Don?t hit rev limiter. - Page 2 - ZR-1 Net Registry Forums

aafc · 07-23-2022

Hi Steve,
Have you checked the fuel pump current draw? I believe its 8-9 amp draw
with both pumps. You may have a weak fuel pump. Next time connect a mechanical fuel pressure regulator and take it for a test run.
John

Young1 · 07-23-2022

Fuel pumps replaced. they pull 8 amps together. FPR replaced so have perfect 50-51 psi. Accordian does not collapse. I have four support hoops inside it. It actually bulges out. Filter is new ACDelco. She gave a 55 code. Fuel lean monitor per FSM. If I take off the air filter assembly and accordion she runs hard to rev limiter. With filter assembly throws code and is a dog.

I ordered a line and coupler to extend my fuel pressure gauge up to the windshield. Amazon should deliver it tomorrow. Maybe I have a defective new fuel pump or FPR? A test run with a gauge is a good idea. My gut tells me fuel delivery. Either mechanical problem or ECM problem. My secondary injectors all tested 12 OHms perfect on the bench. I need to test them from the ECM. Maybe have bad wiring. But it did run strong when it did run. Sheesh

Cruise control all lines and tank hold vacuum with tester. There is vacuum at servo when running. I replaced the 3 way vacuum valve under plenum already. I removed the clutch and brake vacuum and electrical switches and bench tested all good. The line from servo to vacuum switch holds vacuum. The 3 amp fuse is good and there is power at the fuse. Everything is connected above driver hush panel.

Keep ideas coming team.

XfireZ51 · 07-24-2022

You need to ohm ALL injectors after about a 30min heat soak. On the bench is a good start, but need to see if heat affects performance of injectors. It can and does. What injectors are they BTW?
Also, have u checked FP with FPR vacuum line connected and then disconnected?

MALF code 55 is an ECM ERROR according to the OBD1 MALF code list.

https://mechanicbase.com/trouble-code/obd1-codes/

Young1 · 07-25-2022

Car won?t start. Checked fuel pressure. 20 psi. Primary pump pulls 3 amps. Secondary pump .8 amps. Pumps bad, check valve in pump bad, pressure leak or all three with my luck. Appears I have a new part failure now. Saga continues.

55 code per FSM is fuel lean monitor.

DRM500RUBYZR-1 · 07-25-2022

Quote:

Originally Posted by Young1

Car won?t start. Checked fuel pressure. 20 psi. Primary pump pulls 3 amps. Secondary pump .8 amps. Pumps bad, check valve in pump bad, pressure leak or all three with my luck. Appears I have a new part failure now. Saga continues.

55 code per FSM is fuel lean monitor.

Or, something came loose.
While pumps do indeed fail, check ALL of the hose connections on the pumps, as well as the hoses and connectors.

I remain puzzled by the line in your earlier post that stated all was fine with the air duct filter etc. removed.

Investigate, diagnose and correct the lack of consistent fuel pressure first.
Then repeat your attempt for full acceleration with and without the air box setup to see if you experience that again.

Keep us posted of your progress.
You will get it.

Marty

XfireZ51 · 07-25-2022

From the Registry ALDL Fault code thread

http://zr1.net/forum/showthread.php?t=25660

Young1 · 07-31-2022

Yesterday I added fuel to the tank, took it out and it ran strong three times and then threw a code and went flat. I rechecked the pumps. Each pump individually gives 4 Amp and 51 psi. My son encourages me to go out and try it again dad. So we tape the fuel pressure gauge to the windshield I hook up my scanner so he can watch the O2 values. It runs like a champ hits the Rev limiter in three gears has a consistent 50 psi and O2 values of 700 to 800 at wide open. All is well but I don?t know why. Possibly it had some trapped air?

bowtiguy · 08-01-2022

Did you change out the "Y" adaptor AND new submersible fuel lines when you did the pumps? I had one car that had a cracked platic "Y" and another with factory fuel lines that split w/ only 8300 miles on the clock.

Young1 · 08-01-2022

I have on other cars but not this time. All yet quite flexible and plastic Y was good. Holds fuel pressure a good long time after engine shut down. That submersible fuel line is expensive too. I also use high pressure clamps and not the screw type.

aafc · 08-02-2022

Steve,
If you have not replaced your submersible fuel hose you can both from rock auto. Gates 5/16 in x 1 ft submersible fuel hose part # 27093 and 3/8 in x 1 ft
submersible fuel hose part # 27037.
John

07-23-2022	#11
aafc Join Date: Feb 2010 Location: Ochlocknee, GA Posts: 435	Re: Don?t hit rev limiter. Hi Steve, Have you checked the fuel pump current draw? I believe its 8-9 amp draw with both pumps. You may have a weak fuel pump. Next time connect a mechanical fuel pressure regulator and take it for a test run. John

