1998 Buick Lesabre 98 Buick Lesabre cranks but does not sta

Tiny
TERRYS10
  • MEMBER
  • 1998 BUICK LESABRE
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 54,000 MILES
The engine was running just fine and suddenly, while driving, began to misfire and loose power, I managed to make it to my destination, but was unable to start it when I was ready to leave. I checked spark at the ignition coils and got a pretty good orangish arc. I also verified the fuel pump is pumping at least 20 PSI (gauge limit). Plugs look a bit oily but okay otherwise. I did not check spark at the plugs. With the key in the on position I have 6 volts on all fuel injector connectors. Any thoughts?
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Friday, September 10th, 2010 AT 9:48 AM

11 Replies

Tiny
WRENCHTECH
  • EXPERT
Correct fuel pressure is very important so it needs to be measured more accurately.
The spec for this engine is 48 - 55 psi
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Friday, September 10th, 2010 AT 10:40 AM
Tiny
TERRYS10
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I checked the fuel pressure again with a gauge that measures high enough and find the pressure to be about 57 PSI.
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Friday, September 10th, 2010 AT 7:17 PM
Tiny
WRENCHTECH
  • EXPERT
Are you sure about that? You have a 12 volt system so that is something that you need to get to the bottom of. Check it again and if you really only have 6 volts, then unplug all of the injectors and measure it again. If it comes up to 12v now, leave the meter attached and start plugging in injectors one at a time. If the voltage suddenly drops again, that injector is shorted out.
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Friday, September 10th, 2010 AT 7:25 PM
Tiny
TERRYS10
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Yes, I originally checked with all connectors disconnected, but I just did it again to confirm and yes with the key in the on/run position all connectors have 6.01 VDC - 6.05 VDC present.
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Friday, September 10th, 2010 AT 7:44 PM
Tiny
WRENCHTECH
  • EXPERT
Check the voltage on both sides at INJECTOR fuse #7, 10amp in the dash fuse box.
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Friday, September 10th, 2010 AT 7:51 PM
Tiny
TERRYS10
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There are 2 - #7 fuses in my dash box; 1 is 7D which is labeled '10A TCC' and the other is 7E labeled '10A NON-OBDII MISC ENGINE' (no fuses in 7A - 7C).

I measured 12 volts on both sides of both fuses.

Oh, thank you by the way.
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Friday, September 10th, 2010 AT 8:12 PM
Tiny
WRENCHTECH
  • EXPERT
I think your in the wrong box
It's right here


http://www.2carpros.com/forum/automotive_pictures/561653_Fuse_box_98_Lesabre_1.jpg

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Friday, September 10th, 2010 AT 8:20 PM
Tiny
TERRYS10
  • MEMBER
Man, they could have made that fuse box harder to find.

I measured 12 VDC on both sides.
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Friday, September 10th, 2010 AT 8:54 PM
Tiny
WRENCHTECH
  • EXPERT
The injector power goes directly from there to the injectors so you need to find the connector or whatever is causing you to lose that power between that fuse and the injector.
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Friday, September 10th, 2010 AT 8:59 PM
Tiny
TERRYS10
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I originally measured 6VDC across the injector connectors. When I measure the hot wire on the connector to GND I get 12 volts.

Does this indicate an issue with the PCM? What voltage level would I expect to see across the connector?
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Friday, September 10th, 2010 AT 9:24 PM
Tiny
WRENCHTECH
  • EXPERT
No, it just means you just wasted a bunch of time because you didn't know how to measure it. That line back to the computer is nothing but an open circuit to the quad drivers and your real lucky you didn't jump them together or you could have taken out the computer. Your back to square one which is where we should have started.

Here is the procedure. Do every single test.

All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.

Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.

2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.

3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

4) If all of these things check good, then you would need to do a complete compression test.
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Friday, September 10th, 2010 AT 9:28 PM

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