hugh9222

Working on my 1982 CE. Problem is NO FUEL. Replaced in-tank fuel pump. Put just over 4 gallons of gas into the tank to insure the pump was wet. Verified power and pump function prior to installation. Was careful to listen for the pump at the initial start. Heard the pump. Cranked and cranked, nothing. Removed air cleaners and primed both carbs (injector). Fired right off. No gas at carbs except of a drip every second or so on the right hand side. All this was last night. Repeated the start sequence this morning. No initial pump sound and it did not start.
Here is what I plan to do as soon as the weather improves:
1. Verify power to the connector to the pump at the tank connector.
a. If no power, check fuse. I doubt this is the problem, i.e., fuse good but no power.
b. If power, check continuity through the pump. Don’t know the ohm reading I should be looking for. COULD SOME HELP ME ON THIS??
c. With power and a reasonable ohm reading, go to #2.
d. Without an ohm reading, pump bad, go to #3.
2. Install a new fuel filter I've ordered. When the fuel line is open I will test the pump function. The car is outside so I can carefully allow gas be pumped into a catch can. I am assuming that this is not the outcome, i.e., the pump is good and there is a blockage.
3. This probable outcome leaves me with three options:
a. Replace the faulty in-tank pump with a stock replacement. Repeat what I just DID!@#$.
b. Replace the in-tank pump with an 1985 pump to improve performance and give me some comfort for having to drop that d..m. tank again. No, I could not get the in-tank assembly out without dropping the tank. Trust me I tried and this was will be the third pump I have put it this car!!
c. Finally to my main QUESTION: Can I install an in-line pump to replace the in-tank pump?? If so what pump and where to mount it??
Sorry to be so wordy. I needed to vent to someone because there is no joy in my Corvette land today.
Thanks in advance for any help you provide. Hugh

Lakeside49

Just one friendly, albeit unlikely reminder. Be sure to lock your doors with the power locks then unlock the door with the key. You just need to rule out, on a 1982. That you did not inadvertently kick-in the anti theft system. Like I've done.

j61man

Is it possible that you hooked up the two wires to the pump backwards and the pump is running in reverse?

hugh9222

Thanks for the quick replay.
Wiring: I recall mine had a one way only connector. I remember thinking about that and clamps to keep the hose on the outlet.

To the prior comment, I did not know the alarm cut off power to the pump. Will check that first.

Thanks Hugh

DUB

FIRST OFF...DO NOT put an in-line pump in...the in-tank pump is fine.

I assume you have a wiring diagram or a factory service manual...correct????

If the starter engages and want to start the engine...it has NOTHING to do with the theft deterrent system.

The 20 amp fuse in that fuse holder in your battery box is the power to the computer, fuel pump relay and also oil pressure sender on the engine. This fuse should NOT be hot...ever. If it gets hot...clean the terminals.

Sorry to read that you have to drop the tank to service the pump. Hopefully when you have the rear bumper cover off...you replace the rubber fuel hoses with new ones.

NOT knowing if you know or not...but the fuel pump will run for 2 seconds when the ignition key is turned on....then it shuts off.

Checking to see if you are getting battery voltage at the connector is wise...and that is where I would start.

If you are wanting to know what the OHM reading should be. It should be very close to zero. The power wire is NOT a resistance wire...so checking it and it being close to zero is only telling you some information...and MORE is needed BUT....it is not so much the OHM reading but the fact that the wire needs to be able to support the AMP LOAD when it is used.

I would CHECK THE VOLTAGE...and make sure it is battery voltage when it is on. IF not...then this can be repaired fairly easily...in most cases.

KEEP THIS IN mind anytime you have any electrical issues. It may save you a lot of diagnostic time...like it has done for me.

Where to start... If you a have some automotive wire...cut and strip about a 2 inch section of bare wire....so all the strands are exposed and moving around loosely. Now...cut another section of the SAME gauge wire that is 2 inches long and just strip the ends. Take your OHMMETER ( set it on 200 ohm scale) and ohm out the wire that had just the ends stripped and see what it reads. It should be darn near zero. NOW...cut just ONE strand off the other wire that you stripped...and OHM it out. It also....will read zero..or darn near it.

You can do the same exact test when placing one end of the stripped wire on the positive battery terminal or source...and it will read battery voltage as long at the wire is making good contact.

