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How many of you guys adjust cranking timing? Almost never have any issues with LS engines starting up super easy and this one is really giving me hell.
Fuel looks great, no codes, all sensors are correct, timing seemed to make the biggest difference in starting but still very difficult to get to fire off.
Spitters and backfires on cranking which makes me think timing but have tried everything +/- 30 deg from stock settings.
Any ideas are appreciated.
E67 ECU
80# injectors
D1 ProChager
408 cid
Has this engine run before? What are the details on the engine parts top to bottom and the vehicle.
Engine is fresh. Runs great once it fires.
Sheet metal intake, CNC cathedrial port heads, blower cam, etc.
Does adding some throttle help it? Were you playing with the cranking timing?
No adding throttle does not help. It's not airflow based I don't think. Doesn't seem to be fuel based. I retarted cranking timing and it starts better but still not well at all.
It could be injection timing so may play with that next. Unless someone has a better idea.
Have you tried stock injectors and stock injector values in the tune and see what happens?
Also, pretty sure this computer can't be calibrated for injector flow rates more than 63.5lb/hr.
Yeah bro, been doing this for years. We have run 2000cc injectors on these ECU's. It's not fueling. Thanks for your ideas though
Did the Cranking VE table always look like that?... Typically, it's just populated with 100. Based on the fact that the IFR table is flatlined, I'm assuming it's a return style fuel system. Given that, it all needs to be scaled. I forgot to scale the Cranking VE table one time on a car and it wouldn't start worth a damn, even if you gave it throttle. As soon as I dropped the whole table to 75 (whole tune was scaled 75%), it fired up perfect. So hey bro, just because you've been doing this for years doesn't mean Sherminator is wrong about the injector data. Gen IV PCMs are incredibly sensitive to injector data and how it waterfalls through the rest of the tune.
Does the fuel system have a check valve?
Cranking VE was scaled. Return style. Yeah check valves on both fuel pumps.
So let me ask you this. How how much fuel do you normally see on cranking? I usually target 2-2.5x PW at idle for a general starting point. Then adjust from there to get it starting the best.
Doesn't really matter what injectors numbers I have in it for STARTING, if I am seeing the PW that is ideal at cranking it should fire. It might have other issues at other operating ranges if the data is wrong but cranking is pretty simple.
If your having backfire and sputtering during cranking issues, I'd check and make sure your getting the appropriate cam signal from the engine. After the pcm figures out the cam singal is bad it ignores it and starts running right. I've had several built motors with the wrong cam gear that did that. Any cam signal codes?
Quote:
Originally Posted by Bluecat
This is more along the lines of what would make sense to me as well. However it doesn't have any cam or crank sensor codes and I have monitored the counts med resolution and low resloution on the scanner and can watch syn and ref counts are smooth and steady.
Actually I lied. I have no checked codes on it in a while since I've had it on the dyno and it does have a P0341 which is cam sens performance.
Guess I need to look into that one!
My idle pw is 1.8 but on cold cranking it starts out with 30. A second later 15 and that's when it starts and tapers through 6 then 1.8
I think your way way to lean while cranking. Would explain backfire through intake also
did you ever get cranking problem fixed ? I have kinda the same problem throws cam sensor code and hard starts has to back fire a couple time then great after that jus curious in what you did to fix yours