Very lean idle

[TurboGLH]

I've had a busy week, but was finally able to follow up on my phone call with Peter. Based on my cam idle vacuum and motor specs he recommended starting with the largest displacement 35lb map that used a mild cam.

I loaded that map (5037 I think) and reset the adaptive. Idle AFR is spot on at 13.9 w/ 15deg timing. I drove it around some to see how the cruise map was, has some slight stumble at points, but I'm sure that with time the self learn will handle that.

[TurboGLH]

Do you happen to have a part number for the camshaft?

No part number, it's not an off the shelf grind. It's a Comp cams Small block Chrysler Roller using their 4874B lobes.

Advertised Duration 279/279
Duration @ .050 242/242

.381 lobe lift (.571 with my 1.5 rockers) 110 LSA installed straight up.

Cam timing events:

Exhaust Open: 51BBDC
Exhaust Centerline: 110BTDC
Exhaust Close: 11ATDC
Intake Open: 11BTDC
Intake Centerline: 110ATDC
Intake Close: 51ABDC

[BITE_ME]

Do you happen to have a part number for the camshaft?

[TurboGLH]

In regards to low voltage at alt(not what tablet says)....

consider a 12-14awg wire from alt + lug to batt + lug direct as well as a possible 12-14awg grd direct from alt case to neg batt lug as a test or just leave permanent. If you leave the supplemental pos wire permanent make sure its a fusible link wire or fused. Worked for me. Mine reads 14.2 on tablet and at the alt.

alternator is a 90A unit, I've got 6ga from the output, through a 100A breaker and then into the battery, also have a have a 4ga ground to the motor, but not attached to the alternator housing directly.

I need to spin it just a little faster, 2.5" pulley vs the 3" would get me there.

[marc s]

In regards to low voltage at alt(not what tablet says)....

consider a 12-14awg wire from alt + lug to batt + lug direct as well as a possible 12-14awg grd direct from alt case to neg batt lug as a test or just leave permanent. If you leave the supplemental pos wire permanent make sure its a fusible link wire or fused. Worked for me. Mine reads 14.2 on tablet and at the alt.

[TurboGLH]

It was a future proofing measure. Car is 416ci, has CNC heads, 11:1, 3" exhaust. There's no reason to think it won't make over 500, and I like headroom.

I just got off the phone with tech support, ans got the same info. I'm going to try a few things, including a mild cam map when I get home.

[2700 Cast]

Surprisingly the idle vacuum is 15/16in, cam is a custom grind that was picked to work well with efi and they seemed to get it right. Idle timing is 15deg, with 5deg of vacuum advance.

I considered that the maps for a more mild cam might help, I'm sure the idle fuel tables are different, but there isn't one that let's me select 58psi/42lb without selecting 230deg+ on the cam


I've got an upgraded denso alternator, if I bring idle speed up to around 950 I can get the voltage up. The only crank pulley that works with the weird offset on a early fluidampr is a march perf under drive, so I'm stuck with that, but I'm working on a smaller alt. pulley to get the speed back up.

I'm only seeing two 42lb maps in the manual, can you tell me what map number that is? I can bump the idle speed up to get charging system output up over 14v, and bump the idle timing up as well.

I've backed up the maps as i've been changing between them, should i be resetting the self learning parameters as I load each map, or will they be wiped by a map change?

Thanks in advance.

42lb MAP vac.JPG

That CAM doesnt match up to 42 lb/hr. Injectors.

Why cant you run 35lb injectors ?

[My427stang]

I know you tested the O2 sensor, but mine was doing some funky intermittent lean behavior and always passed the gas test.

I certainly wouldn't tell you to spend money on an O2 sensor without following some setup and testing advice from the experienced guys here, but mine was bad, and it was all the O2 sensor. VOltage seems like a good place to start, but if it does the same with the jumper cable, it would take a serious vacuum leak to take a hard to to 20:1 so quickly, especially with the fuel your setup is able to push into the cylinders right now

[TurboGLH]

Surprisingly the idle vacuum is 15/16in, cam is a custom grind that was picked to work well with efi and they seemed to get it right. Idle timing is 15deg, with 5deg of vacuum advance.

