Got a few codes.

[riselly1]

I'm still on the works trying to get an obd1 scanner. My local auto parts say they no longer scan vehicles. ?? 🤔

Anyway, I cleaned the IAC, it had some gunk on it but the bad news is the seal came apart when I sprayed it. It just desintegrated, how bad do you think that's gonna mess me up??

Also I unplugged the brake booster to rule out a diaphragm leak, but the engines behaves the same, so.... NEXT !

[Racinfan83]

Sounds like you have vacuum leak/s to me. MAP sensor connection was my worst one...

[riselly1]

Hey ladies, taking the plenum off tomorrow morning. Did a vacuum test and it doesn't hold ****. Once warmed it's not as bad, som I'm thinking something is expanding and maybe sealing off the leak??

Break booster and secondary pump hold vacuum like champs. I will follow some write up I found here at the registry.

Any words of wisdom?

[XfireZ51]

Before pulling the plenum, pull the BATT - cable and then open the ECM. Pop the prom and then re-seat it until the tabs on either end snap properly and snugly.
See what happens.
If the secondaries are not holding vacuum, that needs to be addressed.

[mike100]

There are 3 or 4 common places under plenum where vacuum leaks and also the map sensor hose is a common failure that causes erratic driveability (many times with no codes associated with it).

Will it idle below 1000 rpm when it is warmed up?

[riselly1]

Tried the battery with no luck and no codes either. Plenum came off !!

First order of business; I found 4 leaks , sweated like a pig and got a sore back. Leaks are as follow:

1) 2 x secondary vacuum canisters; are there guys supposed to hold any vacuum at all, b/c air just whistles right out and I can see a plate moving back and forth as I applied vacuum on both?
2) the T section between the check valve and reservoir; funny thing is it holds vacuum coming from the side plenum line, but when i tried the line coming form the secondary pump it looses all vacuum in 10 s. ** secondary reservoir holds perfect vacuum.
3) driver's side line going into the secondary vacuum solenoid. it just whistles and i loose vacuum in 10s. the right side line is good.

I included a pic highlighting the leaks in blue. Check it out and let me know if something doesn't make sense before I start hunting for parts.

[Top Toy]

Now would be a great time to get rid of your secondaries. Very common mod for LT5's. Eliminates a lot of the headaches you're wrestling with with no loss of driveability. Lots of info on this forum re how to do it.

Sent from my XT1254 using ZR-1 Net Registry mobile app

[Kevin]

Originally Posted by Top Toy

Now would be a great time to get rid of your secondaries. Very common mod for LT5's. Eliminates a lot of the headaches you're wrestling with with no loss of driveability. Lots of info on this forum re how to do it.

Sent from my XT1254 using ZR-1 Net Registry mobile app

I've been kicking around this idea and if I could find a stock cube non-ported car to drive before I do I probably would.

[GOLDCYLON]

Originally Posted by Kevin

I've been kicking around this idea and if I could find a stock cube non-ported car to drive before I do I probably would.

Just do it Kevin and have Dom retune it for ya it. Worked great for me

[riselly1]

Hey guys finally had the time to put everything back this morning. Changed both secondarie canisters and my check valve wasn't working either. The entire system holds 15+ of vacuum now 👏👏👏

Problem: after say 30s-1min of running white smoke/fog comes from under plenum on the passenger side only. She also did it before taking plenum off. I don't like smoke so I didn't play with it anymore, any suggestions???

I also noticed viscous oil deposits on the long piece where the injector housing connects to the block.