Car: 98 GT
Issue: Fuel pump replacement
This post is a bit lengthy but I'm trying to get it all on the table in one shot so I'm not leaving holes.
I have done a lot of searching and I can't seem to find the details I'm looking for as far as voltage for the fuel pump. I have been blessed with the 98 gt blues and I'm at a crossroad with the fuel pump. I have searched several forums without finding the info I need other than what seems to be vague he said, she said stuff.
The pump needs to be replaced but I'm uncertain on which route to go considering that the car is a 98. It has the return style fuel system with variable speed/voltage pump. The problem is I can't find specs on the correct voltage.
I ran a meter on the pump circuit while driving the car through various conditions. To my surprise, I found a very small voltage difference. The car idles, cruises, and WOT at 12.5 volts and then it goes to 13.8 volts at any throttle position or load above 4200ish rpm. It seems to be strictly rpm based which seems odd to me. I'm familiar with other makes that use variable voltage systems but they normally see 9 volts at partial and then 13 at WOT. I find it very odd and useless to only use a 1 volt variance.
The circuit is simple. Battery power runs to the fuel pump relay in the ccrm from the fuse box, then to the next fuel pump relay with the resistor between the two relays, and then from that fuel pump relay to the fuel pump.
I was thinking that someone may have changed or tampered with the resistor but this car is bone stock from the exhaust to the airbox.
Long story short, is the 12.5 volts the correct voltage below the 4200 rpm?
Can the resistor be bypassed to feed constant power on the 98 drop in pumps with out burning the pump up? I would think that it would be safe considering it runs 12.5 volts constant but I'm not sure if the variable speed pumps in the 98 can handle the constant 13.8 volt current. I can't find any solid info on this subject.
I would rather have the constant voltage for the sake of simplicity and diag in the future. It's just one less variable when trouble shooting and tuning a car in my opinion.
My last concern is the 98 basket style assembly. I've read several comments that the basket isn't capable of filling before a aftermarket pump can drain it. The problem is nobody is specifically saying what type of power or injector size where this happens. Doesn't the return line also feed the basket like other makes? The car turns as well so long sweepers are a concern.
If the pump can't be hard wired to constant 13 volts and the basket is a problem than I suppose the only logical solution would be to convert to the 97 style tank and assembly. I'm trying to avoid that to a degree because I'll have to buy the hanger, sending unit, find a pigtail for the sending unit, along with the tank and pump.
Issue: Fuel pump replacement
This post is a bit lengthy but I'm trying to get it all on the table in one shot so I'm not leaving holes.
I have done a lot of searching and I can't seem to find the details I'm looking for as far as voltage for the fuel pump. I have been blessed with the 98 gt blues and I'm at a crossroad with the fuel pump. I have searched several forums without finding the info I need other than what seems to be vague he said, she said stuff.
The pump needs to be replaced but I'm uncertain on which route to go considering that the car is a 98. It has the return style fuel system with variable speed/voltage pump. The problem is I can't find specs on the correct voltage.
I ran a meter on the pump circuit while driving the car through various conditions. To my surprise, I found a very small voltage difference. The car idles, cruises, and WOT at 12.5 volts and then it goes to 13.8 volts at any throttle position or load above 4200ish rpm. It seems to be strictly rpm based which seems odd to me. I'm familiar with other makes that use variable voltage systems but they normally see 9 volts at partial and then 13 at WOT. I find it very odd and useless to only use a 1 volt variance.
The circuit is simple. Battery power runs to the fuel pump relay in the ccrm from the fuse box, then to the next fuel pump relay with the resistor between the two relays, and then from that fuel pump relay to the fuel pump.
I was thinking that someone may have changed or tampered with the resistor but this car is bone stock from the exhaust to the airbox.
Long story short, is the 12.5 volts the correct voltage below the 4200 rpm?
Can the resistor be bypassed to feed constant power on the 98 drop in pumps with out burning the pump up? I would think that it would be safe considering it runs 12.5 volts constant but I'm not sure if the variable speed pumps in the 98 can handle the constant 13.8 volt current. I can't find any solid info on this subject.
I would rather have the constant voltage for the sake of simplicity and diag in the future. It's just one less variable when trouble shooting and tuning a car in my opinion.
My last concern is the 98 basket style assembly. I've read several comments that the basket isn't capable of filling before a aftermarket pump can drain it. The problem is nobody is specifically saying what type of power or injector size where this happens. Doesn't the return line also feed the basket like other makes? The car turns as well so long sweepers are a concern.
If the pump can't be hard wired to constant 13 volts and the basket is a problem than I suppose the only logical solution would be to convert to the 97 style tank and assembly. I'm trying to avoid that to a degree because I'll have to buy the hanger, sending unit, find a pigtail for the sending unit, along with the tank and pump.