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Vette won't start:The Next Generation

rdgfx3

Well-known member
Joined
Jul 25, 2001
Messages
202
Location
Rowlett,TX.
Corvette
2008 Silver Coupe
After reading Tucks multi page headache,I hated to post this,but where else do ya go?Besides,mines a lil' different.

90 L98,laid up since March 24(snif..)

Finally,decided that the body work was more than I could handle or take the time for and sent it to a body shop.

It won't start.

We are getting no power to the fuel pump.I have a factory service manual,but I can only get to a point of frustration and then I have to ask the Action Center.

Relays seem fine.

Code 12(of course)

Guide me to the right pages please.GM factory service manual.1990.

Nothing in the index guides me to fuel pump electrical diagnostic,sooooo......

I get the body fixed and now this.Oh Please.

CALGONITE,TAKE ME AWAY!!!!
 

Ken

Gone but not forgotten
Joined
Jan 30, 2001
Messages
8,236
Location
Hermosa Beach, CA
Corvette
1987 Z51 Silver Coupe
The fuel pump has a relay, just where on yours it is located I can't tell you because I don't know, but on my '87 manual-trans car, it was on the same bracket as the Doug Nash 4+3 relay on the firewall behind the distributor, between it and the windshield wiper motor.

_ken :w
 

rdgfx3

Well-known member
Joined
Jul 25, 2001
Messages
202
Location
Rowlett,TX.
Corvette
2008 Silver Coupe
I believe my 90 has two relays for the fuel pump.The body shop guy was trying to get it running and he readily admits he's a body man,not a mechanic.But he *is*trying to get it going.

When I went over there,he had checked one relay and was trying to find the second relay.It was under the dash on the passenger side,we found it and it was OK.Fuse was OK.

We made a jumper directly to the fuel pump and it wouldn't spin.

Oh,one thing.The car ran of gas while he was moving it around the shop.It was bone dry when the wreck happened,so I'm not surprised it ran out of fuel.He put 5 gallons of gas in so it has gas.Any chance that lack of fuel to that vehicles fuel pump could have damaged it or set off a self protection action?Something that shuts power off to the pump so it's not damaged by fuel starvation.
Just a stab in the dark.

My MR2 has been giving me pure bloody friggin hell lately and I really,really don't need this additional automotive headache.I told my wife that if the Vette comes back and starts giving me problems like the MR2,then they were both GONE!!
She's not gonna be real happy if I come home in a new Vette while she's still in the 94 Cavilier.No sir,she will not be happy.:mad


But I will.At least while she's not around.:J
 

Ken

Gone but not forgotten
Joined
Jan 30, 2001
Messages
8,236
Location
Hermosa Beach, CA
Corvette
1987 Z51 Silver Coupe
rdgfx3 said:
Something that shuts power off to the pump so it's not damaged by fuel starvation.

Hmmm... good question. I've never heard it asked before. I'll see if I can find something but it the meantime somebody else might already know and provide an answer. He (or she) might even ride a Harley too. :L

_ken :w
 

rdgfx3

Well-known member
Joined
Jul 25, 2001
Messages
202
Location
Rowlett,TX.
Corvette
2008 Silver Coupe
Thanks Ken!

Please note I jab the Dealer,not the rider.

My local HD dealer has me riding a BMW.I'm so glad they weren't able to take me for $4000 over list.BMW scooter for $2000 under list is *much* better.And you can actually ride it for more than thirty minutes at a time!!!

OK,I'm through with that rant.:z
 
T

Tuck

Guest
I feel your pain brother!!!

The only thing worse than not owning a vette, is owning one but not being able to drive it!!

Anyway, from looking at my Chiltons manual, and going by what you said about having 2 relays you must have "Sequential Multiport fuel injection" (VIN J).

BUT you said it was a L98 (which unless I am reading the diagrams wrong and probably am since I am a rookie) it would only have one relay. That is "Multiport....." (VIN 8) and would only have one pump.

Makes a big difference in the wiring diagrams which one it is.

But sounds to me (remember I am a rookie) that if you ran a 12 volt jumper all the way back to the fuel pump, it probably doesn't matter-the fuel pump (or pumps) need to be replaced.

Also I could find nothing in the book about a safety shut down.

Good luck getting back on the road.
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Richard.... I feel your pain Bro.

So here's the first test......

Find the OIL pressure switch .
( see Tucks posts)

Remove gas cap & have assistant listen.

Jump the Orange & Red Lines
( Make sure the Orange is HOT all the time)


Is she spinning/pumping?

So how long has the car been sitting WITHOUT gas March 24th??!! Almost 4 months??

NOT GOOD!

If the jumper doesnt make the pump spin.. It's probably seized.. I have seen MANY pumps @ the wrecking yards just rust up if they are NOT submersed in fuel.

Let us know.....

Vig!
 
