having a few issues can someone give some advice
other issue is this...... other day was out logging and working on tune and motor accidently spiked to 25psi at 50% throttle, i instantly let off throttle. little later i went for a another log after i made some changes to tune. it hit 19psi at wot in first and i broke the rear end. well i get everything fixed a few days later and i go to drive it and i notice my truck from time to time drops 1in of vaccum and starts to idle funny. it then goes away. well i pull truck in and do a compression check. it reads from 140 to 147 across the board. no oil in coolant no coolant in oil. no coolant on fenders or anything. oil psi still good. also plugs looked good. i pul my fast and notice the floor of it where it had been repaired was cracked again. i guess the spike blew apart the epoxy on the intake's floor. so i swapped to the ls2 intake i had laying around. started truck up had 10in of vaccum. as it warmed up i lost vaccum to 9 again. im still scratching my head on this. well i figured out why i overspiked. Tial 60mm gate springs are rated wrong.
installed the 5 psi spring and im seeing 8psi. ok this is livable. so i go out and start tuning again for this intake. first thing i notice truck is rich but with the ported fast tune was spot on at 14.7 for out of boost. i also notice my right bank and left bank was opposite. one was calling for fuel other was trying to lean out. so truck wasnt happy with running out of boost. the W02 read richer then target. i drove some more and logs keep looking rich, no matter how much fuel i pulled i was still rich according to W02. i did get into boost for a short time and seemed fine once inboost after this truck the truck started to idle badly and only at 3in of vaccum. i pulled plugs and did comp test all checked out fine again. motor doesnt smoke, no oil in coolant or coolant in oil. motor isnt noisey, still have good oil psi.. i went to start it yesterday after taking days off and i got it to run again and had to use throttle and had no vaccum this time. today i pulled plugs oncei got truck home and plugs were soaked in fuel. can the vaccum be related to a fuel issue? or soemthing else?setup is 02 silverado 4.8 with 241 heads. 8.8cr , 230/236 115lsa, PT88, Tial 60mm. when it first was running it would idle with 10in of vaccum. the drop to 9in doesnt make sense but that happend after the motor spiked to 25 then to 19. the 19 was WOT and since has been giving me issues
thanks and sorry for long post but i have no more patience and cant seem to figure this out
I dont see it as a problem....your problem sounds more like a tuning issue.
On initial key on, the pump will prime for a few seconds, and if the engine is rotating, the pump will also work.
So I dont see why it should cause any starting problems.
The fact you say you are having to go WOT to get the thing started, is very wrong.
next issue to address. see if the spike hurt motor....
did a compression check and motor reads as follows
1=150 2=145
3=145 4=145
5=150 6=145
7=150 8=145
these were all done with a snap-on gauge
ok next test was a leak down. so i started pulling valve cover off to check for valves being bent again and good. as i noticed i pulled the booster line and i had vaccum on this [good sign]
so did a leak down and this motor is claimed to be a 7k mile motor
1=2% 2=1%
3=1% 4=1%
5=1% 6=2%
7=1% 8=1%
guess motor checks out. so tomorrow going to toss plugs back in and give it a try again. i believe my fuel issue was the bad injectors....least motor is sound





