Walbro intank and Bosch 044 lean out issues.
03-13-2013, 10:28 AM
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Walbro intank and Bosch 044 lean out issues.
Been away a while and recently started screwing around with my car again and am having a bizzaar issue that I hope to find help for here. The setup is a Walbro 255 intank feeding a Bosch 044 through Injector Dynamics 1000's. When I first fire up the car it runs fine but after about 10 mins or so it starts running like crap missing, popping and struggles to stay running. The wideband is showing a steady 14.2 at idle when all is good but suddenly goes to a 15.6+.
I originally thought the battery was slowly dieing causing a lean condition but after checking it is fine. The Bosch seems to be making a bit of a higher less consistent pitch than ussual but I can't be sure just yet. Now here is the weird part. If I unplug the power to the Bosch relay the A/F's go right back in check at 14.2 and the car idles perfect. I get about a 15 psi DECREASE in fuel pressure and all is well. How is this possible? Wouldn't it make sense that when the Bosch is running the car would run richer as more fuel is being delivered? At first I thought the Bosch may be acting as a restriction causing a rise in fuel pressure when running but I am monitoring fuel pressure at the rail so that eliminates that possibility. I just can't wrap my head around this.
Has anyone experienced a similar issue or have any suggestions?
I originally thought the battery was slowly dieing causing a lean condition but after checking it is fine. The Bosch seems to be making a bit of a higher less consistent pitch than ussual but I can't be sure just yet. Now here is the weird part. If I unplug the power to the Bosch relay the A/F's go right back in check at 14.2 and the car idles perfect. I get about a 15 psi DECREASE in fuel pressure and all is well. How is this possible? Wouldn't it make sense that when the Bosch is running the car would run richer as more fuel is being delivered? At first I thought the Bosch may be acting as a restriction causing a rise in fuel pressure when running but I am monitoring fuel pressure at the rail so that eliminates that possibility. I just can't wrap my head around this.
Has anyone experienced a similar issue or have any suggestions?
03-13-2013, 10:50 AM
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Re: Walbro intank and Bosch 044 lean out issues.
Forgot to mention I am also running an Aeromotive inline filter between the Walbro and Bosch pumps. I will pull it apart tomorrow morning and see if there is anything clogging it up. Still doesn't make sense to me if that is the case but I will take what I can get lol.
UPDATE: So I cleaned the filter and it had a bit of crap in it. Put a new filter in and it does the same thing.
I did however come to another conclusion. I think it may be a voltage/amp draw issue. When I have the Bosch unhooked and am running just off of the Walbro I can turn on the headlights, heater, highbeams and it runs fine. Now with the Bosch plugged in and running as well I cannot even turn on the headlights with out it going all screwy and leaning out. I have a new alternator with a bit of an underdrive pulley to compensate for my Fluidamper and an Optima red top. Both pumps are wired to individual relays that are activated via the factory fuel pump signal wire. I measure voltage at the battery under all of the aforementioned conditions and am only seeing a .5 volt variance. I am stumped.
UPDATE: So I cleaned the filter and it had a bit of crap in it. Put a new filter in and it does the same thing.
I did however come to another conclusion. I think it may be a voltage/amp draw issue. When I have the Bosch unhooked and am running just off of the Walbro I can turn on the headlights, heater, highbeams and it runs fine. Now with the Bosch plugged in and running as well I cannot even turn on the headlights with out it going all screwy and leaning out. I have a new alternator with a bit of an underdrive pulley to compensate for my Fluidamper and an Optima red top. Both pumps are wired to individual relays that are activated via the factory fuel pump signal wire. I measure voltage at the battery under all of the aforementioned conditions and am only seeing a .5 volt variance. I am stumped.
Last edited by Kwuaymaikrup; 03-13-2013 at 12:14 PM.
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