91' Running Rough - ZR-1 Net Registry Forums

Bob Eyres · 03-11-2012

I just woke up the old beast (91' 66K mi., stock motor, original injectors.) after a few months sitting in the garage. After warmup it idles smoothly and drives normally with the power key off. But at half throttle and above it feels down on power and there is a definite miss, (a sort of flatulence

I always run it with the power key on, (and I'm always winding it up, so it just doesn't need to be "blown out"

. It wasn't until I shut the power key off today that I could clearly feel that there's a problem with the secondary induction.
It's not like the secondaries are not opening, there's no vacuum problem. Before starting, it builds vacuum in about 3-4 seconds. When barely warmed up it had plenty of power to get sideways when I when to second gear, but later, I put the pedal down in third and fourth, and above 3K it's missing and chugging.

I put a bottle of Techron injector cleaner in the tank. So we'll see if that helps.

Any thoughts? Has this happened to you?

VetteMed · 03-11-2012

Original injectors would be my bet.

tomtom72 · 03-12-2012

Yes, vote #2 for the OE injectors falling prey to the ethanol in our gas now a days.....or maybe the secondary fuel pump or both..maybe.

If it's hot and the power key is off you can eliminate the ignition system if she runs smoothly in "normal" power mode.

Tom

03-11-2012	#1
Bob Eyres Join Date: Jul 2005 Location: Jupiter, Fl. Posts: 815	91' Running Rough I just woke up the old beast (91' 66K mi., stock motor, original injectors.) after a few months sitting in the garage. After warmup it idles smoothly and drives normally with the power key off. But at half throttle and above it feels down on power and there is a definite miss, (a sort of flatulence I always run it with the power key on, (and I'm always winding it up, so it just doesn't need to be "blown out" . It wasn't until I shut the power key off today that I could clearly feel that there's a problem with the secondary induction. It's not like the secondaries are not opening, there's no vacuum problem. Before starting, it builds vacuum in about 3-4 seconds. When barely warmed up it had plenty of power to get sideways when I when to second gear, but later, I put the pedal down in third and fourth, and above 3K it's missing and chugging. I put a bottle of Techron injector cleaner in the tank. So we'll see if that helps. Any thoughts? Has this happened to you? __________________ "It's about the car, not the people." 1991 ZR-1 White/Black #1236 (Owner since 1994). Stock engine with bolt-ons: Hurst shifter,"Forced Air" intake, Coplon duct, Bee Cool Radiator, Demon coils, Jeal prom, Watson headers, X pipe, 3" B&B's, Rippie flywheel, 4:10 gears, A molds, Toyo Proxes-R888's 12.06@117mph. 1.76 60ft.

03-12-2012	#3
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,645	Re: 91' Running Rough Yes, vote #2 for the OE injectors falling prey to the ethanol in our gas now a days.....or maybe the secondary fuel pump or both..maybe. If it's hot and the power key is off you can eliminate the ignition system if she runs smoothly in "normal" power mode. Tom __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member

03-11-2012	#2
VetteMed Join Date: Mar 2009 Location: Orlando, FL Posts: 1,828	Re: 91' Running Rough Original injectors would be my bet. __________________ 2004 Z06/Z16 LeMans Commemorative Edition 1991 ZR-1 #302 White/Gray (sold) 1991 ZR-1 #1147 Red/Saddle (sold)