98 Astro 411 swap thread

[redfury]

It went mostly good, though it took me 2 days to accomplish it ( partly due to the cold, and partly due to the lack of sunlight the first day ).

I got it all together with a couple of the spreadsheets and it fired right up!

Once it got into closed loop though, it wouldn't idle. Neither O2 sensor is being read by the computer, so I can only assume there is a difference between the spreadsheets and the original O2 sensor wiring. The spreadsheets show only 2 Tan/White wires for the whole harness, the Astro uses 4, and they are all for O2 sensors, including purple, purple/white. My base tune has the rear O2 sensor removed.

So, now I'm trying to figure out how I need to have these darn O2 sensors wired into the computer. I've got spreadsheets for the 96 S10, 98S10 and 98 V8 truck. I'm not aware of any spreadsheets for the van, so I can assume there are some differences, as there were between all three of those spreadsheets.

[Taz]

For this swap, I take it you are using a 12200411 LS1-B PCM and a tune from a 2002 Express / Savana van equipped with a 5.7L Vortec engine and a 4L60 transmission ?

If so, you will require the pinouts / wiring diagrams from a 2002 Express / Savana to confirm the continuity of all wiring. Following this, a “run test” will be necessary to confirm the functionality of all sensors and components.


Regards,
Taz

[redfury]

Yes, Lextech helped me out with the PCM and some schematics. The only thing I didn't get was pinouts/wiring diagrams for the 2002 Savanna. I think that may have helped me out and had been less to deal with. I could still use it though. I'm working on making an actual ASTRO file.

[Lextech]

I don't have any way of sending you the Express wiring diagram. I only have it on paper. I will try to get the actual Astro O2 sensor diagram and send it to you.

Jeff

[redfury]

What do you mean by a "run test" specifically? I've taken it for a test drive and it shifts like I'd expect, but the idle is poor quality and the O2 sensors will not do anything ( I get PO134 and PO154 No O2 activity ) and will eventually get a random cylinder misfire. I can only assume it is due to needing a crank relearn, but the lack of O2 sensor activity has me concerned. One sensor is BRAND NEW, but I get a code for that bank. The rear O2 has been turned off by Lextech. I need to confirm that I have a V8 MAF sensor.

[Taz]

Step one - confirm the wiring harness is correctly “pinned” for the tune you are using, and validate the continuity of the wiring with a voltmeter (etc.). This is only a check of the wiring harness - not the sensors.

Step two - start the vehicle, bring it up to operating temperature - perform a crankshaft angle variation learn procedure (CASE) and idle learn. Then confirm the functionality of all sensors.

As an example, in your last “run test” you discovered an issue with the O2 sensors - which will send you back to step one - check the wiring.

Regarding your MAF sensor question …. The MAF parameters and rationality tests are the same between a 2002 Astro V6 and a 2002 Express V8 - the only difference is the calibration values (B5001). You should be able to use an Astro V6 MAF sensor if you update B5001 with the appropriate values from the original V6 tune.


Regards,
Taz

[slows10]

He has no way to do a relearn other than the dealer or someone with efilive etc. Your 02 problems and poor idle probably have little to do with a relearn. Although I'd like to see if you just did a relearn by itself before any tuning .If it improved any issues. I doubt it but would be nice to confirm.Just saying dont put all your focus on this if you dont have a way to get it done right away. Im glad to see you contacted jeff. Good guy.

[redfury]

I got ahold of our shops Genisys and did a crank relearn with it tonight, no real change. I did get to access many things with it while I was out there monkeying around.

Fuel trim is disabled, fuel runs only in open loop, never closes. No O2 sensor activity in any test I could perform, but shows .45 volts on each of them.

Multiple misfires on a few random cylinders ( mostly 7/8 in the 2000 range ) one other cylinder was round 1000.

live data shows no activity in any way for trimming fuel.

I'm going to pull the wiring out of the ECM for the rear O2 sensors since they are not part of the base tune anyway and see what happens. Unfortunately, the Genisys goes back in the morning, so I don't have it to play with, but I can confirm O2 activity with my cheap scanner with live data.

testing showed that the heater circuits on the HO2s passed, and according to my readings, the heater circuit for the O2 is separate from the PCM wiring.

My MAF at idle showed 7.8-8 grams/sec with a reading of 1625-1732 hz.

As far as audibly, the engine sounds rough, you can feel and hear the misfires. I'm going after the distributor itself this weekend to determine if I have a bad gear and double check the alignment of the installation since I can only assume the PO pulled the distributor when he installed the motor. could have easily screwed that up. The cam sensor readings were around -20 in live data.

[Aloicious]

-20 cmp retard offset is out of spec, it should be at 0 +- 2*, and its VERY sensitive. even tightening the hold down clamp can change it a couple degrees.

rear O2's shouldn't have any affect on how it runs, they mainly only test cat efficiency.

what spreadsheet are you using for the swap? I have most all of them, I could check it against others and see if there is something askew

[redfury]

I have the 96, 98 S10 truck, and the V8 truck spreadsheets.