Giles' Mystery High RPM High KR

quick side note.. how long does it take you to get the manifold off? when i did it.. i didn't use any hand tools, and im pretty green.. it took like the 2 (half days).. with a few bolts left over lol..

I bet the whole job can be done in under 3 hours..

how long did it take you?
 
If you know the proper order of things and have a GenPu, it probably takes like 1-1.5h. GenWons are a little worse as you have to deal with the PS pump and belt.
 
Enki said:
If you know the proper order of things and have a GenPu, it probably takes like 1-1.5h. GenWons are a little worse as you have to deal with the PS pump and belt.
Click to expand...

The hardest part for me was the nut thing on the egr pipe.. i never got it off, i actually removed the manifold with it connected..

also, finding the bolts on the hpfp rail.. those things are hidden..


once you know everything, and where it is, it makes it much easier
 
automaticonlyspeed3 said:
quick side note.. how long does it take you to get the manifold off? when i did it.. i didn't use any hand tools, and im pretty green.. it took like the 2 (half days).. with a few bolts left over lol..

I bet the whole job can be done in under 3 hours..

how long did it take you?
Click to expand...
I'm not kidding when I say I've got it down to like 15 minutes on my setup. It's 7 10mm bolts, two screws, one hose clamp, and a bunch of connectors. I have a focus ST intake mani using the Damond adapter which simplifies it a lot. Gen2 as well so no PS pump.

0. get under car
1. loosen the hose clamp joining the TB to the IC piping, undo TB connector
2. undo two 10mm holding the vacuum block on (so much nicer than yanking those 3 vac hoses off each time)
3. unscrew meth solenoid and unhook meth line
4. undo five 10mm holding manifold to head
5. unclip PCV quick disconnect, unclip MAP sensor
6. yank manifold, leave dipstick tube attached
 
automaticonlyspeed3 said:
The hardest part for me was the nut thing on the egr pipe.. i never got it off, i actually removed the manifold with it connected..

also, finding the bolts on the hpfp rail.. those things are hidden..


once you know everything, and where it is, it makes it much easier
Click to expand...

That's because you need to use the special EGR tube disassembly tool
zXUiBmn.jpeg
 
@gv_racing you do have it down to a science... Here im trying to remove the intake and stuff to get to the bolts by the egr, and the hpfp line..

by the time im fishing around with the bolts by the dipstick, your already watching tv inside with it finished long ago..

Ps, putting some of those bolts on is unnecessarily hard lol
 
So, it turns out I didn't know how to do a leak down test properly. I was following the instructions for good leak down testers that have an orifice between the two guages, on a cheap leak down tester that does not. Got the following results, and repeated the test a few times to ensure I wasn't feeding myself bad data

Pistons 1, 2, 3 - between 6 and 10 percent leakage
mdI6euQ.jpeg

Piston 4 - between 15 and 18 percent leakage
GCUPeVQ.jpeg


I took my valve cover => TIP tube off and felt the airflow coming from the crank case - definitely more airflow with piston 4 versus any of the other three.

I then sent a bore scope down piston #4, and thankfully did not see any carnage. Some light vertical marks, but I don't think these are cause for concern. Maybe they are, idk, tell me what you think

6oVkUDN.jpeg


So I'm now debating on taking the head off the engine and removing at least piston #4 to inspect its rings. My machine shop gapped and installed the rings on the pistons - maybe they gapped this one huge, maybe a ring is on upside down, maybe one is broken, who knows until I take it apart.

Would it be ill advised to disassemble my motor over this? Would 2x the leakage on 1/4 cylinders actually realistically cause high RPM KR readings like this?
 
Did you ever buy some ethanol or menthol ? When I had KR and some of your same symptoms. No e85 anywhere, I bought some methanol from a local speed shop. No cheap @ 60$ but after running 30% and still KR. Needed to rebuild engine. One cylinder had bad ring sealing. So Rods, pistons, overbore, bearings, deck both block and head. Essentially complete rebuild. Because I knew after the additional alcohol it was necessary.IMG_20250806_180026.jpg
 
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