New Cam = New problems, Im stumped

[b727pic]

Before I do something drastic......ie pull the motor back apart. I thought I would see what you guys think of this issue.

I changed....

New Cam: 229/240 .631/.610 117 LSA
Old Cam: 224/232 .600/.600 114LSA

New Lifters: Rhoads Vmax
Old Lifters: Rhoads Standard

Rockers: T&D Old setup and new.

Springs: Kmotion-K800

Engine is a 403 9.25:1 SCR, AFR Custom CNC 235CC heads, JBA shorty headers 2.5" magnaflow catback. Currently no cats installed.

Issue-

I have been through just about every "idle tune" sticky and thread I can find. Played with the PE trick to lean out idle. tried every timing advance from 18* to 33*. Used VCM controls to try and find the "sweet spot" by playing with the AFR, turning off spark Idle, STIT off, reset fuel trims....etc.

No matter what I do, I can't get rid of the Idle hunting and surging. Now I have only played with idle RPMs between 850-1000, but I didn't think this cam would need any more than that?????

One of the advantages and or disadvantages of the rhoads vmax is to in theory be able to "tame" larger cams. I went this route in the hopes I could get this cam past the smog police here in Cali. I have thus far tried .030 lash and .010 lash. At .030 I had approx 16" of vacuum, at .010 I have about 12"-14" of vacuum. In either case the car does the same thing....surges and shudders.

I have sprayed the intake looking for vacuum leaks, no changes apparent. I used a infrared thermal temp gun on my headers, so significant differences in temp pointing to a specific cylinder.

Attached is the latest tune, with this attempt I simply went back to the OEM timing tables knowing I would be playing with the VCM controls. Also attached is the russK idle scan.

I am assuming I am in "open loop", but I don't understand why if STIT is turned off in open loop, why am I getting such large swings of STIT on the scanner, even hitting fuel trim reset on the VCM controls does not seem to affect it????

This engine with the "old cam" ran great, idled near stock, decent mileage and put down 650RWHP at 5500 RPM, one of the reasons I changed it out was trying to get my last 75HP I felt I was missing as HP peaked 1000 RPM early....theory was I was out of cam given my CI Now the car runs terrible, stinks to high heaven, my eyes burn when it idles in the garage for more than a couple minutes....Unless someone can point me in a different direction, I am about to put the thing back up on blocks and change the cam back to my old one......

Up through frame 6014 I haven't touched a thing. Starting at 6014 I make changes using the VCM controls.

[b727pic]

I guess a tear down is in order. Car is back on blocks, putting the old cam back in for giggles and see what happens.

[04SilveradoMykk]

Give the guys some time respond, this board is slow sometimes. I'll look at the tune and log later when not on my iphone

[mecanicman]

Not so sure I would have given up, your tune leaves a lot to be desired. What injectors are you running?

[b727pic]

Not so sure I would have given up, your tune leaves a lot to be desired. What injectors are you running?

up on blocks, but haven't torn it down yet. most likely won't have time until this weekend.

As for the tune, don't look to far beyond just the idle area's. I did drive around the block just to get the VE "close", didn't go over 3,000 RPM. made a quick adjustment to VE in those area's in hopes of getting the low rpm stuff dialed in. Its a pain to drive, while idle is fairly sustainable in the driveway, most attempts to come to a stop while driving will lead to a stalled engine. which I assume will be fixable with throttle follower / timing adjustments.

I am simply mystified how using VCM controls with all sorts of timing and commanded AFR settings seems to have little affect on taming the beast. there simply is no "sweet spot" with timing and or AFR that has worked thus far............I am open to all suggestions at this point.

thanks in advance....

[mecanicman]

What injectors are you running?

[b727pic]

What injectors are you running?

Siemens 60's

Last pro tune I had done, supposedly had the latest and greatest 60's data uploaded??? not sure if it was Gregs data or not??

I can tell you, that with the last cam the car ran and Idled fantastic with the current injector settings......not to say it was perfect but my seat of the pants feel could not complain about it.

[edcmat-l1]

You need to post your config file too.

VE looks pretty jacked.

No STIT in the scan data.

Need to open the throttle blade a little more and reset the TPS. 40-60 IAC counts when warm.

Need to log Air Fuel ratio Commanded Hi Res so you can plot A/F error.

That's just for starters.......

[b727pic]

You need to post your config file too.

VE looks pretty jacked.

No STIT in the scan data.

Need to open the throttle blade a little more and reset the TPS. 40-60 IAC counts when warm.

