Question: tuning 45% overs

[JOHNBOY]

A Road Runner is a bit quirky until you figure out what you need to do to make it work in various vehicles.

Mine works fine, it will set an occasional security light and hiccup every so often but it works and works well.

DieselMafia,

The rattle is most likely caused by fuel pressure at part throttle not timing.................try reducing fuel pressure 5-10 mpa in the area of the tune where it is rattling.

Remember time/pressure/orifice is key.

You have a larger orifice so depending on pressure you get more or less fuel delivered as well as pulse width.

You will need to increase pilot timing and main injection timing to compensate and probably lower fuel pressure.

Also increase pilot pulse width and main injection pulse width at idle.

White or blue smoke is incomplete combustion, you need "more" fuel to complete the burn and more timing.

Communicating was not the problem. Repeatability was
was. Pull after pull on the dyno it never did the same thing. Put in the old ECM problem solved. SmokeShow had the same troubles.


As for the injectors. Different ways to skin a cat. I like to pull timing. Bump down the pilot and add pressure. Use Josh's calculator to see where you offset is to make sure you not way out in front.

At Idle I don't like to increase the pulse widths. Adding some pressure accomplishes the same thing (adding fuel) and makes for a cleaner burn. The white smoke is not lack of fuel always. It can be fuel that never really got lit to to poor atomization. Fuel haze at idle is a classic example. Even with stock injectors you get it. Not uncommon to see warm idles with main shot timing after TDC. Not all trucks like that. Bumping that degree by degree out of the negative can clear the smoke and smooth the idle.

 

[GMC_2002_Dmax]

I have ramped pressure up to 12K psi at idle to make some of these injectors work right, I would rather leave the pressure lower.

 

[sweetdiesel]

Love the road runner never had any blips or grief with it.....favorite thing ive ever added to the truck


Dont know why you would add pilot timing or PW? dont see the point........but as said more than one way to skin a cat.

For the most part i reduced pw in the main inj by 20% in the low to mid throttle fuel pressure in the low to mid by 10-15%

played a lot with timing and found that if i just left it alone it worked fine. I use the timng calculator so it figures it out for the most part from my adjusted PW and pressure tables

pilot is shut off completly by 2000 rpm except for the 30mm3 and lower area.

Good luck there is lots of info here.....every truck is different

 

[JOHNBOY]

I have ramped pressure up to 12K psi at idle to make some of these injectors work right, I would rather leave the pressure lower.

So have I.

The trouble with lower pressure is you get a poor burn. More like a smolder than a flash. That can cause harm like this.

You can see the build up above the line. That is a very hard coating from a low pressure idle called fuel coking. Like creosote in a chimney.

Using more pressure helped cure that problem.

 

[Mike]

So have I.

The trouble with lower pressure is you get a poor burn. More like a smolder than a flash. That can cause harm like this.



You can see the build up above the line. That is a very hard coating from a low pressure idle called fuel coking. Like creosote in a chimney.

Using more pressure helped cure that problem.

My experience exactly but, I haven't tuned all available injectors

Funny thing I did, not very responsible either I know but, I was welding on a drilling rig sub. I cut a bracket off a brake bar to realign. Hand says hey, there is some water in that bucket and wouldn't you know it, that bucket of water was actually diesel. There might have been a couple of inches on the bottom. Man that smoke was horrible. Plenty of diesel and a quench to boot. lol. Not sure about the moral of the story but I did get white smoke.

 

[S Phinney]

You could use the DVT controller on your EFI Live and up the idle pressure one kpa at a time until the smoke clears up. If it is smoking at idle all the time it and it is an injector problem it will smoke a good bit not just a little. There is a substantial difference from hazing from larger injectors vs bad injectors. If it hazing from larger injectors it should clear up relatively lower in the pressure range vs what it takes to clear up smoking from bad injectors. I didn't have any hazing from the 40 overs at all then I had a injector problem and it became obvious very quickly.

 

[DIESELMAFIAPER.LB7]

well when i put it into gear it sputters for a min an smokes like crazy but is now clean at idle and it sputters around 2k if you rev it

 

[DIESELMAFIAPER.LB7]

well number 4 was bad taking truck apart tonight and tomorrow hope to get it up an going again

 

[DIESELMAFIAPER.LB7]

k well got the new injector in fired it up it loped for a min or two tehn idled smoother as it warmed up let it get warm an try reving it to see if still popped an sputttered and it did again...puffed the white smoke bad but when i rev it light it doesnt pop and chug but if i floor it it hesistates and chugs ect.. is this tunning or am im being dumb and missing something obvious

 

[DIESELMAFIAPER.LB7]

anyone? ive checked lift pump power an flow the cp3 is getting fuel no fuel leaks anywere only one injector failed the tests and it replaced now an i still have the sputtering an shit.

going to take it for a drive maybe i'll shoot a quick vid to show everyone what its doing

 

[Mike_S]

My guess is that it rattles like a dirty bitch just before it starts cutting out? I do believe that we are running enough fuel now to the point of needing to use the MAF limiting tables as they were intended and not just running them maxed out. Its either bursting or throwing enough fuel all at once to put the fire out. Might be able to play with the pilot timing to help this as well.

 

[DIESELMAFIAPER.LB7]

i was wondering if that table was what was causeing some grief but why the white smoke still maybe we need to bump up the pressure like they have been saying

 

[DIESELMAFIAPER.LB7]

Tuning these things is irratating

 

[Mike_S]

Don't forget to tell these guys, you have cut pistons=lower compression...that could contribute to the white smoke at idle.

 

[DIESELMAFIAPER.LB7]

its in my sig dude :thumb:

 

[DIESELMAFIAPER.LB7]

its only doing it once in awhile?? and i didnt take that much out only dropped the comp maybe .5 i didnt cut them just delipped them

 

[DIESELMAFIAPER.LB7]

Well does anyone else have white smoke when they start with big nozzles an it sputtered when I try revin it kinda backfired almost till truck gets warm after its warm never does it again any ideas

 

[Mike]

Sure seems like one or more problems together ie.. Low timing, too much fuel or too little fuel pressure. Try adding a few MPA in your start up fuel pressure table and see if starting is a bit easier. Not saying you are having trouble there but will give you an idea if added fuel pressure will help or hurt. You may notice a bit noisier start like clatter. You could then move on to idle fuel pressure and see if more pressure helps. If it doesn't, you may try lowering it from what you currently have.

One thing to note, larger nozzles could indicate more fuel at all pw even pilot. You may have to adjust pilot to compensate for the added fuel at that event.

I've found some injectors become slower to respond with larger orifices and some only slightly slower and well of course some didn't seem to change.

The backfire thing gives me the idea you are having late fueling issues that could relate to late timing, low pressure or both. Trial and error seem to be what you are going to have to tune by. Good luck.

 

[DIESELMAFIAPER.LB7]

I bumped the rail pressure up to 8k at idle?

 

[Mike]

Could you post a log of the truck idling? Rail pressure * Both requested and actual * along with rpm, baro, iat, pilot and main pw's and both timings.