Pls help, fuel pump frustrations.

[BP68]

Hey all, I really needs some advice.

I have a 68 C10, running a 89 Suburban TBI bottom end with a comp cams camshaft (referred to as a 270 ?) Cast iron Vortec heads and Edelbrock 650 cfm thunder series avs carb and edelbrock intake.

My block was not bored thru for a mechanical fuel pump push rod, so I first went with a Jeg rotoray vane style pump with sep. regualtor. Set at approx. 5.5 psi. Pump was noisy but seemed to work. I have a blazer tank mounted in rear frame rails. Jegs pump was under cab in frame rail about center of door area. Just now getting truck road worthy. After doing some tuning and some WOT test, found pump seemed to be getting hot. Also seemed to be losing voltage. I installed a the fuel pump relay from the 89 suburban.
Pump started acting up again, found 12v and good ground into pump, but no pressure/flow. Pump seemed bad.

Did some reading and got a Master E8153 "canister" type pump. Rated at 13psi max for TBI application. I placed this pump at very rear of frame just forward of the crossmember where tank is mounted in frame rail. I think I read this pump is supposed to be better and self priming, since mounting below tank level is not really an option for me.

Everything seemed great, did some short test drives near work and made trip to gas station and lunch. Planned to drive home today.

Started her up, ran about 1 minute and shut off. Restarted and I was showing maybe 2 psi, then slowly dropped to nothing. I rechecked my ground connection, got truck running long enough to put on rack. Checked my relay, bypassed relay as test after truck died again. Had 12volts going into pump. Pump did not feel hot or like it was working at all. My battery is under the truck on frame, so I ran jumper wires straight from battery to pump power and ground wires. Nothing, no sound, no pressure, did not feel warm.

Everything seems to point to a bad pump. The new pump is about 2 weeks old with almost no run time. (two very short trips - which went fine) The old Jegs pump had been on there a few years, but until now the truck was only started and shut off, or moved short distances.

Just seems odd to me. Any advice. Yall agree it is prob. bad pump ?

Anything wrong with my mounting. Blazer tank is mounted to rear frame rails, with bed brace notched above for clearance. I have a vented cap as fars as I know, the filler vent is connected to the tank vent nearest the filler, the hole to the left of that is plugged and the vent on passenger side is open (planned to later get the motorcyle type vent that allows air in to prevent vacuum, but not out.) From there 3/8 rubber fuel line is feeding from sender to pump Maybe 1 1/2 ft of hose. Then rubber line from outlet of pump to 3/8 hard line to regulator on frame near right front of motor, then up a braided line to fuel filter (which is clean/clear) to carb.

From what I understand, guys run this pump on TBI conversions in a similar manner without issue???????????

[6772owner]

Im not sure on your exact situation, but when I swapped to a rear mounted tank (fuel cell) I had problems burning up an inline pump due to it being mounted too high. It ran really loud and wasnt happy for long.... I ended up lowering the pump to almost sump level and changing the feed line to 8AN (hardline to pre-filter, then pump, then 3/8" hardline out) Of course mine is a Walboro 255lph feeding up to about 60 psi for my LT1.

I would say you either have a feed issue to the pump, undersized feed or tank building vacuum. (???) Does the fuel level seem to affect it one way or the other? I had always planned (might still) to change to a Blazer tank and mod the stock sender to accept an intank pump. That is how the factory TBI blazer/burb set up is to my knowledge, that way the pump runs quiet, cool and almost always has fuel to draw.

Just my .02, hope it helps...

[BP68]

Originally Posted by 6772owner

Im not sure on your exact situation, but when I swapped to a rear mounted tank (fuel cell) I had problems burning up an inline pump due to it being mounted too high. It ran really loud and wasnt happy for long.... I ended up lowering the pump to almost sump level and changing the feed line to 8AN (hardline to pre-filter, then pump, then 3/8" hardline out) Of course mine is a Walboro 255lph feeding up to about 60 psi for my LT1.

I would say you either have a feed issue to the pump, undersized feed or tank building vacuum. (???) Does the fuel level seem to affect it one way or the other? I had always planned (might still) to change to a Blazer tank and mod the stock sender to accept an intank pump. That is how the factory TBI blazer/burb set up is to my knowledge, that way the pump runs quiet, cool and almost always has fuel to draw.

Just my .02, hope it helps...

Pump is pretty high, but right by tank. Feed is 3/8 rubber fuel line right off factory sending unit to pump. I don't think tank is building vacuum, because the right side vent tube on the tank is totally open right now.

[6772owner]

I would bet the 3/8" is big enough for your application and the sender is probably 3/8" anyway. Well if its not vacuum my only guess is that the pump is having a hard time drawing up the fuel, the inlines dont seem to like this much. They are designed to push fuel, not really to pull it, I understand that it is supposed to be self priming and didnt seem to run hot... Im just guessing at this because of what you have said (previous short trips and running loudly) You may just try to run the pump temporarily lower and see if it helps, but my only experience is with my bottom fed fuel cell. I dont know that lowering the pump will help since it still has to pull the fuel all the way up the sender from the bottom of the tank.

My only other thought, is the regulator a return style? Some pumps do not like "dead head" non-return style regulators. The pump might be pushing a lot more fuel than the engine can use and "locking" it up after it builds too much pressure? You might try a return style and run the return to that open vent you still have?

Just another thought.

[BP68]

ttt

[BP68]

So I got my warranty replacement E8153 and installed it today. Truck is back up and running. I let it sit and idle for around 30 mins to see what happened. So far so good.
Pressure never dropped out.
The first pump I got was in a Master box and had a label on the pump that said "made in Mexico"
The new one was in a Airtex box and said "made in USA"
It looks the same, but the mexico one had a slightly bent/misaligned outlet.
New one is nice and straight.

I hope this fixed my problem. Pump get a little warm, but never hot and never cut out.
Old pump just seemed to die, started truck cold, it ran about a minute and then shut off. Barely ran enough to get on rack and then it died and never buzzed or did anything, and pump body did not feel hot at all??????

Time will tell. If this pump fails, I may try to mod my sender to use a intank TBI pump from ac delco, and convert to a return style regulator.

[6772owner]

Well I hope that does the trick for you, I do know that my bro runs his truck with the external pump and a return style regulator with no problems to date. Good Luck!

[BP68]

Originally Posted by 6772owner

Well I hope that does the trick for you, I do know that my bro runs his truck with the external pump and a return style regulator with no problems to date. Good Luck!

Any pics of his setup? Does he have a blazer tank? And if so, where is the pump mounted?

thx

[6772owner]

I think I have some pics, but it is not a GM truck, it is a 54' F100 pick up with a custom fuel cell. He uses a holley pump, mounted on the frame near the front of the bed I believe.

So it is not a perfect model for you, but it was the only thing I had personal experience other than my own FI truck.

I can ask him what his exact set up parts are and get some pics if it will help you at all.

[paaw]

was having same problem with my pump pump was rated 5-7 lbs end up taking regulator off and works fine just pump and filter.