'87 LeSabre 3.8 - Fuel Pump Issues? - Page 4 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


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Old 03-10-2013, 12:12 PM   #31
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The vacuum bit on the transmission you are looking at is the vacuum modulator. It controls the line pressures, which in turn, controls how hard the tranny shifts. If the car shifts fine, it is not leaking vacuum, and transmission fluid is not leaking out of it, I wouldn't worry too much about it. You can disconnect it and try driving without it, but be warned that with no vacuum, it will be commanding maximum pressure, which means it will be shifting very hard.

I agree though, fix your vacuum leak, that is a good place to start. If there is a TCS issue, then either it is not locking up (not a concern here), or it is locking up when it shouldn't be (possible).
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Old 03-11-2013, 09:25 PM   #32
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*rolls eyes* Gotta love the Einsteins at AA...

So I go in this morning to buy a replacement for the vacuum tee I accidentally broke when I connected the vacuum gauge. As usual, it was a <*>comedy of errors</*> textbook case of "Well, you're gonna have to go to a dealer, we can't get that part."

I walk into the store, five minutes after opening (on my way home from work), with the <i>actual broken piece</i> in my hand. I walk straight to the Dorman Help! aisle, and look through everything that'* there. I'd be all set if I needed any of fifteen different brake bleeder bolts, three different remote fobs, ten styles of tailgate cables, numerous other items - but *nothing* related to vacuum.

So I ask the counter help, and he asks if I'd checked their other shelves with the vacuum fittings on it - also a Dorman Help! aisle, about 5 feel long, which is behind the counter and down another aisle. OK, I follow him to that aisle, and we take a 2-minute scan through the generic fittings - tees, elbows, joiners. Nothing like what I'm looking for, and I had to tell him what the part was - I said I was unsure if it was a filter or a check valve. (He then asks what a vacuum filter would accomplish - this guy had ten years or more on me, it wasn't some idiotic kid like they usually have working there.) We go back to the main counter, where he looks up the Year/Make/Model/Engine, and then promptly can't find the part listing *anywhere.* Apparently, the AA Computer God never included listings for most of the parts I have to look for.

So I wasted time and gas driving out there... Tonight, when I woke up, I simply did a Google Image search for "automotive vacuum fitting" - and there, two rows down in the center, is the EXACT item I'm looking for! Shazam!

So I go to the website, lo and behold, the item is a Dorman Help! item! And now I have the part number. Ya know what? I'd be glad to make $9/hr looking this stuff up for the people who don't want to. Even better, I looked up the part number on AA'* website - they carry it - and it'* <b><u>IN STOCK</b></u> at the Norwich, CT store where I was this morning.

Effing A. :-\

So I'm gonna get the part tomorrow, give them a piece of my mind, and try running with both the TCC and the modulator disconnected (one at a time, of course) and see how that goes. I don't work tomorrow night, so with any hope, I'll see some results and either be driving again or at least have something to report back on.
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Old 03-11-2013, 09:25 PM   #33
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Oopsie... I was typing in HTML again.
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Old 03-11-2013, 09:38 PM   #34
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Oh, BTW, the vacuum leak was created when I was disconnecting a line to connect the vacuum gauge. So the broken part of the tee didn't cause the original problem; but AFAIK it'* supposed to be a two-outlet check valve, and it sure doesn't "check."
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Old 03-16-2013, 07:22 PM   #35
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With the new check valve, the car still runs like it did before. Disconnecting the TCC solenoid had no effect, and neither did pulling and capping the vacuum to the shift pressure regulator.

So... I don't know what to check next. MAP? MAF? ICM? Coil Packs? Nothing is triggering the SES light, about the only thing that'* changed is I sometimes have to try multiple times to get the engine started, usually the second or third attempt works.

Thanks, guys, for all your help so far... My mom may have a job soon, so it'* kinda urgent that I get my car running - otherwise I'll have to get the Mighty Max running, and that'* not exactly what I wanted to do since it needs more work (even though it starts and runs beautifully... Front end wobbling, emissions, exhaust, tires, registration, insurance...)
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Old 03-16-2013, 08:15 PM   #36
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Question Knock Sensor, Perhaps?

I've been looking through the paperwork my neighbor gave me when I bought the car from him; and doing some research here on the forums, and I just wanted to throw out there the work that has been done on the car...

