Large Injectors, PW very high when revving only.

[tictakman]

Need some guidance on a tune. Its been tuned before on one ecu and now its on a new ecu with issues.

Background- Ecu and harness (DBW) was from an 04 Suburban. The setup was a 69 Camaro with a forged LS1 with LS3 heads and t56, running two Precision 6766 BB turbos at 18lbs of boost. Jeremy Fromato tuned this car conservatively at 822 rwhp, no running issues.

Fast forward to now, new car and Im trying to learn how to tune; Im using a 411 ecu and harness from a Firebird, stock 4.8 engine, DBC, t56 magnum, same turbos and same injectors. Ive copied the tune from the auto ecu (04) to the 411 (02) manual ecu and I am having running issues, mostly idle so far. Want to get that right before I move on to other things..I am able to drive it around easily but just want to solve this first issue.

Injectors are the same which are Fuel Injection Connection, 1000cc injectors. I gave the injector data to Jeremy originally and still have it too.

LTFT are disabled and the DFCO is set high to 250...

The car is running its FPR off boost reference, 50 with it plugged in and 60 unplugged. The car idled at 12.0 on the wideband with the exact same tune...(camaro was 14.5 though). After researching for a while I found out about the transient fueling. The number was .045... I dropped it to .024 which brought the wideband to a good 14.5 idle. Anything lower and it seems like the engine runs rough. The car has responded well with this change but the next issue that I have found is that it will stall out if I just floor the car (in neutral). If I gradually roll into the pedal it will rev fine. The wideband shows it goes lean but I know thats not the case because the only way I can get the car to run again is if I unplug the injectors and turn the car over...it will run/burn off the fuel. Then plug in the injectors and it will fire back up.

I can recreate this stall at any rpm point, just floor the pedal and it will stall out...sometimes I can catch it and other times it will die. When looking at the scanner I have noticed that the injector pulse width at this time will spike to 500. Can anyone shed some light on to what I can try to change or look at for a positive adjustment? Ive gone through disabling torque mgmt and it was already done.. not sure if its a DBW setting Im missing or an injector adjustment point.

[schpenxel]

It looks to me like something is wrong with the injectors or there's a vacuum leak or something like that effecting one bank more than the other

You're seeing 15%+ differences in fuel trims from bank 1 to bank 2.. so that's an issue right off the bat

There's something else going on too probably but that's the first thing I noticed

[tictakman]

The percentage difference, which bank would be most likely exhibiting an issue? Bank one or bank two?

There are two 450 walbro pumps y'd together -8, then go to the front of the car, then y'd to each rail. Each rail then had a -6 to the fpr back to the fuel tank..

[schpenxel]

I have no idea.. when I see that I usually swap injectors from driver side to passenger side and passenger to driver and see if the fuel trims swap or stay the same first

[tictakman]

Ill do that this weekend. I was reading a little bit about the STFT % difference and it could be a few things. Im also wondering if the plugs are fouled out already from these overly rich stalls...Ive replaced them once before and it did help with the running. Perhaps its time to throw another new set in.

I did look at another scan that I did a few weeks ago and they were closer to eachother than what they are now. lol


Just trying to understand what would cause that very high injector pulse.

[schpenxel]

Yeah, could be a cylinder not firing or something I guess too

Not sure on the high PW, sounds like I gave you an extra project this weekend at least

Hopefully someone else has some ideas.

[Boosted53f]

disable the use of closed loop and MAF and run the car in SD..... see if it still does it and log and see what is happening. If the car does not run well in SD then your injector data is false or your VE and or spark tables have issues??? just a thought

what are your injector settings for flow rate and injector pulse. can you compare to a stock file?

[tictakman]

Im running in SD currently...no maf connected.

[tictakman]

Moving on.. So I tried a friends tune who has a very similar current setup as mine. His tune works fine with my car so this extreme rich point I think is coming from a DBW crossover issue...only thing I can deduct from my limited knowledge on tuning.

