Sending unit
Thread Starter
Racer
Joined: Jun 2012
Posts: 325
Likes: 36
From: Colorado Springs Colorado
Sending unit
I just ordered the 1985 sending unit for my 1984 Vette, there should be no problems with compatibility, right? I want to take advantage of more powerful pump of the 85 unit compared to the 84 one.
Thread Starter
Racer
Joined: Jun 2012
Posts: 325
Likes: 36
From: Colorado Springs Colorado
Race Director
Joined: Feb 2003
Posts: 16,475
Likes: 270
From: Kingman AZ
Cruise-In VII Veteran
Cruise-In VIII
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16
Safety Car
Joined: Sep 2004
Posts: 3,953
Likes: 550
From: Mission Viejo CA
If you compare the fuel pumped by an '84 pump, with the fuel pumped by an '85 pump, with the fuel flowing into a bucket, the fuel pressure will be the same for both pumps . . . zero! The pressure is a function of the pressure regulator, not the pump. The '85 pump has a higher capacity, and the use of an '85 pump in the '84 is a very popular modification.
A garden hose is the same idea. There's no pressure in the hose until you put your thumb over the end of the hose!
Here's a thread with some other discussion on the subject:
corvetteforum.com/forums/c4-tech-performance/3751977-fuel-pump.html
A garden hose is the same idea. There's no pressure in the hose until you put your thumb over the end of the hose!
Here's a thread with some other discussion on the subject:
corvetteforum.com/forums/c4-tech-performance/3751977-fuel-pump.html
Last edited by Hot Rod Roy; Dec 23, 2015 at 02:08 AM.
Melting Slicks
Joined: Jan 2014
Posts: 2,192
Likes: 381
From: Lunenburg MA
Thread Starter
Racer
Joined: Jun 2012
Posts: 325
Likes: 36
From: Colorado Springs Colorado
Today I installed the new pump/sending unit on my 84, the car started right away, no leaks, accelerates good on the lift, I will not be able to road test it until I finish the brakes, right now it looks like I will need new front steel lines since the nuts on the brake hoses do not want to come out and I already damaged the nuts, hopefully I can find them, will let you know how the car runs with the new pump/ sending unit as soon as put it back on the road
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Advanced
Joined: Oct 2014
Posts: 81
Likes: 0
Rough Idle on start up
Hi, I just bought a 84 c4.. I don't know anything about the crossfire injection.. it has 2 flaps on the air breather they are open before I start it and when I start it I think one closes the other stays open it a rough idle until it warm up ... after warm up it runs smooth.. is that normal .. I know it shouldn't idle rough what kind of problem am I looking at... or any suggestion I really thank you for your time...
Thread Starter
Racer
Joined: Jun 2012
Posts: 325
Likes: 36
From: Colorado Springs Colorado
Both flaps are open when the engine is cold, when you start the engine they are supposed to close and open gradually until hot, check for he vacuum hose under the air cleaner to make sure a hose is not broken.