Fuel pump, hard start and AFR lean
10-07-2015, 08:53 AM
#1
Melting Slicks
Thread Starter
Fuel pump, hard start and AFR lean
I posted the same in an old thread (not mine) but probably it's deserve an own thread:
" After a 2 fulll months non using the car, I tried to start the car.
Turned the key and I have not heard the fuel pump prime.
Tried crank it so many times but nothing. I tried so many times that the oil pressure should had reached the right level to allow the fuel pump to start. BUT nothing.
SO i looked at a gauge I have on the fuel rail and pressure was 0psi.
Damn I tried to energize the G terminal. Nothing.
I opened the fuel door at the back to have acces to the wiring at the pump (the pump is a Walbro and I never had a problem).
I touched a bit the connector and wires . and I tried to start again the car several times along with touching the wires and the connector alternatively. NOTHING.
During these operations I had a look at the fuel pressure and I saw the needle at about 20 psi. (?? what caused this I really don't know).
Then I started the car and after few seconds it started , the prsessure jumped to around 50psi . So i let it idle . Returning to the back at the gas door i saw the top left hose (looking from top,) ( feed hose) leaking a massive quantity of fuel.
Tweaked the hose the leak seemed to stops, so I moved a bit the hose clamp and I clamped good to stop the leak.
Then I killed the engine.
I allowed the pressure lowering to about 30 psi and tried to crank it again.
This time I heard the fuel pump priming.
WHat can be happened? what cause the fuel pump to work good when the engine is started?
I ask because then, after, when I used the car I noticed that my AFR gauge (wide band installed) was reading really lean during highway route, expecially at lower speed and with light throttle opening. In highway I usually read 15:1 15,5:1 al light loads.
Sathurday I read even 17,5:1. (but the feeling was that the car was slightly rich as usual).
These problems can be related?
I have to add that when I was opening more the throttle going much more faster I had (like it should be) a spike on AFR due to Delta TPS and a lower (richer) reading .
BTW I can say that an all rpm/loads the AFR was more lean than usual. "
-Beppe-
" After a 2 fulll months non using the car, I tried to start the car.
Turned the key and I have not heard the fuel pump prime.
Tried crank it so many times but nothing. I tried so many times that the oil pressure should had reached the right level to allow the fuel pump to start. BUT nothing.
SO i looked at a gauge I have on the fuel rail and pressure was 0psi.
Damn I tried to energize the G terminal. Nothing.
I opened the fuel door at the back to have acces to the wiring at the pump (the pump is a Walbro and I never had a problem).
I touched a bit the connector and wires . and I tried to start again the car several times along with touching the wires and the connector alternatively. NOTHING.
During these operations I had a look at the fuel pressure and I saw the needle at about 20 psi. (?? what caused this I really don't know).
Then I started the car and after few seconds it started , the prsessure jumped to around 50psi . So i let it idle . Returning to the back at the gas door i saw the top left hose (looking from top,) ( feed hose) leaking a massive quantity of fuel.
Tweaked the hose the leak seemed to stops, so I moved a bit the hose clamp and I clamped good to stop the leak.
Then I killed the engine.
I allowed the pressure lowering to about 30 psi and tried to crank it again.
This time I heard the fuel pump priming.
WHat can be happened? what cause the fuel pump to work good when the engine is started?
I ask because then, after, when I used the car I noticed that my AFR gauge (wide band installed) was reading really lean during highway route, expecially at lower speed and with light throttle opening. In highway I usually read 15:1 15,5:1 al light loads.
Sathurday I read even 17,5:1. (but the feeling was that the car was slightly rich as usual).
These problems can be related?
I have to add that when I was opening more the throttle going much more faster I had (like it should be) a spike on AFR due to Delta TPS and a lower (richer) reading .
BTW I can say that an all rpm/loads the AFR was more lean than usual. "
-Beppe-
10-07-2015, 09:20 AM
#2
might have just been a sticky relay or pump from sitting is it working now and how old are the 02's? what year?
Last edited by antfarmer2; 10-07-2015 at 09:23 AM.
10-07-2015, 09:26 AM
#3
Melting Slicks
Thread Starter
It's a Zeitronix unit. I installed about 4-5 years ago or more (with the correct heated O2). Never had a problem with it. Even 2 months ago it was running Ok showing the right AFR values. I'm running Open Loop and I have not changed the chip code in the last 3 years.
It seems working good when I apply gas. Steady speeds shows leaner reading.
My car is a 1990 vert, with a 396 smallblock.
It seems working good when I apply gas. Steady speeds shows leaner reading.
My car is a 1990 vert, with a 396 smallblock.
Last edited by conv90; 10-07-2015 at 09:33 AM.