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Fuel pump going?

Joined
Oct 30, 2001
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2,273
Location
Glen Burnie, MD, USA
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1986 Bright Red Coupe
Sunday AM I went to start the Vette prior to driving home from PA. Turned the key, did NOT hear the whine of the fuel pump priming. The car started, but had to crank a LOT. Had no problems getting home, no loss of power, but it doesn't start properly now (just happened - Sat night it was fine). Is this a fuel pump problem or an electrical issue elsewhere?

Thanks...
[RICHR]
 

JT ZR-Won

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Dec 6, 2000
Messages
1,291
Location
Bradenton, FL
Corvette
'90 ZR-1 #3010
I'd maybe start with the fuel filter being they're only a few bucks to replace anyway. When my fuel pump quit on my '85 the car turned over but wouldn't start. It is possibly your fuel pump.

Jay
 

vigman

Motor head!!!!
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Feb 13, 2001
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Valencia, CA,USA
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88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
I'm thinking

Fuel pump relay!!!!!


Vig!
 
Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
JT, filter was fresh about 1k miles ago and the car doesn't sit for more than a few days at a time - unless there's a ton of gunk in my fuel system.

Vig, I'll check the relay... didn't even think of that.

Thanks; will report back later. I have all this junk from Carlisle to swap out while I'm playing - new reverse lights, battery cutout, toys Toys TOYS.
[RICHR]
 
D

DHOUGHTON

Guest
Check the pressure at the fuel rail valve.

Refer to the location of the pressure valve on the fuel rail. On my 90 it is on the passenger side and it has a screw cap and looks like a schrader bicycle tube valve. Turn the key to on with the car not running. Press on the needle on the valve, if it sprays fuel out then your pump must be working. Thats my 2 cents. Expecting change back.

Marathoner
 
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Jun 20, 2002
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Tallahassee, FL
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none right now :(
you may want to check the pressure of the system as well... It doesn't take a whole lot of pressure to keep a vette going normal speeds.. did you try going wide open throttle? I am thinking the fuel pump may not be able to handle high pressures anymore, but it is pumping enough to keep her running
 
Joined
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Messages
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Location
Glen Burnie, MD, USA
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1986 Bright Red Coupe
I've got a fuel pressure gauge; I'll try that. I did run WOT a couple times (pesky trucks won't get out the left lane!) with no probs. Did 50-95 mph VERY quickly.

I'm mostly concerned, remember, because I no longer hear the pump pressurizing the system when I turn the key. That's become part of my routine because I'm trying to track a pressuer loss after shutdown (ie, starts on first crank when warm, takes two or three when cold, pressure drops to 3-5 psi overnight - but DID come back immediately to 35 or so when the key was turned, last time I checked).

[RICHR]
 
Joined
Jun 20, 2002
Messages
2,509
Location
Tallahassee, FL
Corvette
none right now :(
Well, I was thinking that the pump may be trying to pump, but couldn't because it is about to go to pump heaven... but, if you can run WOT for a good amount of time (50-95MPH should suffice) then it is pumping fine while the engine is running, if it wasn't the engine would bog a bit until the fuel pump caught up. So, now my guess is it is electrical, and I don't know this system... Vig probably knows best, but my question is: are there separate relays, or switchs for pre-start pump activation Vs. a running engine activation... This should be where your problem lies... even in the pre-start sequence... does it do everything else normal? maybe the car doesn't realize it is about to be started?
 

Mad-Mic

Gone but not forgotten
Joined
Feb 12, 2002
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Annapolis Maryland
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1987 Redskin Red Coupe
Heya Rich,

sorry i missed you at carlisle i reformatted my comp again and lost that email with your #. anyhow seems to me it did the same on mine a month or so before it finally let out acting strange and not wanting to start and sometimes backing up my hill on the driveway seemed to bog down and want to die then all the sudden it just stopped. when the car warmed up it ran flawless so i thought it was it's nature with the L98 motor. after new fuel pump cranks on first turn ALWAYS! much easier on warmups don't bog down when revving up to warm up or should i say to clear it out.......lol she's still a beast. :L from what i hear it's not that hard of a job only bout an hour and half. i'll give ya a hand. i don't think the pump is in the tank but i don't have the book. i let the dealer do mine since it was under warrenty.
 

-=Jeff=-

Well-known member
Joined
Feb 2, 2001
Messages
909
Location
Bartlett, IL. (Chicago Suburb)
Corvette
1990 ZR-1
Re: I'm thinking

vigman said:
Fuel pump relay!!!!!


Vig!

Yeah or possibly the oil pressure sender, which also controls the initial running of the pump
 
Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
By my recollection, if the oil pressure sender is sending less than 4 PSI on startup then the car won't even crank.


Looks like I've got a few things to check for now...
[RICHR]
 
Joined
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Location
Glen Burnie, MD, USA
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1986 Bright Red Coupe
I bow in your general direction, Vigman. I've printed that link and I'm going to run through those tests - tonight if possible.

Many thanks.
[RICHR]
 
Joined
Oct 30, 2001
Messages
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Location
Glen Burnie, MD, USA
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1986 Bright Red Coupe
Riddle me this, Vigman...

Ok. Played with the tests you mentioned, plus a couple from my Haynes.

