77 LS Shark

Hi Guys!

I'm posting this here beccause the HPTuners forums aren't very active.

I've got a slightly modified LS1 going into a 77 Corvette. The LS is from a 2000 model Vette, but the PCM is from a 2001 Camaro. The motor came with all the DBW equipment so I kept it. Here's the deal: we flashed in a 2000 Corvette tune (write entire) and the engine will start and idle, but I have no throttle control. The throttle blade will flutter slightly when you disconnect/reconnect the TAC module cable. All the wiring has been double checked and the appropriate voltages appear to be in place. I get the feeling I'm missing something simple. Should the Corvette tune be enough to activate the DBW? Or, is there something else I need to check/turn on?

To add to the puzzle we tried a known good TAC module without any change. Other items of note are that it is throwing codes. Most of them are expected such as A/C codes (its a non A/C car). 1 code that may apply is P1022 TPS low voltage. When I check the TPS with meter I have a solid 5V on the 2 appropriate lines. I plan to check the "signal" lines for varying voltage tonight. I read here that if you manually actuate the pedal and/or throttle blade you should see the voltage fluctuate on the "signal" lines. Its also throwing a code because the alternator is not hooked up yet.

I'll be at the car this evening and can provide more details to anyone that can give me some feedback on this. Some help would be much appreciated!

Alvin@PCMofNC

Does it have any other codes present? What pedal are you using? Whose harness? Get a schematic for the application your using and ohm every single wire carefully. If anything is odd make notes about it.

The C5 TAC/Pedal/Throttle body all needs to be perfect to work correctly.

77 LS Shark

Harness, pedal and TB are supoosed to be from the same 2000 Corvette. The TAC module is from an unknown vehicle as i had to buy it seperate. Every wire has been checked. Should the Corvette tune be enough to activate the DBW? Is there something else in HPTuners i need to check?

77 LS Shark

Ok before I post all the codes I'm getting can someone answer this question. Is it possible that this Camaro PCM (9354896) will not work in a DBW setup by simply flashing in a Corvette tune?

Harness has been double checked.

Hooked up the alternator tonight.

I do have varying voltage on the signal lines for the TPS.

Here's the codes I get:
P0122 TPS low voltage......my voltages seem correct according to my DMM.
P0452 Fuel tank pressure low voltage......I have no fuel tank pressure sensor N/A
P0412 Secondary Air injection system Valve......not using N/A
P0418 Secondary Air Injection System Relay......not using N/A
P0443 EVAP system control purge control valve......not using N/A
P0449 EVAP vent valve solenoid circuit.....not using N/A
P0480 Cooling fan relay 1......not hooked up yet N/A
P0481 Cooling fan relay 2.....not hooked up yet N/A
P0645 A/C clutch.....non A/C car N/A
P0650 MIL control circuit......not hooked up yet N/A
P0803 Skip Shift Solenoid Control Circuit.....not using N/A
P1637 Generator L-terminal circuit.....This one bothers me because I hooked up a brand new alternator tonight.

Thats it. I'm really starting to lean towards this being a software issue and not a hardware one, but I could be wrong. Ideas?

Old Geezer

iTrader: (3)

There's a forum for help w/ that problem........

77 LS Shark

My apologies. I didn't see the diagnostics and tuning section. I'll move.

Alvin@PCMofNC

That P0122 is the problem. You need to run down the diagnostics for that code and correct the problem.

That is the proper PN for a vette 2000. As long as the file is out of a 99-00 it should work no problem.

spode

Posted some info from this thread
https://ls1tech.com/forums/generatio...ing-wrong.html
Not sure if it fixed his issue but it says you need the "check engine light" connected.
The TAC needs to be one from a LS1 or LS6 corvette.


Quote:
Originally Posted by edwardzracing View Post
Another tip as far as searching goes... sometime the site search can be a real pain. I'm a big believer now in google searching the site by going to google and in the search field typing in "site:ls1tech.com search query" so in your case, maybe try "site:ls1tech.com throttle by wire problems" or something of that nature. Without the quotes obviously, but yeah. I did a test and it brought up a ton of results that may or may not help. Good luck!
Wow, you are not kidding. Bam, "must have check engine light wire connected" I searched for hours today, 2 mins with google and looks like I might have my issue.

Thx much!!!!!!

77 LS Shark

Thanks for the replies.

I have tried a known good TAC from another Vette with no change. Tonight I took an O-scope and checked for the serial data that should be on pins 14 & 15. None was present. The pedal, TPS and throttle motor were checked via the service manual, they all checked out exactly as the manual says. I even took the pcm apart and found nothing unusual. I can hook up the MIL light as suggested next, but i really feel its the pcm and/or tune.

Thanks for the comments!

77 LS Shark

I don't know if this info is of any use but I did write down the VCM OS ID 12202088 and the VCM ID 1EB0ALFV0246.

I seem to be getting more help here than in the "diagnostics/tune" section, so I guess I'll just keep updating this thread. Thanks again for the help!

77 LS Shark

Its fixed!

Thanks for the assistance that some of you lent. Before I explain "how" I fixed it let me say that I have to disagree with the assertion that you must have matched up TAC, throttle body and pedal because mine are not all from the same car.

The problem: I have never used or even seen HPTuners before. The guy that owns the shop where my swap is being performed owns the software and I left the tuning of the PCM up to him. I think this is the first time he has ever tried to tune a non-corvette PCM. He had a valid tune, but did not execute the download procedure correct. I read the "Help" file in HPTuners and performed the download of the tune step by step per the directions and lo and behold the DBW came alive!

Thanks again to those that tried to help