93camaroLT1

Ever since I had heads/cam/intake installed my car has ran unbeleivably rich (to the point where it puts 5 quarts of gas into the oil pan after a few minutes of run time and fouls out all the plugs). It makes around 7-9" of vacuum at idle and after datalogging it, it appear that the manifold absolute pressure readings of of around 20" with the throttle closed would be the cause of it running a 20% duty cycle on the injectors around 1600 rpm. So it appears that the guy I had work on the car messed up on adjusting the valves properly, there is a leak in the intake, the opti may have been installed incorrectly, the cam/crank timing are set wrong or a combination or them (atleast these are the only things I can think of that might be wrong being that all the other sensors are working fine. Also the car is tuned to run in open loop mode all the time and being that it is a 93 it is also running speed density) For now I want to try and check the easy basics being that I actually have some time on my hands right now for once.

My first question is how do you set exactly 0* lash on the comp pro mag roller rockers with the poly loc nuts? I know its suppose to be 1/8-1/4 turn after the pushrod stops spinning, but at what point do you set that.. I was under the impression that it was done at the point where both valve are closed, but my friend was telling me otherwise, so can someone explain were the valves should be when setting 0 lash on the pro mag roller rockers?

EDIT: Nevermind this part about setting 0 lash, I found it on shoebox's website.

The intake manifold and head were both ported by different people (the intake port side of the heads and the area with the ports on the intake manifold appeared to clearly be milled some being that they were both shiny when I recieved them back), which leads to beleive that there could just simply be a leak at the intake manifold. Is there a way to check for leaks at the intake?

FastZinTennessee

How big or what kind of cam is it?? What does your datalogging software show your MAP reading to be in KPa at idle and at what RPM? I have some figures for mine when it was running bad and we can compare........

Also, what kind of lifters?

turbo_Z

What I would suggest is to pull the intake. Then set it back down on the motor without any gaskets to see how your gaps are lining up... you need a gap between the engine block and the front of the intake.

93camaroLT1

Well my car doesnt actually idle by itself because the engine just floods out when you let it drop to lower rpms. But holding the gas around 1500-1600 rpms it is around 80 KPA and when you open the throttle a bit and get the revs up to around 3000-3200 rpms the map is around 40 kpa, the map actually continues to decline the higher the rpm and the vacuum actually goes up the higher the rpms as well. Vacuum around 3,000 rpm is about 14" of vacuum, which is quite odd being that vacuum at first normally goes down when you open the throttle and map normally would go up when you open the throttle but it appears to be doing the exact opposite.

The lifters are stock.. from what I read on shoebox's site about how the polylocs work it sounds like you would have to be a moran to get the valve lash wrong being that the nut stops once you get to 0 lash and then you just set the allen lock..

93camaroLT1

how much gap exactly should I have between the front of the intake and the engine block? What about between the intake ports on the heads and the intake manifold? Should it just be nice and smooth lining up there without any gap?

FastZinTennessee

My cam (see sig) was at about 74 KPa @1000 RPM, which was too high of a reading (not enough vacuum) so it triggered the check engine light. The car would start, run, bog then die. It had so much fuel in the motor that after it died, I could pull the fuel injector fuses, crank it and it would run and settle into an idle before cutting off!! On that try the rockers were set to 0 lash + 1/3 turn.

Next I checked for any obvious leaks and did not find them, so I set the rockers to 0 lash, and if anything 1/16th of a turn. Upon startup it ran and warmed up without throwing the code. It idled pretty well at 950 RPM, and had the MAP reading fluctuating just below 70 KPa. It would start to choke out and die after running for 7-10 minutes, the check engine light would come on again, but if I blipped the throttle a few times the light would go off and it would settle back into idle.

At this point you need to start looking into the tune as well. I'm by no means saying that is the absolute culprit but you have to understand how the PCM sees this. It reasons that a higher MAP reading (less vacuum) means that the motor is under a load- this is how the tables are setup. So for every bit of vacuum you lose, the PCM adds fuel.

It's very hard to say what your actual MAP reading is going to be at idle because you state that you have to keep the throttle open a little for it to keep running. Keep in mind that 100.X KPa is barometric pressure, so if you're seeing 80 KPa there isn't much vacuum present, and it's no wonder the PCM is richening up so much.

We need to know what kind of cam, what tuning.......

93camaroLT1

The cam is a small 224/224 with a 108LSA.

The tuning was done by madwolf... 3 times on two different chips (mail order). So I am kindof just assuming that the tuning correct being that Ion does so many of these and he did mine 3 times. The one thing that is really weird tho in the aspect of tuning is the fact that the car appears to run the same with stock tuning or the piggyback adapter.. rich as hell. But being that the vacuum is so low the tuning doesnt seem to the problem, cuz with the cam being as small as it is I should be seeing 14-16" at idle as oppose to what im seeing which is 14" (at most) at 3000 rpms.