85 60 full desmog, sniper, & tuned headers - questions and progress (4 Viewers)

[brownjeans]

I have the vac line coming out of the intake with a man a fre smog delete going to the PCV valve
I have the distributor advance going to the port specified by Holley on the throttle body. I have the vacuum from the passenger side of the air filter going to the distributor.
Lastly the vacuum for the brake booster is in the stock location on the rear of the intake manifold with the other smaller tube on that fitting capped off.
I’ve also got the AC Delco charcoal canister installed but my truck isn’t near me so I can’t remember exactly how I plumbed that in but if you search for this here you will find some common solutions.
All other lines to the air filter housing and intake manifold are capped off.

Also, where do you have your o2 sensor mounted?

I have the PCV same as you. Charcoal canister - one tube to hard line that goes to fuel tank, another tube to the hard line the wraps around the back of the engine on the firewall and then to manifold vacuum where the brake booster used to be (other thing capped like you). Brake booster to the sniper brake vacuum port (to take advantage of the Sniper's built-in check valve). Distributor - the hole in the cap is run to a T to join the canister tube to the manifold. Standard vac advance to sniper advance port. High altitude advance capped. All air cleaner ports are capped.

O2 sensor - I have the man-a-fre tuned headers and Y pipe. I put an O2 bung on the Y pipe about 8 inches below the merge on the top part of the pipe to keep it from being hit by a rock.

I reset my sniper and went through the wizard again. I set the engine size to 230 this time. Mild cam. 730 target idle. Coil.

Cold starts fine and idle is at ~1200 and all stats are good. After a bit the idle drops and the AFR turns red (high number) and it stalls unless I press the gas pedal to keep the RPMs up.

 

[DrRock]

I have the PCV same as you. Charcoal canister - one tube to hard line that goes to fuel tank, another tube to the hard line the wraps around the back of the engine on the firewall and then to manifold vacuum where the brake booster used to be (other thing capped like you). Brake booster to the sniper brake vacuum port. Distributor - the hole in the cap is run to a T to join the canister tube to the manifold. Standard vac advance to sniper advance port. High altitude advance capped. All air cleaner ports are capped.

O2 sensor - I have the man-a-fre tuned headers and Y pipe. I put an O2 bung on the Y pipe about 8 inches below the merge on the top part of the pipe to keep it from being hit by a rock.

I reset my sniper and went through the wizard again. I set the engine size to 230 this time. Mild cam. 730 target idle. Coil.

Cold starts fine and idle is at ~1200 and all stats are good. After a bit the idle drops and the AFR turns red (high number) and it stalls unless I press the gas pedal to keep the RPMs up.

Hmmm, what altitude do you live at? It should compensate for that but maybe in your early stages of getting it running the o2 sensor got clogged. I would take it out and inspect it and if there is a lot of carbon buildup you can burn that off with a propane torch. Are you able to get a vacuum reading? Sounds like you are really close.

 

[brownjeans]

Hmmm, what altitude do you live at? It should compensate for that but maybe in your early stages of getting it running the o2 sensor got clogged. I would take it out and inspect it and if there is a lot of carbon buildup you can burn that off with a propane torch. Are you able to get a vacuum reading? Sounds like you are really close.

I live at around 4300 feet (just outside Salt Lake City). Because I don't have an exhaust, I haven't run it more than a few minutes - like five. Not even sure it's run long enough to get up to temp. Only a drive around the block and a few mins of idle. The two mile drive to the muffler shop today will be the longest I've run it.
Wonder if I should start with something simple like ensuring the battery terminals are clean and have good contact and the fuel pump ground has good contact. Or maybe just drive it on the freeway for a bit after I get the exhaust done to give it time to learn?

What do you do with all the vestigal electrical connectors from the smog delete? Cover every open connector with finger cots and/or FlexTape?

 

[Skreddy]

What’s your MAP reading? Also, IAC position at that idle.

 

[brownjeans]

What’s your MAP reading? Also, IAC position at that idle.

Good questions - which idle do you mean? Below 1200 RPMs it stalls almost immediately so it's hard to get any readings.
Truck is at the muffler shop today. I'll take a look when I get it back.

 

[Skreddy]

Good questions - which idle do you mean? Below 1200 RPMs it stalls almost immediately so it's hard to get any readings. Truck is at the muffler shop today. I'll take a look when I get it back.

I’d run the setup wizard again once the exhaust is done.

 

[brownjeans]

Okay, got it back from the muffler shop, re-ran the setup wizzard and drove it for a bit. It's at 20% learn now. Just that bit of learning has improved things quite a bit. It still doesn't want to idle below 1200 RPM but it isn't stalling anymore, just idling high. I think I need to adjust the timing as it seems a little off. I will do that today and see if a bit of a twist improves anything. If not I'll put it back to where it is now. I'm also going to spray some starter fluid around the intake to test if I have any vacuum leaks.

Mostly I think I need to drive it and give it time to learn.

 

[Skreddy]

What is your target idle and target idle AFR set to? Whats the MAP reading?

 

[brownjeans]

What is your target idle and target idle AFR set to? Whats the MAP reading?

