MAL Code 23

[mtbraun]

As the title indicates I'm getting MAL code 23. I replaced the IAT sensor and still get the error code. Prior to getting the code I was getting error code 33. I replaced the MAF (from stock) with an LS1 and also changed over to the TR bigmouth cold air intake. I was not getting MAL code 23 prior to the changeover in cold air intake. Is it possible the MAL code 23 was suppressed? What I'm getting at is it possible for the scanmaster to track and display multiple MAL codes? If so, how do I retrieve this?

Ambient air temp was around 30 degrees.

After switching to the LS1 I am not seeing MAL code 33 anymore.

 

[TurboDave]

What Translator are you using with that new MAF.

 

[mtbraun]

Just the regular translator.

 

[mtbraun]

ok, so I picked up the GN from having the exhaust put on today. Also picked up and put in some race gas as I was going to work on some tuning and wanted to be safe. Took it out for a spin. No MAL code. O2s are decent when driving, but the bounce around a lot when idling. Hear a slight drivers side exhaust leak so need to retighten the headers.

New question - I noticed my boost gauge is always reading vacuum. I never showed boost even at full throttle. It never got more than -5in of vacuum. I have the RJC boost controller turned way down, so I would expect the boost to be low but to not even register any seems odd. I have the boost gauge plumbed into the vacuum line near the driver's side firewall, coming off the EGR bypass. I know that is not where a lot of guys are plumbing in, but what could be causing the boost gauge to read incorrectly?

 

[TurboDave]

O2's are supposed to bounce around during idle and cruise, that's normal. As far as reading no boost, it may be where you tapped your boost gauge into the system. You may be on the wrong side of a check valve. Best place to tap in is on the passenger side where there are no check valves in the vacuum lines.

 

[mtbraun]

Yep, that's the problem. I accidentally plumbed in after a check valve. I don't have the fittings handy today to plumb in to the hard plastic line on the pass. side, but was thinking of plumbing into the line that goes to the vacuum ball on the driver's side. There's no check valves on that portion of the line and I can route it neatly with the other lines on that side of the manifold. Should that work?

thanks for your help.

 

[TurboDave]

The boost gauge on my 87 is tapped into the line that goes over to the evap canister. It also has a check valve, but I tapped in near the alternator, which is on the pre valve side of that line.

 

[mtbraun]

yep, that's what I meant, not the vacuum ball. I'll try that. Thanks again.

 

[mtbraun]

Thanks turbodave. Replumbed on the pass. Side and I miraculously have boost. I thought I had the rjc boost cont turned way down but actually read 17 psi of boost at wot. No KR and o2s were good but def the max on the TT street chip.will probably turn down a bit to be safe.