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EGR Valve and dual exhaust

Discussion in 'Engine & Performance' started by mcarlo86, Sep 19, 2019.

  1. mcarlo86

    mcarlo86 Full Access Member

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    The service engine soon light on our 1990 Suburban has been coming on lately so I checked the code and it comes up code 32. I believe that is related to the EGR valve. The previous owner removed the cat, but left the rest of the exhaust stock. The exhaust is shot, so I am planning to have dual exhaust installed. I have heard that EGR valves need proper back pressure to work correctly. Is this true? I have also heard that if I want to put dual exhaust on with no cat, that I should get a 'heated O2 sensor'. I had a 1989 K1500 back in the day that had dual exhaust and no cats and I don't remember having any EGR problems with that. If anyone has any experience with this stuff, please reply. Thanks.
     
  2. Snoots

    Snoots Supporting Member Supporting Member

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    You'll have to check the specific codes for your truck but in some vehicles a Code 32 is a vacuum leak.
     
  3. Nonstop

    Nonstop Full Access Member

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    It should not be too much of a problem with the egr - a lot of trucks came with dual exhaust, no cats, and egr from the factory.
     
  4. mcarlo86

    mcarlo86 Full Access Member

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    Once I read that it could be a vacuum leak, it came to mind that the air only blows out the dash vents and wouldn’t switch to the floor or defrost. I did some checking under the hood and found a vacuum hose that was disconnected from a ‘T’ above the distributor. I hooked that back up and now the heat and defrost work again and I haven’t had the service engine soon light come on since. Had dual exhaust put on and everything seems to be working just fine. Sounds a lot better than the old exhaust with holes in the muffler and leaks in the pipe where the previous owner attempted to weld a pipe in place of the cat. Thanks for the tip!
     
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  5. Snoots

    Snoots Supporting Member Supporting Member

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    Good to hear you got it all straightened out! Sweet rumble!
     
  6. Rusty Nail

    Rusty Nail Fox News SUCKS!

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    WoW tHaT wAs EaSy...:waytogo:
     
  7. mcarlo86

    mcarlo86 Full Access Member

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    Shortly after I posted the reply above that I had everything figured out, the service engine soon light came on again. Changed out the EGR valve and replaced a bunch of rotted out vacuum lines and I still get the light. Any other ideas? Could the EGR solenoid be a possible culprit?
     
  8. Craig 85

    Craig 85 Full Access Member

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    I know your truck has fuel injection and mine is carbed, but I ran into an issue when I had the engine replaced in my truck. The EGR ports/runners in the base of the intake manifold were totally loaded full of carbon crap. Even if I replaced the EGR, there was no way for the gases to recirculate due to the blockage.

    Hopefully that's not the case for you, but I thought I'd throw it out there. I would think your truck would run way better the mine due to FI.
     
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  9. Ricko1966

    Ricko1966 Full Access Member

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    I believe code 32 on your truck is going to be a circuit malfunction not vacuum,not valve itself, not clogged anything. Double check me but if that is a circuit malfunction code it's going to be wiring, com, or solenoid
     
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  10. mcarlo86

    mcarlo86 Full Access Member

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    Looking into code 32 a bit further, I found this:
    http://www.fieros.de/en/v6help/code...ext=EGR duty cycle commanded by,, (7" vacuum).

    Problem Description:
    Code 32 means that the EGR diagnostic switch was not detected closed under the following conditions:

    • Coolant temperature greater than 80 C (176 F).


    • EGR duty cycle commanded by the ECM is greater than 50%.


    • Manifold pressure less than 25 kPa, (7" vacuum).


    • All conditions above must be met for about 8 seconds.
     
  11. Ricko1966

    Ricko1966 Full Access Member

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    So you need to look and see why the switch isn't detected closed. Broken wire?unplugged?Worn out switch?is the switch getting the signal to close.
     
  12. mcarlo86

    mcarlo86 Full Access Member

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    Did a little more investigating tonight. I squeezed the egr valve with the engine idling and it stumbled, so I believe the passages are open in the intake. I pulled the wiring plug off the egr solenoid and I have 12v at the plug. I then used the multi-meter to check the ohms on the solenoid and had around 300, so I think that should be ok? I read somewhere that there is supposed to be a vent on the solenoid that can plug up with dirt, but I have no idea where that would be at on it. I cleared the codes and took it for a drive. After about 15 miles, the check engine light came on. Checked the code and it is still 32. Any other suggestions?
     

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