[Boosted53f]

you arent "moving on" yet. disable the use of closed loop completely... your trims are still active and your injector PW is bottoming out and freezing trims in decel cells.... see my recent post about INJ pulse and lean tip ins. if you slow your logs down you can see this happening. your o2s appear to be switching normally but the VE might be jacked up as well. Is this the same VE table carried over from the 6.0 setup??

you can also see this happening in your Idle cells. Your PW is bottomed out at 1.8-1.9 because your running very large injectors.... and trims are creeping hard negative. please read my post and step one would be COMPLETELY disable closed loop using the ECT enable table. see how it runs after. my guess is much better. You can tune the VE table from here with wideband data.

i cant make sense of your injector data but someone more experienced might be able to.

[tictakman]

Oh I know there is a lot to do in the tune and my learning... I was moving on from the rich idle rev only. Ill start reading your thread and report back.

Forgot to answer about the ve, yes it is the same ve table from the suburban ecu.

[mowton]

Am I seeing the forest for the trees or is my tune down load corrupted. The 0 kPa cell for IFR and offset are both set to 0...which is WOT? You also have adaptive idle disabled, is that your tune startegy?

Ed M

[tictakman]

Lol, yea that was me trying different things to hopefully help get the rich condition to go away. Its been changed back.

[mowton]

SO post the working file with a comparable log please.....

Ed M

[GHuggins]

I'm not on a computer with HPT on it right now, but I know Ed will know what I'm talking about and could point you in the right direction if this is what's actually wrong... If it's overly rich at idle and trims are maxxing out in what they can pull - there are min pulsewidth settings that need to be lowered both under injectors and transients... That should help get things leaned down... Make your injector data correct - don't alter it to try and fix another underlying problem...

Closed loop vs open loop - I tune everything while leaving closed loop in the picture simply because that's exactly how it's going to be run in real life unless your one of those who thinks everything needs to be in open loop to function correctly which is bull if you know how to tune the O2's and transient tables correctly

[Boosted53f]

the reason for turning closed loop off is to 1- see if his VE table is really jacked up... and 2- see how his injectors operate on the map.

your idle is rich because injectors are bottomed out at 1.8 and closed loop cant use pulsewidth reductions to change the AFR. just turn it off any see what happens with injector operation. PW below 1.8 Open Loop or not? you can use vcm scanner to force open loop and go for a test drive.

yes many people can tune in closed loop and this is a reasonable way to tune. But with a setup like yours and being new it is easy to place blame when you start from the Map and work your way out.

[schpenxel]

That explanation makes no sense.

[Boosted53f]

That explanation makes no sense.

what are your having trouble with? maybe I can help. The closed loop tuning comment was in response to Ghuggins opinion on closed loop tuning.

[cobaltssoverbooster]

^+1 Schpenxel and Ghuggins
i may not know everything there is to the v8's because i came from the land of half an engine but after tuning gm ve since 2005 i learned you dont have to force the car into open loop to tune a VE table if you know what your doing.
I still use a wideband because its accurate and provides a better picture due to its speed but closed loop trimming is what is eventually going to be turned back on so if you dont take its errors into account when tuning ve in the first place then you always have an error offset after letting the ecu take back over.

the other reason i agree with schpenxel is, even if the injector sees a massive error at 1.8 that doesnt mean anything until the ve has been verified in that range. If the ve if off far enough in the range of the error then of course it bottoms out in that PW. everything relates back to a well defined ve table. The OP keeps making corrections to the injector base settings but hasnt once shown a file that has a wideband reflecting a tuned in VE. finished the rest of the tune to see the true error in the injector definitions before making a base change. There is a possibility that once the ve is tuned in that this issue partially resolves itself.
Ed told him to post a log with the injector data he should be starting with. i would start with Ed's latest advice, this is how the OP will get his tuning experience to make forward progress again. Please just stop making base injector changes until it has been reviewed with the suggested data first.

[schpenxel]

what are your having trouble with? maybe I can help. The closed loop tuning comment was in response to Ghuggins opinion on closed loop tuning.

As long as it's in SD then the VE table is being used and it's easy enough to see if it's "jacked up"

I understand all of this just fine