Now...both scenarios show to be the same. HERE is where the difference begins. NOW...the 2 inch wire with the ends stripped can be used to power up something...as long as the wire you used was at least 16 gauge or larger....such as jumping your cigarette lighter. BUT...that single copper wire strand can not do jack squat!!!! WHY???? Because the singe strand can not carry the amp load required to power up and run anything because there are not enough stands to do what is needed. But yet...the singe strand... ohmmed out fine and had battery voltage able to flow through it.

SO...just because a wire ohms out fine and has battery voltage going through it means nothing...if the item is still not working after these tests....and that is when sometimes checking the wire circuit in question with a headlight bulb works out well.

I use a halogen headlight bulb. I get both ends of the wire circuit in question removed and able for me to connect to these ends...or at least be able to plug a terminal into the connector to test it. Because...if you apply battery power to one end of the wire in question...and the other end you connect the high beam and low beam wires to it and then ground the wire for the bulb. When you apply power to the wire in question...if the headlight high and low beams burn just like if you tested it at the battery first...then you KNOW the wire is GOOD...and that no strands are broken in the wire. Because there is NO WAY for that headlight bulb would burn brightly...or even light up at all with only ONE STRAND of copper wire. So...if the bulb burns GREAT!

The next 'trick' is making sure that you do not have corrosion at the connections of the fuse and the other connectors...because...it the headlight does not burn brightly...you are having resistance in a loose connection or a corroded connection....and the wire can be perfectly fine.

I run into issues quite often that when the circuit is powered up...it is supplying battery voltage to the component....but when the component it turned on...I loose battery voltage all together. Then that is when the process of elimination is needed because I have to remove numerous items and verify if the power loss is at the source or a component where I have severe arching or badly damaged connectors that can not grip tightly as needed to allow the amps to do their job.

Most of this may not apply to you issue currently...but it is basic knowledge that you can use when needed.

DUB

hugie82

You said the injectors didn't pulse when you turned the key to on. You should see or hear a 2 or 3 pulse the instant that key goes to on. If you don't see that, you'll need to check the TBI fuses first than it might be a good idea to pick up a harbor freight noid light kit. It plugs into the injector harness and let's you know if it's triggering the injector.
If you still have nothing, you will have check wires and look into the distributor. The injector is triggered by the distributor that tells the ECM when to pulse.
As far as the alarm goes, my understanding was a triggered alarm only kills the starter from working. I may be wrong. My alarm was disconnected may years ago.

DUB

That's odd...I have had the air cleaner off on the Cross Fire engined Corvettes before and I have not seen the 2-3 pulses of fuel when you turn the key on. Maybe one pulse...every now and then.

They may not pulse fuel if the pressure is too low....or fuel pressure is dropping like a rock.

DUB

jdp6000

Dub, it may not be as long as a couple of seconds but you should get a prime pulse almost at the same time you here the pump engage. The prime pulse is a distinct sound. If you had the cleaner off you would see a spray of fuel when you hear the prime pulse.

Jim

jdp6000

I don't see any history for what you did. Was the car running before you changed the pump?

Don't just check the fuses. Pull them and reinstall them. Play with the wires coming out of the distributor....wiggle them. Make sure the wires are connected to the oil pressure sensor securely. The oil pressure sensor is bell shaped and located on the driver side behind the head towards the fire wall....can't miss it.

DUB

Jim,
I understand that...and I know it can pulse once.....but not 2-3 rimes like the post I commented on stated. I have never seen it pulse 2-3 times when the key is turned on. This is NOT my first rodeo with these Cross-fire engines.

DUB

jdp6000

I only get one too.

hugh9222

Weather has improved so I went out and tried to get some more info on my 82’s fuel pump. I’m an ME that barely passed intro to EE so go easy on me. AND this was over 50 years age.

There is a three wire pig tail into the tank: Black, Orange (center) and white/brown (WH/BRN).

First, I checked the voltage:
8.3 VOLTS BETWEEN THE BLACK AND ORANGE WIRES
7.7 VOLTS BETWEEN THE ORANGE AND WH/BRN WIRES
.03 VOLTS BETWEEN THE BLACK AND WH/BRN WIRES
2 MONTH OLD BATTERY, VOLTAGE READING AS 12.5

Using the 200 ohm scale on my cheap VOM I got the following readings:
BETWEEN THE BLACK AND ORANGE WIRES—37.8
BETWEEN THE ORANGE AND WH/BRN WIRES—1.0
BETWEEN THE BLACK AND WH/BRN WIRES—1.0

Why the low voltage?? If it is low what could be causing it. If NOT what could be preventing the pump from starting?? Back pressure?? The system was open for 3 weeks and some kind of blockage may have occurred.