07-23-2022	#12
Young1 Join Date: Sep 2016 Location: Ocala, FL Posts: 890	Re: Don?t hit rev limiter. Fuel pumps replaced. they pull 8 amps together. FPR replaced so have perfect 50-51 psi. Accordian does not collapse. I have four support hoops inside it. It actually bulges out. Filter is new ACDelco. She gave a 55 code. Fuel lean monitor per FSM. If I take off the air filter assembly and accordion she runs hard to rev limiter. With filter assembly throws code and is a dog. I ordered a line and coupler to extend my fuel pressure gauge up to the windshield. Amazon should deliver it tomorrow. Maybe I have a defective new fuel pump or FPR? A test run with a gauge is a good idea. My gut tells me fuel delivery. Either mechanical problem or ECM problem. My secondary injectors all tested 12 OHms perfect on the bench. I need to test them from the ECM. Maybe have bad wiring. But it did run strong when it did run. Sheesh Cruise control all lines and tank hold vacuum with tester. There is vacuum at servo when running. I replaced the 3 way vacuum valve under plenum already. I removed the clutch and brake vacuum and electrical switches and bench tested all good. The line from servo to vacuum switch holds vacuum. The 3 amp fuse is good and there is power at the fuse. Everything is connected above driver hush panel. Keep ideas coming team. __________________ Steve Young 1991 ZR-1 Quasar Blue Metallic/Black #729 Second Owner 1991 ZR-1 Dark Red Metallic/Black #2040 SOLD 1990 ZR-1 Dark Red Metallic/Saddle #1670 SOLD Double your happiness.....complain half as much.

07-24-2022	#13
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,698	Re: Don?t hit rev limiter. You need to ohm ALL injectors after about a 30min heat soak. On the bench is a good start, but need to see if heat affects performance of injectors. It can and does. What injectors are they BTW? Also, have u checked FP with FPR vacuum line connected and then disconnected? MALF code 55 is an ECM ERROR according to the OBD1 MALF code list. https://mechanicbase.com/trouble-code/obd1-codes/ __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX Last edited by XfireZ51; 07-24-2022 at 10:59 AM.

07-25-2022	#14
Young1 Join Date: Sep 2016 Location: Ocala, FL Posts: 890	Re: Don?t hit rev limiter. Car won?t start. Checked fuel pressure. 20 psi. Primary pump pulls 3 amps. Secondary pump .8 amps. Pumps bad, check valve in pump bad, pressure leak or all three with my luck. Appears I have a new part failure now. Saga continues. 55 code per FSM is fuel lean monitor. __________________ Steve Young 1991 ZR-1 Quasar Blue Metallic/Black #729 Second Owner 1991 ZR-1 Dark Red Metallic/Black #2040 SOLD 1990 ZR-1 Dark Red Metallic/Saddle #1670 SOLD Double your happiness.....complain half as much.

07-25-2022	#16
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,698	Re: Don?t hit rev limiter. From the Registry ALDL Fault code thread http://zr1.net/forum/showthread.php?t=25660 __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX Last edited by XfireZ51; 03-08-2024 at 02:09 PM.

07-31-2022	#17
Young1 Join Date: Sep 2016 Location: Ocala, FL Posts: 890	Re: Don?t hit rev limiter. Yesterday I added fuel to the tank, took it out and it ran strong three times and then threw a code and went flat. I rechecked the pumps. Each pump individually gives 4 Amp and 51 psi. My son encourages me to go out and try it again dad. So we tape the fuel pressure gauge to the windshield I hook up my scanner so he can watch the O2 values. It runs like a champ hits the Rev limiter in three gears has a consistent 50 psi and O2 values of 700 to 800 at wide open. All is well but I don?t know why. Possibly it had some trapped air? __________________ Steve Young 1991 ZR-1 Quasar Blue Metallic/Black #729 Second Owner 1991 ZR-1 Dark Red Metallic/Black #2040 SOLD 1990 ZR-1 Dark Red Metallic/Saddle #1670 SOLD Double your happiness.....complain half as much.

08-01-2022	#18
bowtiguy Join Date: Aug 2005 Location: Cali-rodo Posts: 270	Re: Don?t hit rev limiter. Did you change out the "Y" adaptor AND new submersible fuel lines when you did the pumps? I had one car that had a cracked platic "Y" and another with factory fuel lines that split w/ only 8300 miles on the clock.

08-01-2022	#19
Young1 Join Date: Sep 2016 Location: Ocala, FL Posts: 890	Re: Don?t hit rev limiter. I have on other cars but not this time. All yet quite flexible and plastic Y was good. Holds fuel pressure a good long time after engine shut down. That submersible fuel line is expensive too. I also use high pressure clamps and not the screw type. __________________ Steve Young 1991 ZR-1 Quasar Blue Metallic/Black #729 Second Owner 1991 ZR-1 Dark Red Metallic/Black #2040 SOLD 1990 ZR-1 Dark Red Metallic/Saddle #1670 SOLD Double your happiness.....complain half as much.

08-02-2022	#20
aafc Join Date: Feb 2010 Location: Ochlocknee, GA Posts: 435	Re: Don?t hit rev limiter. Steve, If you have not replaced your submersible fuel hose you can both from rock auto. Gates 5/16 in x 1 ft submersible fuel hose part # 27093 and 3/8 in x 1 ft submersible fuel hose part # 27037. John