Monday February 13, 2012
Time for an update........I had that guud gubment training so I was gone for a week.
Got all the tuning items from Moates and like anything I had no clue of what it was or how to use it...luckily for me Matt was well versed in this.....It took him a few days to learn the ins and outs of this particular system but once he got it figured out then the ball started rolling.
Our main issue we saw was no vacuum at idle....no vacuum means it is running rich and the computer compensates by cutting fuel. This causes it to die.......So after a few sessions of playing with the tune Matt got the vacuum to around 15 and it idled perfect.
It idled long enough to do some data logging, to check the electric fan for proper function and to begin looking at what the motor was really doing....He played with idle and alot of different parameters to kinda get the best idle quality we could.
Once he got the idle like he wanted he data logged it 3 different times so that he would have some reference points to go off of.
THEN.............................................. .................................................. ....
As with anything I wanted to her it run especially since it was the first time I had heard it run right. SOOOOO we cranked it again.......all of a sudden a LOUD whistling noise was coming from the motor. I thought it may be a bearing on the accessories drives because that would be too easy to fix...........NO not even close.
Next thing is Matt grabbed a can of brake parts cleaner and started spraying the motor checking for LEAKS and in particular VACUUM LEAKS. We noticed that when he sprayed certain areas of the intake that the engine rpm's raised up. HMMMMMMMMMMMMM
So then Matt showed me what was happening. The unit from Street and Performance has to main "stacks" that supply air to the motor. Since the unit is generally smaller and makes it more difficult to work on people normally put "Riser Blocks" on the intake manifold to make things look more proportionate and give you a little more room. They are about 4" blocks and raise the air intake up.
Well at each place they touch the intake manifold and air induction unit there are seems. Well it seems that the bright and shining star who installed the unit on the motor used clear silicone to attach the riser blocks. It wasn't much of a problem before because of the low vacuum but now that the motor has the appropriate amount of vacuum and it is putting stress on the silicone, couple that with the fact of the heat generated and basically the silicone is breaking down and flaking off and when it does it is causing a vacuum leak which in turn makes it run rough.
Kinda like a viscous cycle.
It is apparent that they did not put a gasket on the risers when they put the unit together.
I have no clue why.
So then we started looking at how they attach...........
and the best way to describe it is that the entire unit has to come off the motor as one unit since the air intake and riser blocks are secured internally to the intake manifold...
this is the only way we see it coming apart since the only external bolt we see is the intake manifld bolts. Pretty much have to take the entire motor apart....pull the radiator, A/C, Alternator, pulley assemblies, fuel lines, wiring etc.....to say it is a PITA would be an understatement. Since all of this stuff is chrome it makes it more tedious to take off since we don't won't to tear anything up or scratch anything.
Luckily the only thing the vacuum leak will effect right now is idle quality....Sure the performance will not be dead on but it will run and fairly well but just not right.
I could take the PITA attempt to remove it and install it right at this time but since the truck is going to be painted and the motor removed then...we decided to let it be for now. Once the front clip is removed by the body shop then we will remove the motor and fix and little issues like this since it will be MUCH easier with the motor on a stand than trying to climp over fenders and lift the unit off the motor with outstreatched arms.
Matt is going to work on the rest of the tune and get it right in all ranges and then we should be ready to go for a test drive...Hopefully, fingers crossed, and any other superstition I can think of...LOL.
I should have know this was coming though especially after all the other things we have found...but at least I know it is right this time.