Tune will not lean out

[sanfriz]

5.3 with sloppy 2 cam and Deka 80 injectors in an 86 C10. I had a good idle tune but the drivability was bad and wouldn't build boost. Its a SD tune that the AFR stayed right around 14 just wouldn't rev any higher than around 2800 RPM, with torque management off. I checked compression (lowest was 1 at 160, highest 7 at 195), pushrod length, and put in new plugs.

Now it starts ok and then drops the AFR into the 10's. I pull my VE back far enough to make it not run but still shows very rich. I backed the injector flow rate off 10% and did nothing. I have a FPR with return but have the vacuum line capped so the PCM can control the pressure. I have a gauge that faces me and I'm at 58PSI all the time.

The scanner current misfire's I believe are historical because they don't go away, and history stays at 0. Does not throw a code. Codes are no different than before I did the work.

The only thing I can say changed is I have a little better vacuum and my CA dropped in half and my dynamic air dropped considerably.

Any ideas? I know the injectors are looked down on, but I didn't mess with them.

20231005 New Plugs, still super rich but sounds better.hpl20231005 Idle rich, to much air, took 10% out of injector flow rate, pulled more air.hpt

[edcmat-l1]

First off, let me thank you for a post with detail, capitalization, punctuation, and actual paragraph structure. I done lost my train of thought LOL

Oh yeah, first thing is, vacuum reference your regulator, and drop the pressure to 45 psi, engine running, no vacuum applied to the reg. Then start tuning.

[sanfriz]

I've tried everything to bring down the AFR. I added vacuum reference, dropped the PSI down to 45, cut the injector flow rate by 40%, and I'm still starting good and then dropping to the low 10s. I have my gauge on the regulator right now. I just ordered a fitting so I can monitor it on the actual output line and see if there is a problem there. Nothing in my logs shows anything else changing when the AFR drops off.

[edcmat-l1]

Put it back in closed loop and use the trims to dial it in.

You're logging way too many pids. And coincidentally, not the right ones. I'd drop most all of them and just use what you need for fueling. You need to include injector pulse width. Get rid of all the misfire pids and all the advance pids and knock pids besides advance SAE and knock retard.

[sanfriz]

Why use trims when I have a wideband? I don't even have my other O2s wired up. I had my fuel right where I wanted it. It had other issues and after setting everything up following Evans Tuning Academy. It was still not driving right, no power in the bottom end, wouldn't build boost. I read that could be low compression, incorrect pushrod length, or I didn't follow the proper tightening for the rockers. I checked all and put the rockers back in exactly how they recommend. After this my vacuum increased but my AFR would just drop off for no reason as you can see in the log. Because nothing in the tune, and nothing you recommended in your first post, changed anything at all with this I should assume it's the regulator, right? I am going through gas a lot quicker than I used to too. I was just having problems with cause and effect. I think it might just be coincidence if it is the regulator?

[edcmat-l1]

I've tried everything to bring down the AFR. I added vacuum reference, dropped the PSI down to 45, cut the injector flow rate by 40%, and I'm still starting good and then dropping to the low 10s. I have my gauge on the regulator right now. I just ordered a fitting so I can monitor it on the actual output line and see if there is a problem there. Nothing in my logs shows anything else changing when the AFR drops off.

You do know cutting your IFR by 40% will richen it up, not lean it out, right?

If your fuel pressure regulator is regulating the pressure, and you have a gauge on it, and it's not leaking fuel into the vacuum hose, how can it be the pressure regulator?

Cut out most of your pids. Add in injector pulse width so you know what the injector on time is. That's the only way you're going to know if you're bottomed out. Otherwise you're just spinning your wheels.

[sanfriz]

I did not know that, for some reason I assumed it would pull fuel.

Its a cheap regulator. I had 2 gauges on the port on the actual unit. I am ordering a connector that will allow me to test the pressure on the output side specifically. I am assuming the gauge is mounted in a location it would already be receiving this, but the amount of fuel I am going through, and my rich tune, makes me want to thing mechanical for some reason.

I deleted most pids and added pulse width. I did one and then took 10% from the VE and it did the same thing. it drops off AFR but the pulse doesn't change unless I increase RPMs. Honestly not sure what I'm looking for with these.

20231006 Low AFR with IPW.hpl
20231006 Low AFR with IPW, 10% removed from VE.hpl
20231005 Idle rich, idle air ok, 10% out of VE.hpt

[edcmat-l1]

Try this one and see what it does. Log it as is. Then pull another 20% from the VE and log it again. Post both here.

Can't really tell if the injectors are bottomed because it not in closed loop so it's not trying to lean itself out.

[sanfriz]

No change with either. Same drop-off points.

20231006 Exactly as provided.hpl

20231006 As provided with 20% removed from VE.hpl

[edcmat-l1]

Yep. You're right. Looks like you're up against a floor on your injector on time. Something ain't right in your injector data.

Good luck to you.

