top swap, started engine, scans give me concern, help?.....
 

swap finished last night, changed settings in pcm to lower timing etc etc etc so it doesnt blow up.

car started right up first try and sounds great, idles great, seems like all should be well, BUUUUTTTT......


i am having some issues and any help or advice or first hand knowledge would be greatly appreciated...

here are my swap details....

2002 monte carlo ss
2008 grand prix n/a 3800 bottom end
1999 Buick Ultra L67 top swap

here are the issues that i have noticed.....




O2 sensor stuck at 470, no change at all, car idles for 20+ mins and not once moved. using 08 GP sensor and will be switching over to the 02 monte sensor. interchange does not indicate that these parts are the same, so i believe putting the correct sensor back on will fix this issue.


scan tool and dash gauge indicate no signal from ECT sensor. it should be working, but it is from the 08 GP, interchange says the 08 GP and 02 monte ECTs are the same. will swap out for old ECT from 02 engine. i do not think this is going to make a difference, but i will go through the process just to double check.

both fans stay on when started no matter what. i assume this is from the ECT not registering so it defaults to on just in case. can someone confirm this?

fuel guage is acting wonky, very very wonky. on the first start, it would fluctuate from 1/8th to 3/8th's when ever i would give a little gas, no crazy revving yet. i shut it off for a min to check things over, then restart, and it stays at 1/4 tank, no change, and exactly where it should be. thoughts?????

flashes of light are coming from the Alt. not sure if this was present before or not. they are not large flashes or large sparks, just little ones that you can barely see and only if its really dark in the engine bay. the alt is less than 3 months old. i have never seen this and google didnt reveal much. anyone have an idea on this one?




other than these seemingly minor issues, it sounds and runs/idles pretty smooth.

cant wait to drive it and i hope that is tonight!


thanks to anyone that can help.

Idk bout your light questions but I see you used a series 3 block which had a diff compression ratio then series 2 n/a and supercharged hope you got the right size pulley

Mite b a bad ground somewhere

i have a tuner and will be monitoring the KR and such. through my research, those that buy "canned'' tunes for the top swap use the larger pulley to avoid any "issues"

there are MANY top swaps that run the stock pulley or even smaller depending on supporting mods.

i am comfortable with my setup and have plenty of experience tuning my car.


thought i do appreciate the concern, really i do.

good suggestion, however, i do think i did reattach all of the grounds, but i will double check to make sure.

as far as i know and the only ones i touched is the one by the coil packs, the ones that connect to the transmission bellhousing, and the one that connects right near the intake box tray. i actually took that one off and sanded a clean spot for it and sanded the connector to. so unless there is another one i am missing, i dont think thats it.

but again, i will double check.

Only thing that made me think ground is the fuel gauge thing :)

i will certainly take another look, but where are the other grounds????


if i missed one, then that could certainly be the issue. but i do not recall anymore than the ones i mentioned already.

also, now it doesnt want to start and seems like its just dumping fuel.

i am wondering if the 2bar/gtp map has something to do with this.

i am also wondering if the 2002 mc ss bin file i used is compatible with my PCM.

i will try a different bin file that i have to see what happens.


i swapped out the ECT and it is still not registering on the scanner or on the dash and now the fuel level is doing its crazy thing again.

i have to agree that it sounds like a ground issue, or a PCM issue.

IIrc theres a ground on the end of the front head