I considered that the maps for a more mild cam might help, I'm sure the idle fuel tables are different, but there isn't one that let's me select 58psi/42lb without selecting 230deg+ on the cam


I've got an upgraded denso alternator, if I bring idle speed up to around 950 I can get the voltage up. The only crank pulley that works with the weird offset on a early fluidampr is a march perf under drive, so I'm stuck with that, but I'm working on a smaller alt. pulley to get the speed back up.

I'm only seeing two 42lb maps in the manual, can you tell me what map number that is? I can bump the idle speed up to get charging system output up over 14v, and bump the idle timing up as well.

I've backed up the maps as i've been changing between them, should i be resetting the self learning parameters as I load each map, or will they be wiped by a map change?

Thanks in advance.

Theirs actually a 3rd 42lb map you can try. It's for the 460 Ford.

Anyway.
My guess is your making about 10" of vacuum at idle......what is idle timing set at?

I always had bad luck with factory charging systems on Dodge/Chryslers. Voltages we're always too low.....you can try a pulley from a truck with AC. Or just replace with a high output aftermarket. Low voltages are not good for ignition systems, and this could be effecting your A/F ratios.....basically the coil looses the AMPs, and will have a week burn time.

There's been a lot of Dodge/Chryslers with almost the same issue, and I've been suspecting low voltages.
A MSD unit would help. But getting the voltage over 14 volts at idle would be better.

One of the fixes. Is to run a lot of initial timing...some are running 22 at idle.

If you have a spare good running vehicle, that does +14 volts at idle, and some jumper cables ( battery chargers are too noisy, and week to work for this test ).
Watch the A/F ratio at idle on the tablet, as the vehicle is being jumped.... It's ok to have 2 charging systems tied together. Some times I put 4 systems together to charge absurdly large battery banks.

[BITE_ME]

Theirs actually a 3rd 42lb map you can try. It's for the 460 Ford.

Anyway.
My guess is your making about 10" of vacuum at idle......what is idle timing set at?

I always had bad luck with factory charging systems on Dodge/Chryslers. Voltages we're always too low.....you can try a pulley from a truck with AC. Or just replace with a high output aftermarket. Low voltages are not good for ignition systems, and this could be effecting your A/F ratios.....basically the coil looses the AMPs, and will have a week burn time.

There's been a lot of Dodge/Chryslers with almost the same issue, and I've been suspecting low voltages.
A MSD unit would help. But getting the voltage over 14 volts at idle would be better.

One of the fixes. Is to run a lot of initial timing...some are running 22 at idle.

If you have a spare good running vehicle, that does +14 volts at idle, and some jumper cables ( battery chargers are too noisy, and week to work for this test ).
Watch the A/F ratio at idle on the tablet, as the vehicle is being jumped.... It's ok to have 2 charging systems tied together. Some times I put 4 systems together to charge absurdly large battery banks.

[TurboGLH]

I've verified fuel flow, I got 100ml/s for the 8 seconds the ECU primes the pump. That's approx 350lph, which is right in line with the pumps 340 rating.

I tried a couple different maps, one for the next displacement up and also one for the actual displacement/cam but with the 35lb injectors.

The second should have had it super rich, but still required 20% on the global.

The injector pulse width seems to match what I'm seeing with the +30 short term and the +20 global (should be 1.5ms and I'm 2.5-3.0)

Only other thing that's a possible issue is idle voltage, I need to swap pulleys to get alternator speed up, currently I'm only getting battery voltage at idle, but increasing the idle speed to 1100 and getting voltage above 14v only caused the afr to lean out more.

[fleet man]

save the map you are using and try the other map see what happens. but i would reread the tuning manual to see what adjustments could be changed.

[TurboGLH]

359000 Small block mopar kit.
Injectors swapped for 42/lb, set at 58psi with regulator unhooked from vacuum.
Fuel pump is Holley 340/lph in cell pump, 3/8 line front to rear, and a 40micron filter.

Motor is 416ci, Cam is 242/242 @ .050. Running 5031 base map.

o2 sensor shows 10:1 when warming up as per manual, but shows 21.5-22.0:1 when idling. I doubled checked that o2 is working by using propane to add fuel and sensor responded as expected. I added +30% global after testing with propane and afr is closer to set point, in the 14:1 range.

I haven't verified fuel flow by quantity yet, but that's on my list to do. I'm also considering moving up to the 5035 map.