New injectors = Wow
Thread Starter
Instructor
Joined: Oct 2004
Posts: 208
Likes: 1
From: Santa Rosa CA
New injectors = Wow
89’ 114k miles. Ruff idle, stuttering, limited rpms. Tried new plugs, cap and rotor with little success. Finally after a little searching here, I checked resistance of injectors. The numbers were all over the board, 5 of 8 were bad. Ordered a set of Accels from Summit for $260 (thanks byebyeL98). Sam Lam has a helpful write up on the procedure. I tried his suggestion of not removing the right runner but could not get the plenum to budge without loosening all the lower bolts. I did not need to loosen the left runner. FYI, I had numbered the plugs when I changed them, there was an obvious correlation between the good injectors and a nice clean plug and visa versa.
Now the idle is scary smooth with nice power all the way up.
Now the idle is scary smooth with nice power all the way up.
Thread Starter
Instructor
Joined: Oct 2004
Posts: 208
Likes: 1
From: Santa Rosa CA
Originally Posted by LT4CompYell
So, tell us the truth: around beautiful Santa Rosa---are you enjoying the ride? betcha!
Glad to hear of your "cure".
Glad to hear of your "cure".
Thread Starter
Instructor
Joined: Oct 2004
Posts: 208
Likes: 1
From: Santa Rosa CA
Originally Posted by cplonner
How do you test the resistance of your injectors? Does that have anything to do with the spray test?
Team Owner
Joined: May 2006
Posts: 21,473
Likes: 356
From: Palmdale, Ca----- 2009 Cyber Gray 4LT A6 F55 452 RWHP 422 RWTQ- RIP 1998 C5 734 RWHP & 585 RWTQ-----
So sweet! I remember when I stuck my new injecter's 24lb's in it made a smooth more powerful difference also put on an adjustable fuel pressure regulator and what a diff!
Did you put 24's in or did you go stock do you have a adjustable fuel pressure regulator?
Thanks,Matt
Did you put 24's in or did you go stock do you have a adjustable fuel pressure regulator?
Thanks,Matt
Thread Starter
Instructor
Joined: Oct 2004
Posts: 208
Likes: 1
From: Santa Rosa CA
Originally Posted by madmatt9471
So sweet! I remember when I stuck my new injecter's 24lb's in it made a smooth more powerful difference also put on an adjustable fuel pressure regulator and what a diff!
Did you put 24's in or did you go stock do you have a adjustable fuel pressure regulator?
Thanks,Matt
Did you put 24's in or did you go stock do you have a adjustable fuel pressure regulator?
Thanks,Matt
Safety Car
Joined: Jan 2004
Posts: 3,783
Likes: 15
From: Northern California
Stock Multec injectors are 22lbs. Most people install an adjustable fuel pressure regulator in place of the stock one to decrease the fuel pressure, when using higher rated injectors.
Your engine will just run a little rich if you don't install an adjustable fuel pressure regulator. I'm not sure if the computer will compensate enough for the increased fuel.
Your engine will just run a little rich if you don't install an adjustable fuel pressure regulator. I'm not sure if the computer will compensate enough for the increased fuel.
Last edited by GKK; Aug 4, 2006 at 10:56 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
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
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
George4: Thanks for the "kind" words and I was glad to be of assistance to you. It is amazing how many people with 89 Vetts are having problems with the stock GM Multec injectors. I had 3 of 8 injectors shorting out. Shorting injectors do not create any codes and people spend a lot of $$$ trying to fix parts that are not broke......I sure did!!! If anyone needs more info on this, send me a note to samlam@charter.net 
GKK: Look at your first sentence above. I'll bet you meant to say that "stock injectors for an 89 is 22 pounds". I run the fuel pressure on my 89 at 43 pounds to get the correct ECM readings.
GKK: Look at your first sentence above. I'll bet you meant to say that "stock injectors for an 89 is 22 pounds". I run the fuel pressure on my 89 at 43 pounds to get the correct ECM readings.
Last edited by Sam Lam; Aug 4, 2006 at 10:32 PM.
Safety Car
Joined: Jan 2004
Posts: 3,783
Likes: 15
From: Northern California
Sam Lam: GKK: Look at your first sentence above. I'll bet you meant to say that "stock injectors for an 89 is 22 pounds".
Last edited by GKK; Aug 4, 2006 at 10:54 PM.
Burning Brakes
Joined: Dec 2001
Posts: 777
Likes: 1
From: Fort Worth Texas
Originally Posted by Sam Lam
George4: Thanks for the "kind" words and I was glad to be of assistance to you. It is amazing how many people with 89 Vetts are having problems with the stock GM Multec injectors. I had 3 of 8 injectors shorting out. Shorting injectors do not create any codes and people spend a lot of $$$ trying to fix parts that are not broke......I sure did!!! If anyone needs more info on this, send me a note to samlam@charter.net
GKK: Look at your first sentence above. I'll bet you meant to say that "stock injectors for an 89 is 22 pounds". I run the fuel pressure on my 89 at 43 pounds to get the correct ECM readings.
GKK: Look at your first sentence above. I'll bet you meant to say that "stock injectors for an 89 is 22 pounds". I run the fuel pressure on my 89 at 43 pounds to get the correct ECM readings.
Safety Car
Joined: Jan 2004
Posts: 3,783
Likes: 15
From: Northern California
Each vehicle is different. You will have to have your car tuned or dynoed to find the correct fuel pressure which would make your engine run at the correct air/fuel ratio.
Some engines run best with the fuel pressure set at 38psi and some run best with fuel pressure set at 48psi, you won't know unless you have your engine tuned.
Here is another post on the subject.
http://forums.corvetteforum.com/show....php?t=1459776
Some engines run best with the fuel pressure set at 38psi and some run best with fuel pressure set at 48psi, you won't know unless you have your engine tuned.
Here is another post on the subject.
http://forums.corvetteforum.com/show....php?t=1459776
Last edited by GKK; Aug 5, 2006 at 02:20 PM.