New guy with an issue I am guessing no one has came across.

[Capt. Insaino]

My engine is a 408 iron block with K1 Rods and Crank. Ceramic coated bearings and pistons, which are Wiseco. Dart heads that have been completely gone through by Brett Land at Land Speed Development.

This engine has been together and running for 5 years. About a month ago I ran it at the track on spray and it hit the limiter. The good news is that the nitrous shuts off at 6200 RPM's and the rev limiter is at 7k. I am not sure that plays any part of this, but I'm including it. I checked the valve springs, rockers, all looks good. There is no new noises from the engine. It still pulls damn hard, so I can't imagine anything happened to it. I have been working on LS engines since 1999 when I bought my Camaro, which I still own and is the subject of this post.

This car had great street manners and would idle perfectly all the time.

The issue is now, that it won't idle correctly. It will idle fine in park, but as soon as I put it in drive or reverse it almost wants to die. It started doing this after taking it to the track. Nothing on the car has changed other than install truck coils from a junk yard Yukon that I did BEFORE taking it to the track. I have tried both a new IAC and TPS, cleaned the throttle body as well. I reset the TPS and it will read .04 to .08% I checked plugs/wires.. nothing. The only thing I can see is that the front 2 plugs are a little black, I am running a super Vic intake. I have changed to truck coils with over 100k miles on them, but the car is not throwing any codes. I even unplugged a spark plug wire and it still didn't throw a code.

No one seems to be able to help. I am wondering if maybe 1 or 2 coils are weak causing this issue? Maybe after the nitrous runs something happened? I'm not sure. I am new on here, obviously... I have ZERO tuning experience, I have HP Tuners mainly for logging and changing out between my nitrous tune and N/A tune.

This is my last resort. No one has any idea what the issue could be. Also, I noticed my oil pressure used to be a constant 40psi at idle when hot, now drops down to 20-30 when hot, and once again I am not sure these two things are related. but I am including as much info as I possibly can.

I read the rules and included both my logs and my tune. I am not sure what a .cfg file is though.

So to sum it all up, I am hoping someone on here can look at my logs and I hope and pray something stands out that could be causing this issue. As I have said, this car has run perfectly for years, and now after a couple nitrous runs, it doesn't idle when there is a load on it, but idles good in park.

Thank you all for any help

[2xLS1]

I would check for a bent pushrod. Pull them out and roll them on a flat piece of glass.

[cobaltssoverbooster]

your tune has all factory fuel trimming disabled and your log doesn't show wideband afr.
im guessing your tuning with a wideband, be helpful to be able to read fueling conditions

[Jason B]

your tune has all factory fuel trimming disabled and your log doesn't show wideband afr.
im guessing your tuning with a wideband, be helpful to be able to read fueling conditions

Doesn't seem like he's tuning anything, just diagnosing.

[Jason B]

My engine is a 408 iron block with K1 Rods and Crank. Ceramic coated bearings and pistons, which are Wiseco. Dart heads that have been completely gone through by Brett Land at Land Speed Development.

This engine has been together and running for 5 years. About a month ago I ran it at the track on spray and it hit the limiter. The good news is that the nitrous shuts off at 6200 RPM's and the rev limiter is at 7k. I am not sure that plays any part of this, but I'm including it. I checked the valve springs, rockers, all looks good. There is no new noises from the engine. It still pulls damn hard, so I can't imagine anything happened to it. I have been working on LS engines since 1999 when I bought my Camaro, which I still own and is the subject of this post.

This car had great street manners and would idle perfectly all the time.

The issue is now, that it won't idle correctly. It will idle fine in park, but as soon as I put it in drive or reverse it almost wants to die. It started doing this after taking it to the track. Nothing on the car has changed other than install truck coils from a junk yard Yukon that I did BEFORE taking it to the track. I have tried both a new IAC and TPS, cleaned the throttle body as well. I reset the TPS and it will read .04 to .08% I checked plugs/wires.. nothing. The only thing I can see is that the front 2 plugs are a little black, I am running a super Vic intake. I have changed to truck coils with over 100k miles on them, but the car is not throwing any codes. I even unplugged a spark plug wire and it still didn't throw a code.

No one seems to be able to help. I am wondering if maybe 1 or 2 coils are weak causing this issue? Maybe after the nitrous runs something happened? I'm not sure. I am new on here, obviously... I have ZERO tuning experience, I have HP Tuners mainly for logging and changing out between my nitrous tune and N/A tune.

This is my last resort. No one has any idea what the issue could be. Also, I noticed my oil pressure used to be a constant 40psi at idle when hot, now drops down to 20-30 when hot, and once again I am not sure these two things are related. but I am including as much info as I possibly can.

I read the rules and included both my logs and my tune. I am not sure what a .cfg file is though.

So to sum it all up, I am hoping someone on here can look at my logs and I hope and pray something stands out that could be causing this issue. As I have said, this car has run perfectly for years, and now after a couple nitrous runs, it doesn't idle when there is a load on it, but idles good in park.

Thank you all for any help

You should do a leak down test, idle vacuum looks high to me, and commanded AFR seems to go rich for no reason.
Maybe it has a big cam. Post a list of the modifications that effect why a scan looks like it does, ceramic coated pistons doesn't really mean anything when you're looking at a scan file.

Also add more channels that are relevant to tracking down a misfire.

[Jason B]

So you've had this problem since 2009?
What was the solution to this problem back then?

