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Fuel problems with Offy DP

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redstang347
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Fuel problems with Offy DP

Post #1 by redstang347 » Tue Mar 12, 2013 8:00 pm

Just put an offy dp on my 300 and now I'm not getting any fuel to the #1 cylinder. Has anyone else run into this problem? I checked the intake the best I could when I put it on, I didn't have any compressed air but I blew in all the runners, ran my fingers in it and beat it. Took the carb off and but a vacuum down in the intake, with the plug out a friend stuck his finger over the hole and he could feel it pulling on him. We know its getting spark and we know the valves are opening. I really don't want to pull the intake off so I hope someone else has ran into this. I'm running a holly 390 with a Headman header
83 F150 4x4- 300 4 speed
83 Bronco- 351w C6 and lots of rust
90 Mustang coupe- 347 5 speed (work in progress)
87 Grand Marquis- 306 H.O 5 speed (work in progress)
86 CJ-7 258 4 speed

Crash5291
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Re: Fuel problems with Offy DP

Post #2 by Crash5291 » Tue Mar 12, 2013 11:58 pm

Sounds like you should be getting fuel there.

How did you conclude that you are not getting fuel to the #1 Cyl?

redstang347
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Re: Fuel problems with Offy DP

Post #3 by redstang347 » Wed Mar 13, 2013 6:31 am

Pulled the plug and it was bone dry. I know I have spark and I know the cyl is dead because the header tube stays cold
83 F150 4x4- 300 4 speed
83 Bronco- 351w C6 and lots of rust
90 Mustang coupe- 347 5 speed (work in progress)
87 Grand Marquis- 306 H.O 5 speed (work in progress)
86 CJ-7 258 4 speed

86ford
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Location: karlstad MN

Re: Fuel problems with Offy DP

Post #4 by 86ford » Wed Mar 13, 2013 9:34 am

are you shure you have anny compreshion you could have a saverly burnt valve
only thing better than a diesel is an inline six

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CoupeBoy
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Re: Fuel problems with Offy DP

Post #5 by CoupeBoy » Wed Mar 13, 2013 11:00 am

Is the intake valve opening? Flat cam lobe, bent pushrod, improperly adjusted rocker?

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Re: Fuel problems with Offy DP

Post #6 by Harte3 » Wed Mar 13, 2013 11:44 am

Along with a compression check, check the vacuum. http://www.classictruckshop.com/clubs/e ... ac/uum.htm

I doubt the problem is the Offy DP itself.
'83 F150 300, 0.030 over, Offy DP, Holley 4160/1848-1 465 cfm, Comp Cam 260H. P/P head, EFI exhaust manifolds, Walker Y Pipe, Super Cat, Turbo muffler, Recurved DSII, Mallory HyFire 6a, ACCEL Super Stock Coil, Taylor 8mm Wires, EFI plugs.

BIG 6 farmer
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Re: Fuel problems with Offy DP

Post #7 by BIG 6 farmer » Wed Mar 13, 2013 5:21 pm

Could it be as simple as the intake Gasket? maybe not punched out for that port? :hmmm:
83 F 150 SB 4x4 300 six NP 4speed - - 1950 IHC L162 (1&1/2 ton?) - 87 & 88 T-Bird Turbo Coupes - 2000 Triumph Tiger , 76 Honda GL 1000 , & other toys and parts (& junk) -

redstang347
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Re: Fuel problems with Offy DP

Post #8 by redstang347 » Wed Mar 13, 2013 5:50 pm

Well for whatever reason it didn't seal up around that front intake port, so now I get to have the fun of taking everything back off. Is there some trick to putting it on or did I just have bad luck?
83 F150 4x4- 300 4 speed
83 Bronco- 351w C6 and lots of rust
90 Mustang coupe- 347 5 speed (work in progress)
87 Grand Marquis- 306 H.O 5 speed (work in progress)
86 CJ-7 258 4 speed

BIG 6 farmer
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Location: On a dirt road near Washington Nebr.

Re: Fuel problems with Offy DP

Post #9 by BIG 6 farmer » Wed Mar 13, 2013 6:24 pm

Might be just the fat washers that clamp down both the Intake & your Headers are not on right ? Im guessin your Gasket dropped down a bit, when ya put it together? (easy to do) Try looking up from under @ Gasket, to see if it slipped down. Loosen Manifold bolts, push Gasket up. Re-tighten bolts. A couple studs, instead of bolts. Good to line every thing up.
83 F 150 SB 4x4 300 six NP 4speed - - 1950 IHC L162 (1&1/2 ton?) - 87 & 88 T-Bird Turbo Coupes - 2000 Triumph Tiger , 76 Honda GL 1000 , & other toys and parts (& junk) -

redstang347
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Re: Fuel problems with Offy DP

Post #10 by redstang347 » Wed Mar 13, 2013 7:04 pm

Gasket looks good, its still on that little stud on the head. Tried to swapping some of the washers and no luck there
83 F150 4x4- 300 4 speed
83 Bronco- 351w C6 and lots of rust
90 Mustang coupe- 347 5 speed (work in progress)
87 Grand Marquis- 306 H.O 5 speed (work in progress)
86 CJ-7 258 4 speed

