Has anyone had a problem installing a bigger cam, then pulling out installing another cam. I installed a Comp Cam pn# 20-745-9, for some reason my truck is rejecting it. I had the pcm flashed and still nogo. Im getting ready to pull it out. I want to know if anyone has had the same problem.

 

Thats a pretty hot cam for a mostly stock engine.

Did you replace your lifters?

 

That's not that big of a cam. What did you have in it before? How long have you been driving it with the new cam? Did you reset the computer? It can take a couple of days of various driving conditions for the pcm to relearn the adaptives. Are you still running the 1.7's? You may want to check your lifter preload.
You may have to switch to adjustable rockers. I assume you know about fuel sync since you put a cam in before, so that's probably not it. If you got the chain anddistributor lined up correctly, and have thecorrect lifter preload I would just drive it for a while.

 

I did replace the lifters, and everthing is on right, I even degreed my cam. I had the computer flashed with all the new specs. It is undriveable, it idles fine, but when I rev it up she stumbles, If i shift into any gear, she stalls. My vacuum is low, 14 inmg.

 

give it some more time...my motor did the same when i installed my cam it was reallly hard to get it to idle at first...then once it was idiling fine we set the fuel sync...then we had toslowly accelerate the motor for a good 45 mins. to get the motor to somewhat run right....then i took it out for a good hour just slowly running through the gears and it got alot better over the next 200 miles...

 

I bet you had a hell of alot less than that with the other cam you had in there. How are you reading the 14" -by gauge or by scanner? A scanner will show your absolute manifold pressure, whereas a gauge will show manifold vacuum. At 14 or 15 it's a toss up though. You got the same amount of vacuum (depending on how nice a day it is). Who reflashed the computer and what did you tell them? If you sent it to Dave atB&G and told them that you needed it leaned or richened, that's exactly what he'll do (I made this mistake). The m1 flash that B&G puts out will learn anything fromthestock cam up to a hot street cam as long as the lsa is 114 and you give it time.


Edit: Still wondering- did you set the preload on the lifters correctly? Did you do it with them primed or empty?

 

I broke in the cam as the directions state, 2500 rpm for 30 minutes. I am reading the vacuum with a gauge and a mercury manometer and I have the same reading. When I adjusted my lifters, I did them in sets, waited till they bled down then to the next set, just like how you do it on a Harley.