5.7 Vortec runs better advanced ++? help

[wakerider17]

Ok, here is the deal

I have recently rebuilt my 98 tahoe 5.7. Had the usual trouble getting the timing and distributor set correctly but she runs good right now. The check engine light is still on, using a scan tool i have found it is because the timing is advanced (+6 to +8). I am aware that the timing should be between -2 and +2 but as I turn the distributor to compensate it boggs down the engine. When it reads a +1 advance the engine light goes out but runs terrible. Like I said it runs great advanced with a little shake but I would like to get this resolved. Any suggestions will be appreciated.

[J-Mech]

recheck that the plug wires are in the right order. also, did you get the injector poppets in the right order? (i hope im thinking of the right engine) if you had two injectors that were in close firing order but switched, thatd give you a shake.

[wakerider17]

Thanks for the reply

The plug wires are all correct and yes this engine has the crappy spider injectors (which i replaced long before the rebuild) all in the right location. However I am now convinced it has something to do with the injection. The link below led me to this conclusion. I just do not have the equipment to do this and I don't want to purchase another one just yet.

Here is the link
http://members.shaw.ca/betterthanyou...g%20Poppet.htm

Anymore thoughts would be appreciated.

[wakerider17]

I have determined I need to relearn the ckp correlation. They say this has to be done with the Tec 2 computer. My question is can this be done with an obd scanner that Can reset the computer?

[777stickman]

Originally Posted by wakerider17

I have determined I need to relearn the ckp correlation. They say this has to be done with the Tec 2 computer. My question is can this be done with an obd scanner that Can reset the computer?

Most likely not. Needs a high end scan tool that can access the "CKP variation relearn". This tool is also needed to set the timing properly (cam offset or cam retard).

[j cAT]

Originally Posted by wakerider17

I have determined I need to relearn the ckp correlation. They say this has to be done with the Tec 2 computer. My question is can this be done with an obd scanner that Can reset the computer?

I would re check the ckp install. make sure its in there correctly.

some have had issues with the install.

it takes a very small change to throw off the computer timing .

a gm high end scan tool has the allowed GM secret program to do this adjustment. you may have to go to the dealership for this . it will be over 100.oo if your lucky..try what I suggested first.