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Discussion Starter #1 (Edited)
Well, I finally got my cam install done and now the struggle begins.

I picked the car up Tuesday evening and it ran excellent on the 70 mile trip home. It was raining so I didn't get on it at all.

I drove it to work the next morning and all seemed well until about 1/2 way through the trip. I decided I wanted to test the power a little so I did a quick kick down and ran the car to 6,200 rpm.

Immediately after the WOT hit, I started getting a bad part throttle miss and exhaust backfire from time to time. My HP STFT / LTFT histogram shows the car is really trying to pull fuel out at basically all fuel mass points.

I decided to drive the car to work again today and it seemed to settle out some and run pretty good. I decided to do another WOT punch and it had a BAD miss above 6,000. I let out and the part throttle miss returned with a vengeance.

It actually idles pretty well, although you can hear it missing somewhat at idle. Power seems very good when it isn't missing, so I'm kinda stumped.

The shop that did the install is a respectable shop; however they don't do a ton Mopar tuning work (although they claim to have tuned cams before).

I want to lean toward the tune, but it seems very odd that the car was running great until I did my first WOT pull.

The car is getting air, so it has to be fuel or spark...or a mechanical issue.

The engine is quite under the hood and I installed all new Hellcat lifters and upgraded pushrods. I'm still using the stock springs, but the cam is a MM NSR grind.

It would seem odd that a coil pack would go out, but I may pull the coils and check the plugs to see what they look like.

I'm still learning about cam tuning, but the tuner didn't make any changes to the HP WOT cam tables. He only changed the intake / exhaust max and min under the cam tables.

He also turned off Neutral Network, tweaked the VE tables, PT spark tables, Idle torque tables and that was about it.

Any ideas would be appreciated.
 

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Discussion Starter #2
BTW... during the first WOT pull, the AFR looked decent and there was no knock. There is also no knock at part throttle and I'm not throwing any codes.
 

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WHat tuning software did they use

Sounds like tuning is messed up


Sent from my iPhone using Tapatalk
 

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2016 Jazz Blue A8 Scat
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A cam isgoing to make the engine breath better at higher rpm and worse at low rpm.

So the fueling should also probably follow that trend.

If they didn’t pull fuel down low, when you are cruising around the fuel trim may be pulling out fuel, which it then applies during more aggressive driving?

Just a guess.

Also, what is manifold pressure doing?
Is the cam big enough to give the MAP sensor a false reading sometimes?
 

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Re-reading your post made me think of this:

Pull your plugs and see if they are fouled from an over-rich condition.
 

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2016 SRT Challenger Hellcat
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Misfired

BTW... during the first WOT pull, the AFR looked decent and there was no knock. There is also no knock at part throttle and I'm not throwing any codes.
I had the same problem. I regap my 3 month old plugs and cleaned them and the problem went away.I say my problem happen because some of my plugs were foiled and not gapped properly.My guess it happened when i put racing fuel in but the same problem as you at boost.
 

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Discussion Starter #7
My fear was a broken valve spring since things went south right after WOT. However, both banks are having fuel trim issues, so that points to the tune.

The installer used HP Tuners and actually was able to start with my pre-cam tune.

From what I understand, he didn't make enough changes in the cam tables.

I'm going to reset the fuel adaptives and see what it does. If that doesn't work, then I'll tweak the injector pulse width at various fuel mass points.

I HOPE it is the tune, as that is easy to fix.

If playing with the tune doesn't work, I guess I will pull the valve covers and plugs and see what I find.
 

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Good luck!
 

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You may want to check your plugs to see of the gap is pinched in. That could indicate wrong tune and detonation problem.
 

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If/when you pull the valve covers, double-check head bolt torque.... you're in there already.
 

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This is definitely in the tune. The adaptive fuel tables in the tune make it difficult to tune for a cam, I have all that turned off.

I would still pull and read plugs.
 

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If a coil pack went out, wouldn't it run poorly all of the time?

Which .pids are you monitoring in your logs?
 

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Discussion Starter #14
Well guys.... I have the initial verdict and it isn't good. #3 spark plugs were both closed up tight and something beat them up pretty good.

I think we know what that something is.... most likely the ring land.
 

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Discussion Starter #16
Or maybe they left the plugs in the heads when they pulled them and damaged the plugs while the heads were off?

Buy something like one of these and look in the cylinder for damage before you go any further:

https://www.amazon.com/dp/B01MYTI2HV/_encoding=UTF8?coliid=IK9EIAG0DKHAI&colid=3V6RP7LRATQY2&psc=0
Yes, this is my next step. I'm 99% sure they pulled the heads with the plugs in; however it ran excellent initially (70 miles home). It only started acting up after my first WOT pull.

Whatever happened, happened while I was at WOT. I only pulled to 6,200 rpms and the data log looked fine, so I'm just not sure what occurred.

Most likely, a set of drop in's are in my future.... hopefully the head is still usable.
 

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I think you are jumping to conclusions without enough evidence. Put a fresh set of plugs in and test. Those plugs look awful dark by the way.

Pull all the plugs, if you didn't already. Are they all closed? If not what color are the normal ones?
 

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Discussion Starter #18
I think you are jumping to conclusions without enough evidence. Put a fresh set of plugs in and test. Those plugs look awful dark by the way.

Pull all the plugs, if you didn't already. Are they all closed? If not what color are the normal ones?
Only the plugs in #3 cylinder are closed. All of the plugs look the same (borderline fouled), so I will definitely install a new set.

I ordered a endoscope to check out cylinder #3. Not only are the plugs closed, they are also gouged. Something definitely made contact with them.

I thought I might have broke a spring and dropped a valve, but I don't think a dropped valve would take the plugs out like that and it should make some noise. The engine runs quite, other than the misfire.

The endoscope will be here Monday, so I'll know then.

If the piston is busted, I'll have the car loaded up and sent to DTP. I just don't have the tools or the shop to pull the engine.
 

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Discussion Starter #20 (Edited)
Did you have a dyno tune or canned?
The shop that installed the cam did a dyno tune. They used my existing HP tune as a base and tweaked it for the cam.

One thing I noticed in the tune is that they bumped WOT timing up over my settings. I pretty much had the timing maxed out with no knock. So, any timing past that typically induced knock.

Now... here is where I'm probably partly responsible.. I went very aggressive while desensitizing the knock sensors. The typical thing to do is cut their values in half and I went a little beyond that.

Since the shop pushed the timing back up, they may have killed the piston with true detonation.... especially with multiple WOT pulls.

Yesterday, I sent the tune file to Jay Greene and he said it looked okay, so that is when I decided to pull the plugs. Other than possibly cracking the land on the dyno, I don't believe the install shop is responsible.

I think the other plugs may be a little fouled from getting the tune right initially, but I do believe the tune was okay when I went WOT.

I'm pushing some pretty good power out of the engine now, so that may have been enough to #3 ring land.
 
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