I don't have any equipment to test for codes and don't know anyone within a hundred miles, literally, that has scanning software.

Yes I probably do the start procedure going from the off position to the start position in one single motion. I'd never heard that this was a no-no. Could that have actually been the problem??? Doesn't explain why it didn't start to begin with though.

I did not cut the tube off. I removed the j tube and my machinist ported it and then welded an adaptor to the j tube to fit the 90mm tb.

Your point, and moregrips point, are still valid in that it would be better if I could still run the stock tb and yeah it would have been good to do a test before installation, but not being experienced I didn't think of that and it's a little late to bring it up now.

So... if we can get past you guys and your pecker contest , where are we now?

Tex... does the wiring in the plug I described sound right? Does it appear to be my improper starting process or does it appear to be the tb or???

I won't be able to try anything until I get the harness back form Speartech anyway. Probably Tuesday next week.

 

Hang in there Jim. It's nothing but another hurdle to cross. I just wish I could help

 

Hangin in bud.... hangin in Appreciate the support.

I have to think maybe Tex is right. I'm thinkin I got it workin when I reinstalled the harness... maybe didn't have the connections quite as solid as needed and then the reinstall got it right. Then after shutting it off I tried to start it in a quick motion without letting the electronic components talk to each other. Makes sense. Can't wait to get the harness back and see. I'll bet he's right.

Before I added the 90mm tb I had a problem with the truck not starting on the first try. Ever since I installed the Radix I had to try starting it twice. The first time it wouldn't start but it always started immediately on the second try. Maybe that was the fault of too quick a motion with the key? I'll know from now on to wait a few seconds after I switch the key on. Also makes sense. Let the "juice" flow. Not unlike the widsom of letting the engine idle for a few seconds after starting it to get the oil flowing to all the parts.

 

I have always started my truck with one motion and have never had a problem
JimS you can go to an Autozone and use one of their scanners, you just have to give them a deposit and they will return it when you bring it back

 

Didn't know that. When I get the harness back I'll have to do that. Thanks, Jim.

 

If you can get the codes (2004Denali had a very good point about autozone), we can hopefully tell what what specifically is going wrong. In my testing, believe me, I tripped a bunch of electric throttle codes and each one was caused by something different.

I normally turn the ignition on and stop for a second before I crank it. Not sure if thats proper or not. I usually like to let the fuel pressurize the lines and listen for anything abnormal.

This is partly speculative here - Lets say the TAC module is looking for certain readings from the TB, but also has the ability to adjust to values that are off its normal scale. You turn the key on and it senses the two TB sensors, but the voltages aren't exactly what its expecting to see. Since its running its quick test, it adjusts itself for the new found sensor voltage range and prepares to run. Now lests say yout turn on adn crank in one key motion. There isn't time to learn new TB sensor readings so it must rely on what it expects to see, which isn't correct.

Since the truck did run correctly part of the time, its likely that the TB harness pinouts are correct. You really need to get those codes pulled to kow for sure. Also, you really need to clear the codes afterwards so your next attempt will be a fresh effort.

Does the handheld tuner with the radix program read codes?

 

I'll be back from my grandsons B-day party on Sunday (his first day as a teenager.... remember that one? I remember thinking I was pretty hot stuff with my Elvis/Sal Minio hair cut Of course I was a fat red-headed Swede... rather unlike my heroes ).

Maybe I could read the code with the Auto Zone scanner, regardless of whether I have the harness. So maybe Sunday I'll have some more information on which to base the diagnosis.

Gotta get to bed. Have to be up by 5:30 to leave at 7 tomorrow.

 

Great job keeping us updated on your progress...just keep you head in the game and remember, you are on the "bleeding edge" and are still doing a lot of R and D.
Thanks for keeping us updated, we are all learning from what you are going through!

 

I had NOT looked at that part of the big picture and I appreciate you painting it clearly for me. Also appreciate the support and be sure that I will tell everybody exactly what happens as it happens. I'll be back on it tomorrow and hopefully be able to beg/borrow/steal a scanner from Auto Zone Maybe get some codes to provide clues to the performancetrucks.net slueths.

I don't ever forget that last July when I started lurking here the truck was "all show and no go" and I hated that. I'd take it shows and cruise nights and folks would compliment me on the looks and I'd agree but in the back of myhead a little voice would always be saying... "yeah it looks good but it's all show and no go".

But, I had no idea what to do in order to make a Gen III truck be quick. (Hell I'd never heard the term Gen III !!! ) Well now this truck will soon be very close to 500 rwhp and it's all because of the folks here and on ls1truck.com . And... thanks to you guys I had a hand in almost all the modifications and that means a LOT.

 

Got the harness back today and it checks out. Installed it and tried to start the truck but ran into all the same problems as before. Went to Advance and they loaned me a cod reader.

Codes were; P0171, 174, 1120, 1220, 1258, 1516, 1518, 1120, 1220, 1220, 1516, 1518.

Tried starting it after clearing the codes and it started and ran fine. Shut it off and it wouldn't start. Read codes, 1120, 1220, 1516, 1518, 1120, 1220, 1516, 1518.

Truck started again as soon as I cleared the codes but would not start again and threw the same codes. This patter continued through 4 repetitions.

What now? As usual I'm clueless except that the code reader told me that most of these codes had to do with too lean, fuel air metering, and the TAC.

My TAC is the number provided as being the correct one and I ordered and installed the tb that was recommended.

Some of the time it started and ran just fine, other times it sputtered and other times it would start, then the idle would increase to about 2k rpm and the accelorater pedal would not accuate the tb. I'd press down on the accelorator and get no response...it would just keep on idleing fast.