[Capt. Insaino]

No, this issue started about a month ago. My camshaft data sheets reads Lob separation 113 Intake duration 244 Exhaust duration 252 Intake lobe lift .370 Exhaust lobe lift .382 total intake lift at valve .629 total exhaust lift at valve .649

How do you add more channels and what channels are they to track down misfires? I am so new to this, I am lucky to know how to save a file! lol

Thanks for your responses, so far you all have been much more help than anyone else I have asked.

I thought about maybe a pushrod issue? Could that possibly be a cause of the lower oil pressure?

[2xLS1]

You have a cam that is very tight on P to V clearance and you reved it to 7K or more. Check the pushrods.

[Capt. Insaino]

My PTV clearance is +.180 intake and +.200 exhaust, so I guess my next step is to check the pushrods.

[Jason B]

My PTV clearance is +.180 intake and +.200 exhaust, so I guess my next step is to check the pushrods.

You said it makes no new noises, thats why I said do a leak down test. I've slightly bent a valve before without bending the pushrod.

[veee8]

Check the reluctor wheel on the crank, it may have slipped. Seen it more then a few times.
Easiest way to do it without pulling the engine, is to make a timing pointer marked for tdc on cylinder 1 on the balancer. Needs to be very accurate!
Use the scanner to lock your timing with a fixed amount. Say 22*, then check what your balancer to timing pointer show with a timing light. If it matches, good, move on, if not, time to pull the crank and have it realigned, and welding would be a good idea.

[Jinx]

I didn't see anyone mention this, but maybe an intake leak or leak where the nitrous is introduced? Could cause similar issues and easy to test for with a can of carb cleaner.

[Capt. Insaino]

Update, I just let the car sit because I was not in the mood to mess with it until today. I started the car and as usual, it the idle was fine in park. I tried spraying carb cleaner all around the base of the intake, and any vacuum hoses. Nothing happened. About 30 minutes later I decide to start it up and put it in drive for the fun of it, and it idled perfectly while in gear. Just like it used to. So I turned it off, it sat about 5 minutes, did it again and put it in drive, the idle starting falling again. I turned it off, started it back up about 15 minutes later, put it in gear, and idled perfect again. Another thing I am noticing is at low speeds it feels like it is hesitating, and when I stomp the gas for a brief second, the engine feels like it hesitates then just pulls like a bitch. Since it is intermittent, I wouldn't think it would be mechanical. I did replace the coils with 1xx,000 mile truck coils awhile back, I am wondering if there is a weak one? I did notice that my 2 front plugs are much darker (Black) than all the others which I wouldn't think should happen with having a single plane intake. I just started it again, and once again it is idling perfectly. Thoughts?

[Earwax]

It sounds like it`s missing at idle.
Check the spark with a spark checker while running it.
Do at least the cyls that are black.
Replace the plugs.
Did you check compression?/Leak down test?
Valve springs checked for pressure/broken coils?
Did you check vacuum while this occurs?
How about a couple of logs with and with out the rough idle?

[2xLS1]

What ever you do don't check the pushrods. I would just keep asking questions here rather than working on it.

[Jason B]

What ever you do don't check the pushrods. I would just keep asking questions here rather than working on it.

No shit. I was thinking the same thing before I saw your post.
Heres a post correction.

Update, I just let the car sit because I was not in the mood to mess with it until today. I didn't do shit to it and it still doesn't run right. Thoughts?

[Fast4.7]

Personally I would pull the plugs. Take a look at them. Nitrous is great for burning the ground electrodes off them if it ever leans out (fuel kill).

[gagliano7]

At idle get infrared temp gun and check the temp of all primary tubes if one is good amount lower than the rest that one has the bad coil. I had one that would miss at idle and part throttle but work fine at wot. I found it with the temp gun in a minute.

[Capt. Insaino]

I have dealt with bent pushrod issues in the past, (I have been working on LS1 cars since '99 and have addressed my fair share) which is why I hesitated to do so, this didn't seem to fit the bill, but I went ahead and pulled them all out, rolled them on glass, and everyone of them are fine.

I did a leak down test on every cylinder at 75 psi and every cylinder (while warm) read 70 PSI. So there are no bent valves either.

I changed out all coils with some that are known good, and nothing changed.

I checked the injectors using a ohm meter, and every one read between 14.0 to 13.7.

These are new spark plugs that I put in after spraying, these plugs have never been sprayed.

All valve springs are fine as well.

As far as the relucter wheel slipping on the crank, is that common on a K1 crank?

I have included the log where the car was idling fine. I included a modified tune that we did today just to get it to idle halfway decent, and included log of the car on that tune. This is just a band aid until we can find what is going on.

Today the engine started shaking the car when I went to accelerate slowly from 60 to 70, and it is noticeably down on power now, so whatever it is, it's getting worse. It did this on the log labeled "back from shop". David Griffin is who is working with me to figure this out (If you know him, worked for Hennessy and now SCT, he's pretty good) and modified the tune just to help the idle which did work, but the car is still not obviously right.

So tomorrow I will start putting the pushrods and rockers back on the car, reinstall the spark plugs and button it back up.

Any help without being a dick and causing me to do more work than is necessary is appreciated.

[Capt. Insaino]

At idle get infrared temp gun and check the temp of all primary tubes if one is good amount lower than the rest that one has the bad coil. I had one that would miss at idle and part throttle but work fine at wot. I found it with the temp gun in a minute.

I may still try that. Thank you.