Before I start pulling my hair out, some advice/direction from the PFI intelegencia would be greatly appreciated. 383TPI w/6395 sense resister modded, jumpered memcal, CPI/PFI switch on in bin, injector flow rate set for 30#ers(thanks to GMECMGUY for DRP scaling info) motor is hard to start. Tried switching syncronous fuel at idle on/off, Crank Fuel All Injectors Each DRP on/off, ASDF Crank on/off but doesn't make much diff. Other possibly non-related issue is when motor does turn over, it runs lean (16-17:1) for first 20-30 seconds then settles into "normal" 13.5:1 rich idle condition that plagues these set ups. Ive been trying to read everything from Hauln, Dim, Fast, and others including page 9 of "TBI Guys..."but not finding working 'procedure'. Many thanks in advance!

How does it run otherwise? Ok? Any issues while driving?

Thanks Dim,
daily driver has been running decently on a Howell chip (which I can find nominal changes to the OEM bin) but in the last year I have been lurk/learning about all the research on 0D and MPFI. Ive logged the VE and tweaked fuel a little bit but I want to get this set up a La Hauln'. Ive done the sense resister mod and jumped an extra MEMCAL. I understand that this jumper may be extrainious? But setting injector flow, cyl vol., CPI/PFI bit, ASDF bit, etc described by Hauln or you, it is difficult to start. I have tried this with cold/warm motor with limited success. It seems as though it wants to idle so I want to be sure I am following a logical procedure. Do I need to adjust start routine or other cranking params. really appreciate you advice

Where is this switch located in the BIN? I was looking at several '7427 BIN's last night and didn't notice it, or maybe I overlooked it.

By switch, I mean the flag/switch bits being set or not set.

lol..........I guess what I meant was I cannot locate it in any of the $0 masks I looked in.
I found it in a $31 mask for a 7.4L (IIRC), but not in a $0D/E bin or xdf file.
I'll keep digging, not much else I can do with the snowdrifts halfway up my front door anyway.........lol!

Sorry, not enough coffee in me yet! The CPI/PFI switch is at L400B bit0, the ASDF switch is at L400C bit3, the Crank Fuel All Injectors Each DRP switch is at L400C bit2. These addresses may not be defined as XDF items in your version of the mask. All hail 93V8S10 for his complete mask!

Okay, thanks!

I found 93V8S10's mask and there it was, plain as day!
Not gonna be using it right away, gonna use the 16168625 PCM that's in the truck right now to start tuning and learn how to do it, but next year I plan on going TPI with it and the '7427 I have will be put to use then.

I built a 383TPI cause it looked cool! Little did I know I would find this world of DIY EFI!!
I can't stop learning about it, cause its so addictive! With all the expertise available here and FSC and other forums I must pay back in some way. I'm thinking a DIY EFI for Dummies thread or similar.

You do realize that that 8625 PCM is for all practical purposes, identical to the 7427 in pinout and function.

The PCM does have seperate crank fuel parameters. IIRC, these DO NOT take injector flowrate into account. The routine just uses a straight pulsewidth, which means that ALL the pulsewidths for firing the injectors during cranking must be updated when you change the flowrate of the injectors or how they fire.

Yes, after reading and researching on these boards, I realized that a while back. I'm in the process of getting the first stage of my project done, then next year I will go TPI. My plan is to continue my learning curve with the '8625 and TBI in place, do the resistor mods to the '7427 and pick up a Vortec TPI base, then when the time comes, the changeover will be more or less "plug and play", with the exception of the fuel lines and such.
My son had friends over and they got to tinkering around with the '7427 memcal I was getting ready to mod from RBob's notes; looks like they tried to pry the chip off or something......now it's wrecked I guess. If I desoldered the chip and plugged it into the Autoprom, would I be able to read and save the .bin files from the chip? How do you go about obtaining a .bin file when your broadcast code isn't listed anywhere? Use my Moates Xtreme ALDL and TunerPro RT?
Be patient with me guys, I've been reading on this stuff for a long time, just never had the funds to dive in headfirst like I am now. I've read Fast's posts and wanted to pick his brain, but haven't had any luck getting replies to PM's so some of my questions (those not answered clearly after using the SEARCH feature) and I throw them out on here.

.......and, I get too fixated on things sometimes. More digging on the diy-efi.org board showed me what I was asking.
Gonna order the HDR1 from Moates and accomplish reading the bin file from the wrecked Memcal, if it's not completely destroyed...lol

I am sorry, I don't always check my PMs and sometimes when I do check them, I am too busy to respond. I work full time at a dealership and am taking 12 hours this semester in college. If I wasn't, I would be more than glad to go on yahoo messanger or AIM and chat cars with anyone.

Aw man, I was afraid you'd take that the wrong way..........I totally understand about working full time and college.
Since I got laid off last month, I have way more time to devote to my projects and since we don't live that far apart, and I do really enjoy reading about YOUR projects, I had hoped to visit with you via phone or whatever for guidance on my stuff.
Please don't take that statement you quoted the wrong way, okay, Fast?

I do not really think I was taking it the wrong way..rather informing you what I am up against. I am also working on some projects. I honestly have nothing against sharing information, because I generally learn things trying to help others with their stuff.

This is where my project sits even today. I am in the process of swapping to an 0411 LS1 OBD II PCM and building a 4L60E.



Oh and what area do you live in? DFW?

OK, so I've got this machine running in MPFI fairly decent(need more VE tweaking) but the start/crank issues are giving me brain aches! Can someone go through a logical procedure for the tuning challenged to getting this right? I've tried lowering Crank BPW vs Temp but I don't know if I need to address the scaler for that table. Crank Fuel All Injectors each DPR doesn't seem to make a difference. What other tables are considered fundemental crank fueling tables? Much appreciation to all that have helped me to this point!!

All I had to do with mine was lower the Crank BPW vs. Temp table. One thing that's difficult with cranking is determining whether it's rich or lean during cranking. Try increasing fuel.

How well does it idle?

There's one downside to the earlier PCMs in that the crank fuel is done strictly in terms of pulsewidth. Change the injectors or the way the injectors fire, and all the crank fueling must be recalibrated. One way you can get some idea of what the fueling looks like when cranking is to hook up a wideband run from an external 12 volt source. Immediatly after startup when the wideband start reporting, you can take a look at the wideband readings and see which way you need to go. The readings will not be accurate as this is during cranking and much of the fuel will not be utilized, but it does tell you if the engine is overly rich or lean. Use care, though, as too much fuel can also cause a false lean reading due to plug fouling.

Thanks guys! Stay tuned...get it?!