Am I fighting my injectors? very rich idle

[5.3LS10]

Careful about unplugging the MAF if the IAT sensor is still wired into there.

To add one more thing, reset your fuel trims with the scanner to prevent the old fuel trim data from pulling or adding in any fuel. You have disabled the trims in the tune but haven't reset the trims.

IAT is separate but good call cause that would definitely skew things if it was still connected through the MAF.

I will reset the trims.

At this point I think I need to diagnose a bigger issue. I am going to plug the brake booster and a couple other vacuum lines I have hooked up to help rule out a vacuum leak. Then I will have to do a compression test and leak down.

Anything else at this point that makes sense? It has the LS9 cam but it should make more than 50kpa at idle. I would expect in the 30s.

[CDeeZ]

Your VE table is looking much more sane. Still need to interpolate between vertical bounds though.

And like 5FDP said, you really should get a wideband in there to make it easier on yourself. You can test your NB02s to see if they are good by soaking a rag in brake cleaner, alcohol etc. and wrap the rag around the sensor, this should cause them to read rich in the scanner.

I'd probably leave the closed loop and fuel trims off while you're getting this thing sorted out, can turn them back on later if you want to.

[5.3LS10]

Tomorrow night i will check for vacuum leaks and do a leak down test as well as a compression check.

[5.3LS10]

Okay I lied, I will not have time tonight. Maybe tomorrow

[5.3LS10]

Okay, so I started off by checking for vacuum leaks. I have always ran the engine and used either a propane torch or brake parts cleaner/starting fluid and sprayed around until the engine would rev up. I did not notice it ever changing so I sprayed right into the throttle body and it made no difference.... Sort of strange IMO.

So I pulled the plugs out. Passenger side were very black. I assume this is from the closed loop issues I had with the o2 sensor too close to the end of the exhaust on that side. The drive side looked okay.

I then checked spark on each cylinder. I noticed that the whole driver side seemed weaker than the passenger side so I am going to try and bypass the current ground and then power source and see which one makes a difference. Not a lot weaker but somewhat noticeable.

I started doing a compression check and was having issues trying to get the fitting tight enough. The hose on my compression tester kept spinning and it was too far in for me to reach. I will fix it and come up with a better solution so that I can get an actual reading.

I figured with how bad the plugs were I should toss in a fresh set and see how it responded.

Well the vacuum went down to about 45 kpa at idle now that it is warmed up so I think the plugs may have helped but its still barely 17"

Any idea why the starting fluid and propane didn't do anything even when sprayed right into the throttle body?

[5.3LS10]

I replaced the intake manifold gaskets today and made sure the surfaces were all clean. Oddly enough it now makes around 47kpa at idle but still seems low. Going to finish the turbo piping tomorrow so I can install the wideband and get a better reading on AFR.

[5FDP]

If you have a boost gauge, what kind of vacuum are you seeing?

Anywhere from -18 to -20 is normal.

The more I think about it, 47kpa at idle is actually really high from what I remember seeing. At idle in park I recall 35-40kpa on most of the stuff I've seen.

[5.3LS10]

If you have a boost gauge, what kind of vacuum are you seeing?

Anywhere from -18 to -20 is normal.

The more I think about it, 47kpa at idle is actually really high from what I remember seeing. At idle in park I recall 35-40kpa on most of the stuff I've seen.

I agree which is what has me concerned. I currently do not have a vacuum gauge connected but have tried swapping out map sensors which made no difference.

I keep going back to what kingtal0n said I think I need to do a compression and leak down test to rule out any internal engine issue. I do have other intake manifolds and throttle bodies I could try but I don't think that is an issue at this point.

I am going to finish the turbo exhaust merge and down pipe so I can get the turbo installed and wide band installed.

[CDeeZ]

My boost gauge also reads vacuum.

If in doubt, tests to rule those issues out would be a good idea. I don't think your issue is with intakes or throttle bodies.

I honestly suspect you have an electrical/electronic problem of some kind. I was plagued with many of them when I was getting my turbo LS going. You're sure your MAP sensor settings in the tune are correct for your MAP sensor??

Get that wideband on there so you have some more data to try to go off of.

Im using a ZR1 MAP sensor on my 3 bar speed density 411 PCM setup in my turbo truck. It tends to idle around 30 KPA

[kingtal0n]

1. you should be doing a pressure test to find leaks
2. you need a wideband to tune anything

these guys are trying to help you but nobody can tell you what the a/f ratio is
the engine will run well between 11:1 and 15:1 and you need to stay 14.5+ or else the plugs will gradually carbon up and the engine will start to misfire and run funny, giving you even more troubles.

