Tuesday February 21, 2012
Time for some more updates and lessons learned.........
We have spent the better part of a week tuning the truck. We are using TunerPro from Moates since it is probably the best for TPI/MPI units and they have all the hardware and software needed to be able to tune a vehicle.
Friday night we " THOUGHT " we had the tune pretty good...it was idling fine, no surging, no bucking and it started every time on the first try....but as I said we "THOUGHT". We had tried a "Redneck" fix on the vacuum leak ( Duct Tape) just to see if we could get it consistent.
Since the idle was going so well we decided to increase the load.....and then the problems started. To get the truck to dile correctly we tuned in 15 psi of vacuum at idle.
We ran it up a couple of times to around 4 k rpm's and the vacuum leak came back. No matter what we did it still had a leak. Since the upper air intake and risers are secured to the lower intake manifold I asked Matt a simple question.....Do you think the bolts are loose and what would happen if the came out?
Matt immediately turned off the truck and explained that if the internal bolts came loose that it could ruin the motor if the went into the oil ports. So we decided to take the whole fuel injection unit off. We were going to do this once it was painted but the thought of a loose bolt grenading the motor changed our minds.
So we took the top off the motor. Once we got the throttle body off we noticed fuel squirting in the top of the air intake from a vacuum line going to the fuel pressure regulator....????? I just put a brand new one on it...didn't understand that.
Once we got everything un-attached we pulled the unit and started taking it apart. Good thing was the bolts had no way of coming out since they secured them with SILICONE
What is it with the silicone????
Once we got the whole thing disassembled we started checking things. So as I cleaned all the mounting surfaces to get rid of the silicone Matt checked them for straigtness. We also noticed that all the mounting surfaces were "CHROME".
Chrome is not even and will never be flat....NEVER. So trying to seal a joint with a gasket is futile...that is why they used SILICONE
Every flat surface - intake to heads, intake to risers, riser to upper intake were chrome and were not flat. You could actually set the pieces on each other and the would wobble
....No wonder we had vacuum leaks.
We also noticed that one of the interior runners had a hole in it....it looks like a casting hole so basically air was not going into the runner but under the bottom intake manifold.
Upon further inspection the riser blocks were not port matched to neither the top nor bottom intake manifold.....While this may not actually hurt it does kill power. So Sunday Night I went to bed really pissed.
More on the next post.