Too Rich to Start - Can you guys give this a look before I start pulling things apart

[runpasthefence]

The quick and dirty:

2003 LQ9 that I had running in another swap truck almost 5 years ago now. Been in the process of swapping it into another vehicle for going on 3 years.

Since it last ran I installed:
- LS6 cam
- Magnacharger MP112
- Valvesprings
- Deka 60lb
- 2bar map sensor

It turns over and will stumble and attempt to start, but it never runs for more than a few seconds. It backfires and the plugs are wet-fouled.

I was dealing with this issue a while back with some injectors of ill repute, so I'd just assumed that was the problem. Took me a while to come up with the funds for these new Dekas, and it's pretty obvious I've got something else going on.

I'd seriously appreciate any insight before I start pulling the engine apart.

122915.hpl
SD Tune FIC.hpt

[MikeOD]

Are you running the short or tall SD 60's? The data is slightly different depending on which injector you have.

Either way, under Engine - Fuel - Transient - Min Fuel Milligrams, set that to 0.025, not much change from what you have.

I'm guessing you have a return fuel system and 58 PSI? If so, the flowrate if you have the tall injectors should be 72.9, the short ones 74.8...again, not a major change from your values.

The short pulse limit and short pulse adder seem wrong to me as well...where did you get the numbers in your tune?

Your offset table should be set the way your flowrate table is (if you do indeed have the return fuel system that I think you have)...everything in the 0KPA row should be across the board...it should only vary by voltage. I also don't think the offset data is correct at all...it doesn't match what I've seen for proper calibration on an SD60.

After that, you're not properly failing the MAF sensor. Set the MAF codes to "MIL On First Error". Your VE table numbers look kinda whacked too...where did they come from? This is a stock LQ9 other than the LS6 cam right?

[MikeOD]

...that also looks like a lot of timing and not enough fuel for boost in PE...maybe enough fuel at high RPM if it's not making much boost...I wouldn't think an MP112 can make a lot of boost on a 6.0, but how much should it be making?

[runpasthefence]

Are you running the short or tall SD 60's? The data is slightly different depending on which injector you have.

Either way, under Engine - Fuel - Transient - Min Fuel Milligrams, set that to 0.025, not much change from what you have.

I'm guessing you have a return fuel system and 58 PSI? If so, the flowrate if you have the tall injectors should be 72.9, the short ones 74.8...again, not a major change from your values.

The short pulse limit and short pulse adder seem wrong to me as well...where did you get the numbers in your tune?

I'm running a return system, and all of the data is what came with the injectors from Fuel Injector Connection. It's possible that I misinterpreted some of their data, but I don't think so.

Your offset table should be set the way your flowrate table is (if you do indeed have the return fuel system that I think you have)...everything in the 0KPA row should be across the board...it should only vary by voltage. I also don't think the offset data is correct at all...it doesn't match what I've seen for proper calibration on an SD60.

After that, you're not properly failing the MAF sensor. Set the MAF codes to "MIL On First Error". Your VE table numbers look kinda whacked too...where did they come from? This is a stock LQ9 other than the LS6 cam right?

Yes, stock LQ9 other than cam. 317 heads, stock bore, etc. The VE table came from another LQ9 with similar mods for a starting point. Do you think I should run stock LQ9 VE figures for now?

...that also looks like a lot of timing and not enough fuel for boost in PE...maybe enough fuel at high RPM if it's not making much boost...I wouldn't think an MP112 can make a lot of boost on a 6.0, but how much should it be making?

With the pulley I'm running, it should make right around 9-10lbs. Forgive me if I can't answer questions more adequately. The computer at my shop is the only one with HPTuners on it, and I'm not 100% familiar with the tables without having it in front of me.

[MikeOD]

Well...it looks to me like the FIC data is wrong. If they're actually SD60's. Are they short or tall?

Yes, I think you should revisit the VE table...what you've got in there now doesn't make any sense to me.

[Russ K]

The VE table came from another LQ9 with similar mods for a starting point. Do you think I should run stock LQ9 VE figures for now?

Copy with Labels a stock LQ9 VE table & paste it to your VE. Then copy & paste the 100 KPA row into the 210 KPA row. Next, multiply the 210 KPA row by 1.25. Then highlight the 100 to 210 KPA rows & click on the Interpolate Between Vertical Bounds. Note that when you just copy a stock VE table to a 2 BAR VE table, you will be way too lean due to the lower resolution of the 2 BAR VE (10 KPA vs 5 KPA)

[MikeOD]

Here's a file I read from a Silverado SS...if you want to use it as a reference for an LQ9. I'm not 100% certain it's a completely stock file, but I think it is, and the truck ran fine.

[runpasthefence]

Thanks for the input guys. I found some time this weekend to make it over to the shop and make some changes. I feel like I should mention my goals here. I'm a complete tuning n00b, and my intention with this software was to simply get the tune close enough to get it drive-able so that I can get the truck to a dyno and have a professional tune it properly. And to clarify, I'm using the tall SD60s.

Anyway, I made the recommended changes to the VE table, offset table, and some small adjustments to some injector settings that MikeOD recommended. I also noticed that my fuel pressure regulator was only flowing about 44psi, so I made that adjustment.

Unfortunately, I'm in the same boat, but I may have seen some improvement. The actually started and ran (though, not all that well) for about 20 seconds until I shut it off. Unfortunately, I don't have a log, and it wouldn't start again after. It wouldn't restart due the same recurring issue - wet fouled plugs



My wideband was also reading at about 10.3-10.4. I'm not sure if that's accurate, but I suppose it could be as it looks like the cylinders are flooding pretty heavily.

I'm going to buy a new set of NGK TR6s and see if I can get it to run some more. If that doesn't work, and if you guys don't see anything that'd be causing this in my tune, I'll probably go ahead and start looking for a parts problem. I haven't been able to find a vacuum leak, and spark seems to be strong.

SD Tune FIC.hpt

[blown 04]

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