Nearly 9:30 Monday night -
I have thought about all I wrote.
I went back out and started Carol's engine again.
And it starts so nicely - idles up and as it warms up drops down.
I did not tell that -
I have smoked this intake manifold.
I put an A/C vacumn pump on the source end of the vacumn for the brake booster.
And had an extremely easy assist brake pedal effort.
I checked the inside of the supply vacumn nipple on the new intake manifold
And it passed a 1/4" drill bit with no problem.
Why I changed the intake - was because the butterfly flap was once again stuck -
And I believed it was easiest just to change it - rather than try to clean it again.
But as easy as it is -
I can pressure wash the original intake of the deposits off the shaft and bores -
And put it back on in about 45 minutes or so.
I am tempted to do this - just on principles -
That something is influencing the vacumn source for having a hard brake pedal.
Something - if the engine is in time?
Am - I so sure that the engine is not in time?
It seems to start and do what I would expect an engine to do with a new chain/guides and tensioner.
So - tomorrow - if I can get a visual on the crankshaft/serp belt pulley mark to the correct mark on the pointer - then I will pull the valve cover and verify that the cam gear marks - that are near 3 O'clock on the exhaust and near 9 O'clock for the intake. Before I ever consider the rest of the grunt to pull the front cover again.
Considering - I went to lengths to not turn the engine at all - other than to do the dark links on the chain to the dots on the gears - I am having trouble believing it is out of time.
The engine starts too well.
I just can not explain the low vacumn volume.
Hard to believe a booster went bad sitting still.
The electric a/c vacumn pump makes for an easy assist brake pedal.
The hand vacumn pump shows that the diaphram is not leaking - it holds a vacumn.
__________________________________________________________________________________________.
After that -
I guess I would need to focus
On the Po572 -
What voltage to expect coming in to and out of the Brake Light switch.
The brake lights worked prior to all of this.
The brake lights worked just before I went to pickup and install a new switch.
And I certainly will check to see if the brake lights work again - tomorrow.
But the reading I have done - tells me that the brake switch also sends power
to disengage the cruise control - and the electric controlled torque converter.
So - doing a terminal to terminal voltage check and resistance check back to ground
likely would be a starting point there. I do not have that schematic - nor know the location of the cruise control module or it's grounds. But doing a pin by pin - I know to do - I simply do not have the values and terminal points to go directly to - as a plan of action.
If the brake lights work - and they did.
I have no reason to not believe that they will again tomorrow morning.
Then this reply is what I see all over the place -
"DTC P0572 stands for "Brake Switch 'A' Circuit Low.". This code is logged when the brake switch's circuit "A" shows signs of low voltage. This may be set due to brake switch failure, a faulty PCM, or wiring issues. Common symptoms to watch for include brake lights that won't turn on and cruise control."
So -If the brake lights function -
Am I expecting fused B+ power to come down to the switch and go through the switch
for output to the brake light bulbs and in companion send a circuit signal to the cruise control unit to disengage cruise - or is it some different current flow.
And -
If the proper nomenclature - descriptive term is applied by all people -
Which it is not.
Then is the pcm that is referred to - also the Engine Control Unit that I have replaced?
And -
I did not have this P0572 issue - before doing this work.
If it is so - that this control unit is a reflash -
And there is an issue with the control unit - on this one circuit -
Then perhaps this is the core of the PO572 DTC.
_______________________________________________________________________________________.
So - that is my rethink -
Let me know what if any time you might want to give toward this.
Rowan
An iATN member - since 1998.
Image (Click to make bigger)
SPONSORED LINKS
Monday, July 22nd, 2024 AT 7:09 PM