So just rebuilt my R53 motor and even though I triple and quadruple checked my timing chian marks, what would happen if I skipped it by a tooth?? I started fresh with a new chain so I had lined up the 2 arrows on the crank sprocket and the one on the cam sprocket before buttoning up the front cover. I heard if it was off it would have loss of power and hard start ups, but it certainly fires right up, no loping, and it builds more power as the new pistons seat themselves. BUT, if I run it for awhile, turn it off, then restart it warmed up, it starts right up but then it starts to lope and then smooth out. Is that a timing issue or possibly ignition or fuel? It's not throwing any codes so nothing is freaking it out, but for peace of mind I'd like to get some input if anyone knows what a timing chain off by a tooth might do. Thanks!

 

Doesn't sound like timing to me.

Did you replace/clean your injectors? Maybe one or more is dribbling some fuel after a hot shut down.

 

Actually brand new injectors from RMW so they hopefully aren't messed up. I'm gonna start with fuel pump and filter since they've never been changed since I bought the car new. Might just be starved of fuel. Hopefully that fixes it.

 

I would recommend diagnosing the problem before you start just throwing parts at the car.

You need to watch your smooth running values, fuel trims, have you checked your fuel pressure at the rail? Compression numbers?

What stage of tuning are you in? Have you done your final tuning, or are you still doing your base mapping? The car will run better and better each step you take in the tuning process, but will start off with quirks like you're describing.

 

Ditto, fuel pumps rarely fail, you'll probably just be throwing money away.
And Nick is probably right, sound more like an actual tuning issue, there possibly may need to be some new injector scaling simply because of the difference in the way new parts are working together as opposed to the old ones.
Talk with who tuned the car originally and see if you can get them some data logs.
Remember, custom tunes work by optimising settings for the parts that are working on that car at the time of the tune, if you change any of the parts, esp. major ones, it may effect the tune itself.

 

i actually talked to two different people, Mynes Tuning who did the original tune WITH the upgraded injectors (550) and cam a few years back, (which i installed new injectors with this rebuild just to start fresh) and another tune shop and said the same thing. they both recommended the fuel pump or filter need to be changed. its had some pinging issues since day one and even after the tune, it was never resolved. so mynes is thinking its not getting proper fuel pressure. Soooo with that being said, I'm not sure what is causing it, i am gonna re tune the car after the pistons seat and the motor is broken in, but mynes suggested the fuel issue might not be tune related so to do that work before proceeding with a re tune since i am now running a new manifold and just wanna work out the pinging issue. but back to the original issue of restarts being lopy, i will have to try and figure that out then. I've been told the best coil is the factory one, I'm running a screaming demon, so back to factory and try regapping the plugs to .032 instead of the .044 the step cooler NGK come out of the box with.

 

Yes, coil pack and plugs will be a good place to start, and since you've talked to the tuner then it may be something else, I didn't want to see you just throwing parts at it, without talking to them. But I still would possibly look into finding a fuel pressure gauge before replacing the pump, in the open line you should see a constant 60psi or so, "I think" (it's been a while) it was about 45psi at idle off the fuel rail.
It wouldn't hurt to change the fuel filter, no matter what.

 

i'll test the fuel pressure then before i install the pump but will definitely replace the filter. i'll get the specs for proper pressure and see where its at. never tested that before, just the cylinders, ha… i was just worried that from the beginning it might be a timing chain issue being off and messing up the starts but it doesnt have symptoms of a timing chain off since it fires right up when cold and sits at perfect idle and no loss of power what so ever. i did do some research and the R53's sometimes have a weird idle at times like its gonna stall but picks up. I've read a bunch do that and so did mine but as soon as you tapped the gas pedal it would send it back up to normal idle. freaking minis. its a love hate relationship. i love her but she's always looking for attention in the wrong places :P