[5.3LS10]

My boost gauge also reads vacuum.

If in doubt, tests to rule those issues out would be a good idea. I don't think your issue is with intakes or throttle bodies.

I honestly suspect you have an electrical/electronic problem of some kind. I was plagued with many of them when I was getting my turbo LS going. You're sure your MAP sensor settings in the tune are correct for your MAP sensor??

Get that wideband on there so you have some more data to try to go off of.

Im using a ZR1 MAP sensor on my 3 bar speed density 411 PCM setup in my turbo truck. It tends to idle around 30 KPA

I have swapped back in the factory 1 bar with the stock settings and I get the same reading as I do with the 2 bar and the settings I have so I am confident to say that the MAP sensor is not the issue.

I finished the merge and mount for the turbo yesterday so maybe tonight I can get the down pipe installed with the wide band to get a better idea of what the AFR is.

[5.3LS10]

Well this week I had some time to do a compression test and leak down.

Compression test I did dry on a cold motor and the largest gap was 160 and 185 while most were around 180.

Leak down all cylinders were between 15-20%

I did notice that under Transient for Min Fuel Grams the 80lb injector data I found on this forum had it for 0.019. Mine was still at 0.028, I have changed it.

Tomorrow I will do the down pipe and wide band and go from there. I read a few posts where people were having issues with not getting the injectors to idle down low enough that the above Min Fuel Grams fixed it.

I don't know if that will fix my issue because they could not get the idle PW below 2.1-2.2 but mine is down around 1.6-1.7. I think I may be hitting the min inj pulse width.
http://siemensdeka.com/specsheets/FI114991.jpg

[5.3LS10]

So after changing the min inj pulse width it started stumbling really bad while changing the throttle angle. After looking at the data logs it seems that it is not getting enough fuel now. After doing more research it seemed like that setting is not what is causing my issue. I got the down pipe welded up today. I will install the wideband first thing tomorrow morning.

I will take the vehicle for its maiden voyage tomorrow morning just around the block ( maybe 1/2 mile) and data log it.

[5.3LS10]

So I was finally able to get things finished up to take it down the road and back. So far everything seems okay.

Manifold Vacuum is still low to what I think it should be.

Once up and driving though at light cruise it is down in the 30 kpa no problem.

I was having an issue with tip in transient enrichment where it was stumbling and going very lean so I modified the fuel boiling time map and it seemed to help a lot but I did notice it now goes rich after the transition stabilizes so I am guessing there is more tweaking to do (I will start another thread to deal with the transient issues).

Any other ideas what to test for with the low idle vacuum?

[5.3LS10]

So after changing the min inj pulse width it started stumbling really bad while changing the throttle angle. After looking at the data logs it seems that it is not getting enough fuel now. After doing more research it seemed like that setting is not what is causing my issue. I got the down pipe welded up today. I will install the wideband first thing tomorrow morning.

I will take the vehicle for its maiden voyage tomorrow morning just around the block ( maybe 1/2 mile) and data log it.

Here is a forum post discussing the min inj pulse width again.

I believe the transient issues I thought were related to the min inj mg were not actually after all.

https://ls1tech.com/forums/pcm-diagn...ot-adjust.html

I am going to spend some time doing more reading and try to get this figured out. I am going to change this setting back and see if it fixes the idle.

[5.3LS10]

Here is a forum post discussing the min inj pulse width again.

I believe the transient issues I thought were related to the min inj mg were not actually after all.

https://ls1tech.com/forums/pcm-diagn...ot-adjust.html

I am going to spend some time doing more reading and try to get this figured out. I am going to change this setting back and see if it fixes the idle.

I changed the setting to 0.018, 0.012, and 0.008 with no differences. Still will not idle under 48-50kpa.

[5.3LS10]

Any ideas?

[Scaldeddog911]

Is your egr still enabled??

[5.3LS10]

Is your egr still enabled??

No it is not. Currently it is enabled in the ecu but that is because I am using the input pin for the wideband input but it is not physically installed. I was not getting the wideband to read into the computer and after I enabled it I can now see it but have had the low vacuum all along

[Scaldeddog911]

if the egr is enabled its going to be looking for extra air flow from the egr at idle. Try enabling stall protection under torque management. if you are using drive by cable and not a drive by data wire then you may want to check your idle air control valve on the side of the throttle body. on your egr diagnostics turn them to where it doesnt run any diagnostics for the egr. just becuase its disabled under DTC doesnt mean the computer will not be looking for the values.