Fuel pump function...or lack thereof

1945 - 196*, Willys CJ series, questions, discussions, regarding anything related to the post war jeep.®
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Wolfman
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Re: Fuel pump function...or lack thereof

Post by Wolfman » Thu Jul 12, 2018 7:03 am

Condensers are nothing more than an electrical storage device.
When the points are closed, current is flowing through the coil primary to ground through the closed points.
When the points break, the momentum of the flowing electricity does not want to stop, so, with no place else to go, there would be a lot of arcing at the points, which would quickly burn them. The arcing would also give an erratic, weak spark out the coil secondary. This is bad.
Enter the condenser. When the points break, a condenser gives the electrical energy flowing some place to go. The condenser stores it until the points close again and then the condenser discharges and waits for the next cycle.
When a condenser goes bad, it may be shorted. This would kill the ignition and can be checked with an Ohm meter. Or, it's ability to store energy may be reduced, resulting in a weak spark. Not so easy to test. You need a tester to check the later. The tester checks the condenser's storage ability and the break down voltage. In this case, the condenser may store some energy but short out at a lower capacity than it is rated for. This is harder to check. The condenser will not test shorted with an Ohm meter, but you will still have a weak, erratic spark.
Best way to deal with a suspect condenser is replace it. See what happens. A lot cheaper than the tester, unless you test condensers on a daily basis.
Mike Wolford
CJ-2A
VEP GPW
Comm./Inst. SEL
AOPA ( 44 yrs)
EAA ( 44 yrs)
4th Inf. Div. - 5th Inf. Div. - 2nd Armor Div. - CIB

tcrozier
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Re: Fuel pump function...or lack thereof

Post by tcrozier » Thu Jul 12, 2018 7:49 pm

athawk11 wrote:
Wed Jul 11, 2018 7:59 pm
Well, it sounds like you're getting all the bases covered. One thing I learned the hard way is that it is important to polish the tongue/tang on the float...that contacts the fuel inlet needle. Any scratches, burrs, etc can cause the needle to get stuck. It's prone to scratches if one is a little aggressive whe setting the float level. Although, it's more common for it to get stuck in a way that causes the bowl to overflow.
Thank you, that's a good idea and if things don't get better quickly then re-checking my carb rebuild to include the float are a near term idea that's certainly possible. I can see where your suggestion makes really good sense, if it comes to tearing it down then a good polish is in order!
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Re: Fuel pump function...or lack thereof

Post by tcrozier » Thu Jul 12, 2018 7:52 pm

artificer wrote:
Wed Jul 11, 2018 8:03 pm
Go to HF & spend $14 on a fuel pump vacuum pressure gauge....https://www.harborfreight.com/fuel-pump ... 62637.html
This inexpensive tool can be used for check fuel pumps, engine condition, tune & timing. Indispensable on these old vehicles in diagnostics & eliminating good stuff to find the bad.
I looked this one up, thank you for the link, I like tools and have yet to acquire two of everything :( ...this one will follow me home before week's end!
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Re: Fuel pump function...or lack thereof

