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Discussion Starter #1
Hey!

I am having some issues that I am trying to sort out and could use some experience on the matter. This will be a bit of a read, but I tried to search out all probable causes and am just reviewing them here.
I am currently running a 2.5 stage 5 tune, +40's, 3 bar, etc...

Right now, when i start the engine, cold, or warm it starts up fine without any hesitation. about 30 seconds later (10 for warm) my AFR pings my gauge onto the lean end and the engine doesn't sound happy. My vacuum goes unsteady around 15, and slowly over the course of about another 30 seconds, the vacuum comes back to a nice 20 and my AFR becomes steady at 14.7-ish. This doesn't happen again until another key off, and start again. I do try and do as much research as I can before posting, and the only thing I can really find is that the ecu goes into some sort of fuel trimming loop at some point. Im really not sure.

I had an AFPR on the engine originally, and had the same exact problems. i soon took it off before I could start messing with it as it didnt hold pressure when the engine was off like it should, which I still need to look into how to fix. I had the base psi set to 55. I now have the original FPR back on and have a base pressure of around 57(high right?), and only drops about 3 psi with a vacuum source, which from what I know, should drop a heck of a lot more.... The AFPR went down to about 47 anyways.

Second mind puzzler.
Everything drives nicely and I don't really have any issues at all, but i'm always stressed out about the AFR numbers so always have my eyes on it. Really, if I didn't have a AFR gauge I wouldn't think anything was wrong at all.
Numbers stay in the 14.7-ish range all the way up to 0 vacuum, and then drop to the 13's until about 5psi, at which point it holds and then starts creeping up into the 14's until about 10psi :eek:mg:
Obviously when this happens i get right out of it to avoid blowing something up. This is all done at about 1/4 to 1/2 throttle, maybe a bit past 1/2
I tried this again but at WOT, and my AFR is pegged at the rich end of the scale being 10:1, so I imagine it could be richer than this. It is like this throughout the entire boost range up through 15psi where I start to get off it.

Being that currently I cant mess with my fueling I just drive it out of boost for obvious reasons, but I was just wondering if anyone could point me towards what could be the problem. My main guess is that my fuel pressure is too high, and need to be lowered as so many others with a stage 5 have done, but i'm not sure if that is the answer to all of my problems, from the strange starting symptom to the lean condition under boost.
MAP sensor has a direct read off the engine, and I'm not throwing any engine lights or things like that and the plugs actually look really nice :rolleyes2

I'm just looking for some advice as to what could be the problem, if you actually took the time to read all of that :)
Thanks in advance!
 

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Right now, when i start the engine, cold, or warm it starts up fine without any hesitation. about 30 seconds later (10 for warm) my AFR pings my gauge onto the lean end and the engine doesn't sound happy. My vacuum goes unsteady around 15, and slowly over the course of about another 30 seconds, the vacuum comes back to a nice 20 and my AFR becomes steady at 14.7-ish.
This is all tuning. There are three table that the ECU look for cold start temperature and richen the mixture up.


57(high right?)
Nope, sounds perfect for a 3.8 bar stock regulator.

at which point it holds and then starts creeping up into the 14's until about 10psi :eek:mg:
Obviously when this happens i get right out of it to avoid blowing something up. This is all done at about 1/4 to 1/2 throttle, maybe a bit past 1/2
I tried this again but at WOT, and my AFR is pegged at the rich end of the scale being 10:1, so I imagine it could be richer than this. It is like this throughout the entire boost range up through 15psi where I start to get off it.

Again, this is tuning. There is a part throttle table and there is a WOT table. Your part throttle table is too lean while your WOT table is too rich.



This is why I stopped using off the shelf tune and started to make my own calibration with MPtuner. I would start asking your local TD communities and see if you can pay someone for their time to tune for you.

MPTuner
 

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Discussion Starter #3
This is all tuning. There are three table that the ECU look for cold start temperature and richen the mixture up.




Nope, sounds perfect for a 3.8 bar stock regulator.




Again, this is tuning. There is a part throttle table and there is a WOT table. Your part throttle table is too lean while your WOT table is too rich.



This is why I stopped using off the shelf tune and started to make my own calibration with MPtuner. I would start asking your local TD communities and see if you can pay someone for their time to tune for you.

MPTuner

Alrighty then. Fuel tuning it is. I have looked into tuning myself, but aftermarket ECU's are currently out of my price range, which led me to modifying my stock ecu with a chip, but apparently all the hardware needed to tune the chip is really hard to come by, and the tutorials start to get fuzzy at times.

thanks for the info. I sorta just needed a confirmation on my theory
 

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but apparently all the hardware needed to tune the chip is really hard to come by
You already have a socketed ECU.
Burner and chips are all you need.
C2 SST 27SF512 Chip [C2] - $5.00 : Moates.Net
'BURN2 Chip Programmer' [BURN2] - $85.00 : Moates.Net

Or use an Ostrich (chip emulator) for real time burning. This is what I did, tune it until everything works than burn a chip.
'Ostrich 2.0 : The New Breed' [OSTRICH_2] - $175.00 : Moates.Net

and the tutorials start to get fuzzy at times.
They could be, but if you don't start, you'll never learn. Download MPtuner and calibration and start playing!
 

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+1 to everything Tryingbe said. I spent a couple years messing with tunes people said would work and sent me way back when tuning on these was just getting started. I got one of the 1st flashable ECU setups and have never looked back. So nice when all it takes is an afternoon and a 1/4 tank of fuel to have the tune spot on. A wideband an a Scanner that'll show you knock on the cylinders and a laptop is all you really need.
 

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Discussion Starter #6
You already have a socketed ECU.
Burner and chips are all you need.
Well then. That is news to me. I guess that makes sense if I think about it. Sorta just passed it by as something that's not in my realm. Im more comfortable with a wrench in my hand then a computer. I will absolutely look into these. Maybe find one used.

Thanks for the info from everyone.
 

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To add to this, you will also need a USB FTDI cable to talk to the ECU and datalog to get tuning info. They are available online for about $20.

Download MPScan & MPTune. MPScan lets you datalog your ECU, MPTune lets you program the chip using the Burn2.
 
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