Sputtering, Hesitating, stalling

junkpile · Jul 29, 2019

I have a stupid question. 440 +0.30 over 484/284 cam. Considering I have recieved help on everything with my carb and ignition, and have corrected and fixed issues with timing and carb flow ( metering rods, step up springs, and accelerator pump nozzels) and all has improved the car greatly . I have an issue when car is fully warmed up, sometimes it will sputter, hesitate and even stall when pulling into traffic from a side street. Now this is driving me crazy because the car runs perfect everwhere else in the spectrum.

So the thought hit me, could the mechanical fuel pump have an issue where its not supplying enough gas for this acceleration but still working normally otherwise? like a warning of pump going south. Its the only thing in the system not changed, its the higher volume carter pump (as my son called it the "flying saucer). I have read somewhere that a bad pump could cause this issue but never heard of it before.

Anyone have any thoughts

Dennis H · Jul 29, 2019

Engine temp with IFR when this happens?

junkpile · Jul 29, 2019

alright I don't want to seem stupid, but what does "IFR" stand for?

My engine temp in traffic is no higher that 200, typically running is between 180-190 depends on back roads or highway.

Dennis H · Jul 29, 2019

Sorry. Temperature gun not relying on factory gauge.

68 Sport Satellite · Jul 29, 2019

I had that happen due to two separate reasons: fuel vapor lock when the fuel boils and the motor won’t run right and another time after motor warm the coil was going bad and when it got too hot from idle to low rpm it would sputter then if I applied half throttle it would smooth out. I had just changed the coil the month before. I moved the coil location and made sure not close to anything else it could radiate heat from and got a duplicate of the old coil and all was happy.

crash89 · Jul 29, 2019

I had a similar issue last year.. Mine wasn't the pump, but the rod between the cam eccentric and the fuel pump. It had worn down. Drove me nuts trying to find the issue. Only happened when warmed up for me. When cold, it would run normally (at least in the beginning). Hope this helps.

junkpile · Jul 29, 2019

The coil suggestion is great, mine is till in factory location on the motor. So i will test that.

The rod between the cam and pump never occured to me. I could try that as well. Who sells the Rod?

Dennis H · Jul 29, 2019

Is heat an issue? After 203-205, mine got weird. Unhappy.

junkpile · Jul 29, 2019

My engine temp in traffic is no higher that 200, typically running is between 180-190 depends on back roads or highway.

RJRENTON · Jul 29, 2019

Junkpile,
You mentioned that you had experimented with "metering rods and step-up springs and accelerator pump discharge nozzles". Judging by your referral you MUST have an Edlebrock (aka "Eddy") / Weber OR perhaps an original CARTER carb. But have you looked at the accelerator pump stroke and linkage position? These adjustments affect the when and how much fuel is delivered during off idle to when the main fuel system starts to deliver fuel.
IF you have an original CARTER carb, the later versions of the carb had an off idle stumble due to the lean condition of the off idle transfer circuit, which was factory adjusted and sealed. This condition is readily fixed by a simple readjustment to eliminate this lean condition. Most self-proclaimed "experts" are unaware of this adjustment and do not understand how it functions. The idle fuel and off idle transition circuit is NOT controlled by the jets, rods or step up pistons and springs but rather in the primary venturii nozzle assemblies and the fixed fuel feed orifices and air bleeds in the emulsion tubes in these removable assemblies, which provide the fuel air mix to the drilled passages in the carb's body.
Are these items a possible cause of your issues? Yes. Are there other possible sources...? Yes. It is highly unlikely that it is the fuel pump push rod or pump cam lobe is at fault. Possibly the coil is at fault...easy to change to confirm. Possibly the percentage of ethanol in the fuel composition due to its vapor pressure and heating value (higher percentage of ethanol generally means more fuel must be added to the engine).
Bear in mind that Edlebrock (Eddys) carbs use 2 step metering rods and step up pistons therefore the calibration points and operation are different than the original CARTER carb. The two methods can be interchanged with discretion providing you recognize the difference.
Depending on your ignition system, electronic or points, may also be contributing to the issue as well.
These are just my opinions of course, others will probably disagree.
Bob Renton

Dennis H · Jul 29, 2019

Boiling point for ethanol is 173.1 F. Even if our cars are running perfect, it is hard to overcome today’s fuels.

junkpile · Jul 29, 2019

yes the carb is an EDDY. I have a 750. with the .043 accelerator pump nozzel, Pink step up springs ( can only go tthe the silver to hold it rich a little longer during WOT) Everything with it works right. It has been adjusted so its not running lean (.071 x.030 metering rods thru the .010 jet) Timing is spot on 12 degree initial 36 total. the only thing not changed is the fuel pump and now I have a lead on the push rod which may not be allowing the pump to operate fully. I was actually so frustrated with problem last year that i was going to pull the motor and look for a nice stock 440 and scrap the one I have. Right now trying a 20 buck pushrod seems like something to give a try.

