I performed the MPFI marine intake swap on my '99 4.3 S10.
I changed the tune to 24# injectors, it drives very nice, but
I'm getting these DTCs:
[PCM] P0172 - Fuel Trim System Rich Bank 1 (Pending) (Immature)
[PCM] P0175 - Fuel Trim System Rich Bank 2 (Pending) (Immature)
What are my troubleshooting steps to try and resolve this?
just a suggestion is that you need to scale your injector constant to match your new injector size
Does anyone know a stock Vortec 4.3 fuel pressure rating?
My understanding is that the marine intake has a similar size
injector but that the fuel pressure is higher. I suppose that
this means I need to adjust even higher. Do I increase the
size of the injector to compensate, or is there something I'm
able to adjust based on a higher fuel pressure?
If it were me I would just hook a fuel gauge up at the fuel rail if you can and see what you got.
2017 Silverado LTZ
Yes, I can do that, but I don't know the stock fuel pressure?Originally Posted by KLUG'S SS
I bumped up the fuel injector size and its doing much better.
Still a little rich on decel, but part throttle and idle are good.
No more "rich" codes are being thrown.
Is there anything to tune for decel situations? Or is that just
the way it is going to be? It immediately goes rich, but evens
out in a few seconds. Not rich enough to throw codes.
Just wait till you throw boost on this thing and start tuning
~Scott
Possibly play round with DFCO. some engines you have more features as with on the alloytecs its not as developed in this area so in my case ive managed to compensate with fuel injector multiplier table like placing fuel at different rates in the timescale at different rpm to coinside with the variable intake cam timing i have in my engine, in turn there is an upside on my machine its helped to supress some KR
I'm not sure how HPTuners compares to LT1edit, but a buddyJust wait till you throw boost on this thing and start tuning
who's done a bunch of LT1 tuning said to not even worry about
a rich condition on decel if it's not impacting the way the motor
runs (no backfires, no stumbles, etc). So I'm leaving it as is.
To come back to this issue, I only get rich LTs/STs when
I'm idling or in a cruising state with 0% TPS when I let off
the gas. Under throttle the LTs/STs look great. Does this
mean anything? The truck runs great.
It would mean that you need to work on the air flow calibration at idle, cruising load zones.
Thanks, now I just need to find those...
Bringing this back to the Top Hemi, do you have a way I can chat with you for a few about this? I am looking at doing something similar.
Ben
Last edited by Injected1; 12-26-2008 at 08:43 PM.
99 Camaro Z28 - Kali - Bolt-Ons
03 Silverado V6 - Stock
BCG Tuning becuase a custom tune should take longer than 10 minutes.
With the holidays I haven't had the time to mess with the idle air and cruising load zones yet.
If you're talking about the S10 intake swap, send me a PM.
I just did the marine intake swap on my 1998 GMC Jimmy. Right now I have the 24lb/hr@ 43.5psi . My fuel presure reads 43psi, engine off key in the on position, 50 psi engine running and it jumps up to 59-60 when I open up the throttle. I should use what I'm getting while the throttle is open to scale my injectors right?
Also, In hpt with my 98 pcm I have "flow rate" Which I'm going with 27lb/hr. Then there's "Offset" right now it's at 0.941 msec. Does that have to be changed? Does the offset change in relation to injector size? In other words, would the new larger injectors have a diferent offset then the stock ones?
Man, it's been while since I messed with this, but I believe
you use the idle fuel pressure w/o vacuum. I believe that
I was getting 58 psi on my truck. Then use whatever the
formula is (Google it) to scale the injector appropriately.
From what I understand, the offset and entire offset table
are specific to each model of injector. Ideally, you get the
specs on your specific injectors so the variables are correct.
However, theory aside, as in my case, I was unable to find
the specific specs for my injectors. I left the offset and the
offset table as-is and made slight adjustments via my flow
rate to compensate accordingly (to fix fuel trims).
It's not ideal, however, at least in my case I got the truck to
run pretty good so I'm not going to mess with the fuel injector
settings any further.
Ok. So by entering in 27.7lb/hr under "Flow Rate". That put my LTFTs right at 0. But...When I tap the throttle it bogs....
I ran into the exact same problem, mine is still not 100% solved.
I tried new injectors, flow rate changes, air flow changes, etc and
nothing seemed to help. What did help the most, though, was to
remove the TM from the tranny. Now I have only minor bog when
cold and almost no bog at all once it's warmed up. It's fixed well
enough that I'm no longer worrying about that problem.
Thanks for your help. If I find any info I post it here.I ran into the exact same problem, mine is still not 100% solved.
I tried new injectors, flow rate changes, air flow changes, etc and
nothing seemed to help. What did help the most, though, was to
remove the TM from the tranny. Now I have only minor bog when
cold and almost no bog at all once it's warmed up. It's fixed well
enough that I'm no longer worrying about that problem.
I started a thread with my tune and a log. Hopefully someone with experience tuning the crappy black boxes will post up.
I've been messing with the tune and it seems that I just might being getting the hang of it. I got part throttle driving pretty damn good. No more bogging. Seems 27.9lb/hr did the trick. I might try 28.18 tomorrow. Thats what the 24lb/hr injectors are @ 60psi. WOT my AFRs are still in the 10s though.
Feels like the marine intake with just the injectors it came with made the truck pull harder. That's the butt dyno though. By the time I get to the track I should have this PE thing figured out.
I'm getting weird lean spike right when I floor it. It seems to always happen at around 2000 rpm and 103 kpa MAp. I can't figure it out... I drove around while logging and just tapping the throttle. Every time I did it I got a lean spike.
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