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Luke's GTP

prop the head so the valves are up, then pure some break cleaner or other liquid over the valves, see if it leaks out past the seats.
 


sure would. if its leaks liquid, it leaks even more air.

if you do this test, tap both valves on the spring side to make sure they are seated fully.
 
If its not a valve seat leaking compression, (probably is), but you never know, check the #3 intake camshaft lobe and lifter for wear and/or damage.
 
I will do the liquid test. Good tip Scotty. Hopefully tonight. We are hosting Thanksgiving this year, so this week is kind of a bust. I got started on the rear exhaust mani last night but had to quit. I wanna see those rear pistons as well.

My plan is still to take out the engine. I wanna drop it out the bottom, subframe and all. Removing the entire top end should make that easier, and lighter, and don't have lift the car as high, so safer.

@QUICKSILVER462 - How do I get a look at the camshaft lobes? I can kinda see it under the valley there.

No one is mentioning head gasket as possible source of leakage. Is head gasket out as a possibility?
 
Another detail about the compression test. Of course I tested #3 multiple times after it seemingly failed. First test was 90psi, then 60psi, and then 30psi was final reading.

Also, to refresh memories, this started with a WOT run on the e-way, car blipped/glitched during WOT run, check engine light flashing, reader showing misfire on 4, possible fried plug wires. Two days later I drove (30min roundtrip) with misfire and that's when shyt went downhill fast. While driving back home, engine started running like death. Burning smell in cabin. Stalled out when pulling into parking spot. Next day changed wires, no start, no start, no start, then started with lots of gas pedal action, but RPMs wheezing like a serious vacuum leak. And then compression test, and here we are with heads off.

Misfire on 4, but compression failure on 3? Huh?
 


If your intake valve seat was letting compression leak by, that would through a whole lotta things out of whack, especially intake manifold vacuum, the map sensor reading would be crazy, then so would the a/f mixture, this is probably why the exhaust valves are not white in color, in theory that is. I would take out #3 valve and look at the seats and valve before doing anything else, unless your heart is set on dropping the engine.
 
I will be taking a look at the seats, for sure. Valves need the guide seals replaced. Probably clean and polish them as well. I'm pretty set on dropping the engine so I can completely re-gasket the entire thing. Oil pan is leaking something fierce. It will also give me a chance to clean up the engine bay and take a look at the pesky power steering pump which looks to be leaking again.
 
Your head gasket looks fine, valve guides thats a machine shop deal, valve seals themselves is easy with a socket and a small hammer.
 
Haven't posted in a while, but the Grand Prix junkie in me is alive and well! For the GTP, I did the liquid leak test on the front head and the results are confusing. Cylinder 1 valves leaked the most, and cylinder 3 valves the least. BUT it was Cylinder 3 had the low compression @ 55 psi (tested three times that night). I don't know. I have been working on tearing the engine down to the minimum so it will be easier to drop out the bottom. Or maybe out the top? Still trying to visualize it all. I've been skimming eBay and craigslist looking for a L67, or a whole Park Avenue Ultra for cheap and remove engine/trans from that. I want this car up and running by end of March.


The blue Turbo GP, the GTPT, has been getting some drive time. Just a few weeks ago, I drove it the longest it’s probably ever been driven, to Kalamazoo and back. She's a screamer. She also doesn't like the cold; more than any car I've ever owned. Just now, just recently, I started having some issues with the car surging and I can't pin-point the issue. Maybe a separate thread on that? But basically I let off the gas, RPMs don't drop like they should, they stay locked at15oo or higher, and continue to climb ever so slightly with no foot on gas. The car accelerating slightly to its own. I checked the cable, the gas pedal, the floor mat, the throttle body, and replaced the TPS with the one from the GTP. Vacuum lines are new and silicone and good for the next 20 years. Ohh, another clue! When it's self accelerating like that, and I pop it into neutral, RPMs scream to 2500+ and stay there, then continue climbing, ever so slightly.

And, Happy New Year ya’ll! Wishing you all health, fortune, no coolant leaks, and forever working transmissions.




To remind everyone, the low compression reading on Cylinder 3:


20181008_232018.jpg



Liquid leak test results. Front head:


20181222_222817.jpg



20181222_222825.jpg



20181222_223624.jpg





After 1 hour:


20181222_231007.jpg



After 24hrs:


20181223_134833.jpg







Disassembly of GTP engine continues. How it looks as of right now:


20190105_163958.jpg



20190105_164006.jpg





ASS to ASS:


20181208_113208.jpg
 


She needs bullitts re installed........ hint hint!:th_jester:

I keep thinking about this..... IAC? I really have no clue wtf would make a drive by cable car accelerate without manual input
 


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