Need to log Air Fuel ratio Commanded Hi Res so you can plot A/F error.

That's just for starters.......

Config file posted....

looks like STIT data was scanning??? early on in the idle log running in the10's but I don't understand how, I thought this was turned off in the tune???

Was wondering why I couldn't log AFR error on the idle config, thanks for that.

As for changing the IAC, not quite sure how to do that with the cable driven TB. I will search on the forums to see what I can find out...

[mecanicman]

and the injector data is right and wrong, the parts that are wrong will most defineatly affect your idle.

[b727pic]

and the injector data is right and wrong, the parts that are wrong will most defineatly affect your idle.

That is a bit confusing. So some of the data needs to be updated, but not all?
Of course that is way above my paygrade, so......

Would these injector setting only become an issue due to the "new cam", not to say they were correct for the old cam, just wondering if the new cam duration and small overlap is making these injector settings more obvious than the old setup????

[mecanicman]

It is possible to tune around bad injector data to make a car run reasonable. But change anything and your band aid gets ripped off, anything like a camshaft....

[b727pic]

It is possible to tune around bad injector data to make a car run reasonable. But change anything and your band aid gets ripped off, anything like a camshaft....

Sounds reasonable. So I guess I need to find said data.

Once the injector data is up to par, I assume run through the RAF drill a couple more times. Then attempt to get the VE dialed in at the lower RPM regions. With the VE squared away I can come back to finalizing the idle parameters

[b727pic]

So short of ordering the DVD can I get some help on this injector data?

I am still not convinced its the "only" issue I am dealing with. If someone can help with the incorrect Injector data enough to prove to me that its purely in the tune, I'll order the DVD and concentrate my efforts in that direction.

injector pulse widths, and the myriad of the tables that go with it are still simply black magic stuff to me at this point.

[mecanicman]

I am still not convinced its the "only" issue I am dealing with.

I never said the injector data was the only issue, your tune is kind of a train wreck. The injector data is the first thing you put in before doing anything else as all other tuning is built on that data.

Bannish injector data has copyrighted written all over, so posting in a public forum is a no-no. The dvd is well worth the money, more then just injector data there.

[edcmat-l1]

and the injector data is right and wrong, the parts that are wrong will most defineatly affect your idle.

eh, I could probably make it idle just fine with the data that's in there.

[b727pic]

I never said the injector data was the only issue, your tune is kind of a train wreck. The injector data is the first thing you put in before doing anything else as all other tuning is built on that data.

Bannish injector data has copyrighted written all over, so posting in a public forum is a no-no. The dvd is well worth the money, more then just injector data there.

eh, I could probably make it idle just fine with the data that's in there.

The engine does idle, it just stinks to high heaven and playing with commanded AFR and timing on the VCM controls does not lead to a "sweet spot".

All I am after is a little help with idle area's of the injector data. if that does not solve my immediate issue, then it must be mechanical. As stated I simply didn't think the "new" cam was "different" enough to cause the issues I am seeing.

I understand copy right, not asking for any laws to be broken, simply looking for a little guidance on what I might "try" before digging into the motor.

As for the tune being a mess, if I can't get passed decent idle qualities how am I supposed to further on down the trail???

[edcmat-l1]

Don't take it apart. Everything with the exception of the smell can be fixed in the tune, and even that might be able to be improved.

[edcmat-l1]

Have you opened the throttle blade some and done the TPS relearn? Need to do that. Get the IAC counts down to 40-60 when the engine is at 200 deg. Make sure tour TPS % is still at zero. Need to get this done first. You may end up having to do it more than once, after the fueling and spark is straightened out, but it needs to be done now. The timing is pegged high, your STITs are way through the roof. Getting the throttle blade, IAC and TPS right should allow it to use the idle spark over and under speed tables which will control the idle much better.

[b727pic]

Don't take it apart. Everything with the exception of the smell can be fixed in the tune, and even that might be able to be improved.

Have you opened the throttle blade some and done the TPS relearn? Need to do that. Get the IAC counts down to 40-60 when the engine is at 200 deg. Make sure tour TPS % is still at zero. Need to get this done first. You may end up having to do it more than once, after the fueling and spark is straightened out, but it needs to be done now. The timing is pegged high, your STITs are way through the roof. Getting the throttle blade, IAC and TPS right should allow it to use the idle spark over and under speed tables which will control the idle much better.

I bought a new set of intake mani gaskets, don't really expect that to be an issue, but for the price and an hour or so of free labor I thought it worth the effort. Will swap those out tonight and then work on the IAC counts.

Thanks for the support, will report back with findings.