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gm 383

I do not know the specific difference between the L30 and the L31 tune but I am fairly certain there is a difference. Your current PCM is going to need to be sent to someone that can reflash it with a tune more appropriate for the HT383. Have you posted in the Injection section of this forum for help with this?Another forum that I would highly recommend is this one.

http://www.pacificp.com/forum/index.php

There are several guys there that are gurus on not only the L31 Vortec but what needs done when replacing one with a 383. They can also recommend someone that can reflash the PCM for you. I would also recommend against halfassing anything just so your nephew can drive it to work. That could prove to be a very expensive mistake.
 
got motor running today. installed the 350 pcm motor had a miss recheck timing ,turn distributor would not run better. installed the original 305 pcm motor idle great. didn,t get it warm up just ran for a few minutes at a time. now the 305 pcm has 4 plugs and the 350 had a 5 plugs,and with the 350 pcm fuel gauge was not working.he,s going to search for a different 350 pcm tommorrow.
 
brian wafer said:
got motor running today. installed the 350 pcm motor had a miss recheck timing ,turn distributor would not run better. installed the original 305 pcm motor idle great. didn,t get it warm up just ran for a few minutes at a time. now the 305 pcm has 4 plugs and the 350 had a 5 plugs,and with the 350 pcm fuel gauge was not working.he,s going to search for a different 350 pcm tommorrow.
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You can not turn the distributor on the L30 and L31 Vortec engines to change the timing. The distributor must be installed according to proper procedure and left there. The PCM changes the timing accordingly with feedback from various sensors. This engine is not going to run correctly on either a factory L30 tune or a factory L31 tune in the PCM.
 
its idles pretty smooth, my genisys doesn,t give me much information. all i can do is a crank relearn, done it on ls motors before but never on vortecs. he going to go to the scrapyard ,and try to find a 4 plug 350 pcm. will see from there.
 
the 96 to 97 have 5 plug pcm,97 to 99 have 4 plugs. we got truck timed with my genisys,useing the cam retard fonction. now we ran it a bit with 305 pcm spark plugs are lean . we order a scrap yard 1998 (his truck a 98 i always though it was a 96) 350 pcm. installed pcm today after a 3 day wait,now truck starts and stalls after a few seconds. the security light flashes,truck thinks its being stolen! he leaving in 3 days, were going to try and bypass theft deterrient. i ask if he had a plan B !!!
 
Have you contacted any tuner companies, if it were me i would be talking to 208motorsports about your computer problems.
 
i tried googling 208motorsports and i come up with a racing team! if we can,t get it running he will be gone for another 14 days. so that could be 2 weeks of time to send pcm somewhere. i would like to send pcm to a reliable place. do you know these guys john!
 
brian wafer said:
i tried googling 208motorsports and i come up with a racing team! if we can,t get it running he will be gone for another 14 days. so that could be 2 weeks of time to send pcm somewhere. i would like to send pcm to a reliable place. do you know these guys john!
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Yes, racing is part of what they are tied into. Not intimately familiar, but someone with that username has posted information on injection stuff here multiple times, I don't see any reason not to support forum members. I've not heard anything bad here about them, although always a good idea to google companies you are unfamiliar with to see if there have been any issues. Keeping in mind that the customer isn't always right. :)

http://www.team208motorsports.com/tuning.html
 
They are a vendor on this site and used by others on this site. I have not personally used them but I am in the near future. Check with Babaganoost he has used them
 
thanks for the tip. we tried a few different ways of bypassing the thief deterrient none worked. phone the local gm garage they said it would need a program to recognize pcm. so he drove truck about 30 miles to gm shop,with the 305 pcm. they got the 350 pcm to work ,but!!! when we got it started with the 5 plug 350 pcm truck idle rough. then we put the 305 pcm it idle nice. when we did the cam retard procedure you have to pass 1100 rpm,truck had a bad vibration. so when he drove down to the gm shop,he said he felt the vibration between 1100 rpm to about 1500rpm over that he almost didn,t feel it. we though it would be corrected with the scrap yard 4 plug 350 pcm. it does the same . the guy that work on his truck,said you mix the wires! so he recheck wires and timing and its ok! he thinks there,s a balance problem damper or flywheel. they all came with the motor! were trying to get some kind of help line from gm. hopefully get a phone call today!
 
got a fax today saying to check if damper has a weight bolted to it. there was no weight bolted to the aluminuim damper,so they will send another damper. 2 to 3 weeks delivery!
 
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