EGR Valve and dual exhaust

[mcarlo86]

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.

 

[Snoots]

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

 

[Nonstop]

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.

 

[mcarlo86]

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

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!

 

[Snoots]

Good to hear you got it all straightened out! Sweet rumble!

 

[Rusty Nail]

WoW tHaT wAs EaSy...

 

[mcarlo86]

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?

 

[Craig 85]

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.

 

[Ricko1966]

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

 

[mcarlo86]

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.

 

[Ricko1966]

Looking into code 32 a bit further, I found this:
http://www.fieros.de/en/v6help/code32.html#:~:text=Code 32 means that the,closed under the following conditions:&text=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.

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.

 

[mcarlo86]

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.

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?