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Im finally getting around to finishing my car up (i hope), but have several concerns right now.
Some background on the car- new 408, new heads, cam, big fuel, etc etc. Everything is brand new except the Novi 2000 on it. The PCM was replaced with another one when ECS put a tune in it for me to fire it off. Right now I have a few codes showing that may be contributing, unless these are normal for a new pcm/motor install?
- P1336 - crankshaft position system variation not learned
- U1000 - class 2 communication malfunction
- U1064 - normal software function, history status upon ignition cycling.
I tried to fire the car off once and got a few cylinders to fire followed by a massive backfire and shutdown. Thats when I decided to type this up and slow things down a bit. Where should I go from here?
Try to start it and hope for idle? Does the crankshaft sensor need to be relearned with tuning software?
Thanks for the help.
2001 car
2001 harness
PCM year unknown since they sent me a core. Is there a way to find out?
24T reluctor
LQ4 iron block
crank sensor off of my original block
I did go back out and try to fire it again. No start at all this time. Almost sounds as if its cranking with little to no compression...(granted, I havent heard it crank in over a year) but it sounds like its turning over very easily.
Its a 24x reluctor.
Cam gear part #12576407
The pcm is not the original out of the car. When I sent it to ECS they found it to be "locked" by the previous tuner that used different tuning software. To expedite the process they sent me a different ecu back with a startup tune file on it.
At the time I was traveling and did not have the vin number with me when they requested it. Is it possible that has something to do with it since they couldnt program it with the car's vin #? Currently I do not have any VTD codes showing though.
You really need to pick one or the other to get started... is it mechanical? or Electronics? It may be both, but I would start by eliminating which ever one makes the most sense first...
Timing gear not installed correctly I would think could cause backfire and cranking weird symptoms...but, if the mechanical pieces are all working together, I can see the PCM making something fire at the wrong place at the wrong time and cause a backfire.
I guess if the valve train/cam could also have issues that would cause backfire if something wasn't the correct part or bad.
I wish I had more LS experience to know where to go to help more, but maybe this will help some.
2001 car
2001 harness
PCM year unknown since they sent me a core. Is there a way to find out?
24T reluctor
LQ4 iron block
crank sensor off of my original block
I did go back out and try to fire it again. No start at all this time. Almost sounds as if its cranking with little to no compression...(granted, I havent heard it crank in over a year) but it sounds like its turning over very easily.
So, when you last "cranked" it...did it start and run?
No. It did not start and run. Seems like it TRIES to run after the initial fuel pump prime possibly. If I keep the key turned over to the crank position for 5-10 seconds it doesnt even try to fire off.
No. It did not start and run. Seems like it TRIES to run after the initial fuel pump prime possibly. If I keep the key turned over to the crank position for 5-10 seconds it doesnt even try to fire off.
On that particular effort, no, it did not start or backfire.
Sorry, let me try to clear up some confusion:
Initially when I tried to start it the first time it MAYBE "fired off" a few cylinders and then on the last combustion attempt it backfired. The car has not ran for more than 2 seconds max (If I had to estimate). And when I say run I mean its stumbling around trying to get an idle. After than ititial attempt I cam in and posted this thread.
After that I went back out to check the crank sensor connection and decided to try it one more time. That time around it really did not seem as though it was trying to start at all.
Now, this morning I went out checked the static fuel pressure (I have it at 52 during prime) and decided to try it again. This time I decided to give it a small percentage of continuous throttle (maybe 10%). If I keep my foot on the gas it will try to run but carries on and stumbles quite a bit. Usually the last combustion effort ends with a small backfire.
At this point I believe I can rule out a fuel issue or PCM compatibility issue. Agreed?
Is it possible the lifters arent pumped up enough and the aggressive cam (620/596) is making the initial start up a bit more challenging than normal? I did prime the motor with an electronic oil pump until I saw oil coming out up top at the pushrods...but that was probably 3 months ago.
Lastly, I'm just wondering if the tune may be that far off causing these issues? ECS and I did have the understanding that the "mail order" tune they were going to send may or may not work considering everything that is done to the motor/car. The tune was only meant to get the car running/driving (at best) for me to test all systems at home before a dyno tune.
Some more info on the car:
408- Lunati crank, Wiseco pistons, Compstar rods
TFS 245 heads
620/596 cam by Brian Tooley
Morel Pro 5206 linkbar lifters
YellaTerra rockers
3/8" pushrods
Ported throttle body
Novi 2000 overdriven w 3" pulley
Twin Walbros
ID1000 injectors
For the sake of this discussion I think thats all that is relevant.
Dont mind the mess please, I still have some lines to clean up and a few to reroute.
Last edited by 96TTdodge; 03-28-2015 at 02:03 PM.
Reason: pic
How OLD is the fuel? I know this sounds too simple but I have had nearly the same symptoms from bad fuel...just trying to help.
Did ESC have all the info above for the tune they sent?
This is just a question that someone much smarter than me will need to answer...can you borrow PCM from someone and try and see if that makes a difference?
Last edited by 73Corvette; 03-28-2015 at 01:58 PM.
03-27-2015, 05:59 PM
new build- car wont start
