I have a 2008 Hybrid Mariner I swapped a newer 2.5L into last year, but have run into a bit of a weird symptom on startup that seems to be timing related.

On cold startup, for the first few revolutions or so there is a ticking that sounds like premature combustion/detonation. The issue goes away shortly (a second or so) afterward before anything has really warmed up.

My guesses:

• CPS isn't quite right which means that until the cam sensor makes a few revolutions it is trying to ignite at the wrong angles
• CPS is right but the knock sensor triggers and retards the timing a bit.

Anyone know of any decent ways to figure out what is going on (e.g. is there a bus address somewhere I can query to get CAM/CPS positions and try to verify that they line up? Same goes for the knock sensor.)

 

My $0.02: Sounds like VCT filter or solenoid. Or you've got a sticky lifter that eventually fills up with oil and works properly.

 

You should get FORScan and run it. Its use has been discussed thousands of times by now here on the forum.

https://forscan.org/home.html

 

Will poke around with that and see if I can find some sensor readings that help narrow it down.

The VCT solenoid is actually unplugged because the 08 2.3L ECU doesn't support it, I have the intake cam from the original 2.3L and a fixed sprocket on it so its not just blowing oil through it at least since there is no slot for it on that first cam journal. Given its unplugged not sure what the behavior of that solenoid itself is on startup so that could be related when pressure comes up when its cold.

 

Well, I don't know what to tell you. Swap in a different motor without the right connections plus pieces and parts swapped around and why are you expecting anyone to answer your questions? If you want to make a Frankenstein, you're on your own. The 2.5 liter engine in the Hybrid should have the solenoid, the filter, and the rest of the components.

What you should have written was: "Hi everyone, I'm trying to do something the ECU wasn't designed to do with a motor the car shouldn't have, plus I swapped some other parts around, and now I have problems."

 

I asked just to get anyone that had additional ideas. Just because it isn't stock doesn't preclude anyone familiar with the system from throwing out possible ideas.

 

My guess is some minor and temporary valve noise until the engine warms up. Using a different brand of oil can help per my experience with other vehicles. For example Mobil 1 full synthetic, which is a good oil will cause some valve tick but switching to Valvoline same viscosity full syn eliminated 90% of the problem. The additive package in the oil is what usually makes the difference.

 

You're fine, ask away.