Injector Pulsewidth

My other thread was getting a little long so I am starting a new thread for each problem I run into. I think it will make finding answers easier for others in the future. So first my question and then the reason I ask.

Currently I am using 93V8S10's $0E .xdf and .ads. In the ADS it shows the Injector BPW coming from L3856. Is this just "[u]Base[u] Pulsewidth" or is this actual PW at the Injector. I was going though the BJKZ .hac, and found it was referencing Sync PW from L024D. I guess the bottom line is what location do I put in the ADS as true injector pulswidth. I want to make sure I am seeing the correct data, because if I am seeing "BASE" PW before any adders, then I want to know. This issue may then really be a fuel pressure issue.

Here is what I am seeing now.
@WOT the car pulls really well @ around 4ms pulsewidth until AE runs out at around 3000rpm, then it drops over a couple of samples to 3.1ms and stays there until I let off. The problem is as RPM increases it just lays down and gets leaner and leaner. At 3.1ms I still have pulsewidth available to use just can't figure out why it doesn't. At first I thought is was fuel pressure dropping off, but when I saw the PW dropping and then staying @ 3.1ms I knew it wasn't a pressure issue. PE stays on the whole time. Snych to Asynch map and RPM threasholds were set to 104kpa and 6375 rpm. I am going to try lowering the Asynch threasholds to actually come on and see if that helps.

:nta:

I was thinking of this for a topic of week. It's easy for me to come up with topic of week, it will usually be something I don't know about...

not too familiar with TBI stuff, but i do know that around 3.x PW, the only possible adder to the PW would be battery voltage correction, since you'd be far out of the low BPW adder at that point.

Well, trying to invoke asynch fueling either failed or made it worse. At 60 mph WOT it just went 19-20:1 and fell flat on its face. I don't have the laptop with me today to look at so I have no hard data to put up here, but I am really leaning towards putting a new fuel pump in it. Tomorrow I am going to extend the fuel pressure gauge on a hose up to the air cleaner so I can watch it while it leans out and that should tell me for sure what is up with the pump. If it leans out and FP stays @13 psi then I will look somewhere else.

UPDATE: I watched the pressure gauge while it fell on its face, and it stayed nice and steady @ 13psi, so for the time being I have plenty of fuel. I attached my multimeter which has the ability to measure pulsewidth, and I tapped it into the injector wire coming from the PCM and it showed a max of 1.57ms when it went TU. Attached is the datalog from saturday night, most of it is just cruising but the problems get really bad at around 37:47. Have a look tell me if you see anything odd.

So are you still loosing presure?

Biggest problem I have had with big fuel engines is loosing pressure at RPM! No one knows untill they get a fuel presure gauge that can be read while driving. I have same hose and couplings and I run it up to windsheild...

Only pressure drop is while opening the throttle, for just a fraction of a second, then back to a nice stable 13psi. I think I figured out this problem tonight.

I decided to try to trick the PCM (only for diagnostic purposes) and I changed the injector flow rate from 130lb/hr to 100lb/hr to make the PCM think that the injectors were smaller and thus open them longer. Bottom line it worked. And here's why. I decided to install the 350 injectors I had cleaned and serviced, they were all four 5235206 55lb injectors. The ones I took out were (2) 5235206 and (2) 5235203. The '203s were so gunked up enough that I mistaked them for '206s. Well then I put in the (4) 5235206s and it runs pretty good, only issue is it runs a little rich at idle. I think I may go ahead and have the '203s cleaned and put them back into the front TB.

SO the WOT pulse width is somehow tied to the injector flow constant and it seems like it disregards the PE requirement for 12.5:1 AFR. Even though I had unused pulse width available to use, it didn't use it until I put a smaller injector flow rate in. Now my pulse width is up around 5ms while in AE. Oh well I really wanted to start over on my tune. :rolleye:

sounds like you just needed to correct the VE in the area.

I am going to try the new injectors first, set injector constant to 110lb/hr for 2 55lb injectors, and go from there. I was sitting at 0.5ms at idle and it was reading 12.2 AFR, a little to rich I think. I may set the minimum sync pw to a lower number to try and get the idle AFR up and still keep it stable. If I can't get a nice stable stoich idle then I will probably try the smaller injectors in the front and adjust accordingly. Another thing I forgot about is the PE AFR vs RPM table. If the PW is figured off the PE AFR vs RPM then I could probably use that to cover the lean out at the top end. I will just have to see how it goes.

Another question: If I disable PE for tuning the VE table what is a reasonable kPa to go up to. I only ask because I would think that whenever I am at say 80kPa I am pretty sure that I WILL be requiring PE, so does it really make any sense tuning those areas without PE?

UPDATE: WoooHoooo. I left the "new" injectors in, started with a bone stock BJKZ .bin, for a 454, imported my trans tables, changed injector flow, and cylinder size, along with normal WBO2, and misc. datalog stuff. IT RUNS SO MUCH BETTER. I can't hardly believe it. It stays between 12 and 13:1 all the way to redline. I have the idle down to .4ms but it is still slightly rich at around 14:1, but not too bad. So now I just need to work on the VE table a little bit, and need PE to come in just a little earlier. It is just so much better. I am plenty rich at the top end, 12.0:1 with 80.9 in the VE table @5500rpm. I may try the smaller injectors in the front pod and see just how it runs. I have more than enough fuel with these ones, so I think I may be spot on with the others.