| johnmyron | -- 02-24-2014 @ 2:54 PM |
|
Had fuel pump issues with my freshly overhauled 53 Sunliner. Installed a 12V electric pump, and pressure regulator stright to a brand new Dennis Carpenter Carburetor.Idles great and run at speed ok but stuttere and seems to miss on acceleration. Fuel pressure regulator set at 3 psi. Could it be starving on acceleration, or flooding, or? lack of vacuum advance on distributor? Any thoughts?
|
|
| 40 Coupe | -- 02-24-2014 @ 3:05 PM |
|
3# is a bit too high, take the pressure down to 2.5 Max, 2# Nom.
|
|
| ken ct. | -- 02-24-2014 @ 3:54 PM |
|
Coupe is correct 2-2 1/2 is more like it. ken ct omo.
|
|
| supereal | -- 02-24-2014 @ 4:01 PM |
|
Stumbling on acceleration is often due to insufficient accelerator pump delivery. With the air cleaner off the car, look down the carb as you work the throttle with the engine off. You should see two ample jets of fuel. If your carb has an adjustable pump link. Put it in the longest stroke to see if the problem changes. Stumbling on acceleration is seldom due to high fuel pressure, but more often on low fuel level in the bowl. Be sure your float is at correct adjustment. Being new doesn't always mean it is correct.
|
|
| ford38v8 | -- 02-24-2014 @ 4:10 PM |
|
I'm sure my buddy Supereal meant to instruct to do that test with the engine off. Looking down the carburetor while pumping the accelerator can be like looking down the barrel of a gun even if the engine is running good. Alan
|
|
| Stroker | -- 02-24-2014 @ 4:22 PM |
|
Alan: Go back and read Super's instructions.
|
|
| johnmyron | -- 02-24-2014 @ 5:13 PM |
|
Will crank the pressure down and try it. So, if you are saying pressure is too high, the stumbline would be to flooding on acceleration? Checked accelerator pump delivery when I installed new carb and it looked ample. Thanks to all you who replied.
|
|
| johnmyron | -- 02-24-2014 @ 9:13 PM |
|
put fuel pressure down to 2 psi. adjusted accelerator pump linkage to longest stroke. No real change. Still seems to almost miss, or run rough on acceleration. What next?-pull the new carb apart and check the float level. These carbs are advertised as "Bench Tested." Again-idles great and runs smooth once you reach level speed. Original distributor worked fine and put it back in with a pertronix unit. Could it possibly be vaccum advance?
|
|
| ford38v8 | -- 02-24-2014 @ 9:15 PM |
|
Dan & Bob, A mistake on my part, for which I'm only too happy to apologize... Still much better than a face full of carburetor backfire from misreading the instructions as I had. Alan
|
|
| cliftford | -- 02-25-2014 @ 6:29 AM |
|
Given all of the above info, I would suspect the acceleration pump check valves. Cliftford
|
|
| supereal | -- 02-25-2014 @ 6:38 AM |
|
The reason I included that in my post was a vivid memory of having lost my eyebrows years ago when I worked as a mechanic st a Ford dealer. A local ice cream plant would bring in one of their trucks, often at the close of the day for repairs. Two of us would tackle the job. That day, it was my job to install points in the distributor of the six cylinder engine, while another pulled the carb. We didn't know that the service manager had killed the engine while pulling it into the stall, and forgot to turn off the ignition key. When I "bumped" the starter to recheck the point gap, it set off a spark that ignited the gas fumes under the hood and "poof", my eyebrows were trimmed!
|
|
| 40 Coupe | -- 02-25-2014 @ 6:38 AM |
|
It is possible the problem you experience is NOT fuel pump pressure related, but the pressure you related is too high. If lowering the pressure does not solve the stumble than keep the pressure between 2 to 2.5 and look elsewhere.
|
|
| ken ct. | -- 02-25-2014 @ 9:15 AM |
|
Did you use any Teflon tape on ANY of the gas connections??? ken ct.
|
|
| TomO | -- 02-25-2014 @ 10:11 AM |
|
Do you have the Pertronix unit in your distributor or a set of points? You may not be getting the correct advance with the Pertronix unit. Pull the distributor and have it set up on a distributor machine by someone who is experienced on the loadamatic distributor. Tom
|
|
| supereal | -- 02-25-2014 @ 2:20 PM |
|
Be sure you do have the correct carb. When Ford went to the vacuum only distributor, the carb tap is above the throttle plate, instead of straight manifold vacuum. A quick check with a timing light will give you a look at whether the advance is actually working. I've seen lots of problems with pointless conversions, and poor routing of the wiring below the plate that prevented full movement by the vac diaphragm. I'm with Tom on having it checked and set.
|
|
| Stroker | -- 02-25-2014 @ 4:38 PM |
|
Super's note is well advised. Some decades ago, the late great Barney Navarro emphasized this issue in a white paper on the "new Ford ignitions" Following is his quote: "Ford's latest method of controlling spark advance employees an ingenious system utilizing manifold vacuum and venturi vacuum. With this system the flyweight governor is eliminated and in its place is nothing but a diaphragm. This diaphragm not only advances the spark to conform to rpm changes but is also makes load compensation adjustments. All ´49 through ´54 Ford and Mercury carburetors have in addition to the conventional manifold vacuum takeoff, such as is found in the throttle body of most passenger car carburetors, a connecting venturi vacuum passage. The manifold vacuum, as usual, is obtained from a small port in the throttle body located slightly above the butterfly's closed, position, on the side where the butterfly swings upward to open. When the throttle is closed at idling, the vacuum port does not receive vacuum because it is on the opposite side of the butterfly. As the throttle is opened slightly, this port is uncovered and a vacuum is applied to the distributor diaphragm to advance the spark. If the throttle is fully depressed, the manifold vacuum is destroyed and no advance takes place. As speed increases, however, the venturi vacuum increases gradually and advances the spark to conform to the rpm. Letting up on the throttle increases the manifold vacuum (Provided it isn't let up all the way) and the spark receives load compensation. A balance is always maintained so that the correct amount of spark advance is supplied for all speed and load conditions".
