Idle AFR changing whilst Idling

[kur4o]

GM 12561462 is ls1 28 lb/hr at 4 bar pressure.
If they are stock I can get you the correct voltage offset settings.

The best injectors will be the gm stock production ones or ford SVO.
Cal data is readily available from stock tunes.
Ls7.ls9 are really big improvement but alot shorter and needs modification to fit.


I guess fic don`t provide injector data, because they don`t have one.

Wrong plugs can get you alot of pinging. If they heat too much.
Get us a pic of your current ones.
Maybe try 1-2 points colder splugs.

[spfautsch]

GM 12561462 is ls1 28 lb/hr at 4 bar pressure.
If they are stock I can get you the correct voltage offset settings.

None of these are stock - FIC remans / modifies injectors. They remove the pintle cap, clean and replace with caps (and possibly do something else) to give the flow rating the customer orders. Normally they grind off all part numbers and paint the injector bodies light blue, but in my case they only removed the Bosch P/N and left the GM P/N. They advertise these sets as flow matched Bosch D3s and that they will come with a flow test printout, but mine did not. Mitch was able to pester them enough to send offset data for his, but I didn't bother because mine idled well using the SVO offsets and minimum PW I found @ 3 bar.

This is purely speculation, and I hate to bag on FIC but it's possible Mitch has a mix and match bunch of injectors that may or may not be electromagnetically similar but are minimally flow matched (at some pulsewidth). I ordered mine to flow 42lb/hr, and based on my VE trims they flow closer to 44. But thankfully I know mine at least match electromagnetically. When pull my engine next month I plan on sending mine to a third party to flow test.

[Terminal_Crazy]

Ok I’ve got a few things to pull apart and check again tommorrow.
See what I find.

Most info I’ve found so far on the injectors is to just zero the low pw tables.
This motor is idling about 1.8ms with the 42lb
I don’t see the voltage offsets having a major effect on the fueling once the motor is running. Voltage is pretty stable by then.

Thanks
Mitch

[spfautsch]

Most info I’ve found so far on the injectors is to just zero the low pw tables.

As long as what you have are all Bosch type III I think you should be fine zeroing that table. But without any part #s you're taking FIC at their word. If you have one or two that are completely different from the other six or seven except in gross flow rating, all bets are off.

I don’t see the voltage offsets having a major effect on the fueling once the motor is running. Voltage is pretty stable by then.

Cooling fans draw a fair amount of power, especially on high. It sounds like you've jettisoned your A/C but the blower and the additional draw of the cooling fans keeping the A/C condenser working make a noticeable difference, especially at idle when the alternator output is fairly limited. You also have an electric water pump right? All this stuff makes an impact on system voltage.

Long story short, I wouldn't dismiss offsets completely. I pay attention to the ECMVOLTS pid frequently enough I've considered making the "User Parameters" PID selections in eehack remember the last selection.

Edit: It may be reaching, but are your injectors painted? If so have you considered filing through the paint to see the color of the base plastic?

[kur4o]

Here are some good articles.

[Terminal_Crazy]

Thanks for those.
I’ve got a couple of Greg’s books.

Mitch

[Terminal_Crazy]

Little update on this issue.

Removed plugs from motor and they were oily/carbonized and sooty.

Checked the PVC valve and had tape stuck over the end where I'd tried to fatten the valve into the grommet.
Replaced valve anyway

Bought a cheap Endoscope off ebay but couldn't get a clear view of the cylinders.
Tried viewing into the inlet manifold port runners and again couldn't really see any definitive detail.

Made a smoke machine with a stainless chamber & a small compressor
Pumped several smoke pellets into the crankcase through the rocker cover.
had smoke forcing its way out of the dipstick hole
I could NOT see any smoke in the manifold runners which I suppose is good in a way.
Certainly ticks the box the manifold is sealing.

Resealed the AIR tube plugs in the exhaust manifolds with epoxy metal and replaced.

Started the car and the RHS O2 started to drop after a minute or two.
Vacuum gauge was pretty stable.
Tailpipes were smoking white quite a lot, it's freezing and snowing here.
So I let it warm up and did a water decoke into the inlet manifold.
Used about 1.5 pints over several minutes.
The O2's and wideband all flatlined.
Retarded the timing with EEHack (Thanks Steveo) to pump heat into the exhausts.

After another 5 minutes or so the O2's came back on line
Wideband followed suit.
The smoke has cleared up from the tailpipe.
The smoke from the rear of the inlet manifold also had cleared up so PCV seems to be working now.

Car is idling pretty sweet.
The RH O2 sensor is now consistanly reading higher than the left as i'd fattened it up slightly which it has never done before
and the wideband reading was also more stable around 12.5

I'm just waiting for new O2 sensors and plugs to arrive.
I will monitor this for a while before changing anything over and see what develops.


Thanks guys
Mitch