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Old 06-29-2013, 07:32 PM   #1
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Default Revs up and goes back to idle speed repeatedly with pedal floored

I have a '91 Lesabre Custom with a 3800 V6.

I have been having this issue for a while, recently had a shop replace all of my fuel lines and a new filter installed, thinking it would fix the issue because I thought it was due to me breaking one of the lines.

So it won't go WOT.
And at idle, in park, with the pedal to the floor, it just revs up and down, even when I am slowly increasing throttle application.

I have replaced the following:

Fuel lines
Fuel filter
Spark Plugs
Spark Plug Wires
Ignition Coils
A very weak battery
Idle Air Control
Cleaned the MAF


At this point I'm a bit confused. I would have hoped the issue would be fixed by now. Any advise or ideas? I would really appreciate it. Want to get this beautiful car on the road.
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Old 06-29-2013, 07:34 PM   #2
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Forgot to mention that it acts like it wants to stall on deceleration, and any more than 25% throttle while driving will cause it to bog way down and cut out...
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Old 06-29-2013, 08:50 PM   #3
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Have you tested the throttle position sensor?

Has fuel pressure been checked?

Check this out to help you test the TPS.
https://www.gmforum.com/trouble-shoo...sensor-279319/
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Old 06-29-2013, 10:11 PM   #4
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Thanks. I didn't realize a mechanical throttle car would have a TPS. Found it and tests OK.
So I disconnected the fuel line and dripped the tank out by cycling the fuel pump. Took forever. Dropped the tank and pulled the pump. Pump is cracked and leaking in 4 places under the sleeve and the strainer is completely clogged up. Evidence of overheating and blue metal in places.

I'm happy now. I will replace the fuel pump, bolt that tank back up... gonna need new straps though. Want to get this old girl running right and drive her until the frame rusts out! I AM NEVER GIVING UP!!
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Old 06-29-2013, 10:18 PM   #5
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Will update when I get around to putting the new pump in and getting her back together.
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Old 06-29-2013, 10:46 PM   #6
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Quote:
Originally Posted by Timmah View Post
Will update when I get around to putting the new pump in and getting her back together.
Looking forward to hearing how it goes, while you are at it I'd check the soft rubber connector that connects the EVAP line to the hard metal part of the tank, on my 96' PA I found that the soft rubber needed to be replaced at both ends of that rear EVAP nylon line, near the tank, and near/almost under the fuel filter.

When done be sure to keep an eye on the quick connects you had to disconnect, from what I learned recently from Justin, they can leak if you disconnect them, and reconnect them, not always of course, but there is always a chance.

Also, try to avoid getting the Airtex pumps, they are not that reliable, I recommend ACDELCO Part # EP378, along with the strainer ACDELCO Part # TS32
You will spend about 80.00 total if you get it from RockAuto, and you can even save a few bucks if you check our thread that people post rockauto discount codes in.

https://www.gmforum.com/general-gm-c...279335/page10/

There are no valid codes posted currently, but I am sure somebody will have one soon.



If you have an Amazon Prime account you can save a few more dollars, total is 72.33 shipped with Amazon Prime, wait,,, just checked and you can get it shipped free even if you do not have a Prime Account, but it will take a couple of days to get, stock is really low though, so if you order it from Amazon you better order it ASAP.

Amazon.com: ACDelco EP378 Fuel Pump: Automotive Amazon.com: ACDelco EP378 Fuel Pump: Automotive


ACDelco TS32 Fuel Pump Strainer : Amazon.com : Automotive ACDelco TS32 Fuel Pump Strainer : Amazon.com : Automotive
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Old 06-30-2013, 12:39 AM   #7
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You have been very helpful, thanks.

Ah, that pump is a 1.45" in diameter and mine is 2" in diameter. I measured it. The dimensions of that pump wouldn't fit properly in the sender unit on my car.

The weird part is, I see both the 1.45" and the 2" pumps on Rockauto. I thought maybe these pumps were for use in the 4cyl models until I realized they didn't make a 4cyl that year??

Mine looks like this

https://www.rockauto.com/catalog/mor...685&cc=1019573

I think I may simply buy from the local Advance Auto Parts as I have a $25.00 off coupon for orders over $50.00...

And yeah, those Snap-Grips are a PITA. I think I'll buy some from my boss at work, we use them in our product. Will keep me from having to buy a whole bag of 'em. :P
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Old 06-30-2013, 12:41 AM   #8
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Oh yeah, talk about a stupid mistake. My neighbor gave me a spare fuel pump he had lying around... wanted to test it and STUPIDLY hooked it up to 120V instead of 12V on my tester. It smoked like crazy, I think I killed it
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Old 06-30-2013, 01:19 PM   #9
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I was a little confused about the different pump sizes also, which is why I recommended one that was listed as one of their more popular parts, I guess it is more popularly sold overall, and not for you car as they'd lead you to believe.
Sorry about the mistake, glad you caught it!

I'd take the old pump with you to Advance Auto when you go to get the replacement, just in case.
I am not sure if they carry Delphi pumps or not, but I am pretty sure the Delphi brand is the OE pump.

Sucks about the neighbors fuel pump, definitely sounds like it burnt up, getting 100% more voltage will definitely do that.
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Old 06-30-2013, 05:49 PM   #10
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SWEET SEXY JUMPING JESUS!!!
Just picked up the following:

Spectra Premium/Fuel Tank (GM20B) | AutoZone.com

Spectra Premium/Fuel Pump (SP07B1H) | 1991 Buick Lesabre 6 Cylinders C 3.8L FI OHV | AutoZone.com


From my local Autozone store, along with some new tank straps.

Installed and started in less than half a crank, runs circles around its former self.
Hit the JY and pulled a Catalytic Converter and complete exhaust, but cut the muffler out and replaced it with a glasspack...

Was still running off so drove it over to Autozone and picked up a new TPS.
Now it idles so smoothly and instant response under acceleration...

HOLY SHXT I CAN'T STOP LISTENING TO THE IDLE!!
Please pinch me I'm in hog heaven!
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