testing egr valve

Discussion in 'Domestics' started by eddieguy, Aug 4, 2011.

  1. eddieguy

    eddieguy Sr. Member

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    sometime back i posted that my check engine light had come on in my 96 buick lasabre and one of the members on here shared with me what the code p1406 was and i have come across a site called easyautodiagnostics.com that shows how to test the egr valve but the steps suggest using wire piercing probes- i dont have these probes and i just want some opinions on if they are really needed and if so where would be a place to purchase them. my car gets pretty bad fuel economy and i have had the normal stuff done such as fuel filter, plugs and plug wires, clean air filter, and proper tire inflation- i thought i would try and test the egr and from what i have been informed, a bad egr valve can contribute to really bad fuel economy. i have experienced torque convertor shudder but after adding lubeguard the product did indeed make a world of change for the good. thanks for replies in advance
     
  2. Gus

    Gus wrench

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    Check the fuel pressure regulator for fuel in the vac line.....

    The usual problem for the EGR is not the EGR itself, but the pintle position sensor.....Need a bi-directional scan tool to look at the position of the EGR.....key on, engine off, should be a 0%....then you command it open in 10% increments.....the EGR position should match what the command is....if it doesn't, and isn't zero when it should be, that will set the code....

    What is your gas mileage? Fill tank up...set trip odom to zero.....when gage reads 1/4.....fill again.....write down gallons used to refill and divide it into the mileage on the trip odometer......mainly highway or city driving?
     
  3. eddieguy

    eddieguy Sr. Member

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    i will do as you said and post back and as far as gas mileage is concerned i get about 18 mpg on hwy and about 11 in the city. i was keeping track and the the numbers are pretty much consistant. the 11 mpg in the city is the most i get
     
  4. Gus

    Gus wrench

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    My wife's old '92 Bonneville usually got 26/30.....in ten years, there hasn't been much improvement on v-6's....
     
  5. NickD

    NickD wrench

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    Not sure what vehicle this is, when I first got that 92 DeVille was only getting around 17 mpg on the highway, base timing was way the heck off, like 13*, that and a good tune up, upped that to 32 mpg on the highway. But that is at 53 mph, go faster or slower, fuel economy is degraded

    EGR came with unleaded fuels, mainly to control combustion chamber temperatures, was speculated to monitor chamber temperature, but way to expensive. First systems were a bad joke using venturi vacuum with a fixed jet carburetor to take a wild guess at chamber temperature. Was also proposed for each cylinder to have its own O2 sensor, but out of the question, again due to cost. By using one to monitor the entire engine A/F ration, half the cylinders can be running rich while the other half running lean. And we all know if just one cylinder misfires, the entire engine is screwed up.

    A permanently closed EGR actually gives improved performance, burning real fuel instead of a 30% mixture of burnt fuel. But only last a short time, your engine will internally burn up. Exhaust valves go first.

    Was trying to figure how my 5.0L Chevy marine engine can get by without an EGR. Exhaust manifolds are constantly cooled with cool lake water, barely get warm to the touch. Try touching your land vehicle exhaust manifolds after running 4,200 rpm under full load.
     

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