The nylon timing belt gears (what was GM thinking?) were already changed out and fortunately they went on startup - not while cruising, so I'm eliminating that and valve damage as a possibility.

Also, as described previously, the ICM and one or two coil packs were replaced. Brand-new 02 sensor (which wouldn't affect it, I assume).

Recent repairs I've done include a PS pump, tensioner pulley, tensioner assembly. This is due to a loud rattle at idle that came out of nowhere. The rattle goes away at 1000 rpm, and is definitely belt-driven, and I've narrowed it down to either alternator or water pump. Leaning towards water pump, since it spins freely but the pulley has actual in-out movement. It was kinda low-priority to fix, since all it did was annoy people at stoplights.

Now, I could be wrong, but I have a theory that I'd like your input on... At first I didn't think it could possibly be related, *buuuuut*...

Could the water pump be causing vibration/noise within the engine that the knock sensor could be "hearing," and adjusting timing accordingly, thus causing the lack of power? It would be just my luck if it was some sort of cascade failure, or something seemingly unrelated that caused the problem.
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Old 03-31-2013, 08:56 PM   #37
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*bump* LOL

OK, so I've purchased some tools, and done some poking around under the hood in preparation for another Day of Diagnosis.

I've pulled the IAC, cleaned it. Pulled the MAF, cleaned it. Cleaned a lot of crud out of the throttle body. Checked every single vacuum line and fitting. Checked every connector and connection. I pulled the coil pack and checked wiring - one wire was unattached, but I assume that happened when I separated the coil pack and ICM. I even checked my TPS, and it was flawless from 0% to WOT.

My next step is to put gas in the tank (ran it empty last time I was charging the battery), swap the battery back over from the Mighty Max to the Buick, change the water pump (at least I can cure the obnoxious rattling, so it won't be as bad nosing around while the engine is running), and then test the ignition system. I have a good feeling that my wires are to blame; they're almost 4 years old (with less than 20k miles, though). I figure, it can't hurt. Plus, I'm sure that at least one of these wires would break if I pull a plug to check them.

If anyone else has any ideas, I'd love to hear them. Still stumped tracking this down; and Mom starts her new job tomorrow so I gotta get my arse in gear.
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Old 04-03-2013, 06:58 PM   #38
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You might want to remove the o2 sensor pre catalyst. Then run the engine. If it dramatically improves look for a clogged exhaust. Most likely culpret is the Catalytic converter but a bent shut pipe anywhere would do it. GM fuel pumps usually just fail completely. Seldom have I seen low fuel pressure on one of these Buicks
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Old 04-13-2013, 07:51 PM   #39
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Lightbulb *sighs dramatically* Some days you're the windshield, sometimes you're the bug...

So I finally got under the hood... I've had to pull a few extra shifts at work, deal with some interesting weather, and today started wrenching some more.

As I predicted, spark plug wires broke. Five out of six, in fact. They were AC Delco, replaced with *shudders* Xact brand. Eeesh, absolute crap wires. Anywho, two of the six spark plugs broke upon removal. I replaced AC Delco plugs with AC Delco plugs, I figured I didn't want to think of putting pricey plugs in with junk wires. :-\

While under the hood, I was going to replace the water pump... My memory was faulty regarding the in-out play in the pulley, there really isn't as much as I thought. I did, however, discover the cause of my obnoxious rattling issue.

*insert trumpet fanfare here, followed by fart noise*

Harmonic balancer. With engine off, I can rotate it by hand, either direction, part of a turn, and at either end of movement, it makes the obnoxious clunk noise that I have come to loathe.

So! I know I've got to change the balancer, and there are two different types based on three stamped numbers. (And the option of $92.99 or $164.99) So, one part is coming in tomorrow, and the other on Monday afternoon. I guess I gotta get a breaker bar on the crank and rotate the engine to see if I can find what number is stamped on the factory one.

Would the defective harmonic balancer throw the timing out of whack? Does it mess with the crank sensor signal at all? (Come to think of it - might as well change the crank sensor while I've got it apart, eh?)
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Old 04-13-2013, 09:22 PM   #40
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A bad harmonic balancer can definitely cause the performance problems you are experiencing. Absolute good sense to change the CPS while you are changing the harmonic balancer.
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