pressure.. I have tried tightening and loosening the adjustment screw a number of times with no luck..

Checked timing like 3 times..

I removed to sight plug on the carb to check float level, and fuel poured out indicating it could be too high.. But then again, if it was getting too much pressure, wouldnt the bowls constantly be full and then of course fuel will come out when i remove the plug??

Can someone explain the correct way in detail to check float level?? car on or off,etc..

Also, is anyone familiar with this regulator and know if the pressure could be set w/out a fuel pressure guage?? like say, bottom out the screw, then back it out 3 turns.. that should be 7psi.. just for example.. Or must i have a guage to adjust the pressure..?

If I need to guage, Summit sells one that will connect directly to the banjo fitting on my carb.. Its is made by Segis..or something.. will this be ok for what I need?? I really dont wanna go cutting fuel line to splice ina guage b/c it is all braided line and a PITA.. but, if i gotta.. i gotta..

The model of the carb is 80457S.. It is brand new out of the box.. Nothing has been touched, except the float level which i lowered a little..

Any ideas on whats going on???


Also, aftet i stopped cranking when I was trying to start it, I looked down the carb and fuel was dripping out of the jets.. What does that indicate???

I also pulled plugs and they were not soaked/fouled..

Any help a/s/a/p appreciated.. I'd really like to get this thing running tomorrow..

Joe
 
All gaskets are good? Make Sure the idle screw is backed down pretty low. Umm, make sure no plug wires are crossed, definately take a look at that fuel pressure, check vaccum lines... eh i dunno.

Not a solution at all. Just if I had your probs that's all the crap I would look at. ALSO, exhaust leaks can cause some of your "ailments."
 
You really need a fuel pressure gauge! It sounds like your regulator is set too high, this forces fuel past the needle and seat and you get flooding! A holley blue runs around 15psi, holley carbs are only going to take 7psi then the pressure will force the needle off the seat, gas will fill up the bowls and run out the vent tubes and all kinds of places!!

Also, level is checked with the car running, pull the site plug and fuel should *just*trickle out as the engine shakes! The rear could be a tad bit higher, but not running out!
 
Yep, you really need a f/p gauge... I didn't read the whole thing cause it's too long for my A.D.D. lol... But hell... a carb needs an ignition, like an MSD with uhhh... power, ground, and ignition on... two wires to the dist, and two to the coil... Not too hard. Should fire right up as long as the pump is working and you're actually getting fuel. Even if it's too much pressure, it should still fire, and maybe die. You can push the needle from teh seat and screw it up pretty good. Turn the pump on, open the butterflies and check to make sure you're squirting fuel in there. Good luck man! :nice:
 
thanks... I'm gonna try an find a guage locally today and install it & see what happens.. if not gotta order from summit..

If it still doesnt start once the pressure is right, then i guess it is timing related..
 
yep I would have to agree as well with stang8. I have a question for you did you use the stock efi fuel pump? and that is why you are running the after market fuel pressure regulator thanks.
 
no. i am using a holley blue electric fuel pump.. I removed the stock pump & pickup assembly and used a grantielli motorsports fuel tank insert.

I'll be getting the guage on by the end of the week so hopefully it'll work out. I found a fitting I can use in Jegs w/out having to cut any lines.. It has a 3/8" female & 3/8" male & 1/8" port.. I will unscrew my lines going to the carb from the regulator, screw in this fitting, then screw in the line going to the carb into the female side, and the guage into the 1/8 port..

Should work with no probs..

thanks again
 
91FrankinStang said:
To set timing, i removed #1 spark plug, had someone bump over the motor till it blew my finger out of the spark plug hole.. Check the mark on the balancer and its close to BTDC.. I turn the motor by hand to 10* BTDC. lift dizzy enough to turn rotor till it drops in with the rotor pointing to the #1 spark plug.. Snug dizzy, reinstall spacer & cap.. Verify correct firing order and it is counter clockwise..


When you bumped the motor over til it blew out #1 you shouldnt have really had to turn the motor. Did you drop the distributor in with the 0 line on your balancer centered in the round hole on your timing pointer? That would be the first thing id check and definitely gotta get a fuel pressure gauge on there. good luck with it

kevin
 
Are you 100% that you’re using the CORRECT firing order’for the Motor and CAM that’s in the Car? That can change the firing order, depending on the year Cam..That sounds like an Ignition or Valve timing issue, as previously said- Valves hanging up..Cheers!
 
Are you 100% that you’re using the CORRECT firing order’for the Motor and CAM that’s in the Car? That can change the firing order, depending on the year Cam..That sounds like an Ignition or Valve timing issue, as previously said- Valves hanging up..Cheers!
This was like... 13 years ago... I’m guessing he got it. I hope
 
No clue. I wish people would make a effort to post the conclusion in posts like this.
No clue. I wish people would make a effort to post the conclusion in posts like this.
Yes,, agreed. After people are willing to help, & the issue is correctly diagnosed, people just forget to take the time to say “Thanks” (think how much time was saved by using this Site, they’d likely still be stumped)., and/or reveal what suggestion(s) were helpful, helping those involved, and possibly another down the line with a similar issue. Might be a useful Guideline, to officially close a Suject with the conclusion by the one who created it..