I rarely see the BLM's get above 108 113 the highest so far. The injectors are the SLP LS1 25lbs. In the chip its set on 25. any idea what I can do to lean it out?>

 

Play with the injector constant a bit and see what happens...

Also, are the BLM's constantly showing rich?

 

its ALWAYS 108 except a few time son the highway when I gave it gas it was showing 111 113 then 108. The Tech 1 is moving from lean to rich normaly and the 02's are 170-800 while driving. The plugs look fine but blow black smoke when reved.

 

Are you burning your chips yet? I think that tuning the injector constant at first will be your best bet...

Another option could be if your o2 sensor is failing, thereby giving the ECM bad info...you should check the cross count info when scanning to see how it is...I think it should show up as around 50-55 cross counts on average in closed loop...

 

I had the chip burned from a friend. He said he was going to change the constant to 29 i guess. He figured that out somewhow. I'm in the process of buying my own stuff. O2 sensor is brand new. The 02's are always moving. Never a dull moment. I'm getting no knock readings at all eather. But of course I never got on it yet since theres only about 30 minutes and 30 miles on this new motor. Its a 383 10:3:1 TF heads SR and 219 cam

 

That should be interesting to see how it impacts you.

Too bad you don't have an emulator yet...You could figure it out in an hour...


Also, when an o2 sensor starts to fail, the cross counts still happen, but the goes way down to like 5-10...it can still be undesirable and be providing some data.

HTH,

 

I would set the inj constant at what the injector flows and adjust the MAF tables or VE tables based on the data logged and what the plugs are telling you.

 

What kind of fuel pressure are you running?

 

Fuel pressure is bone stock. The screw is allllll the way out.

 

Check for a VSS signal to the ecm.

 

Vehicle speed sensor? My guages work fine when I drove it.

 

I think the problem might be with those LS1 injectors. I'm not sure if they use the same pressure and are comparable to the non-ls1 injectors.

I thought you didn't have an afpr? I didn't think the stocker had a screw-type adjustment on the fuel pressure regulator? Check your fuel pressure first to make sure it is around 42lbs.

 

I picked up a used crane one. Doing a search I cant find anybody who had a problem with these injectors running a 25 constant.

 

Just a thought, but have you had the FPR vac line disconnected recently, for any reason? Either setting base fuel pressure, or ???

A FPR with a leaking or ruptured diaphragm will flow extra fuel into the intake manifold via the vac hose -- which would account for the rich condition you're seeing.

I'm sure you'd have noticed this immediately if you'd disconnected the FPR vac hose, though. Even if the pump was off, I'd think some residual fuel would probably drip out of the hose.

 

I ran this FPR a little last year with no probs I had 22lbs injectors on my old 350 . Almost same comb. BLM's were all within 4

 

I also used those same SLP 25#/hr injectors on my E-Tec 355.. You'll need to retune the VE tables for that engine (I had to do a lot of VE changes on mine. I would imagine plenty would be required for a hopped up 383).. That will get your BLMs in the right range.. I set my constant correctly (did you also change the cylinder size constant to reflect the increase in cubic inches?) and was running with 108 BLM's just like you... Now I'm right around 128 after my tuning...

EDIT: this is for my speed density setup, not sure of what you need to change on a MAF system..

 

What???ls1 injectors???? Naw...you might want to rip them out. They are rated at 55-61psi. So you better have a good fuel pump and raise the pressure unless you want to run them at less psi than designed for. Then you have like 19lbs injectors at stock (l98) f/p setting.


I mentioned the vss signal to the ecm not speedometer. Make sure you get a mph readout through your scan tool. Otherwise BLM cells are more or less disabled...

 

The injectors that SLP sold [a while back] were rated 25# at 3 bar (43.5 psi)... At least, thats what they were advertised at...

 

Those injectors are rated at 25#/hr @ 43psi or 29#/hr @ 56 psi. I'm running the same ones in my 91 formula and they work fine.

 

that clears things up. Thanks for correcting me. I knew the rating lowered but was not sure the exact amount.

I wonder if the spray pattern will be as good.

 

Results are in. Went from 25# to 28#. Idle is still 111 bu as soon as I get on the gas a tad it bumps up to 124 and the more and more I press on the peddle the BLM's go up. Highest I saw was 129 so far but as SOON as I let off the gas it goes to 108-111.

 

new update. I installed 89GTA383's 29.2 Injector constant chip and it bumped the blms up. Cruising in 4th from 50-80 the blms are 127-129. Idle is at 120. Car runs better now. Just letting you guys know. Its weird having people set it at 25 and everything is perfect then me with 29 and its good. thats a big differance.

 

Kinda makes me wonder if either your fuel pressure, or ignition voltage might be running a little on the low side.

Looking through the previous posts, it doesn't sound like you've checked the pressure with a gauge yet.

(Edit: Yup, brain fart, I typed "low" when I meant "high" )

 

Fuel pressure would have to be high for that to have worked out like it did, somewhere in the neighborhood of 50+ psi. It seems to be acting as if the pressure is set at or near the LS1's pressure, where the injectors were originally flow rated at.

 

I'm showing 41 PSI at idle 47 with it disconnected. I have an AFPR but its set allllllll the way down to where the screw is coming out.

 

Set the pressure to 43 with the vacuum line disconnected, this should get you around 36 with it hooked up at idle. This is what the factory regulator was supposed to be set to. Still in all it doesn't seem like that difference in pressure should be making it that far off flow.

 

Cant go no lower. The screw is basically only on the thread in the cap.

 

Well that sux. What brand is it? I've heard others say the same thing, I can get my Accel to drop to almost 0.

 

I'll tweak the maf table to get it to 128 by leaning it out by roughly 120/128=6%. It just goes to show that everybody's combination is a little bit different, and tuning takes time and patience.

 

You may want to consider going to a Holley unit if you can. I had the type you seem to have and it sucked. I couldn't get it any lower than what you are describing. Bought a new holley (which comes with a diaphram) and things have been great since then! The holley is also hand adjustable. No more little wrenches to drop into the black hole of the engine bay.