- Joined
- Nov 30, 2009
Good catch Chuck , I didn't see the green part of that connector. Should be grey wire , black connector.
fuel pump not getting power
- Thread starter garrett
- Start date
gunzandgearz
gearzandgunz
- Joined
- Aug 24, 2015
Time for a voltage drop test,very first test is to check for power at or as close to pump as possible not maybe I do or maybe I don't.check for power with a meter, if you have its probably a pump, if you don't start backtracking with a schematic until you find youre voltage and then you can isolate the circuit between where you have voltage and where you don't.good luck.
That would tell you if all the wiring is OK from motor compartment back . As in no bad grounds & poor connections or open connections . You got to start somewhere and eliminate things before changing out parts . I do this everyday at work .
I'm embarrassed to say that I've been away from the Buicks for several years. Today I decided To take another look at the problem. Starting with a well charged battery, I made the jumper wire to go directly from the battery, to the grey wire /black plug at the back of the alternator. The one that you can hook up to turn the fuel pump on. I cranked the starter for 30 seconds to build up oil pressure. Going directly from the battery, to the grey wire with a black plug, nothing happened. I do have power on the orange ECM wire going all the way back to the ECM. I also made a jumper wire to go from the middle of the relay pin to the solo pin on the bottom. That yielded no results either. I don't have power at the middle pin of the relay plug. Only on the far right pin. I switched out computers and that did not solve the problem . I'm kind of out of ideas.
I should also mention that I had the ignition key in the run position for 45 minutes and the ECM go warm. I don't know if that is normal.
I'm going to try to use the jumper wire to go from the battery to the black wire with orange strip next to the brake booster. I will have someone key the ignition on as I test for voltage back at the gas tank. Tat will at least tell me if the pump works, I guess.
RmvBfrFlght
Well-Known Member
- Joined
- Sep 28, 2007
Isn't that wire for the underhood light (BLK/ORG)?
The fuel pump prime wire is gray, and should be located near the tach wire.
RemoveBeforeFlight
278.C.I.STAGE 2
Active Member
- Joined
- Aug 9, 2007
Have you look at the oil sender plug at the front of the motor, make sure the plug didn't rot off or the wires aren't touching the block.
- Joined
- Feb 18, 2006
Like mentioned,
The fuel pump test lead iis the grey wire with black plug behind the alternator
Yes, you are right. I am not getting power back to the tank, but the pump is bad. It's been sitting for too long in a dry tank. I will now be dropping the tank. I will probably replace the whole assembly with the sending unit and float. Thanks to all that replied. What is th best pump to get these days? Dershwerks to Walbro? I only need a single pump to support up to 450 hp.
Also considering the Racetronic 340LPH pump. Any thoughts?
- Joined
- Feb 18, 2006
I have had pretty good luck with the Turbo Tweak gearator pump. Others have had good luck with the Deatschworks pump. All the pumps you mention would do the job. Main thing is make sure you have a good hot wire kit and a solid ground. Run a extra ground from the tank shell to the car body. Then make sure your ground from the motor to the firewall is solid.
I have a hotwire kit from 2005 and I do have the tank grounded to the frame. I was looking at the Racetronix gen 2 340LPH pump and the 255LPH. The 255 seems like a no hassle replacement, but the 340 LPH seems like it would allow for future growth. I wonder if I would have to do anything else to run the 340LPH pump?
I took the tank out today and it is beyond help. There is a 1/8 inch of sediment and rust over the entire tank. The hanger and sending unit/float is rusted and also beyond repair. So i will need more than just a pump. I'm going all new, as I don't want to have future problems. Any thoughts/advice?
1986 Buick GX1
GX1 #001 [The One and Only]
- Joined
- Apr 24, 2015
If the search function works look for fuel tank threads to get the correct tank.
Some have had trouble with incorrect baffling and slow filling necks.
I bought mine from gbodyparts (goodmark brand), so far so good.
Kirban performance has a nice tank as well.
1984 1985 1986 1987 Buick Regal Grand National T Type Turbo T 3.8L REPRODUCTION GAS TANK
www.kirbanperformance.com
Full Throttle has racetronix stuff including the correct fuel sender resistor if you have a digital dash.
Fuel Pumps and Accessories
All fuel pumps specifically designed for the Buick/GN Application
www.fullthrottlespeed.com
When running a 340lph pump, it circulates a large volume of fuel at idle.
The stock fuel return line has trouble retuning that much fuel back to the tank and most have trouble keeping fuel pressure down to 43 psi (line off) especially with gasoline and sometimes with E85.
Some get by with drilling the flared tubing at the saginaw fittings coming out of the fuel pressure regulator and the connection on the frame near the power steering pump.
Most seem to run a complete new -6 fuel return hose kit and eliminate the stock return line.
If the search function works look for fuel tank threads to get the correct tank.
Some have had trouble with incorrect baffling and slow filling necks.
I bought mine from gbodyparts (goodmark brand), so far so good.
Kirban performance has a nice tank as well.
1984 1985 1986 1987 Buick Regal Grand National T Type Turbo T 3.8L REPRODUCTION GAS TANK
Full Throttle has racetronix stuff including the correct fuel sender resistor if you have a digital dash.
Fuel Pumps and Accessories
All fuel pumps specifically designed for the Buick/GN Application
When running a 340lph pump, it circulates a large volume of fuel at idle.
The stock fuel return line has trouble retuning that much fuel back to the tank and most have trouble keeping fuel pressure down to 43 psi (line off) especially with gasoline and sometimes with E85.
Some get by with drilling the flared tubing at the saginaw fittings coming out of the fuel pressure regulator and the connection on the frame near the power steering pump.
Most seem to run a complete new -6 fuel return hose kit and eliminate the stock return line.
Thank you. This is very informative. I was leaning toward the tank from Gbodyparts. I think I'll go with a 255LPH pump to avoid problems with the fuel lines. I should be OK with that pump I guess. I do have a alcohol injection system to add more fuel under boost. I'm running 60lb injectors and a TA 49 turbo right now. I may switch to a 62 ball bearing turbo in the future.
TexasT
Texas, Where are you from
- Joined
- Sep 10, 2002
careful trying to supplement fuel with the alchy injection. While it can perform that function it can also create a distribution problem for the engine. The 60lb injectors should be able to supply plenty of fuel but keep an eye on the duty cycle to make sure and let that alcohol do the chemical cooling.
1986 Buick GX1
GX1 #001 [The One and Only]
- Joined
- Apr 24, 2015
I was answering your question, but wasn’t thinking ahead towards future upgrades. Shame on me!
Another option is a double pumper setup with two 255lph pumps so one pump runs at idle and doesn’t over power the return line and the second pump kicks in at 15 psi boost to provide the extra fuel when needed.
When looking at a new hanger and pump and return hose kit and possibly a larger fuel pump in the future, maybe the double pumper doesn’t seem so bad?
mikestertwo
Well-Known Member
- Joined
- Sep 13, 2006
Ground the tank to the body not the frame as Rick mentioned. The frame is a poor ground.
OK. I doubt I would ever do the E85 thing, unless that is all we can buy at the gas station, at some point. My main question is, would I need more fuel than a 255 LPH pump can provide, for a 62MM ball bearing turbo?