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think this may be a problem?
#1503486
09/17/13 09:58 PM
09/17/13 09:58 PM
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Joined: Jul 2006
Posts: 4,179
California
mickm
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,179
California
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so i've been chasing an issue since not long after the engine went in, where it is breaking up, more missing really, at anywhere about 4500-5000, and doesn't have the power it should below that. had issues with the msd box for a while, and while ignition still isn't ruled out, i decided to check my fuel pressure. i bought a carter pump from mancini that was supposed to be calibrated for the carter/edelbrock carbs, so about 5.5 - 6 psi. put a gauge inline today, and it almost immediately jumped to 10 psi, which is pegged on the gauge!  and that was barely above idle! i'll call them tomorrow and see if i have the wrong pump, but i'll have to take of this before i go on. sigh... well, hopefully it will be this easy!
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Re: think this may be a problem?
[Re: Cab_Burge]
#1503491
09/18/13 09:06 AM
09/18/13 09:06 AM
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Joined: Dec 2009
Posts: 21,192
in a cattle trailer down by th...
Guitar Jones
Paddle faster! I hear banjo music!
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Paddle faster! I hear banjo music!
Joined: Dec 2009
Posts: 21,192
in a cattle trailer down by th...
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I've had a problem like that. I had the coil mounted on the fender apron, I added a ground from the bracket to the engine and the problem went away.
"Come get your wife"
'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion.
'74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Front and rear disc and hydroboost conversion.
2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
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Re: think this may be a problem?
[Re: Cab_Burge]
#1503492
09/18/13 10:59 AM
09/18/13 10:59 AM
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Joined: Jul 2006
Posts: 4,179
California
mickm
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,179
California
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Quote:
Verify your fuel pressure gauge, if it has to much pressure it shouldn't idle worth a hoot, it should load up and die   All the carbs(more than one  ) that I had to much pressure on did
that did seem strange, but we used two different gauges, exactly the same reading.
i figured the result of this would be much worse as well, and can't really explain it.
i just made a new line to one of the carbs from the tee, which consists of a rubber hose with another tee in it, and that tee goes to the gauge, which i have taped to the windshield. nothing wrong there?
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Re: think this may be a problem?
[Re: Guitar Jones]
#1503493
09/18/13 10:59 AM
09/18/13 10:59 AM
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Joined: Jul 2006
Posts: 4,179
California
mickm
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,179
California
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Quote:
I've had a problem like that. I had the coil mounted on the fender apron, I added a ground from the bracket to the engine and the problem went away.
coil is mounted on the intake manifold. hopefully there is no issue there.
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Re: think this may be a problem?
[Re: mickm]
#1503494
09/18/13 11:07 AM
09/18/13 11:07 AM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Pressure is a by product of flow versus restriction so instead of getting a lower flowing pump just put one of the Holley regulators in the line to drop the pressure to 6-ish... those carbs do use less pressure than a Holley needle and seat 
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Re: think this may be a problem?
[Re: Thumperdart]
#1503496
09/18/13 11:35 AM
09/18/13 11:35 AM
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Joined: Jul 2006
Posts: 4,179
California
mickm
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,179
California
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Quote:
If you`re stuck on the mechanical pump then just install a regulator............. 
that is what i may end up having to do. i have to check the number on the pump to see if it is the right one, and go from there. i talked with mancini and either way i may return and exchange the pump, if it's the race one i don't want it, and if not, it may just be unit that is way off.
i have a stock appearing setup, and was hoping to avoid needing a regulator, which is the reason i paid for this particular pump.
i'm going to temporarily install a regulator and see how it behaves and go from there.
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Re: think this may be a problem?
[Re: Cab_Burge]
#1503499
09/18/13 08:31 PM
09/18/13 08:31 PM
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Joined: Jul 2006
Posts: 4,179
California
mickm
OP
master
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OP
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Joined: Jul 2006
Posts: 4,179
California
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Quote:
I can't remember if we have discussed the needles and seat sizes, have we? If so what size are in your carbs. now? If ther smaller than .090 you may want to change thme to .110 or larger BTW, I have one or two sets of the new Carter .110 left from racing my stocker  
i have thought about that. there is probably no reason not to on an engine this size.
i'm going to get the regulator in there (hopefully tonight) and take things from there. one step at a time.
but i do need two sets, (nudge nudge, wink wink, say no more, saaaay no more)!
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Re: think this may be a problem?
[Re: Cab_Burge]
#1503502
09/19/13 12:58 AM
09/19/13 12:58 AM
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Joined: Jul 2006
Posts: 4,179
California
mickm
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,179
California
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well, got the regulator in.
set it at 6 psi, and took it out for a drive. under full throttle it steadily dropped off until it leveled at about 2psi. that was about 5500, and by then it was breaking up. not falling off, but missing and breaking up, the problem i'm going after.
A/F mixture stayed the same, in the low to mid 12's, even when it was at 2psi.
now at first i thought that was a big deal, but since it actually had pressure, that means there was something that was resisting it, namely closed needles and seats. also, if it truly was unable to keep up with the demand, then it would have gone lean once the pump could no longer keep up can supply the engine with the gas it needed.
make sense? am i off base??
we are going to tackle the ignition next. we're going to put a points distributor back in and eliminate the entire ignition system and go from there.
someone mentioned a rocker arm. i just adjusted the valves, so i know that isn't an issue.
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Re: think this may be a problem?
[Re: Cab_Burge]
#1503503
09/19/13 01:01 AM
09/19/13 01:01 AM
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Joined: Jul 2006
Posts: 4,179
California
mickm
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,179
California
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Quote:
Another thing to check, if you haven't already, on both the Carter and Eddy carbs. is the float drop and float level  I like to have both at the longest travel,lowest float drop and the highest, without dripping or flooding, float level on those two brand and type carbs. 
so how far beyond the stock settings do you go? until it does start dripping or flooding?
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Re: think this may be a problem?
[Re: mickm]
#1503504
09/19/13 11:44 AM
09/19/13 11:44 AM
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Joined: Jul 2004
Posts: 19,318
State of confusion
Thumperdart
I Live Here
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I Live Here
Joined: Jul 2004
Posts: 19,318
State of confusion
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What fuel line sizes r u running.............? Stock tank?
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: think this may be a problem?
[Re: Thumperdart]
#1503505
09/19/13 12:27 PM
09/19/13 12:27 PM
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Joined: Jul 2006
Posts: 4,179
California
mickm
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,179
California
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stock tank, new fuel lines, 3/8" to the pump, 5/16" to the carbs.
now, before anyone jumps all over that as not enough, i'm going by what tim banning does. he uses this setup on all his 572, 750+ HP street bemis, unless the customer asks for something different. it certainly is possible that in my case it isn't enough, and if so i'll figure that out and change it, but there is a proven track record of this combo working, so until i prove it isn't, i'll stick with it.
it looks to me like for whatever reason, the carbs were holding out well against that 10psi most of the time, as it really didn't run differently with the regulator in place.
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