1. Key in and turned to ON, pressure gauge hooked up. No fuel pump hum, ZERO pressure.

2. Jumped ALDL G to 12v (friggin' long wire... :) ). Fuel pump growls merrily away. ZERO psi pressure at the gauge. WTF?

3. Try to start car. Takes two tries of about 15 cranks each before it reluctantly starts. *STILL* ZERO psi at the gauge. Gauge may be faulty; when I disconnect it, fuel does drip from the fitting so there is indeed something getting to it. Gauge worked last I tried it...

4. Briefly saw SES light yesterday, but it went away on power off. Tonight pulled code: 54. Fuel pump circuitry problem. Ok, code makes sense... but can it be any LESS useful?

So pump works and will energise - but NOT when key is turned. Will borrow another gauge later this week and test again. Did one piece of fuel system restoration while I was playing - replaced the rubber bump stops under the fuel door :) .

[RICHR]
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Fuel gauge problem

If the car is running.. and the gauge shows "0".. well I dunno.. bad gauge..bad schrader valve....


re-lay re-lay re-lay re-lay re-lay re-lay re-lay re-lay re-lay re-lay re-lay re-lay

A quote from the book of the holy scriptures
6E3-A-60
Psalm 54

Code 54
Fuel pump circut
LOW voltage

The status of the fuel pump (crkt120) is monitored@ pin B-2 of the ECM.

54 will set IF the voltage is LESS than 2 volts for 1.5 seconds..since the LAST reference pulse was recieved ( assuming run( stored voltage) then stop then START)

"The code is designed to detect a faulty relay, extending crank time....."


re-lay re-lay re-lay re-lay re-lay re-lay re-lay re-lay re-lay re-lay re-lay re-lay


:j



Vig!
 
Joined
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Glen Burnie, MD, USA
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1986 Bright Red Coupe
Well... when I jump ALDL pin G, I hear a relay by the firewall click on and off. Unless there's another relay actuated by that test. If it is just a relay, I'll be quite happy - it's new tire time and the fun fund is low after Carlisle.

I'll check the relay itself tonight.
[RICHR]
 

vettn94

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Aug 9, 2002
Messages
181
Location
Warrenville, IL.USA
Corvette
1994 Polo Green Convertible
With the code sounds like vigman is right, it's probably the relay.
If (when) you check the pressure again tape the gauge to the windshield so you can watch it while you are driving. If pressure falls off then the problem would most likely be the pump. It should actually increase a little while under hard acceleration.
Checking it with the key on, engine off or just at idle dosen't really help, it needs to be checked under load.
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
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Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
When you do the jump

Your testing the UNUSED pins in the relay pin G ties to the fuel pump in the normally CLOSED position.
This is only a path to juice the pump externally without ripping everything apart.


The FOOL pump relay

Pin C ties to pin G of the ALDL connector( red ) Normally closed

Pin E ties to the Fool pump fuse 10 amp
then goes to the actual pump ( Tan/White)
Relay swinger

Pin A is the +12 from BATT via fusible link "H" Normally open

Pin F is coil ground
Pin D is from the ECM pin A1 which is the 2 sec pulse to prime the system.

So the ECM pulls pin D HIGH(+12)
The relay goes CLICK
there is a closure between pin A(+12) and pin E ( to pump )


So to test... hang a test light in the fuse box on the fuel pump fuse.

Turn key on

The light should light for 2 sec.

If no light... relay BAD


Vig!
 

WhalePirot

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May 9, 2002
Messages
2,942
Location
SoCA
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1984 White Z-51/ZF6-40/Shinoda body
CODE 54 is the key, and most of this has nothing to do with it LOL

I'm not sure that the relay is the problem. Use the advice given to trip the relay on, while looking at the press. gauge, taped to your window. If you can trip the relay and get pressure, the startup signal may be missing, for whatever reason.

None of these cars can run without a fuel pump, as the injectors do not gravity feed. The system requires such high pressure, to run at all, that a return line is installed to return excess fuel. Dripping from the schraeder valve is not positive pressure. I should squirt out, (there IS a bleeding procedure to be followed before servicing these lines) unless the pressure has bled down; the timing of which should be specified somewhere. (I'm looking.)

One or more injectors, or some fitting between the pump and injectors may be leaking, which requires the system to pressure up with each start, which takes time. I had this problem on a BMW.

BTW, there are two fuel filters. There is a 'sock' (woven plastic)on the fuel pump pickup tube, which is easy to get to (pull the pump). I don't suspect this is your problem, but if the other filter was clogged, I'd check it. This filter is said to be self cleaning, unless there is excess sediment or water in the tank.

I believe the key, in this case, is the start signal, as your car will run once it starts and you therefore have fuel pressure at SOME time. The Code 54 spells it out.

The computer IS your friend and the manual's flowchart leads to the fix.

:x
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
My take

"Turned the key, did NOT hear the whine of the fuel pump priming. The car started, but had to crank a LOT. "

AND

"1. Key in and turned to ON, pressure gauge hooked up. No fuel pump hum, ZERO pressure."


This is what leads.....ME..... to believe that the relay is bad.....

So Whale... I disagree with your theory.



Vig!
 

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