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bubba22349
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Re: Fuel problems with Offy DP

Post #11 by bubba22349 » Wed Mar 13, 2013 10:10 pm

Have you done a compression test yet?
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

redstang347
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Re: Fuel problems with Offy DP

Post #12 by redstang347 » Wed Mar 13, 2013 10:47 pm

I know that's not the problem, engine ran fine before I put the intake one. Sprayed carb cleaner around the port why it was running and it smoothed out for a min
83 F150 4x4- 300 4 speed
83 Bronco- 351w C6 and lots of rust
90 Mustang coupe- 347 5 speed (work in progress)
87 Grand Marquis- 306 H.O 5 speed (work in progress)
86 CJ-7 258 4 speed

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CoupeBoy
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Re: Fuel problems with Offy DP

Post #13 by CoupeBoy » Wed Mar 13, 2013 10:56 pm

Possibly the intake or exhaust flanges not straight and true?

BIG 6 farmer
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Location: On a dirt road near Washington Nebr.

Re: Fuel problems with Offy DP

Post #14 by BIG 6 farmer » Wed Mar 13, 2013 11:23 pm

It is obvious you have a bad vacuum leak on that port. You prob. gonna have to pull the Intake Manifold back away from engine. (i know it sucks) :bang: to see whats up. But first, ck. to see if your getting a good clamp between Intake & Exhaust Header(with fat washers). Problem might be with your Headers? sometimes on an inline Engine with Headers, the bar thats welded to the Header Flange can be the wrong thickness. Your fat washers need to apply even clamping pressure to both sides. Some times you need to add a shim to get that. My guess is the bar on Header next to that Intake port is too high? Causing not enuff clamping force to that leaking port? Hope this helps. :)i hope you have a heated plate under your intake? Or you might have drivability & tuning problems on anything below an 80 degree day.
83 F 150 SB 4x4 300 six NP 4speed - - 1950 IHC L162 (1&1/2 ton?) - 87 & 88 T-Bird Turbo Coupes - 2000 Triumph Tiger , 76 Honda GL 1000 , & other toys and parts (& junk) -

Baron Von Ottomatic
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Re: Fuel problems with Offy DP

Post #15 by Baron Von Ottomatic » Thu Mar 14, 2013 9:23 am

Which brand gasket did you use? I've had good luck with one from Mr Gasket. You might try some Gasgacinch or another gasket sealer to help keep the new one tacked in place while you're reinstalling all the manifold bolts.

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THE FRENCHTOWN FLYER
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Re: Fuel problems with Offy DP

Post #16 by THE FRENCHTOWN FLYER » Thu Mar 14, 2013 12:54 pm

X2 on Mr. Gasket part #260.
FORD 300 INLINE SIX - THE BEST KEPT SECRET IN DRAG RACING

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80broncoman
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Re: Fuel problems with Offy DP

Post #17 by 80broncoman » Fri Mar 15, 2013 12:39 am

Have you Swapped that #1 spark plug+ plug wire with another cylinder to see if the problem is still at #1 cylinder.?
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Real men don't wear Bowties
When it come to engines If its .001 loose nobody knows, But if its .001 too tight EVERYBODY KNOWS!!
80 bronco FUV (farm utility vehicle)300 T-18 3.50s EFI head, offy C dual plenum, 500 edel carb, 1.7 roller rockers, Crane 260 cam EFI Exh

redstang347
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Re: Fuel problems with Offy DP

Post #18 by redstang347 » Fri Mar 15, 2013 8:46 pm

Well put a Fel-Pro gasket on it and its hitting on all 6 again. Had already got it before I got home and seen the Mr. Gaskets posts. At least I'm getting pretty good at pulling the intake and exhaust off now.
83 F150 4x4- 300 4 speed
83 Bronco- 351w C6 and lots of rust
90 Mustang coupe- 347 5 speed (work in progress)
87 Grand Marquis- 306 H.O 5 speed (work in progress)
86 CJ-7 258 4 speed

greg_a_morton
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Re: Fuel problems with Offy DP

Post #19 by greg_a_morton » Tue Apr 02, 2013 11:10 pm

I had a similar problem with my industrial manifold and stock intake. I had to take back off and have both machined together to have a true flat surface and im using the MG gasket. When intake was bolted to the exhaust manifold there was enough gap on the intake to run a sheet of paper in between intake and gasket and exhaust manifold was good and tight.
1967 mercury 350 International 7.3 IDI ats turbo kit c6 gear vendor overdrive 3.73s rolling on 19.5s
1971 f100 body on 1979 f350 frame 460 c6 dana 60s 3.54s dually
1974 f100 longbed baby blue & rust 240 3 speed 3.70s sitting on the ground!
1990 f250 extcab xlt lariat efi 460 e40d 3.55s daily driver
and 1 Bump parts truck.
Possibly looking for my next bump or dent right now!

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