Fuel Pumps

[Daniel_Mc]

Hey guys I am having an issue with a 91 Z. It will turn over just fine but not fire. The fuel pumps are not priming and the owner told me that the Z had a stumble to it the last time he drove it. However I do not have a fuel pressure gauge to check. I have checked the fuses but could not locate the relays. I looked in the passenger side dash under the carpeted area and removed the glove box and didn’t see the relays. I have 2 new fuel pumps should I just change or try tracing the relay first? I am trying to have the car ready to leave for BG at 3AM tomorrow.

Thanks,
Daniel

[Blue Flame Restorations]

Daniel, I wish I could help but I don't know the answer and was hoping someone here would chime in. Did you call Marc or Pete?

[Daniel_Mc]

Brett,

No I sure didn't (don't have there contact info). I am just going to change the pumps and see how it goes. This was going to be the owners first trip to the NCM (new Corvette owner) and it would be nice if he could bring his Z! I am hoping this is the issue the pumps are not priming and the owner said the Z had a stumble under load when he was driving it the last time.

Daniel

[VetteMed]

pumps go bad way more often than relays. Given the lack of a FP gauge, If you have the pumps, and a 10mm socket wrench, I say swap the pumps.

[VetteMed]

BTW: the relays are mounted horizontally, attached to the plastic carrier, so you may not immediately recognize them as relays with a quick glance.

You cannot access much of anything via the glovebox removal. Removal of the passenger hush panel should be all you need to access the components in that area.

[sammy]

the secondary fuel pump fuse is under the hush panel . you can buy a fuel pressure gauge at the parts store for about 40 .

[scottfab]

I'd do a little measuring before swapping pumps.
You can easily add a new problem to the original
without knowing what is going on.

A fuel pressure gauge is relatively cheap.
Get one. ($20 for a whole kit at Harbor Freight)
You should see 50-55lb. The attachment is a
schrader valve at the front of the fuel rail on the
passenger side.

As a quick test you could listen to the car as
you turn the key on (but not start the car).
You should hear the two pumps kick on for 2seconds.
(the noise will come from the tank)

If you heard the noise (and have not bought the pressure gauge yet)
then you can see if there is pressure by momentarily pushing in
the schrader valve with a small screw driver. Be careful and
use a rag to capture any fuel that squirts out.

If you don't hear the pumps kick in for 2sec and/or you
get no fuel to come out the shrader valve (or preferably use
a pressure gauge) then it's time to measure the voltage back
at the wire harness going into the top of the tank. If you get 12v
for the first 2sec after key-on then it's time to pull the pumps.
Here is one link for a how to do this. There are others too.

http://www.zr1netregistry.com/Old_Proj/old_proj11.htm

PS
NEVER test the new pumps with 12v before installing in the tank
with gas in it!!
this destroys them or greatly reduces their life time.

[XfireZ51]

Anyone ever try the Bosch rotary pumps?

[VetteMed]

Anyone ever try the Bosch rotary pumps?

I've been running them for 2 years now:

http://zr1.net/forum/showthread.php?t=9778

No complaints.

[Blue Flame Restorations]

QUESTION???

Is it ok for the green replacement strainers to just "hang there" instead of being tucked up against the fuel pump "holder", like the original sock strainer was originally?

Are original LONG and SHORT strainers still available vs the replacement semi-long green strainers?

[VetteMed]

QUESTION???

Is it ok for the green replacement strainers to just "hang there" instead of being tucked up against the fuel pump "holder", like the original sock strainer was originally?

Are original LONG and SHORT strainers still available vs the replacement semi-long green strainers?

The aftermarket strainers are all the same length, as far as I have seen, at least in the Airtex brand.

I don't think there's a functional difference in having the strainer hanging in the breeze. I suspect the factory secured it to ease installation/removal of the entire assembly, and to reduce the chance that the free end could get hung up on something during installation and potentially fall off the intake of the pump.

[scottfab]

I agree. Doesn't make a difference. And they are green to start out.
They turn dark over time.

[Blue Flame Restorations]

Thanks, guys. :cheers:

Just as I figured. I'd still like to find original length strainers if they're available. Probably not though..........