alright guys yesterday i did a cam swap on my 05 gmc. its got the 4.8 engine. Before anyone comments negatively on my cam of choice, id like to remind you that i am trying this for everyones benefit as i dont believe it has been done before. But i could be wrong. Cam specs are, 236 242 .580.590 @ 050 on a 112 lsa Also used comp 7.4 pushrods, and patriot gold spring kit. Alright the thing sounds MEAN but will not idle on its own. Big problem with that, as it being a stick it makes it almost impossible to drive. I have an appointment tuesday to get a live tune with a local tuner. Question i have is after the install the maf perf code is on and wont go away iv tried everything. From what i understand when this light is on, it goes into speed density mode and wont allow the computer to adjust to its new parameters. If i were to get this to go away, do you think the computer will learn to idle on its own? Also, its recommended taht 7.45 pushrods be used. Will i hurt anything with the 7.4's i didnt notice this until i had the entire thing apart and was like screw it no turning back. thing pulls strong up top 4k rpms+ which is what i was going for. do you think its the tune or the pushrods causing no idle? I also changed to larger injectors as well even tho i know i dont need them. thoughts???

 

You can't just put larger injectors in and expect it to run. You have to get it tuned for the larger injectors. I'd start by putting the original injectors back in until you can tune for the new injectors.

 

yea i kno that, it wouldnt idle before i put them in. I figured the cam was just sooo huge in such a tiny motor thats why it wouldnt idle on its own. It wants too. just seems like the idle needs to be turned up. I believe this can be done in the tune? also, i knew i was getting tuned, thats why i installed the larger injectors. does anyone know if the tune will clean up the problems i have?

 

have my appointment tuesday for the tune so im leaving them in for the 2 days i have to wait. not a big deal...

 

Lol you seriously thought the computer was going to compensate for that ? haha

 

ha noooo i def didnt think it would. was just hoping it would atleast idle so it wouldnt be as sketchy as it is driving an hr away to the tuner as it is... wondering if there was anything i could do myself to help it

 

I don’t have a clue from your post as to how big of injectors you installed, but you need to be careful running it without being tuned for them, as you can wash down a cylinder very easily.

If you do, the term aftermath will be correct!

 

huge cam for that truck and u to what i believe u might not need bigger injectors but only ur tuner can tell u that.. and if on small cams its hard for them to idle what did u expect from this one.. i say run stock injectors take it to get tuned and then u will c if bigger ones r needed.. goodluck..

 

I also think you should put the stock injectors back in and get it tuned, see if you need them later. I definitely wouldn't be going WOT or driving much with the wrong injectors.

 

put the stock injectors back in and when you get it to your tuner put them back in and have him tune for them.. it wont run because of the cam.. If tuned right by a good tuner you wont have any idle issues.