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Rob B · 08-28-2002, 08:20 AM

Begining of the month I replaced Fuel pump, filter, regulator and lines to the carb. Installed a MAL Comp140 pump and regulator and is 100% 1/2 line all the way to the float bowls. Everything was fine until last night. Pressure was previously set at 6.5psi and stayed there until then. Went for a short drive and now the guage drops down to 2-3 psi then jumps up to 10-12 psi and basically is going haywire! If you stand on the gas just a little, it will level out around 5-6psi. Even when it shows 10-12 psi, I would think the needle and seat would let go and flood the carb but that doesn't happen. I am going to pull the regulator off and check/clean it to see if that is where the problem is. Anybody had this happen to them before? Suggestions?

Rob B · 08-28-2002, 11:58 AM

No spikes, voltage guage is steady and Pump is wired to a relay that is wired direct to the battery.

Pressure will bounce around sitting still in the garage.
Pump is mounted about 1" lower than sump on tank and tank is a 1/3 full but I will fill it up just to make sure it isn't sloshing. Fuel slosh was never a problem before.
Now that I remember, At Norwalk, it seemed I had to keep readjusting the regulator on Sunday because it would be at 6psi steady then next time I'd start it up/run, it would drop down to 4.5-5psi but was not jumping all around like it is now.

Rob B · 09-01-2002, 08:14 AM

No return line style regulator.
Problem is still there. After the first time run, pressure started bouncing all over the place and never stopped afterward.
I can start out doing my burn out and stage with it at 6-8psi bouncing and by the time I'm at the end of the track it bouncing between 12psi and bottoming out on the guage trying to overflow the bowls.tried re-adjusting it with no success

Scott E.
If your reading, I'll call you on Tuesday.

Rob B · 08-28-2002, 08:20 AM

Begining of the month I replaced Fuel pump, filter, regulator and lines to the carb. Installed a MAL Comp140 pump and regulator and is 100% 1/2 line all the way to the float bowls. Everything was fine until last night. Pressure was previously set at 6.5psi and stayed there until then. Went for a short drive and now the guage drops down to 2-3 psi then jumps up to 10-12 psi and basically is going haywire! If you stand on the gas just a little, it will level out around 5-6psi. Even when it shows 10-12 psi, I would think the needle and seat would let go and flood the carb but that doesn't happen. I am going to pull the regulator off and check/clean it to see if that is where the problem is. Anybody had this happen to them before? Suggestions?

Half-Inch Stud · 08-28-2002, 12:17 PM

...difficult to have spikes in power when there is a 3Joule 12 Volt Lead-Acid capacitor on one end.

all_ryze · 08-28-2002, 08:34 AM

Rob,
Do you have a filter between the tank and pump?
I've seen dirt get into the impeller of the pump and do weird things!

SCOTT ESTERLE · 08-28-2002, 03:30 PM

Give me a call.

Rob B · 08-28-2002, 08:40 AM

Yeah, There is a good (new) filter between the tank and pump.

Taff · 08-28-2002, 05:06 PM

Faulty fuel pressure guage maybe? Try another before you strip the system.

SCOTT ESTERLE · 08-28-2002, 10:24 AM

Check the reg.

oneace · 08-28-2002, 09:46 PM

i'd go with taff and check the gauge. are you having driveability trouble also or is performance the same as it has been?

all_ryze · 08-28-2002, 10:53 AM

Bad ground or loose wire at the pump?????

Rob B · 08-29-2002, 08:10 AM

Took the regulator apart last night, cleaned it, put it back on and appears to be better. Didn't find or see anything odd or inside of it so who knows! The pressure now varies between a half a psi to sometime 1psi instead of bouncing all over the place. I can live with that (I think).

I don't think it is the guage because I never had a problem with it before with my old set-up and everything was replaced (pump, reg., filter, etc.) except for that.

Scott E.,
If you are reading this, I will see what happens with it over the weekend, If it doesn't go crazy again then I guess it will be okay. If it does, I'll get a hold of you on Tuesday and we'll figure something out. Thanks for the help.

Rob B · 08-28-2002, 11:32 AM

No, bad ground or loose wire. Pump Is wired direct to the battery (10GA) with a relay.
Scott,
I purchased all of the stuff through you at Summit back at the end of July/1st of August (cust#4429475?)
What's involved in replacing the regulator? Since it Came with the pump, will I need to ship them both back or just the reg by itself? could I have another reg sent to me then send back my defective one in that box? Would like to get it straightened out for this weekend. Should I call you instead of playing message tag?

SCOTT ESTERLE · 08-29-2002, 10:32 AM

No problem Rob let me know. I know Mallory used to say a 1psi fluctuation was acceptable with there check ball type regs but i don't know with the diaphram style.

Goatman · 08-28-2002, 11:36 AM

Sounds like you have a spike in your current. ALWAYS run a relay between your pump and power source. That will smooth things out a bit.

dutch injun · 08-29-2002, 03:55 PM

Do you have a deadhead regulator? I had one and had pressure fluctuations. I now run a return style regulator, and it's much better now. I do have my pump in the trunk, not ideal, and had pressure decrease on heavy accelleration, that's gone now, pump runs quieter also.

Roger C · 08-28-2002, 11:43 AM

Anyone thought of Fuel Slosh in the tank?Is the pump mounted above or below the pick up?were you at a full tank or lower..
Later,
Roger

KS circutguy · 08-29-2002, 11:13 PM

Return line?

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