Mechanical Fuel Pump Pressure @ 3lb: Push Rod? Bad Pump?

[Johnnys440Charger]

Hi all,

I have a 69 440 Charger with a Holley 650 (4777) carb, my fuel pressure reading is 3 lbs.  I have measured this with my liquid filled fuel pressure gauge and also separate gauge to verify its accuracy.  The 3 lbs reading occurs at idle or reving.

I am going to be changing the fuel filter first to rule out, and possible purchasing a new mechanical fuel pump down the road. 

But I am looking to find out more information about the fuel pump push rod and how this works.  Does it wear?  Does it adjust?

I am thinking about purchasing the Carter CRT-M4589 fuel pump over the Holley HLY-12-440-11.

[Ghoste]

It's not adjustable and there should be a number of threads talking about it.  If you remove the fuel pump, just below it's mounting hole in the block, you will see a pipe plug.  Remove the pipe plug and you will gain access to the pushrod.  A new one is part number P5249569 from your Dodge dealer and your old should be 3.25 inches long.  Shorter than this means it is worn.

[gojo64]

Most likely you have a worn push rod. There was a bad batch of these made & they wear out easily. I had the same thing happen & it was the push rod. Make sure you change the oil & oil filter. If you are planning on a new mechanical pump, stay away from Carter, they are junk. I got a bad one right out of the box. I put a new push rod in, a new stock mechanical fuel pump, & changed the oil & filter. I also put a new Mallory electric pump on as back up & to prime the system upon initial start up, works perfectly now.

[Ghoste]

When did you buy that Carter pump?  I've had a few and they've all been good.  In fact the one on my car right now is a Carter that I bought about five years ago.

[firefighter3931]

I've had very good luck with Carter pumps....sorry to hear of the problems. 



Ron

[BrianShaughnessy]

Do you got a factory type vapor separator on it?    I bought a repro awhile back and there's supposed to be a restriction in the 1/4" return line but there wasn't.   

[Johnnys440Charger]

Cool.  So I gather that a worn push rod can cause lower fuel pressure.

To remove the push rod, its not a nut but i'll need an Allen Key, correct?

If I remove the fuel pump, then the push rod, will engine oil start pouring out?  Should I drain the oil first?

[Ghoste]

Fuel pump first, then pushrod, no oil will leak out.   Although you may invent a few new curse words on this easy two bolt-one Allen screw plug job. 

[471_Magnum]

If I remove the fuel pump, then the push rod, will engine oil start pouring out?

Only if you've got about 10 quarts  in the crank case!

Should I drain the oil first?

You will want to drain the oil at some point. When a pushrod goes, it deposits quite a bit of metal into the oil.

[Ghoste]

Don't laugh, at a dealership I once worked at, a novice lube guy filled the crankcase to the top of the valve covers. 

[Johnnys440Charger]

Some pics...

[Johnnys440Charger]

More pics...

[Steve P.]

Don't laugh, at a dealership I once worked at, a novice lube guy filled the crankcase to the top of the valve covers. 

I ran the Auto Hobby Shop on base years ago and had a guy do the same thing.. While I was standing in the tool shack talking to another guy I noticed this guy tossing the empty quart bottles into the garbage can. After about the 8th one (THAT I NOTICED), I yelled over to him, ( how many quarts have you put in that motor?). He started counting the quarts left in the CASE!!!!  Oh shit!!!!!!!!!!!!!!!!!!!    
He thought it was supposed to come up to the fill cap..

Shortly after that we made a sing reading, (IF YOU ARE NOT SURE, ASK).....  We hung them everywhere...

[Steve P.]

If you are planning on a new mechanical pump, stay away from Carter, they are junk. I got a bad one right out of the box.   

One bad anything that is built in mass quantities is not all junk. I have used Carter pumps on hundreds of cars over the years and never come across a bad one. Not one just out of the box anyway.  I have replaced a few  old ones..

[rt green]

you said you checked the pressure with another gauge to be sure. was the 2nd gauge liquid also? when liquid gauges get hot, they lie.

[firefighter3931]

Based on those pics the pump and pushrod should be swapped out. The pushrod is showing some wear and the pump has seen better days. The Carter HV street pump will give you 6-8 psi and 120 gph flow.....more than enough for any engine making less than 600hp. 

Fwiw, the pump in your pic is a stock replacement unit which flows ~40 gph. The fuel pump rod should measure 3.25in and it does not....it's worn down.



Ron

[Johnnys440Charger]

Based on those pics the pump and pushrod should be swapped out. The pushrod is showing some wear and the pump has seen better days. The Carter HV street pump will give you 6-8 psi and 120 gph flow.....more than enough for any engine making less than 600hp. 
Fwiw, the pump in your pic is a stock replacement unit which flows ~40 gph. The fuel pump rod should measure 3.25in and it does not....it's worn down.
Ron

Here are some better pics.  I'm swapping out the Fuel Pump For Sure!
PartSoruce quoted me $ 40.99+tax (canadian) for the Carter M4589 model and for the HP version M4434 $47.18+tax.  Although, I cannot find any specs/pics for this M4434 model.

you said you checked the pressure with another gauge to be sure. was the 2nd gauge liquid also? when liquid gauges get hot, they lie.

The second gauge was a not liquid filled.  It was a fuel pressure/vacuum gauge.  Same results under cold and hot conditions with both gauges.

[firefighter3931]

The M4589 looks like a nice hi-flow version of the stock pump. 

See link :

http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_159020_-1

That is a better pic of the pushrod. Looking at it from that angle it doesn't look to be worn down significantly. I would re-use it based on your latest pictures. 



Ron

[Johnnys440Charger]

Bought this one.  Apparently its more expensive than the M4589.  Will let you guys know.

[jg68]

I bought the M4845 (70 440 HP) Carter, so far, so good.