How to test a fuel pump on 1966 L36 no A/C.
I am looking for advice on how I can check to see if my fuel pump is working. After making some minor adjustment to my idle mixture screws and idle speed screw, I have achieved a good, steady idle. After 2 weeks of sitting in the garage, I attempted to start it and it just wouldn't turn over. I noticed while the car was turned off, I was getting fuel drips in the carburetor bowls. Eventually I got it started and drove it without any troubles. The car has been sitting for another few weeks and today, Ive tried to start it and nothing, almost as if no fuel is reaching the carburetor. Would like to trouble shoot this myself before taking it to the shop.
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Re: How to test a fuel pump on 1966 L36 no A/C.
Jerry,
Couple of things. How long have you owned your '66? You stated that you "attempted to start it and it just wouldn't turn over"...are you saying it wouldn't start or that the starter didn't even turn the engine over as though you had a dead battery?
With today's ethanol blended fuel, if you let your car sit for more than a few days, the fuel in the fuel bowls will evaporate. The technique to use in that case is (without touching the gas pedal) turn the ignition key to the "start" location as though you are attempting to start the car. Allow the starter to turn the engine over for 3-5 seconds...this will allow the fuel pump to fill the fuel bowls in the carburetor. Then, depress the gas pedal fully to the floor to engage the choke, depress the gas pedal two more times to squirt some gasoline into the intake plenum. Wait 15 seconds to allow fuel to to vaporize to a gaseous state. Then, without touching the gas pedal again, start the car. If it doesn't fire off immediately, pump the pedal once again, wait 15 seconds and it should fire off.Leif
'67 Coupe L79, M21, C60, N14, N40, J50, A31, U69, A01, QB1
Top Flight 2017 Lone Star Regional -
Re: How to test a fuel pump on 1966 L36 no A/C.
Leif,
I have owned the car for 4 years and never had many issues to deal with. The car does turn over, battery is new. when trying to start it it just doesn't want to take. I saw where using a syringe to inject about 3 oz of fuel into the front stack could help so I tried that and the engine made a small attempt to start but then nothing. I'll follow you suggestion and see what happens. Thanks.Comment
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Re: How to test a fuel pump on 1966 L36 no A/C.
Jerry,
I had fuel issues with my '66 L36 -
First to answer your question on checking fuel pump pressure, disconnect the fuel line to the carb and put a 12 or 15 psi gauge on the fuel line. Just crank the engine and fuel pressure should read about 7 psi - 8 psi is OK but carb guys will tell you 9 psi will overpower the needle valve and flood the carb. Mine was high, I changed the pump but it did not solve my problem ( my car was flooding out at idle). My issue ended up to be a warped front metering block resulting in internal fuel leaks.
You seem to have the a different problem - no fuel. crack the line going into the carb, if fuel is leaks with the motor running or just after you shut it down, issue is in the carb. Take the float level adjustment plugs out of the side of the front and rear fuel bowls. Should be fuel at or just below the windows. No fuel, clogged fuel filter (in carb) or stuck needle valves. Check or change the filter and/or take off the fuel bowls and replace or free up the needle valves. That should get you started. That is if your no start condition is fuel not spark.
JoeComment
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Re: How to test a fuel pump on 1966 L36 no A/C.
I haven't been back to this post for a while but have been trying several methods including shots of starter fluid into the carburetor. Nothing has worked and now I'm thinking there is no spark. Its a month wait here in Phoenix to get to a shop I trust so wondering if anyone has advice on how I can check for spark and maybe a faulty distributor. I have a short window to take advantage of decent weather before we hit the 110 degree days.Comment
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Re: How to test a fuel pump on 1966 L36 no A/C.
I have not solved my "no start" issue yet but have had some suggestions from Corvette Forum to replace my ignition coil. Carb is getting fuel so it seems to be a spark issue. Also reading the current Technical Discussion post on "Reproduction TI Amp issues", the coil may also be a part of the problem. Any suggestion on the proper coil for my 1966 L36? I see them on Summit Racing and Zip Corvette ranging in price from $29.99 to about $50.00Comment
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Re: How to test a fuel pump on 1966 L36 no A/C.
!!!! UPDATE !!!!. After ruling out fuel/carb issues, I purchased a $35.99 NAPA part # MPE IC12SB Ignition Coil, spent 1 1/2 hours installing and she runs great. Started right up and drove better than it has in the recent pass.Comment
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