|
|
| johnmyron | -- 02-25-2014 @ 10:05 PM |
|
Will check my wiring beneath the breaker plate to make sure the diaphragm can advance it fully. However, when I check it with a timing light and rev it, it advances quite a ways and without hesitation. I set the timing with a light as per the manual, with the vacuum line off the distributor. When I put the vacuum line on, however,the timing is 3-5 degrees advance via the light, at idle.Also speeds up the idle slightly.
|
|
| supereal | -- 02-28-2014 @ 10:45 AM |
|
If you haven't solved the problem as yet, one more thing to check: if the muffler is old, tap it with a hammer. If you get a "clunk", instead of a "clink", it may be full of carbon and is choking off the exhaust flow. Also, if your car has a "flipper" exhaust valve on the outlet side of the exhaust manifold, be sure it moves freely. A restricted exhaust will allow acceleration until if diminishes the flow, then as the force increases, will have less effect. I have seen mufflers so full of junk that they were very heavy.
|
|
| johnmyron | -- 03-02-2014 @ 5:01 PM |
|
Thanks, but have new glass packs and no heat riser valve
|
|
| johnmyron | -- 03-08-2014 @ 10:04 PM |
|
problem solved. To follow up on all your helpful suggestions, tried them all to no avail. Car seems to run rich as only neee the choke very briefly. Pulled a few plugs and found them carboned up, and suspected running too rich. Took the new Dennis carpenter carb apart and checked the float level. According to Ford measurements (which apparently have no meaning on this carb) the float was too low already making the carb lean. Lowered it some more and voila, the stumbling stopped, and acceleration is good. It was drowning not starving! How to optimize float level? Trial and error? exhaust gas analyzer?
|
|
| TomO | -- 03-09-2014 @ 8:25 AM |
|
To get the best fuel level, use a fuel level gauge that fits in one of the drain holes. If you do not have one available, run the engine and then take off the air horn and measure the distance between the gasket surface and the fuel. It should be between 23/32" and 25/32" with the rubber tip needle or the ball type valve and 21/32" - 23/32" with the steel needle valve. The rubber type valves are not as consistent as the steel valves in stopping the flow of gas, so the lower level works better. Tom
|
|
| johnmyron | -- 03-09-2014 @ 7:17 PM |
|
Thanks so much-exactly the kind of info I was looking for. Will do.
|
|
| johnmyron | -- 03-09-2014 @ 7:19 PM |
|
one other topic-many of the folks above are saying take the fuel pressure reg to 2 to 2.5 psi. Yet the shop manual states that when testing the conventional fuel pume, should show 3.5-4.5 psi at the carb inlet. Who is correct? Does it really make any diff? seems to run about the same at 2 or even 4 psi.
|
|
| johnmyron | -- 03-09-2014 @ 7:25 PM |
|
Will this measurement also work on the carb for my 47? Suspect it runs a bit rich as well, although not as much as the 53
|
|
| ken ct. | -- 03-09-2014 @ 9:53 PM |
|
I set all my floats on 94's at 1 7/16" upside down w/steel needles [no gasket] and 1/8" float drop right side up. OMO ken ct.
|
|
| TomO | -- 03-10-2014 @ 8:38 AM |
|
I use the shop manual for determining the correct fuel pressure. The needle valve can make a difference in how the fuel pressure affects fuel level. Most of the current ones will allow a pressure of up to 4 lbs. All of the 94 type carburetors have the same fuel level. I personally like to set the fuel level 1/32" lower because of the alcohol in the fuel. If the needle valve has rubber parts, I like to set the level 1/16" to 3/32" lower to compensate for the softer close. I made a float gauge out of 1" aluminum that sits flat on the housing. It has go and no go sides. The go side is 1.353" and the no go side is 1.322". I use it as is with the steel needle and use it with a new gasket if the needle valve contains rubber. Tom
|
|
| johnmyron | -- 03-10-2014 @ 9:49 AM |
|
Thanks Again-practical and useful info
|
|
| johnmyron | -- 03-13-2014 @ 9:19 AM |
|
USed your fuel level and go/nogo gauge information. Still seems to run better with a depth below gasket surface of 1" rather than 25/32. THis again is a Dennis Carpenter repro carb. Will it run too lean at this level and damage valves, etc? If it is too lean, will not run well, correct?
|
|
| TomO | -- 03-15-2014 @ 8:41 AM |
|
A fuel level that is too low will show up in turns and at high speeds as fuel starvation. The mixture will be very close to normal under slow straight driving. The readings that I gave you are done while the engine is running. The engine stopped measurements can be lower. If you are concerned about running lean, check your spark plugs after running the car for a sustained period at highway speed. Here is a link to a chart for reading spark plugs. http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp?mode=nml Tom
|
|
| EFV-8 Club Forum : | https://www.earlyfordv8.org/forum |
| Topic: | https://www.earlyfordv8.org/forum/viewmessages.cfm?Forum=18&Topic=7062 |