Another Jimmy fuel pump question (sorry, long post)


Powerarranger
04-05-2005, 08:13 PM
We have a 93 Jimmy 2WD 4.3 Vortec. The truck suddenly turned off as I was driving on the highway. It wouldn't start again for about an hour, then it started again but ran only for a minute or so...shut off, then wouldn't start again for a while. I noticed that I wasn't always hearing the fuel pump kick in when starting.

Found out the hot lead on the wiring harness to the fuel pump was corroded and had broken off. We replaced the sending unit assembly and the strainer, but kept the old pump which was replaced nine months ago with a part from Advance Auto.

The truck started fine. We drove for ten minutes, turned it off for three. It wouldn't start. Couldn't get it started...left it for the night. Next day it started fine. We drove it to the garage, changed the fuel filter. It still wouldn't start. It seemed as if it had to completely cool down before it would start again.

Towed it home since it wouldn't start. Of course, it started up as soon as we got it home. Run for awhile, bada bing, dead again.

In the past 2.5 years we have replaced the distributor and ignition module, the injector assembly, the alternator, and the original fuel pump. AC/Delco plugs are less than a year old, as are the ignition cables.

Should we go ahead and replace the fuel pump? We have an OEM pump ready to install. Should we replace the pulsator as well (I'm assuming that's what the pump plugs into)? Could the pulsator(?) be the problem?

FYI, we're getting a good spark...everything seems normal, but maybe we're missing something. We've pressed the schraeder valve and gotten some fuel but the pressure seems weak. Gonna do some pressure tests with a real gauge in the morning before we drop the tank again. Any and all ideas as to what we could be missing would be greatly appreciated!

Cheers!

rlith
04-06-2005, 06:22 AM
I would replace the pump, and certainly replace the pulsator. I had my pulsator die on me a month or so back... Change it while you have the tank out.

Powerarranger
04-06-2005, 09:09 AM
I would replace the pump, and certainly replace the pulsator. I had my pulsator die on me a month or so back... Change it while you have the tank out.

What are the symptoms of a bad pulsator? What does the pulsator do?

rlith
04-06-2005, 09:50 AM
The pulsator meteres the gas, it can cause anything from bad running to (in my case) a dead car...

Powerarranger
04-06-2005, 02:49 PM
The pulsator meteres the gas, it can cause anything from bad running to (in my case) a dead car...

Thanks for the tip! I checked at the dealer and several auto parts stores - nobody has it in stock. I'll have to order one.

Found out that the old pump was over-amping and burned up the new connector. I'm going back to the dealer in hopes that they can repair the connector - otherwise, I have to buy a whole new sender to the tune of $300!

Thanks for all the help!

rlith
04-06-2005, 02:51 PM
Thanks for the tip! I checked at the dealer and several auto parts stores - nobody has it in stock. I'll have to order one.

Found out that the old pump was over-amping and burned up the new connector. I'm going back to the dealer in hopes that they can repair the connector - otherwise, I have to buy a whole new sender to the tune of $300!

Thanks for all the help!

You can get a new sending unit for $180.00 at advance autoparts

Powerarranger
04-06-2005, 06:45 PM
You can get a new sending unit for $180.00 at advance autoparts

Great! Thanks for the tip - I'm going to have to stop temporarily. Gotta go to work so I can afford to buy these parts!

Thanks for all the help - I'll keep you posted when I start work again in about a week.

BlazerLT
04-09-2005, 03:06 AM
chekc fuel pressure.

Should be between 56-64 psi with the key on and the engine off.

BotaLadyG
04-10-2005, 08:23 PM
I was having similar issues with my '95 Jimmy and I found the problem was my fuel pump relay (which I found in my glove box?! contrary to where the local GM dealer said it would be)

Might want to look at that as a possible problem too it costs alot less to replace than the pump and sending unit... trust me!!! :banghead:

Nicole

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