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jlisenbe · Jul 23, 2014, 02:12 PM

Just took it off. Looks like it is 50 years old. Two questions:

1. Can I replace just the pump and not the rest of it?

2. Either way, what is a good place to buy the parts? Should I try online, or go with a local place such as Advance Auto?

It is a 1989 Chevy S-10.

TxGreaseMonkey · Jul 23, 2014, 04:28 PM

Do all of it. Advance Auto Parts is fine.

CaptainRich · Jul 24, 2014, 05:17 AM

It would be a shame to replace just the pump and then next month or so have the sender fail and have to take the tank down again. Best to replace the entire pump/sending unit and be done.
I use Advanced Auto.

jlisenbe · Jul 24, 2014, 04:14 PM

Thanks, guys. I'll let you know how it goes.

jlisenbe · Jul 25, 2014, 07:41 PM

Went to Advance Auto to order pump, but they did not have one, so I decided to just order off their website. Found the pump referenced below on AA for 238.00. Found what seems to be the same pump on Amazon for 95.00. Same model #, looks the same, etc. I like it since it is all metal and not plastic. So I ordered it. Let you know what happens when I get it in.

Might add I hadn't cranked the truck in a few months. Many wasps had to be subdued.

http://www.amazon.com/s/ref=nb_sb_no...der%20Assembly

jlisenbe · Aug 1, 2014, 05:29 PM

Finally got the new pump in. Tried hooking it up outside the truck. Turned on key, got a good ground, but nothing. Same thing was true of old pump, but I thought it was the pump in that case. Am I missing something here?

TxGreaseMonkey · Aug 1, 2014, 05:45 PM

. Check all under hood and under dash fuses with a test light or multi-meter.

. Check/replace fuel pump relay.

. Check ignition switch for wear, pitting, or melting.

. Ensure battery is fully charged, terminals and connections are clean and tight, and the main ground is good.

jlisenbe · Aug 2, 2014, 09:07 AM

Battery is good...new. Ignition switch seems to do everything it is supposed to do.

Where is the relay? I've posted what seems to be two good possibilities.

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TxGreaseMonkey · Aug 2, 2014, 09:53 AM

Check your Owner's Manual--it may be in the under hood fuse/relay box. Sometimes, you can substitute one of the other relays in the under hood fuse/relay box, provided they are identical. Then, if it solves the problem, buy a new relay.

If it is not in the under hood fuse/relay box, I would lean towards it being one of the relays in the first picture.

Did you check all fuses?

jlisenbe · Aug 2, 2014, 11:52 AM

OK. Problem solved. The relay is in the pic of the two relays sitting side by side. One serves the AC clutch and the other the fuel pump. They are identical. So here I am putting in an unneeded fuel pump because I did not know there was a relay. At any rate, I guess it's a good idea to put in a new pump after 25 years. The old one did look pretty bad.

Might add that I did not locate a fuse which controlled the pump. Owner's manual did not specify one. I checked them all just to be safe.

Thanks for your help.

TxGreaseMonkey · Aug 2, 2014, 11:56 AM

So the fuel pump works and the engine starts? If so, you've had a good day.

jlisenbe · Aug 2, 2014, 02:45 PM

Originally Posted by TxGreaseMonkey

So the fuel pump works and the engine starts? If so, you've had a good day.

Celebrated a little soon. The relay works and the pump cuts on. Tried it one time outside of tank to be sure. Ran it for a couple of seconds only. Put pump in. I can hear it kick on when I turn on the key. It stays on for a couple of seconds and cuts off. It's my understanding that it's supposed to do that, then cut on when you crank it. Well, it'll crank just fine when I prime it, but won't hit a lick without the prime. So far as I can tell, I'm not getting gas to the carb. So what's next? Filter?

BTW, new pump is AC-Delco and put a new filter on the pump as well.

TxGreaseMonkey · Aug 2, 2014, 03:07 PM

The fuel rail, going to the Throttle Body Injection (TBI), needs to be fully pressurized in order for the engine to start--you do not have a carburetor. Turn the ignition switch to ON and wait for the fuel pump to stop. Then, turn the ignition switch OFF. Repeat this sequence two more times. On the final time, turn the ignition switch to START. Hopefully, it fires right up. Make sure you have more than a token amount of fresh gas in the tank.

jlisenbe · Aug 2, 2014, 03:31 PM

Tried that several times. No luck. Won't hit a lick.

How can be sure that the pump is actually pumping gas? I know it's kicking on.

TxGreaseMonkey · Aug 2, 2014, 04:00 PM

Check the pressure at the fuel rail (Schrader valve). Otherwise, check the flow through the fuel filter.

Is the gas tank full? Have you checked for spark?

jlisenbe · Aug 2, 2014, 04:19 PM

Originally Posted by TxGreaseMonkey

Check the pressure at the fuel rail (Schrader valve). Otherwise, check the flow through the fuel filter.

Is the gas tank full? Have you checked for spark?

Put some gas in it. Not full, but should be plenty. Haven't checked for spark, but it will fire up fine when I prime it. Won't do anything without it but turn over.

Did not see a schrader valve. I'll try to check the flow tomorrow. Much as I hate to admit it, I might be whipped. Might have to get it towed. It's just an old pickup that it's nice to have around. Hate to spend a ton on it, but I guess I'll have to spend some. Thanks for your help. I might hit it again a little more next Saturday. I have located the filter. It's kind of tucked in between the engine and firewall.

TxGreaseMonkey · Aug 2, 2014, 04:27 PM

Consider replacing the filter--it may be clogged.

When did the engine last start and run normally? I ask because I sometimes see engines that will start with starting fluid but not continue to run. Frequently, it is because the Ignition Control Module (ICM) is bad.

jlisenbe · Aug 3, 2014, 04:56 AM

Been a few months. This is my dad's old truck. It has never run well for me. Had to have it towed a couple of years ago. Fuel related issue that time as well. I noticed there seems to be a lot of material at the bottom of the fuel tank.

How would an ICM disrupt fuel flow? Would that happen at the injectors?

TxGreaseMonkey · Aug 3, 2014, 05:52 AM

Likely dirt and/or rust--one reason the fuel filter may be plugged. The tank should be dropped and cleaned out or replaced.

A good ICM ensures the plugs fire when they are supposed to. A failing ICM may fire the plugs at the wrong time but give the appearance that everything is okay, when starting fluid is used. Starting fluid ensures all the plugs have fuel for a short period of time; however, the engine won't run for long. The ICM doesn't disrupt fuel flow; instead, it allows the plugs to fire in sync with the fuel injector system. In other words, starting fluid can mask a faulty ignition system and lead you to the wrong conclusion (i.e., instead of being a fuel problem, it's really an ignition system problem).

jlisenbe · Aug 16, 2014, 12:38 PM

OK. Back at it. I know the pump is pumping. Ran it through a two foot or so line into a plastic container. Seems to be pumping good and strong. So I guess the filter is the next likely place to look. Try that today.

Question. When the line exits the filter, it goes around the end of the motor and disappears. On the other side, there seems to be three lines. One goes into the back end of the manifold, while the other two enter the carburetor looking device, one on either side of it, and seem to lead to the injector at the top. If that is the case, then there must be some device that takes the one gas line and splits it into two. Is that the case?