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Weak Ignition??

waynehartwig

waynehartwig

www.jeeperman.com
Location
Mead, WA
The problem I have with the spark issue, is they have been using two 4 barrels (or 3 - 2's) on cars way before MSD or HEI was ever around. We're talking the old stock round coils that only put out like 30k volts with little to no saturation. I mean these were the same on 429 cobra jets and old school hemi's. That's why I'm saying it's not spark, it's fuel.
 
7

78mitsu

Registered User
sounds like you've got a power valve blown through on one side or the other, the power valve also carries the fuel curve over as the secondaries open, so if you've burned through one you'll either get fuel starvation as the secondaries open or you'll suck too much fuel through the pv, it's about $20. I'd replace both, if you're happy with the performance leave them the way they are. match the 4.5 or 5.5 etc.

also, I'd run a bottle of Valvolene fuel system cleaner through the carb, it's about $6.00/bottle. run it on half a tank it works! if it's just a little dirty you'll notice the difference right away.
 
gijohn40

gijohn40

too poor to wheel... :(
Location
Layton, Utah
from what I have read.. it sounds like the accelerator pump... its set to give too much of a supply of fuel when you step on it... but then again you say that it goes away ifyou let off the gas... so maybe not... I know that on my Holley 4 bbl I had to adjust it cause it was giving too much for my small engine (4.2)...
 
waynehartwig

waynehartwig

www.jeeperman.com
Location
Mead, WA
gijohn40 said:
from what I have read.. it sounds like the accelerator pump... its set to give too much of a supply of fuel when you step on it... but then again you say that it goes away ifyou let off the gas... so maybe not... I know that on my Holley 4 bbl I had to adjust it cause it was giving too much for my small engine (4.2)...
Click to expand...

Accelerator pump only works through about mid throttle after that point the power valve takes over.
 
waynehartwig

waynehartwig

www.jeeperman.com
Location
Mead, WA
Shawn said:
Not the jets, I think at this point I'm going to replace the cap and rotor and look for a MSD 6.
Click to expand...

I'm a MSD dealer ;)

But I think before I did anything, I would put the carb back to the way you received it - jets, valve, etc.. I really think that you have several problems kicking your butt right now...
 
Shawn

Shawn

Just Hanging Out
Location
Holly Day
waynehartwig said:
I'm a MSD dealer ;)

But I think before I did anything, I would put the carb back to the way you received it - jets, valve, etc.. I really think that you have several problems kicking your butt right now...
Click to expand...
It ran horrible the way I received it. It was so rich I couldn't run it in the garage.

You can always PM me a price fro the MSD 6A Ignition, let see, what do I always say??? Humor me... :rofl::rofl::rofl:
 
Shawn

Shawn

Just Hanging Out
Location
Holly Day
waynehartwig said:
The power valve works off of vacuum. When the vacuum drops below x amount, the valve opens, dumping more fuel. The power valve only works at WOT, so maybe not. But if it's too light maybe? They come in different spring/vacuum stages. ie 3.5, 4, 4.5 inch of vacuum. If you're cracking the 4 barrel open, it might be dipping too low and causing it to open up? See...It's been too long away from Holley's and I don't remember this crap now.
Click to expand...

UPDATE.

I lowered the power valve to 4.5 from 7.5 (I think) It seams to be right on. I spent the day yesterday pulling the HEI out of the Cruiser and installing it in the Jeep (PITA). No change in the problem so I focused more on the carb. After doing some more research I swapped out the power valve and I think we are in business again.

Thanks,
 
waynehartwig

waynehartwig

www.jeeperman.com
Location
Mead, WA
Shawn said:
UPDATE.

I lowered the power valve to 4.5 from 7.5 (I think) It seams to be right on. I spent the day yesterday pulling the HEI out of the Cruiser and installing it in the Jeep (PITA). No change in the problem so I focused more on the carb. After doing some more research I swapped out the power valve and I think we are in business again.

Thanks,
Click to expand...

Schweet! :cool:
 
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