E38 ly6 408 tune setup problems

[98vortecSilverado]

First of all I'm new to the Gen IV engines.

I picked up an iron block 11:1 408 (4.03 bore x 4.00 stroke) 58x shortblock, put L92 heads and a truck intake with 50lb flex fuel injectors and stuck it in my 1997 silverado.

I got a wiring harness and e38 that was supposedly from a 2009 savanna. The hpt file says tahoe with a 5.3 so I'm not sure about that.

I got the wiring pretty well sorted out, disabled VATS, changed the displacement in the tune, and had spark and fuel pressure. I am using the trucks original starter relay and circuitry. It didn't seem to be pulsing the injectors even though the scanner showed it steady at 32 ms. If I manually grounded out several injectors (to spray gas in the intake) it would then start and run.

I then found this http://www.hptuners.com/forum/showth...8-from-scratch post #5 gives some ideas that I thought might apply to my situation. I got my ls3 MAF installed and put the MAF table from an ls3 camaro in, then multiplied it by 1.8 I think. It still wont start unless I manually give it some fuel to fire on, then once it fires the injectors go to a more normal 5ms or so and it runs. I had to give it a little throttle to keep it running, but before I got the log started the pedal went unresponsive and it revved to 4000 rpm!

The "high idle" log and the hpt file were from last night. The "partly start" log was from earlier to show what the injectors do when it fires.

What I would like to know is whether I should be changing airflow tables in the tune, Or if I still have a VATS issue somehow (I tried grounding the starter enable relay wire and the powertrain relay wire, doesnt seem to change a thing)

Also the throttle going unresponsive kind of worried me. It works fine with the key on engine off. Is that something that might work ok when I get the airflow more realistic? I don't have the wideband on yet, Still working on the exhaust.

Thanks for any help or criticism!



GreenTruck 408 LS3 X1.8.hpthigh idle.hplpartly start.hpl

[98vortecSilverado]

I believe I figured out the high idle. I had plugged an aprox. 3/4" hole in the top of the intake, and the plug got knocked out. So it had a massive vacuum leak. I'm guessing thats what caused the throttle to quit working also.

I would still like to know if it sounds like a vats issue. It seems like since it will actually run it couldn't be vats. But then again its already calling for 32ms of injector (and still not getting any gas) so I don't see how changing startup airflow or whatever will make it start.

Would there be any sensor that could fail and keep it from starting, but still let it run? Kind of a dumb problem to have

[98vortecSilverado]

Ok actually got this figured out. One of my 12v switched ignition wires was not staying hot during cranking. Finally got it figured out when I noticed the "control module voltage" was going to 0 volts when cranking.

Had me puzzled for a bit as it would actually run if I gave it some starting fluid to get started on.