Changing Fuel Pumps Tomorrow

[Blue Flame Restorations]

Pretty sure I'm only running on one pump. Yesterday, it fell flat on it's face trying to shift to 2nd gear going out of the neighborhood. Felt weak after that. Stumbled a little this morninig but ran ok . I did notice when I was in 2nd or 3rd gear, it would not throw you back in the seat when WOT. Just gradually climbed RPM's. Not like the Permagrin requires.

Ran to Indy today to drive around the Indy 500 Speedway. Definitely no secondary Permagrin. Sounded a little different as well.

It's always bugged me that I haven't done the fuel pumps. Looks like I'll get to do it now. If that doesn't cure it, I'll check the relays. I already have the pumps and a spare sending unit I got with the car.

[GOLDCYLON]

Pretty sure I'm only running on one pump. Yesterday, it fell flat on it's face trying to shift to 2nd gear going out of the neighborhood. Felt weak after that. Stumbled a little this morninig but ran ok . I did notice when I was in 2nd or 3rd gear, it would not throw you back in the seat when WOT. Just gradually climbed RPM's. Not like the Permagrin requires.

Ran to Indy today to drive around the Indy 500 Speedway. Definitely no secondary Permagrin. Sounded a little different as well.

It's always bugged me that I haven't done the fuel pumps. Looks like I'll get to do it now. If that doesn't cure it, I'll check the relays. I already have the pumps and a spare sending unit I got with the car.


Fuel Filter ?

[Blue Flame Restorations]

Yep, it's being changed at the same time. I bought all the parts for #702 and wish that I'd changed them out when the car was with Pete. Just kinda forgot at the time.

[GOLDCYLON]

Yep, it's being changed at the same time. I bought all the parts for #702 and wish that I'd changed them out when the car was with Pete. Just kinda forgot at the time.


No Brett Im thinking it maybe something simple like a clogged fuel filter. Id start there.

[Paul Workman]

Could be a pump, but it is easy enough to check them to be sure.

See LINK (http://www.zr1.net/forum/showthread.php?t=16978&highlight=amperes) to post #7 in this thread re how to test to see if the pumps are both running. And, connect a fuel pressure gauge to the fuel rail.

A fuel pressure gauge connected to the fuel rail (Schrader valve) should be about 52# when you energize the test connector (key OFF).

The current draw is about 4-5 amperes per pump, so you should have approx 8-10+ amperes - will indicate both pumps are running, along with the 52# at the rail. If you have 4-5 amperes, it could be a pump or an electrical failure (fuse/relay, etc).

photo showing proper meter configuration and indicating over 8 ampers (pumps are drawing the proper current, at least).

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/Fuelpumpcurrentcheck005.jpg

A dynamic test will confirm or deny if the fuel system is working in real world situations. To do it, you can tape the pressure gauge to the windshield and monitor FP in normal and WOT conditions.

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/FPtestLarge.jpg

At low throttle the pressure should be in the mid to upper 40s. At WOT the pressure should jump to about 52# and remain steady to 7k. If it isn't holding pressure at that level, delivery is in question (fuel filter??).

Of course, you could just change out the pumps and not bother with what I've suggested. But, I DO suggest this logical approach cuz I had the pleasure of installing new pumps once and had a failure right out of the box, AND a clogged filter to boot (gotta love multiples...makes troubleshooting less mundane, doancha think?). The procedure I just described sorted out the pump AND filter issues at the same time, and will work for anybody contemplating a possible fuel delivery issue.

I'm just sayin!;)

P.

[Blue Flame Restorations]

Thanks, guys. Good info for sure!

Brett

[scottfab]

Here's an oldie but goodie.
It's come up before but the last time I saw anything on it was
over 10yrs ago and was on the old ZR-1 Registry mailing list.

Keep your tank over 1/4 full.
If you run out of fuel or run low when doing hard corners
you run the risk of running the pump(s) without fuel.
This is a known "no no" and damages the pump(s).
There is a "tub" inside the tank that keeps fuel close
to the pumps in hard corners but alas...... it is ineffective.
The other failure mechanism is leaving the car sit with low fuel
levels. If air gets to the contacts in the pump..... no good.

Tomorrow is Memorial Day. My undying gratitude goes to those
who have died in the service of this nation.
:saluting:

[Blue Flame Restorations]

Well, tomorrow was a few more days than I had anticipated. Got the pumps changed and it runs fine. I did the old" turn the key off and see if I could feel a difference in power" trick. Permagrin!

Now, if I could just get the fuel gage to register correctly. It reads fine with the key ON. But....after the car is started, it reads near full (and it's only 1/2 full).

The unit did not want to seat when it was about .50-1.0" from the bottom. I wiggled it a bunch before it finally seated. Maybe the float is rubbing in the tank???

[Daniel_Mc]

The unit did not want to seat when it was about .50-1.0" from the bottom. I wiggled it a bunch before it finally seated. Maybe the float is rubbing in the tank???

Brett,

CJ's did not want to seat but I wiggled and gave it about a 1/4 turn and it sat right down, no forcing it at all. I would check that first the float could have gotten in a bind or slightly bent.

Daniel