1990 TBI/Auto Code 32 after Header/exhaust install
 

Ever since installing a set of Hooker headers and full exhaust (cat delete), I get a code 32 after 15-20 minutes of highway cruising (60-70 mph). Didn't get check engine light before exhaust install and I have read a few "comments" that decreased back pressure can trip a code 32 on SD TBI. Is this true? Anything I can do to prevent this?

Re: 1990 TBI/Auto Code 32 after Header/exhaust install
 

this is a common occurrence

Re: 1990 TBI/Auto Code 32 after Header/exhaust install
 

You are correct about the exhaust back=pressure. There are three different types of EGR valves, positive pressure, negative pressure, and neutral pressure.

Changing the valve from the current type to one of the others should clear up the malfunctioning EGR.

RBob.

Re: 1990 TBI/Auto Code 32 after Header/exhaust install
 

I did not know that. Very interesting. How does one ID one from another? Any common substitutes used in this scenario? Like '92 G-van or some such?

Re: 1990 TBI/Auto Code 32 after Header/exhaust install
 

The egr usually has a letter on it to identify if it’s p or n pressure.

Re: 1990 TBI/Auto Code 32 after Header/exhaust install
 

Yes it is ...
To fix it you need to drill the hole in the EGR valve a few thousands to allow more vacuum to the valve to make it open. Don't go too much or it will cause problems (stumble).

Re: 1990 TBI/Auto Code 32 after Header/exhaust install
 

Quote:
Originally Posted by RBob View Post
You are correct about the exhaust back=pressure. There are three different types of EGR valves, positive pressure, negative pressure, and neutral pressure.

Changing the valve from the current type to one of the others should clear up the malfunctioning EGR.

RBob.


Thanks. Is this technique verified? That would be great if it's that simple.

Re: 1990 TBI/Auto Code 32 after Header/exhaust install
 

Is the hole you're referring to where the vacuum line attaches?

Re: 1990 TBI/Auto Code 32 after Header/exhaust install
 

Does anyone know whether the SD TBI EGR is positive or negative? I have read differing specs. I think I see an "N" on mine, but the one RockAuto specs is a "P".