Ever since I my motor refreshed and threw on the LE 1 heads/cam package I haven't been able to get this car running right. As of right now it runs extremely extremely rich (the plugs foul out after every run and it drops a LOT of gas into the oil pan in a couple mins of run time.)

So far here's what I have looked at:

-The tuning has been done 3 times on 2 different chips by Ion, the tuning is done for 42# SVO injectors, I swapped the stock 22# injectors back in and it still runs rich enough to foul out all the plugs after every run. Also the injectors are NOT leaking and when the car is off (there is no fuel dripping through them into the cylinder.)...

-The injector duty cycle is close to 20% at idle!!

-It is set to run in open loop and the O2s are removed, the EGR, Canbon Canister, and the AIR pump are also removed and the codes for them are deleted, but all the sensors that are still hooked up are working perfectly (I checked a few of them with the multimeter and ALL of them through datamaster DA.)

-I ran a compression test and all the cylinders make very good compression and the highest to lowest cylinders are at a 6-7% variance. (the motor has only been run for the cam break in and then for a few minutes here and there and thats it.)

-I just double checked the valve timing and it was dead on with the cam and crank gear.

-I also just double check the Opti and it was installed properly and was reinstalled properly (the missing tooth on the opti rotor and cam gear and lined up with the missing gear on the splined shaft.)

-I check ALL the valve lashes and when every valve is closed the pushrod can spin by hand, which would not be possible if the it was adjusted to tight and the valve was sticking open.

-All the vaccuum hoses are hooked up (besides the EGR hose, which is blocked off nicely) to the intake manifold and there are no leaks there.

-I just started up the engine again with this warmer weather it appears to warm up right away and there is literally no backfiring (it is really apparent when it backfires at all through the open headers.) and it appears to run just fine and also drives fine (I drove it down the block and back around), minus all the smog all the unburned gas running through it..

Anyone got any other ideas to what could possibly be wrong and to why it is running so damn rich? What else is there that could be causing it to run this rich that I should look at? I don't know.. at this point i'm just starting to think this car is just doomed to run like crap.

 

Any clues to what else to look at? The only thing I have noticed is that the vaccuum on it is a bit low.. I email lloyd and he said I should be getting around 12-14" of vaccuum at idle with a tune that is dead on and the TPS at 0% with this cam and I was around 8" of vaccuum at idle with the throttle stop screw set a bit too far, I closed it all the way so I probably picked up a little vaccuum there (I haven't tested it again since then) and the tune isn't dead on (its a mail order tune for injectors that are too big for my setup)...

So it seems that I would fall maybe a couple inches of vaccuum short of where I should be, would this seriously be enough to cause the ecm to run a 20% injector duty cycle at idle and run so rich that it fouls out the plugs after every run?

Is there any other areas that I am overlooking as to what is causing this?

 

Fuel Pressure Regulator ?

How are the MAF readings? You didnt happen to oil your filter recently did you? One time a car came in at the garage I work with doing the same as yours ( Was a 4 Banger Cavi though) and it turned out that the kid over oiled his KN filter. This soaked the MAF with oil, screwed up the readings, and was causing it to go through a set of plugs every few days or so. MPG were low too. It's a long shot, but worth mentioning.

You dont have an exhaust leak before ( Or immediately after ) the 02's do you? Even open headers is close enoguh to the o2's to make a car run like dick and use too much fuel.

I dont think that your tune could suck that bad. Ion, as far as I know, does some of the best mail orders you can get.

 

Fuel pressure sits at 39PSI with the vaccuum line attached.

There is no MAF.

That's what I hear

 

Are you sure it's in open loop? I once had what I thought was a open loop tune but it was going into closed loop I later found.

 

Low vacuum tells the ECM the engine is under load, increases the calculated mass air flow rate. You've got to look at what controls the speed-density setup, and MAP and IAT are critical inputs - a faulty MAP or IAT sensor could cause the engine to over-calculate air flow, which would add too much fuel. High MAP means dense air, dense air means high mass flow, high mass air flow divided by A/F ratio means high mass fuel flow. You can probably assume the RPM is OK, and that the program has the correct engine displacement and VE table. Other than the mass air flow calculation, there's not much left to go wrong with your ECM.

Also need to check the coolant temp. Lower than actual coolant temp would cause the ECM to richen the A/F ratio.

 

When I hook up the datalogging cable to my car the IAT reads out fine.. It is at the correct temp also the ECT reads out correct.. They both ussually are right around the tempreture of my garage before starting the car.

The MAP sensor is also working properly.. It reads out the exact difference between the vaccuum and the barometric air pressure. The only thing I did notice here is that my vaccuum is a good 2-3" BELOW where it should be.. With everything absolutly dead on and the throttle blades fully closed at idle it should be around 12-14" of vaccuum, before when the throttle blades were cracked open a bit (1.03 TPS at idle) it was making around 7-9" hg of vaccuum, I didn't check it again after I reset the stop screw to fully closed, but i'm guessing its most likely at ATLEAST a constant 9" of vaccuum at idle now which is still a bit low, but I can't really seem to figure out where i'm loosing the other 2-3" of vaccuum, there is no leaks at any of the hoses and they are all hooked up (except EGR hose which is blocked off nicely), the distributor, valve timing are also dead on and there is more than sufficient room on the lifter before it would bottom out and cause a valve to stick open a bit (all the pushrods can be spun by hand when the valve is closed with the rockers adjusted).. So I can't really figure out where I am loosing that little bit of vaccuum from, But is it even realistic for a loss of 2-3" of vaccuum to cause the ECM to run it at 20% injector duty cycle at idle (with programming for 42# injectors)??

 

Actually I posted about this running excessively rich problem a quite some time ago:
http://web.camaross.com/forums/showthread.php?t=407325

I've pretty much gone through everything on there and then a few other things for what could be causing this problem and pretty much just found out everything is working as it should be and correct out of all of that (well that and I just wasted a **** ton of time.)

Now i'm just trying to figure out what else there is that I should be looking at?

 

ttt

 

To be honest with you it sounds like the problem lies in the tuning.

 

To tell you the truth, I can see no difference whatsoever with how the car runs with the stock tuning or with the piggy back chip installed. (yes, I am absolutely positive it is in correctly and it is not going into "fail-safe" mode and there is no check engine light on)

I was actually thinking about it and pretty much seems like there are 2 things left that it could be that I could think of.

1. I've read a bit about the opti spark distibutor, but still don't fully understand how it works. But from I do understand the timing (as long as the splines are matched up correctly, which they are) is fully controled through the ECM from the low res and hi res wheel signals. So, correct me if i'm wrong but if the timing is off some (too late) in the programming that would definetly cost me to loose some vaccuum (up to 5" hg of vaccuum, maybe more) which that right there on a speed density setup (where there is no MAF there to tell the ECM how much air is flowing in) would easily screw up the a/f ratio being that the MAP sensor is now reading higher than it should be.

2. I'm not sure if the cam was double checked to see if it was degree'd properly Comp Cams. If it wasn't I suppose it could be possible that the cam is off slightly which would mess up valve timing and definetly cause a loss in vaccuum leading up to my problem. Although it seems that it is very unlikely that it is off by a significant amount (2 degrees or more) being that it is Comp Cams that ground the cam and nowadays its not even like Sancho is sitting there on a lathe grinding the cam, it is all done through CAD, but nonetheless i guess it could be a possibility.