Post by tcrozier » Thu Jul 12, 2018 8:06 pm

Scoutpilot wrote:
Thu Jul 12, 2018 3:16 am
To add to Artificer's suggestion, locate and purchase a good Dwell/Tachometer.
Aluminum distributor contacts do not pass the amperage required for a decent, bright blue-white spark. Brass does. "Resistor"-type plug wires have a carbon core which will not pass the amperage required for a decent, bright blue-white spark. Copper core wire does. You don't want resistor wires unless you are an avid AM Radio listener. A spark plug emitting a less-than decent, bright blue-white spark is more susceptible to fouling which further degrades performance. If your timing is set dead nuts on 5º BTDC you may need to advance it to accommodate the modern fuel. 5º is perfect for 67 Octane fuel. You're likely running 87 Octane. In which case 5º is too late for a complete burn. The higher the octane rating, the slower the burn rate. Slightly retarded timing will lead to carbon fouling in the cylinder due to incomplete burning. If you wish, I can send you a link to a video that shows exactly how to perform an often overlooked final stage of a complete tuneup.
This is a great tool! I did a little reading and then looking for one on the interwebs, this is a fantastic tool! This one has great reviews, Actron CP7605 Dwell/Tachometer/Voltmeter Analyzer. Would you agree with that? I will definitely source one before the weekend is out. I found that the local Napa also has the condenser, brass contact distributor cap and copper core plug wires, I will be picking them up tomorrow. I really appreciate the insight with regards to the fuel differences and yes, I am burning the real 87 octane go go juice. I don't yet know what the timing is set to but I will check it and can already agree that I have seen evidence of what I had originally thought was a too rich air/fuel mix but now believe could be the poor burn you referenced above. I would love to get that link, I thought I already knew everything but my wife set me straight right before I went to bragging about it to my buddies. Anybody know jack? My wife said I didn't know him... :lol:
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Re: Fuel pump function...or lack thereof

Post by tcrozier » Thu Jul 12, 2018 8:11 pm

You guys are amazing! Thank you so much for the feedback, I have an overwhelming feeling of certainty that I am going to whip this thing with your collective help! Very sorry for the late reply tonight, got caught up replacing a starter on one of the kids' rice burner cars tonight...dad-burned Hondas, taking away from my little jeep money pile! lol

Respectively,
Thomas
1952 M38 - restoring


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Re: Fuel pump function...or lack thereof

Post by tcrozier » Thu Jul 12, 2018 8:12 pm

Wolfman wrote:
Thu Jul 12, 2018 7:03 am
Condensers are nothing more than an electrical storage device.
When the points are closed, current is flowing through the coil primary to ground through the closed points.
When the points break, the momentum of the flowing electricity does not want to stop, so, with no place else to go, there would be a lot of arcing at the points, which would quickly burn them. The arcing would also give an erratic, weak spark out the coil secondary. This is bad.
Enter the condenser. When the points break, a condenser gives the electrical energy flowing some place to go. The condenser stores it until the points close again and then the condenser discharges and waits for the next cycle.
When a condenser goes bad, it may be shorted. This would kill the ignition and can be checked with an Ohm meter. Or, it's ability to store energy may be reduced, resulting in a weak spark. Not so easy to test. You need a tester to check the later. The tester checks the condenser's storage ability and the break down voltage. In this case, the condenser may store some energy but short out at a lower capacity than it is rated for. This is harder to check. The condenser will not test shorted with an Ohm meter, but you will still have a weak, erratic spark.
Best way to deal with a suspect condenser is replace it. See what happens. A lot cheaper than the tester, unless you test condensers on a daily basis.
Thank you, I really had no idea what the condenser did but the local Napa has a replacement on the shelf, it's getting replaced tomorrow!
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Re: Fuel pump function...or lack thereof

Post by Scoutpilot » Fri Jul 13, 2018 3:00 am

'70-'71 'A' Batt., 377th FA, 101AB
(Slicks and LOH's)(Col's LOH Pilot)
'71-72 CHARLIE TROOP,
16TH AIR CAV, 1ST AVN BDE (AEROSCOUTS)
LOW LEVEL HELL.
'46 CJ2A
'47 CJ2A
'48 CJ2A
'48 B1PW126
'69 CJ5

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Re: Fuel pump function...or lack thereof

Post by tcrozier » Sat Jul 14, 2018 5:24 pm

Thank you, I think that even I can follow that! I ordered the Actron CP7605 Dwell/Tach/Volt Meter Tester yesterday, could only find it used but here's hoping it's in decent shape. Replaced the distributor cap today, and will try to source new copper core plug wires this week, while I try and patiently wait for the dwell/tach meter to arrive.

Thank you again to all the info you guys have collectively provided, I hope to report the all clear by week's end, fingers crossed! Best part is of course I am learning some really good old school engine skills.

