Jona91

So i changed my heads and installed a cam to my 5.3 at initial startup i noticed the truck wouldnt idle as it should even with a cam swap. So today i took it to my tuner and he monitored cylinder 6 and 8 were misfiring. What can it be?? I sprayed carb cleaner around the intake idle didnt change swapped spark plugs and checked for spark the two had spark. Can i be that the headgasket got damaged? The shop did check for cracked heads and it passed. Im still not sure if my fuel injectors and good. Im going to do a compression check later to find out. Im not sure if i truly double check my timing tho

dsmmace

Make sure you have the injector connectors swapped. Been there done that...

Jona91

What do you mean? But #6 wont reach all the way to #8, when i disconnect the fuel injector on either 6 or 8 theres no engine change, but when i remove another one the engine vibrates even more, so maybe i somehow got them clogged when i had the intake manifold off?

dsmmace

I had 5 and 7 swapped myself, that was a stupid mistake that took more more hours than I'd like ot admit to prove out.

Jona91

Lol. I swapped them out and made no difference. Its almost like theres no fuel being dumped on those cylinders.

Jona91

Just as i thought, cylinder 6 and 8 have zero pressure all other ones have 190-195. Maybe the headgasket went to crap when installing??
My tuner told me my 7.5 might be too long for those two cylinders. Going to measure and replace as needed and ill post an update

1FastBrick

iTrader: (17)

Pushrods are too long.

Jona91

But wouldn't it effect all cylinders if pushrods are too long?
Ill measure on those two cylinders and get some that are 7.450-7475 🤔

1FastBrick

iTrader: (17)

Nope.... The Block is not always 100% flat.
If the heads were milled at all, they will require a shorter pushrod.

You should always Physically check for length when doing a cam swap.

Jona91

I checked them using the comp cam pushrod checker. Maybe i measured wrong. But when i did measure it was 7.45 plus .05 preload thats how i got the 7.5s maybe i did it wrong.