hey guys , my cars not running well at all , its leaning out the mix and detonating its *** off once it gets to around 220degrees . I put a vacuum guage on the egr port and im readin 8.5 inches ??? Im guessing thats low , but If I have a leak why is it leaning out the mix ? im confused.

 

Stock cam will pull 20-21"Hg. I wouldn't think the HOT cam would be any less than 17"Hg.

 

my guage read in inches is that the same ??? also , the car is pullin fuel from both sides , is there a chance the low vacuum is causing the fuel pressure reg to raise fp enough to add enough fuel to have to cut fuel back even with a hugh vacuum leak ?

 

Its "inches of mercury". The only other scale would be "inches of water", and 8"H2O would be virtually no vacuum at all.
If you have poor vacuum, the rail pressure should increase. The purpose of the fuel pressure regulator is to maintian the differential pressure between the fuel rail, and the intake manifold. As vacuum drops, you have to raise the rail pressure to keep the differential pressure at 43.5psi. The injectors flow the "programmed" rate at 43.5psi differential. If the FPR didn't raise the fuel pressure on low vacuum, the injectors would flow less than rated, and it would lean out.

Try another vacuum port, just for the heck of it. Or if you have access to a scanner, read the barometer (BAR) and MAP and calculate the true vacuum by subtracting BAR - MAP.

Can you hear "detonation"? Do you have the knock sensor hooked up and working in the PCM? If you do, its extremely unusual to hear detonation. Do you have any O2 data for WOT?

Sounds like you need a good data log of idle, normal driving and a WOT pull to track down the problem.

 

it wont detonate unless its in the warm range around 220 you , im in traffic with ac on , and not while idleing , but as soon as I crack the throttle is like chug chug chug , but it dont feel like a miss . it feel like the cylinders are firing hard. The rear o2s are unhooked at the present but Ill try and get a data pull tonight because im going to hang out with my friend tonight and he happens to have autotap. how do I send it to you ???

 

oh yeah , I have a hypertech with a scanner cartridge and whent he car is cold itll have a map usually in the 50s but when it gets warm it can go into the 70s , bar is 104 as im at sea level.

 

Have you had the pcm programmed for the cam and heads? If not that is one of your problems that should be solved before you will be able to find anything else. By programmed I do not mean hypercrap those are bad for a stock motor and completely wrong for a modified one.

Oh I see 17-18 with a low idle ZZ3 cam, if I hold the idle a little higher it can be 19", depending on idle speed I would guess 16-17 for the HOT cam.

 

programmed by pcm4less.com. also forgot to note , took it to a friend of mines shop and used his scanner to open and close the egr while the car was at idle , there was absolutely no change in idle whatsoever.

 

Has it done this since the conversion? Might go back and adjust the rockers. If you get a few of them messed up they can create a low vacuum. Make sure you didn't burn any plug wires also.

 

You're saying that at idle, with the engine fully warmed up, your MAP is 70+ kPa? If that's what you are saying, you do have 8.5"Hg vacuum. Way too low. Valves too tight? Major air leak? ?????

Are you sure the timing marks were aligned 100% correctly when you installed the cam?

 

im gonna go thru the egr checklist in the service manual. Like I said my friend used his scanner to open and close the EGR valve and it didnt change the idle a bit !!! MAPS usually between 50 and 70 sitting at idle warmed up . cruising around 30-45.

 

update: scratched the egr check and went ahead and installed the blockoff kit , vacuum is at 11" today map in high 50s 60s reset comp , as soon as it hit closed loop it started dumping fuel on bank 1 like 26% then dropped as it warmed up ended up settling around +6% , BANK 2 is still leaning itself out to -11% or so while cruising , im gonna get a mirror and check the back of the intake altho I didnt find any oil by touch back there . car didnt detonate any this time but you can feel and hear the banks are out of balance or something , the car didnt get very warm tho because I came home to get ready for work . ANY IDEAS about what can be causing this wierd stuff ???
thanks , Justin

 

ok got autotap logs finally , anyone who can decipher them please let me know and I will email them to you. Injuneer im gonna go ahead and mail it to you because I think you mentioned something about them before. Keep in mind I have egr blockoff plates now

 

ttt