Finally, back to my original question. Can I install an in-line fuel pump?? If I can how do I do it?? I’m not to interested in installing the fourth pump in this car!

Thanks in advance. Hugh

jdp6000

I don't think you can install an inline fuel pump.

Have you tried grounding terminal g to a on the connector under the ashtray? See link for instructions:
https://www.corvetteforum.com/forums...questions.html

Sean82

I remember on one of my fuel pump installs that the wires were backwards on the pump. - it turned the wrong way.

also the car will not start without oil pressure - there is a sensor to detect oil pressure. it cuts the fuel if not enough oil pressure

DUB

hugh9222,
DO you have a factory service manual?????

"Why the low voltage?" as you wrote....because you have an issue BEFORE the connector at the fuel tank.

Do you see the fuse INSIDE your battery box....mounted against the wall near the wheel area???? OF SO...this fuse ...which should be 20 amps if I am not mistaken...should have battery voltage going through it AT ALL TIMES. IF you check it and you have battery voltage on the 'in' side of the fuse block...meaning the power from the battery cable itself...and then the voltage drops below battery voltage on the fuse on the other side of the fuse block...then you have a contaminated fuse connection and HAVE TO MAKE SURE that you get battery voltage on BOTH sides of the fuse when it is installed...and ALSO check the terminal where the fuse contacts it. THIS IS CRITICAL...because if you do not get battery voltage at the fuel tank connector...it will not run.

More later. ...see how this goes first.

DUB

terry82

fix the pump that is in the tank .a inline fuel pump is not the fix that you want.you do not have to drop the tank to change the pump.it will come out the top.if you have low voltage that is what is burning up the pump.

hugh9222

NO GAS!!
Back again with an update on my failed efforts this past weekend. New fuel filter, replaced fuel relay, verified fuse was good (put a new one in just in case), removed and cleaned both rear grounds and checked voltage at the fuse. With the fuse out I inserted my VOM ‘s pointed probes into fuse receptacles. Zero volts with key off, 12 volts for about 2 seconds with the key in the ‘on’ position and 12 volts with the key in the ‘start’ position. Installed the new fuse and tried to start it, no gas.
I now have a wire diagram but it not helping me much. I’m sourly disappointed that GM was so cheap that they show the fuel pump in the engine compartment!! I had a hell of a time finding it. I can’t figure out how they limit the voltage to just under 2 seconds when turning the key to the ‘on’ position.
Again, with the key in the ‘on’ position, I have about 8 volts at the orange and tan/white wires at the connector just before the tank. Because there is zero voltage after 2 seconds, this voltage must be some kind of bleed over. From my reading of the wiring diagram the fuel pump and fuel gauge sending unit are independent. I can’t understand why there is not 12 volts on the orange wire at the rear tank connector.
Someone was in the fuel relay area earlier. My AIM showed it behind EMC mounting bracket inside battery bay. Of course I pulled all that crap before I did not see that the relay was missing! Found it on the right side after removing the storage tray.
I had to work alone this weekend. My grandson is available this week I’m going to check the voltage at the rear pig tail while he moves the key from ‘off’ to ‘start’.
What am I missing or did I just install a bad pump!!

jdp6000

I can't comment on the voltage difference, I've never checked that.

Everything is controlled through the ECM. You need to bypass by activating pump through terminal G under the ashtray, this runs 12 volts directly to the pump. Does the pump run when you do this? If it runs its primed the line. Once its done that you should get a prime pulse from the injectors. See if it works this way. It could be your ECM and not another faulty pump.

If the pump runs for a couple of seconds just by turning the ignition on get some one to listen at the rear of the tank for the sound from the pump and the sound of fuel being pushed around. Did you replace the black rubber hose that's in the tank? Some don't and if its broken the pump will push fuel around in the tank and not through the line to the injectors.

Jim

DUB

If you get frustrated....PM me and I will give you my shop number and we can go through this on the phone.

Not getting battery voltage is EASY.

DUB

hugie82

I was told the ECM has to see oil pressure to send power to the pump. If the oil pressure sending unit underneath the distributor is bad or you lose oil pressure, the ECM kills the power to the fuel pump. This might give you a new place to look.