Help! 1988 E Z Go Backfiring

[JDAR1946]

Backfiring took out fuel pump-Wrinkled rubbers and one diaphragm tore. What is causing this? Just to check out further, installed gas tank above to gravity feed carb and still backfiring has HEI system Hmmm???

[cart around]

Does it backfire all the time, or only when you let your foot off the gas?

Backfiring is usually caused by the throttle cable not having a spring behind the throttle lever. It's purpose is to hold the lever closed tight when your foot is off the gas. That way it doesn't draw fuel in when there is no spark.

[JDAR1946]

As I am going and also when I let off. Thanks for responding

[cart around]

The torn diaphragm in the fuel pump is a major problem.

It's allowing fuel to be sucked directly into the crankcase. That's flooding the plug, and causing you to lose spark. Spark comes back, and ignites all of the gas in there at the wrong time.

A new pump costs as much as a rebuild kit. Change the fuel pump, rig your throttle to look like mine, and hope that the crankshaft seals haven't been damaged yet.

Backfiring will blow them out of the case.

[JDAR1946]

I was wondering about that because the way it was acting. Now with the fuel pump out of the equation, will this still happen? Or... maybe the seals are gone. I will do a compression check and see what that shows

[99cobra2881]

Compression test won't show blown crank case seals.

Easy crank shaft seal test.

Remove intake tube and exhaust. Cover both openings with duct tape.

Remove fuel pump.

Use a mityvac or similar device to pull a slight vacuum on the engine block through the fuel pump vacuum port.

It should hold a vacuum. Bad crank seals will show themselves through no vacuum being held and you'll be able to hear the air leaking in to the engine block past the seal or seals.

My recently rebuilt 2pg popped a front crank shaft seal and I used this method to diagnose the blown seal. Compression test showed 130psi. So I thought the fuel pump had quit and I used the vacuum pump to check the diaphragm inside the fuel pump. The fuel pump checked good so I knew I was fighting another issue.

I couldn't hear the leak over the sound of the engine cranking but the mityvac showed the leak instantly. New seal is loctited in place and is running good.

[cart around]

Seals have no affect on compression.

Clean, or replace your spark plug. Then see what happens with the new pump.

[JDAR1946]

Checked compression and it was low 85 at best and would not pull vacuum. Sooo, I guess a rebuild is in order?? Costly?? I will call around and see if anyone in my area works on these.:(

[JDAR1946]

Putting unit into the shop for TLC. Thanks for the responses and all the other threads on the Gas EZGOs

[JDAR1946]

We are back up and running again!! Rebuilt motor; fixed the carb; new fuel pump; new ignition components; and belt unit for the rear drive. The grandchildren are ready for the 4th of July Parade. Thanks to all that corresponded.