S

Shadowing1985v

Guest
hmm

this is a easy simple fix

same thing happen to my 85

get a torque wrench,,

i think all the screws are torque

take off the gas lid
then the gas cap

now unplug the wiring

get a ohm meter , turn your key on
and measure voltage

if u are getting voltage that means your relay is fine and your pump is bad, don't sit there and try to mess with relays messing with relays is a bad thing, cause relay's don't go bad as offten as most people think cause there are fuse links and fuses to protect them, check the voltage and it will be the easiest way,,,, i had my pump stop working on me,, one day it worked next day it didn't, hope this helps you out
 

rdgfx3

Well-known member
Joined
Jul 25, 2001
Messages
202
Location
Rowlett,TX.
Corvette
2008 Silver Coupe
Makes a big difference in the wiring diagrams which one it is.

As a matter of fact,I did catch Cody(body shop guy)looking at the wrong section in the manual.Told him about it.It is indeed an L-98.

We are not getting voltage to the fuel pump.

WITHOUT gas March 24th??!!

Very little gas.It had less than a half gallon by my best guess.
That makes me wonder.
Did it actually run out of gas or did the fuel delivery system malfunction.Hmmm..

No voltage to fuel pump.So I'm told.I will have to go down there (body shop)and verify he is correct on some of what he's told me.If he is looking at the VIN J info,he's gonna have trouble diagnosing.
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
On a 93 fuel system

Don't have a 90 book....

The relay pins are
1) Red ( Output to pump ) WHICH IS FUSED FP#1 in fuse panel

2) Black/White ( Ground for Coil of relay )

3) N/C

4) Red Hot feed from Fuse panel
( Fuel pump feed 20 amp MAXI fuse)

5)Drk/ Green/White from pin D-5 of ECM
Fuel pump drive ( Line goes HIGH when VATS is happy & start is issued)


Vig!
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Again with the 93 info

The relay for fuel pump #1
L-98


This is a bit trickey....

The way the drawing shows

Under the PASSENGERS SIDE of the dash there are 5 relays

From centerline of car moving out

Fog lamp relay
Courtesy relay ( interior lights )
SPACE

Fuel pump relay
Horn relay
Rear Defogger relay

Now the drawing a bit to cryptic to give you a better location than this.

And the tops of the relays are facing the front of the car.....

IF your 90 & 93 are similar... which I think in this reguard they would be.

Vig!
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
And more 93 info

1) The HOT line @ the Tank might be a GREY

2) The Oil pressure switch ( For this year ) has a 4 pin connection

Pin C Orange ( Main switch )
Pin D Red ( Other half of main switch )

Pin A Tan ( To instrument panel )

And a connection to grnd internal of the sender.


Vig!
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Yet MORE 93 Fuel pump info

So it looks like you must drop the TRIM panel
Pass side to get access to the fuel pump relay


Vig!
 

rdgfx3

Well-known member
Joined
Jul 25, 2001
Messages
202
Location
Rowlett,TX.
Corvette
2008 Silver Coupe
Been down to the shop.The guy made the car look perfect.

But he's no mechanic.

Talked with him and found out:

1.The car indeed had gas when it stopped.He said it was running,then started stumbling,then quit.Wouldn't restart.

2.The relay has NOT been checked.

3.The fuse IS good.

4.Communication IS necessary.

5.Tommorrow I will be down there and *I*will go thru it.

If he was online at the shop,this would be easier.Something about a perfect world or along those lines ya know.
 

vigman

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

The car dosen't run.......

The car cranks.......

The fuel pump is not running ( No power )

The car sputtered & died... and has been left that way for SOME time.


Am I missing anything ( So far )


Vig!
 

rdgfx3

Well-known member
Joined
Jul 25, 2001
Messages
202
Location
Rowlett,TX.
Corvette
2008 Silver Coupe
No Vig.
It sat in my garage for several weeks after the ..uh,....*damage incident*.(Approx.3-24 to 7-15).

I started it,pulled it out of the garage,let a flatbed car hauler take it to a body shop.

Body shop had it several days,moved it a few times under it's own power,then it started,sputtered,died and stayed dead.It died last friday.Otherwise,yes to doesn't run,does crank,and no power to fuel pump.

Somehow I missed your posts earlier.I'm gonna have to say though that the 93 is quite a different beast than my 90.LT-1 started in ....92?

I do have the GM service manuals for my year model.How ever,these manuals are based on the assumption that the user is a qualified service tech,which I am not.So sometimes they can be a little to follow.It's still the best $125.00 I've spent on the car.
 

rdgfx3

Well-known member
Joined
Jul 25, 2001
Messages
202
Location
Rowlett,TX.
Corvette
2008 Silver Coupe
One more.

It did have gas in it when it died.He says it showed one bar on the fuel gauge.Then he added 5 gallons cause he thought it ran out of gas by the way it acted.
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Well you have a cross platform

The 93 info will be ( I think correct ) as far as the dash wiring goes.

The info in the Ken post should be correct as far as the engine side of the firewall is concerned.

The ONLY thing I'm confused about is where the actual fuel pump relay exists.

Your ECM is under the hood... correct?


Vig!
 

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