GSL-SE fuel system
03-16-12, 05:17 PM
#1
GSL-SE fuel system
Hey y'all,
I have a few questions I havent been able to answer by searching. Summer is almost here now and my SE is starting to show symptoms of vapor lock during normal driving. It is a 1985 streetport with RB exhaust.
The car will buck or stutter when accelerating from a stop and I can usually keep this from happening by feathering the throttle until cruising. The car bucks/stutters no matter what if you floor it.
The car was sitting for 7-8 years before I started working on it and I have cleaned the whole fuel system. Just a couple weeks ago I replaced the fuel filter and the symptoms are still showing.
I think I have a pretty good handle on what the problem is but I'm looking for more experienced opinions.
My idea is that the fuel return line and maybe the fuel feed line are gunked up from sitting. I visually inspected the ends but anything could be in there. The gunk is causing my fuel pump (Airtex replacement pump, questionable quality) to overwork itself and cavitate or just thermal out.
Things that support this theory: feathering throttle can alleviate most symptoms, mechanic took temp readings last summer and said my pump temp was matching exhaust temps. I've read that the return line is a smaller diameter than the feed line so even minimal gunkage could screw it up noticeably.
My plan to solve this problem is to replace the metal feed/return lines under the vehicle and upgrade to the Walbro 190lph. I also plan to insulate the fuel lines in the engine bay to try and keep the fuel cooler / more dense.
? 
?
I have a few questions I havent been able to answer by searching. Summer is almost here now and my SE is starting to show symptoms of vapor lock during normal driving. It is a 1985 streetport with RB exhaust.
The car will buck or stutter when accelerating from a stop and I can usually keep this from happening by feathering the throttle until cruising. The car bucks/stutters no matter what if you floor it.
The car was sitting for 7-8 years before I started working on it and I have cleaned the whole fuel system. Just a couple weeks ago I replaced the fuel filter and the symptoms are still showing.
I think I have a pretty good handle on what the problem is but I'm looking for more experienced opinions.
My idea is that the fuel return line and maybe the fuel feed line are gunked up from sitting. I visually inspected the ends but anything could be in there. The gunk is causing my fuel pump (Airtex replacement pump, questionable quality) to overwork itself and cavitate or just thermal out.
Things that support this theory: feathering throttle can alleviate most symptoms, mechanic took temp readings last summer and said my pump temp was matching exhaust temps. I've read that the return line is a smaller diameter than the feed line so even minimal gunkage could screw it up noticeably.
My plan to solve this problem is to replace the metal feed/return lines under the vehicle and upgrade to the Walbro 190lph. I also plan to insulate the fuel lines in the engine bay to try and keep the fuel cooler / more dense.
? ?
03-16-12, 06:37 PM
#2
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your fuel pump is 1500 degrees? that would be bad.....
i think step 1 would be to disconnect the fuel lines at each end and blow air thru them. step 2 would be to check replace all THREE fuel filters. there is one in the tank, one before the pump and one after the pump .
and then go from there...
i think step 1 would be to disconnect the fuel lines at each end and blow air thru them. step 2 would be to check replace all THREE fuel filters. there is one in the tank, one before the pump and one after the pump .
and then go from there...
03-17-12, 12:54 AM
#3
your fuel pump is 1500 degrees? that would be bad.....
i think step 1 would be to disconnect the fuel lines at each end and blow air thru them. step 2 would be to check replace all THREE fuel filters. there is one in the tank, one before the pump and one after the pump .
and then go from there...
i think step 1 would be to disconnect the fuel lines at each end and blow air thru them. step 2 would be to check replace all THREE fuel filters. there is one in the tank, one before the pump and one after the pump .
and then go from there...
The lines have been blown out.. they all seemed to flow. I have no filter after the pump because the old cone I couldnt source. I will inspect the fuel pickup filter when I work on the metal lines but the tank was professionally cleaned and I replaced that filter at the same time. The injectors also were cleaned. If the filter in the tank has clogged the only source for the gunk would be the fuel feed/return line, I believe.
03-19-12, 12:17 AM
#4
sorry to double post, BUT. I did a fuel volume test and got bad results... In the end there was only about 1/8th of a gallon after a minute of flowing.
It's obvious to me now the metal feed lines have nothing to do with my issue and I should check pickup tubes / pickup filter.. I plan to buy cleaner pickup tubes since mine weren't cleaned with the tank.
It's obvious to me now the metal feed lines have nothing to do with my issue and I should check pickup tubes / pickup filter.. I plan to buy cleaner pickup tubes since mine weren't cleaned with the tank.
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