Have had car 6 years no problem

Tiny
AAJILON
  • 1994 BUICK LESABRE
  • 54,000 MILES

Have had car 6 years no problem. Southern Car. Winter car for so it sits in summer. Gas tank got low this past summer. Then the problem started. Now intermittmently stalls out. The longer you drive it the more it stalls. Then finally can't keep it running for more than a minute or two. Cleaned MAF. Had Computer module replaced. Ignition module was eplaced. Before it stalls it runs fine

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Tuesday, October 30th, 2012 AT 1:13 PM

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Tiny
HMAC300
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Scan for codes and check fue pressure first.

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Tuesday, October 30th, 2012 AT 1:24 PM
Tiny
AAJILON
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The fuel pressure has been checked and was told it is okay. Given off different codes for computer module which was replaced, MAF which was cleaned. Or no code at all.

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Tuesday, October 30th, 2012 AT 1:28 PM
Tiny
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Check cranks sensor and connections then, what were the codes? Fuel pressure should be 41-47 psi at idle. If below that it's a pump. Clean throttle plate on both sides and iac hole as well.

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Tuesday, October 30th, 2012 AT 1:30 PM
Tiny
AAJILON
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I will check on the fuel pressure psi. I do not believe that the cranks sensor has been looked at nor the throttle plate. Thank you.

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Tuesday, October 30th, 2012 AT 1:58 PM
Tiny
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Also have the resistance checked in crank sensor as they can have to much resistance and fail when hot.

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Tuesday, October 30th, 2012 AT 3:16 PM
Tiny
AAJILON
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Thank you. That might explain why the car stalls more often the longer I drive it. Will definitely have that checked.

The fuel pressure is in the 40s

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Tuesday, October 30th, 2012 AT 4:58 PM
Tiny
CARADIODOC
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Hi guys. Excuse me for butting in; I was just passing through. Don't overlook a plugged pickup sock in the gas tank. They can collapse and block fuel flow, then stretch out again after the engine has been off a while. The main comment I wanted to share is with an intermittent problem like this, any testing, especially things like fuel pressure, has to be done while the problem is occurring, otherwise it's irrelevant.

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Wednesday, October 31st, 2012 AT 9:34 AM
Tiny
AAJILON
  • MEMBER

Thanks for all the suggestions. My Buick is now fixed. Ended up taking it to a Buick Dealership after my local mechanic had the car for over 3 weeks with no diagnosis. Well it turned it turned out to be the computer module. The part which I asked the local mechanic to make sure was good and he did not. Cost me a chunk of change because he did not do one simple thing. Check to see if the part was good.I am going back to them today to request a refund! The Buick dealership had my car in and out in about a 1/2 day!

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Monday, November 5th, 2012 AT 2:26 PM
Tiny
CARADIODOC
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You asked him to do something that is almost impossible to do, especially with intermittent problems. When the engine is running, there is no defect to be found so no matter where or how hard he checks, the computer is doing what it's supposed to do, ... Running the engine. Engine Computers really don't cause as much trouble as most people think. GM computers from the late '80s were the exception. Mechanics changed so many of them that that's the first thing many of them jump on today.

When you have a no-start condition, it's rarely caused by the computer but when it is, you know it as soon as you plug in a new one because the engine fires up. With intermittent problems that are hard to duplicate when you want them to act up, all we can do is try the most likely causes to eliminate them as suspects, THEN assume it's the computer after there's nothing else left. We have the same trouble with integrated circuits in tvs and vcrs, There is no way to test them. We have to check power supply voltages, grounds, input signals, and be sure the outputs aren't shorted. That takes a long time, but then we can make an educated guess that IC is bad if everything around it is good but it doesn't do what it is supposed to do.

The other problem with intermittent problems is you can never know it's fixed if it doesn't act up after you replaced or did something. If it acts up again, you know it's not fixed. But if it doesn't act up, is it fixed or it just hasn't acted up yet?

Don't be too hard on your mechanic. The only way he could have done what you requested would be to send your old computer to a rebuilder with very expensive test equipment dedicated to your specific computer, or he would have to have a known good used one on hand to plug in and try. As you can see, that still won't tell him definitively if the old one was bad.

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Tuesday, November 6th, 2012 AT 9:47 AM
Tiny
AAJILON
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Thanks for your reply but you are dead wrong on this one!

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Tuesday, November 6th, 2012 AT 2:30 PM
Tiny
CARADIODOC
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What am I wrong about? If you mean testing your computer, I challenge you to find any test procedure or list of steps in any service manual for any brand of car. You requested something that can not be done. All you can do is test other things to eliminate everything but the computer. The people at the dealership only see certain brands and models and they're familiar with seeing the same failures and same causes over and over, so of course they're often going to know the fix sooner. They will also know that when a '90s model GM car has an intermittent problem it is often caused by the computer. I just got done having a conversation with someone who is angry because their mechanic said the problem WAS caused by the computer. The owner spent a pile of money on a rebuilt one and is having the same intermittent problem. What would YOU think of someone who didn't bother to do other tests to rule out other potential causes? No matter what we do, the customers get mad.

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Wednesday, November 7th, 2012 AT 7:22 AM
Tiny
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Ya but will they complain when a doctor screws up slightly like that, probably not. It's always been that way and will continue because mechanic are thought of as the next thing to dirt.

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Wednesday, November 7th, 2012 AT 1:48 PM
Tiny
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I just reread the original post. The problem started after he ran it low on gas, (which is a normal condition on any car), so he suspects the Engine Computer. Huh? Where did that logic come from? Then he says the computer was replaced. At least that's more detail than we're getting from many other people lately, but if he had the same problem before and after the computer was replaced, why would he suspect it again? Especially with all the different problems and symptoms they can cause, what's the chances of him getting the only two that will cause exactly the same problem?

There's no denying a third computer solved the problem, and I'm happy for that, but how do we know it's really solved? It's an intermittent problem and maybe it just hasn't acted up yet. We're all frustrated by intermittent problems because we rarely know for sure when they're solved.

I guess the moral of the story is don't run your car low on gas because it will damage the computer.

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Wednesday, November 7th, 2012 AT 6:25 PM

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