Still working on my front cover solution- The marine cover won't work due to the short water pump I need for the Corvette and the diameter of the 4x reluctor.
Working on plan 'B' that utilizes the plastic from cover with a spacer thick enough to allow for the dual roller timing set. All I need is like an 1/8" to get it to fit without rubbing. I'll keep everyone posted on how that goes-
OK- It's been a while.
I'm starting to ramp-up for my EFI swap this winter.
The one thing I'm beating my head over is trying to find 12200411 pin-out diagrams for the 2001-2002 circa 4.3 V6 so I can compare them with the L31 V8.
My dilemma is over the Knock Sensors- I REALLY want to use flat response (2-wire) variety vs the resonant style.
I had a custom harness made but I believe the wrong pin-outs were used for the 2-wire sensor.
My harness has the Dark Blue wire at C1-51 and the Gray wire at C1-49. Of course, any diagram I've found so far for the L31 Express Van says C1-49 is unused but C1-51 is for the resonant type knock sensor and not the flat response.
From what I've pieced together so far surfing on-line is that the V6 using the flat response sensor uses C1-9 but I have no idea where the second wire goes-
It also appears that neither the L31 or the V6 uses dual knock sensors, regardless of type?
My question is where can I find an accurate wiring diagrams for both the L31 (2002) Express Van and a 2002 V6 Blazer with the 12200411?
I don't want to install anything until I validate all this wiring and have it 100% correct.
Any help or advice (other than don't use them :-) would be most appreciated.
pm me your email address
Now that I have the info I need (Thanks mecanicman!), here is an off the wall question:
Most of these flat response sensors only have an opening that accepts an 8mm bolt, which on a Gen I SBC is going to be a 5/16" bolt. Not a common bolt size in the block.
Is it possible to carefully machine the hole in the sensor to 10mm so it can accept a more readily accessible 3/8" bolt?
It looks like there is enough 'meat' on the sensor to do it safely.
OK, it's been a while (I hate it when life gets in the way ;-) but I finally got everything together and fired up.. Well almost..
The car will fire and run for a few seconds and then die-
It almost acts like it's not getting enough fuel (40# injectors @ 58 PSI- Plenty of fuel for this engine).
I've got good spark (lights right up and runs smoothly for the few seconds it does run) but I don't know how to tell if the distributor is perfectly set since this is an aftermarket intake and the Vortec distributor doesn't allow for adjustment without modifying the clamp.
Now for the fun part, how do I troubleshoot something that only runs for a few seconds?
Are there any logs I can pull from the PCM to help point me in the right direction?
I started off with a 2002 L31 Express Van tune and modified it accordingly.
Sorry if this is a really basic question but I'm just trying to determine where to start with troubleshooting 101-
Any advice would be most appreciated.
Fuel pump runs and ignition fires, I just can't keep it running.
I suspect if VATS was an issue, I wouldn't even get that far?
I ran into the same issue when I retrofit a 12200411 PCM to my 455 Pontiac. The problem was that the VE table I started with was far
too low for my application. The 411 uses a VE table whose entries are proportional to engine displacement, so if your engine is much
larger in displacement than the stock calibration you started with, you will need to scale the VE table accordingly, just to get in the
In my case, the finished VE table for my 455 was nearly 2x that of the L31 calibration I started with in the idle/low load areas that
you'd be using when transitioning from startup fueling to the VE table. This meant that before I made the correction, as the PCM
transitioned from cranking fueling to run fueling, it would be VERY lean and would stall.
OK.. A little embarrassed here. It appears I 'thought' about disabling VATS but never actually changed the setting.
So even with VATS enabled, the fuel pump runs and the ignition will fire?
I'm learning something every day with this stuff!
Is this the only place this needs to be disabled (System -> Theft -> Parameters)?
ScottP's comment is probably also valid-
I'm running a healthy 409 CID and I have not touched the VE table.
Guess I need to disable VATS and move to the next step.
Thanks everyone! I will keep you posted.
Last edited by ezobens; 04-19-2016 at 11:37 AM.
I can't believe it's 2017 and I still don't have this car on the road! The good news is that the car starts and I was able to dial in the CMPRET to +-2 degrees. The challenge I'm having is getting the car to start and run consistently. Sometimes it will start right up, other times I have to hold the throttle open to get it to finally start. Once I do get it started it will typically (but not always) idle pretty smoothly around 1000 RPM. I tried to do the CASE re-learn but I can't get the car to run well enough (consistently) to finish the process. The latest behavior is that it now will surge from around 900 to 1700 RPM at idle and I am at a loss to explain why when it hasn't surged before? A little background since it's been a while: Car is a 69' Corvette with a 409 CI Gen I SBC running a FIRST TPI intake and a 2000 Camaro Fuel module with a returnless fuel system (C5 Corvette fuel filter/regulator). I started with a 2002 L31 tune and swapped segments for the transmission (running a manual), MAF (running a 5-Wire LS1 Corvette MAF) but am still running the L31 coil and Vortec Distributor. I've updated the injector table for 40# injectors and updated the engine parameters to the current displacement. It's basically a 409 CI version of a TPI motor (complete with IAC, MAF, MAP and TPS sensors) running a 411 PCM. I am running a mechanical flat tappet cam (233/241 @ .050, .505/.520 Lift, 110 LSA) so the vacuum at idle (1000 RPM) is about 12". I know I've made a fair amount of changes to the various tables to emulate the fuel and spark tables of a LS1 Corvette but I'm somewhat stuck as far as where to go from here with interpreting the datalogs and how to systematically dial in the tune to make the car driveable. The only DTC I'm getting to date is the P1336, which to be expected since I have yet to complete the CASE relearn. I've found several threads with good information but I'm not really sure as to the order to tackle them since everything seems to be interrelated. I do have a wideband O2 sensor but until I can get it running more consistently, I'm not sure there is a need to use it just yet. Any suggestions would be most appreciated. I can also post my EFI Live tune and datalogs if anyone needs a good laugh. Thank you for your time! Elm
Did you change the injector flows for a return-less system? ... See attached pictures. David