6.2L L94 & 6L80 into my 1992 Blazer

[NTYHOE]

Thanks for the update!

 

[Nak]

Had a few problems. I was missing a couple of breakouts on the harness, not a big deal--easy enough to add. Then I realized my fuel sender was wrong. I switched to a '98 tank to get the 40-250 ohms fuel level sender. Here's the problem: '98 till about 2004 is 40 ohms empty and 250 ohms full. After 2004, 40 ohms is full and 250 ohms is empty. (I need the ECM to have the correct fuel level because of my plans for my instrument panel.) Anyways, after some research I figured out how to calibrate the ECM for a reverse fuel curve with HPTuners. After some tests it looks like it works fine. Hopefully I won't have any issues down the road with the fuel sender curve being reversed. (I want things like fuel mileage and distance to empty to work properly.)

So, I'll finish wiring the fuel sender tomorrow--maybe an hours work--then I'll fill the fuel tank one gallon at a time so I can calibrate the fuel level. After that I've got just a few small things to do; so barring any problems I'll start her in the next day or two.

 

[SunlitComet]

The scanguage 2 has trip computer functions that will get you your readings.

 

[Nak]

The scanguage 2 has trip computer functions that will get you your readings.

I understand that, but I will want my readings on my dash. My main concern is that the reversed fuel sender curve may cause problems with those or other readings. I don't know that it will, but as of yet I haven't been able to verify that it won't. For instance, having the MAF curve reverse anywhere can cause the engine to die as it passes that point in the curve. I just have no idea if a reversed fuel sender curve can cause problems; I'm guessing that only someone who has done it would know for sure. Anyways, soon enough I'll post my results up and anyone trying this down the road will know.

 

[Nak]

Getting close. I filled and calibrated the fuel tank, installed the intake and a few other details. I pressurized the fuel system and no leaks! Yay!

Here are the calibration values for a 1998 fuel tank & sender with a L94 engine. Your numbers may be slightly different, but these should get you pretty darn close:
Empty, 14.2%
1 Gallon, 14.2%
2 Gal, 16.4%
3, 19.2%
4, 22%
5, 23.6%
6, 25.8%
7, 27.4%
8, 29%
9, 31%
10, 32.6%
11, 33.8%
12, 35%
13, 3.2%
14, 37.2%
15, 38.4%
16, 39.6%
17, 40.8%
18, 41.2%
19, 42.8%
20, 43.6%
21, 44.4%
22, 45.4%
23, 46.2%
24, 47%
25, 48.4%
26, 49.2%
27, 50.2%
27.5, 50.6%
28 - 30 gallons, 50.6%

 

[Nak]

Started her up tonight! Some problems though... First, I get a DTC "No comm with TCM" and the transmission won't go into gear. I'm thinking I'll have to have my TCM reflashed at a dealer. Second, I show nothing for oil pressure or temp. Not low or zero, nothing. I'm guessing there's a problem with the harness. Third, One of the trans cooler fittings I had welded up is leaking at the weld. That'll have to come off & get re-welded. Fourth, I have no tail lights at all. No brake lights, turn signals, etc in the rear. I'll have to trace that one down.

Other than that she ran rough for a while but is running fine now. The exhaust sounds excellent, at least at idle with minor revving. Very quiet. Hopefully the valves in the mufflers will open open--like they are supposed to--during hard runs.

I'll get a first run video up soon along with a few more pictures.

 

[SunlitComet]

follow the dtc codes diag procedures to the key and apply changes to them as it interacts with the vehicle wiring and you will locate the issue. why do you think the tcm needs reprogramming tho?

 

[Nak]

follow the dtc codes diag procedures to the key and apply changes to them as it interacts with the vehicle wiring and you will locate the issue. why do you think the tcm needs reprogramming tho?

Already fixed everything but the tranny not going into gear. As far as that goes, It's either an OS compatibility between the TCM and the ECM--most likely I think--or a VIN incompatibility--Less likely I think. Either way, It's going to take a re-flash at the dealer to get the TCM and the ECM talking. Also, the diagnostic procedures completely ignore those issues as they wouldn't exist in a factory vehicle.

 

[SunlitComet]

they have codes. even for the ram and rom's in them.

 

[Nak]

they have codes. even for the ram and rom's in them.

Yes there are codes. It's just that the diagnostic procedures assume compatible OS's and VIN's. So when you get a U0101 code, the diagnostic procedures never mentions OS's or VIN's; the manual assumes those are correct. (And yes, I checked out the procedures in case it was something else.) But when you do an engine swap and change the OS in the ECM and have a random OS in the TCM, they may be incompatible. Not to mention that my harness has components that definitely aren't factory.

The ECM OS was changed to accommodate the brake switch in my 1992. The original OS required a variable voltage from the brake pedal switch for factory cruise control to work. Since that would be exceedingly difficult to retrofit into my 1992, we flashed an OS that used two wires from the brake pedal; one 12v when brake off, one 12v when brake on. That switch was already in place from the factory on my Blazer.

Depending on who you talk to, either the mismatched VIN or the mismatched OS, or something in the tune is responsible for my issue. It's not covered in any manual outside of internal GM engineering documents, so you have to rely on people with experience. A re-flash by the dealer will address all three possibilities, so it's the logical next step. I'll just have to bring my Laptop with me so I can disable VATS with HPTuners after the re-flash. I'll also have to change a few other things too: Fuel Pump control, alternator control, & a couple of misc items. I'll disable DOD/AFM for the first 1,000 miles as well so the engine can break in properly.

If it was just the VIN, EFIlive would be able to fix the problem. But a re-flash by the dealer will be cheaper than buying EFIlive. I could chase this problem for a long time, or fix it with a tow and a $109 flash at the dealer.