Edit: You'll need to figure out what's wrong in your injector data. Your goal is idle pulse width under 1 ms. Ideally you'd want control all the way down to about .5 ms but if you can get them to .9 or .8 you should be in reasonable range.

[Alvin]

The likely cause to this is ECM 2284 I see this and run into it often.

Zero it out and try it.

Where did you get injector data from?

[edcmat-l1]

The likely cause to this is ECM 2284 I see this and run into it often.

Zero it out and try it.

Where did you get injector data from?

Already got that down to .010. That ain't it. It's in the actual injector data.

[sanfriz]

I zeroed out the min fuel and it didn't change anything. Ran for a few seconds at 14.5 then dropped to the low 10s. I am going to try another O2 tomorrow, but I can smell the fuel. When I had the regulator on 15 it let the AFR come up into the 13s. I will be able to check the fuel rail pressure tomorrow to verify its matching what the regulator is telling me.

Injector data is from this forum. I have a spreadsheet and an actual tune file from someone that uses the injectors. I just checked the resistance on them, and they are all very close to each other. There is power to all of the injectors with key on too. The current codes are the same as its always had.

[sanfriz]

Injectors worked fine before I did the compression check, reset the rockers, and added new plugs. The only thing I changed was to make the flow static when I hooked up vacuum. When I had it the other way with vacuum capped it made no difference. I had it idle tuned for a few months now, this is only a few days old and very frustrating. I've tried to idle tune multiple times using the steps from Evans and I can't get the AFR under control again at all. When my AFR drops nothing seems to tell it to do that in the scanner. Thats why I had so many up in the beginning. I can't find the cause in the data.

[ns158sl]

Soooo. yeeeeah. Wrong injector data is probably most of your issue. IDGAF if you thought you found another "toon" with correct data. Its wrong. Are they for sure the correct like FRPP 80's? You are worried about stoich and WB data when the engine is cold/warmish just after startup? Plus 35 PSI compression between cylinders? Uffda

Plus your timing tables are a mess. 25 degrees seems quite high also.

[sanfriz]

If you look for Deka 80 tune on HP Forums, you will find the exact same data I have on multiple posts. There is even a few YouTube videos showing people running cheap Deka 80s with the same data. I subscribe to Evans Tuning Academy and had a good idle tune following his videos.

My drivability was bad, and I had no bottom end power. I was told my tune should be good enough for the truck to run better than it was so I started checking the mechanics of the engine. The plugs had a ton of carbon, so I changed them after the compression test. Now my AFR starts at 14.5 and drops to 10 after 10-15 seconds of running. I can turn it back off and it does the exact same thing, regardless of temperature. I have tried multiple things in the tune including what was suggested. I have trouble believing my injector data is causing the issue when the exact same data didn't before. After trying what was suggested and it not working I am going to back to the engine.

My timing tables are a mess because I have been trying to just get it to idle again and haven't worked on them at all. I was at 25 before with no issues for idle. There is no knock at all so why is it too high? I like to start with the AFR and then go from there. I've never encountered a problem were nothing I do changes the AFR in the tune.

Compression can be 30% from what I have found for an LS, I'm at 18% difference.

[gtstorey]

Where did you source the injectors?

[ns158sl]

wtf.. where did you "read" or "understand" 30 % is ok??... holy hell. I like also.. " for an ls", what makes an LS different than another ICE? You said cheap 80's? IDK what that means? IS this like a de-capped thing? You keep stating Evans tuning like he is the all-know. I can promise he isnt lol. You are in open loop and it is commanding richer than stoich and nothing is matching, my guess your VE table is way off and nothing will match probably because of bad injector data. Besides that. Holy compression difference. Is the low cyl pressure on the same bank as your WB side?

[gtstorey]

Just for the heck of it, I did a Google search on the allowed cylinder variation. Of about 10 random sites, I found 1 that said up to 25%. The rest all said the expected normal variation of 10 and maybe up to 15% percent at the the most.

[SiriusC1024]

The injector data is not correct.
https://forum.hptuners.com/showthrea...=injector+data

The data you had looks like:
- IFR: 3 bar n-heptane rating adjusted for gasoline (n-heptane *(1.04 to 1.07) = pump gas). Unit is lb/hr. It's mass flow. n-heptane has lighter density. Needed 4 bar IFR.
- MinPulse: Now matched to Min Fuel Qual in the Transients tab (mg*~31.2 = ms). All selected for bulk correction of SPA table.
- Offset: Application of dsteck's Ford-GM conversion spreadsheet and the 6th order curve-fitting (notice flat zone then upward trend at higher Volts).
- SPA: "Good 'nuff" rounding? Idk.
- Injector Timing: Stock - adjusted for your cam. Used SS2 cam specs, Summit valve timing calculator, and this spreadsheet: https://forum.hptuners.com/showthrea...highlight=eoit

I've attached both referenced and non-referenced versions for 4 bar (58psi). What you're describing is non-referenced regulation, but I don't see the sense in that. You mentioned boost, so you should be running a 1:1 regulator. For that use the referenced data.