I haven't done anything to change the timing or check for vac leaks yet.
Target idle RPM is 730.
I brought it up to temp and here are some screenshots:

 

[DrRock]

You really need to check for vacuum leaks, that AFR is very lean. Also, once the engine is above 160F, it should switch over to closed loop and be using the o2 sensor to adjust AFR. Recommend getting a good vacuum gauge and hooking it up to one of the ports on the intake manifold and see what the reading is and if its stationary or bouncing around. Reading should be 15in/Hg or higher. I see 20-21 in/Hg at sea level.

 

[brownjeans]

You really need to check for vacuum leaks, that AFR is very lean. Also, once the engine is above 160F, it should switch over to closed loop and be using the o2 sensor to adjust AFR. Recommend getting a good vacuum gauge and hooking it up to one of the ports on the intake manifold and see what the reading is and if its stationary or bouncing around. Reading should be 15in/Hg or higher. I see 20-21 in/Hg at sea level.

When it is at cruise (between 2000 and 3000 RPMs) the AFR is pretty close to the target of 14 (assuming that 14 is the correct target). It also runs ClosedLp and Learn when cruising but switches to OpenLp and NoLearn when I take my foot off. I don't know if any of that means anything or not.

I'll get a vacuum gauge and test it. Test at an idle with no throttle, right?

 

[DrRock]

Just test at an idle with no throttle, right?

Correct! Keep us posted, you’re getting really close

 

[Skreddy]

What he said! That MAP reading is super low but I’m assuming you were holding the throttle part open? If not you have a big vacuum leak.

I guess the other thing: have you adjusted the idle set screw on the throttle body to get below 1200 rpm? They are not factory set and need adjusting.

 

[brownjeans]

What he said! That MAP reading is super low but I’m assuming you were holding the throttle part open? If not you have a big vacuum leak.

I guess the other thing: have you adjusted the idle set screw on the throttle body to get below 1200 rpm? They are not factory set and need adjusting.

So vacuum holds at 15. I forgot to get some starter fluid. I'll get some and spray around the intake to see if there's a change.

I wasn't touching the throttle. I know nothing about MAP. Not sure what it does or what it should be. I haven't touched the idle screw. It's still set as it came.

I think the timing does need a tweak. It misses a bit. Not sure how to loosen the distributor to be able to turn it.

 

[Skreddy]

Back the idle screw out while it’s running. Ideally, you want the throttle blade pretty much closed and the IAC should do the work of letting idle air in. IAC should be 1-5% at idle, so you’ll shoot for IAC at 1-5% at your target idle. I also like an idle closer to 780-800 rpm to keep everything wet and slippery, but that’s just me. Also, in case you’re unaware, any time you make idle screw adjustments, the key needs to be cycled to reset the TPS.
I really recommend setting up a custom screen with TPS, MAP, IAC, AFR, Coolant Temp and tach. You can also resize the dial tach in the middle so it’s a smaller range. Mine is set to 5000 max with redline at 4000.

MAP is manifold absolute pressure; it’s what the sniper sees as vacuum. A low MAP number correlates to a big vacuum leak (if at idle). Idle MAP with 18” vacuum is around 80-85 I think. Your 15” vacuum is a little low (depending on altitude) and I bet it is due to the throttle blades being more open than they should be, which is also causing the higher idle.

Here’s the idle screw to adjust.

 

[brownjeans]

Okay. I got some carb cleaner, sprayed all around the sniper base, under the stock heat shield thing, on top of where the manifold meets the head, below where the manifold meets the head, where the block-off plate is and where all the things screw into the top of the manifold. Nothing changed. I think things are sealed pretty good.

So on to the sniper screw. After many cycles of asjusting the screw, turning the truck off and back on again ("have you tried turning it off and back on again?" - this is what we get for introducing a computer into things I guess). Here are my readings:

That MAP still seems lower than the 80 ish. When I start it, the IAC Pos, % starts at around 30, then settles to here. The AFR, A/F moves .5 above and below 14 (what is in the screen shot is me catching it at the high end). I retested the vacuum pressure on the manifold, it is now holding at 17 at 4300 feet elevation. The only hiccup I have is that when I press the accelerator and then lift, the AFR, A/F spikes super lean for a sec - the truck acts like it might stall, but then it recovers.

I also went through the setup wizzard again to re-set things. What do we think? Are there other things I should check or is it time to drive and let it learn?

 

[DrRock]

Awesome! The learning will help with the of throttle stall potential, at least it did on my setup. You are really close, congratulations! Were you able to verify your timing?

Cheers, James

 

[brownjeans]

Awesome! The learning will help with the of throttle stall potential, at least it did on my setup. You are really close, congratulations! Were you able to verify your timing?

Cheers, James

Once I had it idling, I marked my distributor and made some minor 1 to 2 degree adjustments advance and retard and decided the changes seemed pretty minor, so I put it back to where it was. If it doesn't make an appreciable difference, I'm gonna leave it alone.

 

[brownjeans]

On the MAP reading. Watching this Holley video

They show a MAP of high 30s while at idle. So maybe my MAP is normal?

 

[DrRock]

I’d recommend verifying the timing with a timing light. You should be able to rent one from a local auto parts store.