As for fuel, I have been running either 90 octane pump gas, ethnol free 92 octane with 104 octane booster.

junkpile · Jul 29, 2019

OH forgot, electronic ignition with orange box. box is new as of last year, same with distributor. New plugs and wires, and new fuel filter.

RJRENTON · Jul 29, 2019

JP,
If you are going to replace the pump's push rod, change the pump as well. Remember, if you think you have a fuel starvation ptoblem, it will usually manifest itself at full throttle, say at the end of a 1/4 mile contest or climbing a long hill, not at idle. Starvation is a VOLUME issue not pressure issue or a line size issue. The pump's internal spring determines the delivery pressure, the diameter of the pumping diaphragm will determine its volume AND the pump's operating stroke is determined by the cam's lobe. Yes.....this may be the problem....but not likely. Just my opinion of course.
Bob Renton

RJRENTON · Jul 29, 2019

Dennis H said:
Boiling point for ethanol is 173.1 F. Even if our cars are running perfect, it is hard to overcome today’s fuels.

Yes...you are correct.....but today's fuel are a blend of ethanol plus gasoline and the fuel's boiling point or fuel's VAPOR PRESSURE is determined by the percentage of the lowest boiling point component of the blended mixture. Different suppliers may supply a different composition of their fuels. Usually, slightly richer mixture will fix the problem.
Bob Renton

RJRENTON · Jul 29, 2019

junkpile said:
yes the carb is an EDDY. I have a 750. with the .043 accelerator pump nozzel, Pink step up springs ( can only go tthe the silver to hold it rich a little longer during WOT) Everything with it works right. It has been adjusted so its not running lean (.071 x.030 metering rods thru the .010 jet) Timing is spot on 12 degree initial 36 total. the only thing not changed is the fuel pump and now I have a lead on the push rod which may not be allowing the pump to operate fully. I was actually so frustrated with problem last year that i was going to pull the motor and look for a nice stock 440 and scrap the one I have. Right now trying a 20 buck pushrod seems like something to give a try.

Why not...for $20????...what a deal... I think you meant to say the primary jet is 0.100" diameter not 0.010". Remember to compare effective AREA of the rod diameter and jet diameter not just diameters. Area = radius squared x Pi (3.14259) then subtract the dimensions to get the EFFECTIVE area of the jet and rod relationship for the best accuracy.
Just remember to put the push rod in with the SPHERICAL end to the cam. Grease up that end and insert it thru the hole provided below the pumps mounting boss...use a new gasket...the grease will jokd the rod in place while you mount the pump. Others may have other ideas.
Bob Renton

As for fuel, I have been running either 90 octane pump gas, ethnol free 92 octane with 104 octane booster.

junkpile · Jul 30, 2019

What pump do you recommend? I am looking at a carter 8-9.5 psi for 440. that is what I have used for over 10 years.
I dont know much about edelbrock version but its flow rate is up to 6 psi.

RJRENTON · Jul 30, 2019

junkpile said:
What pump do you recommend? I am looking at a carter 8-9.5 psi for 440. that is what I have used for over 10 years.
I dont know much about edelbrock version but its flow rate is up to 6 psi.

JP,
Suggest the Carter pump based on your prior experience. REMEMBER, if fuel starvation is your underlying consideration, consider the VOLUME capabilities of the pump. Pressure and volume are not the same thing. Pressure is stated as PSI, pounds per square inch and Volume is stated as gallons per minute or pounds per hour. Too much pressure will result in leakage at the carbs needle and seat. Many people install a regulator to reduce the pressure instead of just buying the correct pump. Higher pressure is not better. The stock Mopar pump will provide the correct volume at the optimal pressure. A 750 CFM Edlebrock carb will be more than satisfied with the stock pump. OR use the Carter pump that was standard equipment on the HEMI, and it handled the two Carter AFB's just fine. It will fit and function correctly. I'm sure that others will have their own opinions and preferences.
Bob Renton

khryslerkid · Jul 30, 2019

If you have the blue accelerator pump, get rid of it. Use the 1467 instead. The blue one that came in the rebuild kit didn't last 100 miles.

Use a phenolic carb spacer to dissipate heat. Blocking off the crossover passage in the manifold really helps also.

3.220 is what your fuel pump push rod should measure. Use this one if you have a regular cam, not for a roller cam.

junkpile · Jul 31, 2019

o.k. thank you all for the advise.

one more question coming. I am running the Eddy 750 on this 30 over 440 with a 484/284 cam and have run this fuel pump for years. Would you suggest using the Eddy fuel pump that flow 110 gph at 6psi max or the Carter that flow 120 gph but has a range of 6.9-9.5?

I definately dont want too much pressure, just volume. Carter has a super street pump that is rated at 120 gpm at 5.5-6.5 but I see no listing for use with a 440.

Sputtering, Hesitating, stalling

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