Could this be a fuel pump issue? - ZR-1 Net Registry Forums

captcorvette · 01-26-2012

Brought my '90 Z back from the paint shop to my hobby garage on a recovery. The ramp into my shop puts the nose 4 to 5 inches lower than the rear when backing into the garage. The recovery has to back in from the street so the car is rear end up and nose down. Car would start but immediately shut down after any throttle was applied. The fuel was showing a little over half tank. Scratched my watch and wound my backside trying to sort out what had happened now to my favorite toy. Tried all the first come to mind issues, fuel, vacuum lines off, battery voltage with no obvious issues.

Then for grins & giggles I added 5 gallons of petrol to the tank. Car started up and could be backed into the garage. One of the fuel pumps not working? Fuel gauge appeared to correctly add the 5 gallons of fuel added to the indicator.

Then I noticed that the paint shop had lost the valet key. Panic set in so located the spare key I had made last year. It is only a regular chevy door lock key but cut to match my original valet key. Does the valet key have an embedded ohms chip in it? If not then will the door key properly cut work?

Current problem is ever since the last shop worked on the engine (while I was in the hospital) the car runs OK but not great in the normal position without the full power switch being turned on. Still has a miss but is a slight miss and seems to miss on varying cylinders not just one constant miss. If I put the switch to full power then it starts to run like a out of balance washing machine. The missing increases to almost stalling the engine. If I turn the full power switch back to the normal position it takes a while before the missing decreases in intensity. Have checked vacuum lines and pump----all seem to be not leaking and the pump does turn off after running a few seconds.

Have recently installed the intake stiffener to keep the intake accordion from collapsing but that seemed to have no effect.

Have cruised my service manual and cannot find anything that seems to fit the symptoms. My scanner (Techscan 7,000) doesn't give me any codes. All advice humbly accepted and requested.

sammy · 01-26-2012

no pellet on the power key . does the full power come on in the info center when the key is turned on ? do you have a scan tool to ck for codes ? need port throttle selinoid failure .have your injectors been replaced ? if not you could have some failing . early cars injectors fail due to todays gas

VetteMed · 01-26-2012

Yep, first thought was injectors, if OEM then that's where I'd start.

captcorvette · 01-26-2012

No codes show up on my scanner. We don't have alcohol in our fuel over here and this was a sudden problem.

Still curious if the nose being 4-5 inches lower on the ramp when the car wouldn't run indicates that one of the fuel pumps isn't operating? Full power light does come on.

Hib Halverson · 01-28-2012

If you suspect a fuel supply issue, the first thing to do is run the fuel pressure tests listed in the Factory Service Manual. Make sure you run the tests for both pumps.

Do that and post the results.

Also, if your service engine light is not on and there are no history codes stored, then there are no engine controls faults.

GOLDCYLON · 01-29-2012

Could be a primary fuel pump failure. Swap over to the secondary pump and see what happens. Change the fuel filer while you at it. GC

01-26-2012	#1
captcorvette Join Date: Jan 2011 Location: Dubai, United Arab Emirates Posts: 449	Could this be a fuel pump issue? Brought my '90 Z back from the paint shop to my hobby garage on a recovery. The ramp into my shop puts the nose 4 to 5 inches lower than the rear when backing into the garage. The recovery has to back in from the street so the car is rear end up and nose down. Car would start but immediately shut down after any throttle was applied. The fuel was showing a little over half tank. Scratched my watch and wound my backside trying to sort out what had happened now to my favorite toy. Tried all the first come to mind issues, fuel, vacuum lines off, battery voltage with no obvious issues. Then for grins & giggles I added 5 gallons of petrol to the tank. Car started up and could be backed into the garage. One of the fuel pumps not working? Fuel gauge appeared to correctly add the 5 gallons of fuel added to the indicator. Then I noticed that the paint shop had lost the valet key. Panic set in so located the spare key I had made last year. It is only a regular chevy door lock key but cut to match my original valet key. Does the valet key have an embedded ohms chip in it? If not then will the door key properly cut work? Current problem is ever since the last shop worked on the engine (while I was in the hospital) the car runs OK but not great in the normal position without the full power switch being turned on. Still has a miss but is a slight miss and seems to miss on varying cylinders not just one constant miss. If I put the switch to full power then it starts to run like a out of balance washing machine. The missing increases to almost stalling the engine. If I turn the full power switch back to the normal position it takes a while before the missing decreases in intensity. Have checked vacuum lines and pump----all seem to be not leaking and the pump does turn off after running a few seconds. Have recently installed the intake stiffener to keep the intake accordion from collapsing but that seemed to have no effect. Have cruised my service manual and cannot find anything that seems to fit the symptoms. My scanner (Techscan 7,000) doesn't give me any codes. All advice humbly accepted and requested.

01-26-2012	#2
sammy Join Date: Jun 2010 Location: Lone Pine, CA Posts: 580	Re: Could this be a fuel pump issue? no pellet on the power key . does the full power come on in the info center when the key is turned on ? do you have a scan tool to ck for codes ? need port throttle selinoid failure .have your injectors been replaced ? if not you could have some failing . early cars injectors fail due to todays gas

01-26-2012	#3
VetteMed Join Date: Mar 2009 Location: Orlando, FL Posts: 1,816	Re: Could this be a fuel pump issue? Yep, first thought was injectors, if OEM then that's where I'd start.

01-26-2012	#4
captcorvette Join Date: Jan 2011 Location: Dubai, United Arab Emirates Posts: 449	Re: Could this be a fuel pump issue? No codes show up on my scanner. We don't have alcohol in our fuel over here and this was a sudden problem. Still curious if the nose being 4-5 inches lower on the ramp when the car wouldn't run indicates that one of the fuel pumps isn't operating? Full power light does come on. Last edited by captcorvette; 01-26-2012 at 10:44 PM. Reason: omission

01-28-2012	#5
Hib Halverson Join Date: Jun 2005 Location: CenCoast California Posts: 898	Re: Could this be a fuel pump issue? If you suspect a fuel supply issue, the first thing to do is run the fuel pressure tests listed in the Factory Service Manual. Make sure you run the tests for both pumps. Do that and post the results. Also, if your service engine light is not on and there are no history codes stored, then there are no engine controls faults. __________________ Hib Halverson Technical Writer former owner 95 VIN 0140 current owner 19 VIN 1878 Last edited by Hib Halverson; 01-28-2012 at 11:18 AM.

01-29-2012	#6
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,120	Re: Could this be a fuel pump issue? Could be a primary fuel pump failure. Swap over to the secondary pump and see what happens. Change the fuel filer while you at it. GC __________________ GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V Last edited by GOLDCYLON; 01-29-2012 at 03:23 PM.