Anyone else had their timing skip? I have a laundry list of mods all being top notch parts. HKS to AEM to Pauter and Arias. APS twin setup. I compression tested the motor and I'm within 5 psi on 4 cylinders which read 95-100 psi and not even a flicker on the drivers side front two cylinders. They stay at 0 psi. I'm at a loss on what to do. The car had a complete build at GTM a few years back and made 577 whp on pump. Any ideas on what I should do? I called GTM and they were clueless and also 1,500 miles away. The entire car only has 9,000 miles on it. One more thing was the last time I fired it up the car stayed running for approximately 5 seconds with the key off and out with no turbo timer on the car...???

 

by timing do you mean valve timing or ignition timing? it actually sounds like the possbility you where running really hot in the combustion chambers and melted two pistons, would also explain the continued running after the car was off it kept going off fumes and the heat left in the cylinders although very unusual on a fuel injected vehicle. kinda hard to tell without ripping the engine apart though which from what your saying about the 1 and 2 cylinder is going to be required.

 

Sounds like the motor requires rebuilding or replacing. 0 psi! You don't have any options.

 

I was referring to cam timing. Sorry for the confusion. My thoughts were that with forged arias pistons that possibly a valve burnt up. My pistons and rods are top notch products (nothing is indistructible I know) but my valves are stock. That would in my mind explain the 0 psi readings. The car running AFTER I take the key out...on a FI system is nuts. I've never heard of that! When it would still start my AFR's would, at cold engine temp, read 14.7 perfect. As the car would warm up it would almost simulate WOT as it would read down to 10.5 at idle. I dont know if cam timing being off would cause that or not...? Now it won't even start. It turns over just fine tho. The 95-100 psi readings again I was chocking up to my exhaust valves staying open too long. It flickered, the gauge I mean, way past 100psi but wouldn't hold. And all four that had measurable psi were in a 5 psi range. So opinions are speculated that the issues I am describing could be the cause of a burnt/melted piston? Would it be odd to have two go out simultaneously on the same 'V-bank' right next to each other? And to still turn over?

 

Valve timing

 

Is another possibility a burnt valve or two?

 

Due to the fact we have timing chains not belts it is fairly unlikely it skipped but not impossible. I have seen cars run for a few seconds after they are shut off, usually ones that were pig rich. Sounds like a tear down is the only answer you should know as soon as you get the heads off.

 

Its possible but untelling until the engine is apart. This is something that can only be told ince its apart and considering whats going on it has to come apart. Luckily whatever it is you can buy singles of if it is a piston. Just have to contact a distributor.

 

cylinder leak down test will tell you where the compression loss is going too

 

Unfamiliar with what that is...?

 

It was DEF running pig rich. I saw a reading as low as 7.4!

 

If you skipped timing your car would not start at all. I know this first hand. My crank pulley cracked in half from being loose and the crank key chipped so the gear that sits on the crank did not spin. This happened at 3k rpm and all my exhaust valves hit the pistons. No bent valves but they did not seal properly. I only found this out after a tear down. I kept getting crank position sensor code. I changd all the sensors on my rev up tottal of 5 and nothing.

Maybe your lifter seazed up causing the valve to stay open. That would explain the knocking noise now and the 0 psi. I would get one of those flexible camera things and stick it down the spark plug hole. Or take the intake manifold off and see if the intake valves are ok. Take the turbo manifolds off and with a mirror and a flashlight look at the exhaust valves. That's the best thing you can do withought ripping the engine apart.

 

Update...

Snapped my timing chain and stripped my cam gear. Issue solved. $3k later lol