2000 Suburban

Tiny
2000BURBAN
  • MEMBER
  • 2000 CHEVROLET SUBURBAN
  • V8
  • 4WD
  • AUTOMATIC
  • 248,000 MILES
240k miles.
Rough idle and low oil pressure at start-up.
After 15 mins of running all signs of any problems are gone. Replaced in the last 2 months all 4 o2 sensors(ac delco), Fuel pump-warranty -(airtex), battery, starter, coolant temp sensor-(ac delco). In last 12-18 months MAF-12/09-(delphi), water-pump, power steering pump, Alternator, belts, hoses, tensioners, transmission. I have read different threads about intake gaskets and cat converters, but I don't have rough or sluggish running when the vehicle warms up. These problems only occurr when cold. I have read some about the oil pressure switch causing some issues, and after replacing two fuel pumps in two years, I'm considering replacing that switch. I have two mechanics that are good on heavy truck and 4x4, and they have not been able to fix specific issue. I have done regular maintenance and don't want to just throw parts at this problem, but I'm at a loss at this point.
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Friday, January 21st, 2011 AT 5:40 PM

3 Replies

Tiny
JDL
  • EXPERT
If you already had two professionals look at it, I'm not sure how to help? Found the service bulletin below.
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Friday, January 21st, 2011 AT 5:56 PM
Tiny
2000BURBAN
  • MEMBER
One of my mechanics is a heavy truck/equipment mechanic and can fix just about anything. Not sure if he is too good at diagnosing problems like this. The other is great at replacing parts or fixing the obvious. Neither has extensive computer abilities. What I'm saying is they could fix the problem if I could tell them the problem. What I need is causal relationship problem solving. EX.I replaced two fuel pumps in a year and come to find out that the oil pressure switch will turn the fuel pump on and off depending on oil pressure-right? Well i'm thinking this switch might need to be replaced because my fuel pump may be turned on and off too often based on my oil pressure readings-right? Or my oil pressure is literally fluctuating that often and there is another cause for that issue. FYI-My two mechanics are not in shops that have the latest and greatest test equipment. They both have scanners and can get codes, but I have that ability here at my house.
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Friday, January 21st, 2011 AT 6:35 PM
Tiny
JDL
  • EXPERT
No, Your oil pressure shouldn't have anything to do with fuel pressure/fuel pump. Some GM vehicles do have an o/p switch in the fuel pump circuit, wired in parallel with the fuel pump relay. Because it is wired in parallel, the o/p switch can't kill the engine or keep it from starting as long as the relay is functional. It's just a redundant power supply to pump. Your vehicle doesn't have that according to my wiring info.

As far as updated software for idle issue, you may have to talk to dealer?
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Friday, January 21st, 2011 AT 7:26 PM

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