Regards,
Thomas
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Re: Fuel pump function...or lack thereof

Post by Ben Dover » Sun Jul 15, 2018 5:16 am

Still curious, did you remove the glass fuel pump bowl?
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
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Re: Fuel pump function...or lack thereof

Post by tcrozier » Sun Jul 15, 2018 7:28 pm

artificer wrote:
Sat Jul 14, 2018 10:58 pm
Thanks for the positive feedback. It is most welcome & why some are always trying to help

It is really great that some really practiced old time mechanics, Scoutpilot, Mike et al can now comment without getting continually rubbished by recently minted experts, with little hands on experience & can't respond for fear of being continually rubbished by amateurs or worse banned.

All mechanics have & hobbyists should have the following simple, inexpensive tools that help one quickly diagnose.
This alleviates time wasting & THEIR money on replacing good parts with sometimes inferior NEW parts.
1. Pressure vacuum gauge
2. Auto multimeter [dwell/tach/ohm/volt etc.]
3. Trouble light.

Thanks Scoutpilot & Mike!
Now we can really help folk without a lot of uneccessary static currently being peddled on another BAIT thread started by guess who?.
If anyone wishes to listen, learn & absorb we can realy help them. JG.
You're welcome, it was due and deserving and yes sir, preach on!! To heck with the nay-sayers, momma said say something nice or hold your tongue (I cleaned that up a bunch :lol: )
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Re: Fuel pump function...or lack thereof

Post by tcrozier » Sun Jul 15, 2018 7:40 pm

Ben Dover wrote:
Sun Jul 15, 2018 5:16 am
Still curious, did you remove the glass fuel pump bowl?
uh oh, busted. I did but in my defense I had previously removed it in the 4 yrs that I've owned it :-|. When I first acquired this I had to clean the entire fuel system from tank to pre-carb inline filter. I had quickly discovered that the sending unit and pick up in the tank were extremely rusty, so much so that the fuel filter had become completely stopped up in the first few weeks of ownership. A bodyshop guy built me a really nice stainless steel tank that looks quite original, still have to replace the sending unit though, in the meantime a clean 12" piece of wood dowel makes a great fuel gauge, lol.

Thank you for asking. I also need to post that I do have around 4 psi of fuel pressure at the carb, it had been previously suggested that I ascertain this number.

I'm pretty excited about getting the dwell/tach by week's end too, it'll be hard to keep my hands off the jeep until then!
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Re: Fuel pump function...or lack thereof

Post by Wolfman » Mon Jul 16, 2018 5:55 am

:shock: Stainless steel !
Bet that was a pricy piece.
Using a stick to check the fuel level isn't new. Farmers been doing that for years. 8)
Mike Wolford
CJ-2A
VEP GPW
Comm./Inst. SEL
AOPA ( 44 yrs)
EAA ( 44 yrs)
4th Inf. Div. - 5th Inf. Div. - 2nd Armor Div. - CIB

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Re: Fuel pump function...or lack thereof

Post by artificer » Mon Jul 16, 2018 6:08 pm

Not thread relevant but of interest.
Our Army Issued Landrovers in the 60's had a dash fuel gauge & a brass dip stick in the fuel tank/s accessed through a hole under the seat/s.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: Fuel pump function...or lack thereof

Post by Ben Dover » Mon Jul 16, 2018 6:41 pm

Many Army Drivers of the various class MV's acquired the habit of sticking or visually looking into the fuel tank neck to confirm the fuel level.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
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Re: Fuel pump function...or lack thereof

Post by Scoutpilot » Tue Jul 17, 2018 3:37 am

Not a bad habit to get into. Takes seconds to accomplish just before sitting in the seat.
'70-'71 'A' Batt., 377th FA, 101AB
(Slicks and LOH's)(Col's LOH Pilot)
'71-72 CHARLIE TROOP,
16TH AIR CAV, 1ST AVN BDE (AEROSCOUTS)
LOW LEVEL HELL.
'46 CJ2A
'47 CJ2A
'48 CJ2A
'48 B1PW126
'69 CJ5

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