ejscarfo

I have seen some aftermarket replacement fuel pumps for the C4 and some say not to use the factory pulsator but to install a length of fuel hose in its place. I know the Carter pump falls into this category. Has anyone experienced this? I have a Facet-Purolator pump that I was going to use (supposed to interchange with AC EP241) and I'm wondering if this too does not need the pulsator.

RetiredSFC 97

You'll have to see. I am not familiar with this pump but I would imagine they are similar. Use a piece of "fuel injection hose". Do not use just any piece of rubber hose. you can use the pulsator if you wish and you have one but they are prone to failure.

ch@0s

Interesting do they leak?

ejscarfo

I haven't pulled the assembly from the car yet, but I am sure the assembly has been pulled at least once before. I will see what is connected and to what once its out. I have another complete assembly for the car that's on my workbench now and I am using it for reference. The spare has the OEM pump and pulsator and I have matched up the old pump to the new one for size and the electrical connections, they are nearly identical and the plug fits fine. I shouldn't have to use the new plug and wires that came with the new pump.

I have seen other replacement pumps and they are shorter than the stock ones, so the use of a piece of fuel injection hose seems warranted in that case. I have a new pulsator and plan to use it with the new pump. I am wondering what fails on these?

The whole reason I am replacing the pump is that it doesn't hold pressure after the car is off (drops to 10psi in 5 minutes) and the pressure when its running with vacuum hose connection to the FPR is only 31psi, it used to be higher. The FPR tests fine but when I did the fuel pump test (clamp return hose, etc.), it pointed to a faulty pump.

RetiredSFC 97

yes, they cause a leak down causing hard cold starts. That's why many people who have a pulsator repair it by just replacing it with a piece of hose and from all my research that's the recommendation. IIRC my manual talks about both the pulsator and just the hose of things to check with leak downs.

a lot of times it's a pulsator issue and not a pump issue, when we think it is. Nowadays most pumps come with a hose instead of the pulsator, which is there for noise issues, from the pump, for some reason. I guess it was intended to quiet the pump but causes more problems than it helps.

I replaced my pump a while back and I have a leak down again and I'm certain it's the pump or the hose causing it. Most likely the hose.

Hondo48

I had this same decision earlier this year. I replaced the fuel pump and ordered a new pulsator. I know allot of guys believe it's not needed but I figured allot of time was soend designing this system. I did talk to Jon at FIC and his opinion was to keep it factory. The worse that would happen if you eliminate it is you may hear the pump running. I don't believe it affects performance one bit.
By the way, you should definately change the wires while you have it apart. They tend to fail.

Brett Richmond

RetiredSFC 97

yep that's typical.

but I would replace the wiring if you have new wires. JMO

ejscarfo

Well the new pump and pulsator are in!

I had a spare assembly that I planned to use because it was clean and the wires looked like new. However, when I pulled out mine, I noticed it was wired differently and the wires were a different color as well. For example, on mine, the black wire from the pump was grounded directly to one of the tubes. One the spare, all 3 wires went into a little box and it was grounded toward at the lip. There are still tags on the spare so I will look it up and see what year it belongs to.

I also found a lot of rust on the mounting surface. The gasket fell apart and was dry rotted. I took my time getting it all off and keeping it from falling into the tank. I sanded what I could on the tank and the mounting lip on the unit the best I could. I wound up using a bit of RTV on the corners to keep the gasket in place. I used a paper type gasket that I got from Corvette America, I hope its ok.

The wiring on the old pump was fine. It was actually replaced as I suspected so it saved me some work. I didn't use the strainer that came with it though. I had an NOS one and I used that, it fit better actually. I replaced the pulsator with one made by Motormite. I even cleaned the sending unit with a little WD40, my gauge seems to work now. WOO HOO

All in all, it wasn't a bad job. It took me 2 hours and 1 beer. The best part about it is that now its holding pressure when the car is off. My pressure gauge hit 32psi when I turned the key and stayed like that when the car was running. It moved up to 40psi when I gave it gas. I'm thinking I still need a FPR. But at least its 30 minutes later and its still holding at 32psi. By this time with the old pump, it would down to 5psi.

Thanks to everyone here that gave me their thoughts, advice and experience. Without you guys, I wouldn't know what to expect.

RetiredSFC 97

Another success and a lot of money saved.

But you weren't trying very hard if you only had one beer.

ejscarfo

It was a big beer I left the gauge on overnight and this morning it was holding 20psi.