Y2KC5NBM

Long story as short as I can make it. lol

I had the G5X3 cam installed in my C6. I've taken it to two tuners, and I'm still having drivability issues.

1. The car dies or nearly dies when coming to a stop. If it doesn't die, it chokes down to about 200 rpms then bounces up to 1200 rpm's. It does this 5 times or so until it finds the idle.

2. Surges and bucks alot. I know that at lower rpm's it's going to do that a bit, but I'm talking going 70mph in 6th gear with cruise on. RPM's are running around 1550 at this point. If going down a small hill and the cruise starts to back out of the gas....the car will start surging. I don't feel that the surging stops until I'm above 2000 rpm's.

3. When starting the car, I have to use my foot on the accelerator to get it running....and then have to use my foot to keep it running for about 20 seconds or so.

Now here's the kicker....the car was throwing a P0106 code, which is a MAP performance code. So, I unhooked the MAP Sensor and the CAR RUNS PERFECT! No idle problems, no starting problems, etc. So I replaced the MAP sensor and it didn't change anything. (I did some research on the G5X3 cam and this code and found this:

"Code P0106 is pretty normal for a larger cam. It can be tuned out. Both HPT and EFIlive have P0106 min/max fail tables, that need to be adjust, because with a cam with that profile, the idle vacuum is such that the computer doesnt like it.
You dont need to turn off the code, or anything like that. You (your tuner) need to tweak the tables, setting the max fail at 0 and 10% throttle versus 800/1600 rpm, up to around 85 Kpa, where as the stock settings are something like 65 or so @ 0%/800 rpm."

After hooking up a Tech 2 to my car, I verified that the KPA was running at 65 at Idle. When unhooked, it shows 10 KPA. I sent this information to the tuner that was working on my car and asked him to make the changes mentioned above. I went tonight and took the car in to him so he could make the changes. While the changes made did shut off the check engine light (He set the MAP test to run above 1600rpm's only), I'm still having starting, idle, and surging problems.

This to me sounds like some kind of MAP problem, but I'm not a tuner. When the MAP is plugged in, the car runs like crap. When the MAP is unplugged, it runs great!

Somebody PLEASE help me out. I'd be glad to pay for the correct answer. I've been working on this for 2 months and I've about had all I can take.

Thanks,

Brian

SpinMonster

All big cams have some minor bucks at the 1600 range. It varies as the cams get bigger.

All of the issues you describe are from the running airflow table and timing curves off idle to 2krpms. If you were local I would do it for you for free.

The knock sensitivity at idle is just a matter of loosening up the test at idle rpms and you should not have the test bypassed altogether for safety reasons.

Shrike6

I have one of LGs larger cams, and had the "bouncing" idle problem along with bucking and surging below about 1800 rpm. After I took it to Jeremy Formato for a retune, the idle problem was better, but this kind of cam seems happier over 2000rpm. I have to do a lot of stop and go driving around town in traffic, and it's still somewhat of a pain.
I don't think it can ever be totally be tuned out.
GM

Y2KC5NBM

I did some research on this before putting the cam in, and didn't see anything about bouncing idle problem's or hard starting. I have found several video's on youtube with guy's starting up their cars, revving them, etc. with no problems on returning right to idle. There's definately something wrong in the tune.

I don't know where you live SpinMonster, but I wish I could lived within driving range of you. I've seen some posts by people that had cars tuned on by you and how great they run. I'm about ready to put the thing back to stock if I can't get it right. I cannot drive a car that dies everytime you come up to a stop light, this isn't an old 1970's Carbeurated P.O.S.

Spinmonster, how far of a drive?

Craigster05

It's actually a fairly cheap flight.....It's the big dinner that's going to cost you...

Shrike6

It's not really the dinner....
it's driving through New Jersey
GM

andreas g.

No matter what a tuner tells you (LG) The cam you selected isn't a street daily driver cam. It's a paintshaker. Bigger isn't always better in term of drivability. I'm sure you're painfully aware of that now. Most of these tuners are in the business of making money and having dyno numbers that are better than any of there competitors. It's a pissing contest, it always has been. I've been modding LS type motors since 1999 and have made my share of mistakes. Big cams on the street are just that, big cams and all of the issues that come with it. The only thing that might save you right now is Speed density tune which in effect removes the MAF altogether. All you need to retain is the IAT sensor which you can get as an individual part from the dealer. You've got to remember that you don't spend all of your driving time at the redline, it's the mid range where you spend most of you driving time. You look at the dyno numbers and what does it tell you? Max power/Max torque. Smart people look at the sheet and see what power is made under the curve and how flat the torque curve is, because that where you live. My LS2 made461rwhp/435rwtq with a small cam 224/228/581/588/114. smooth idle slight lope , great milage. My new forged 427 Makes 525rwhp/500rwtq with a small cam for a big inch motor, 232/234/595/598/112LSA. It idles perfect at 850rpms nice lope, and good milage 27mpg highway. It has a SD tune. Sure I could have made more power with a big stick, then I'ed be on the forum next to you with the same problems you've got now. The only compromise I've had to make with this motor, is when it's cold After I push the start button and it fires, I've got to open the throttle a little then it catches and idles fine.
Otherwise it woun't start. Small price to pay for an otherwise perfect motor. Interesting how some of these tuners promise you tons of power and forget to mention the problems that can come with it. So if you're willing to live with it keep what you've got, if not, you're going to make some changes and it woun't be free. Nothing is!! Good luck

andreas g.

SoldSyclone

I have a few friends with the G5x3 and stock Autos they like the combo, but it did take some tunning A big name great tuner here had similar problems. Dan from dynojet fixed it.

Do you have HPtuners? or Know somone that does?

KMK454

LGM put a G5X3 in my car and told me everything I was about to get into, good and bad; they didn't play any games with me. I like a lopey idle and the mean sound the cam gives the car, and I also like the extra power it gives. Sure, we spend most of our time in the mid-bands (I daily drive too), but it's not like I'm going 100% around town all the time anyways. I did "lose" some mid-range torque, but nothing big. And of course, when I have to open it up, that's what the redline is for, right? And that's where the power is, right? So I don't see what the problem is...

My car doesn't have the idle issue. It does fine and returns to its normal idle without a problem. There are a few spots where it will surge or buck below 1700 RPM, but for the most part it is dialed out and I can effectively cruise down the highway in 6th at 1700RPM all day long. I do need to slip the clutch a little more while leaving a light, but it's easy to get used to. It's all in the effectiveness of the tuning, and from what it sounds like, you need a good tune on that LS2 with the G5X3!

andreas g.

It works for you, but it isn't working for him. One man's meat is another man's poison. Every car is different especialy with the other parts used as a package. It's the whole package that has to work not just the cam alone. His isn't working.

0Anthony @ LGMotorsports

Street manners and a car's drivablity are all up to the eye of the beholder. What I might think is normal for a street car and what someone else's idea might be completely different. This is why we have a number of different cams, and cam packages. This is also the reason we will custom tailor these person's needs.

One of the nice points about our Executive series of cams is that they do offer a very smooth power band without a radical idle or lope. We also offer much more aggressive cams such as the XX cams for the more hard core race fans.

Numbers aside, the G5X3 has been a very popular street/track cam package that a lot of customers have been very happy with and is a very proven package. A lot can be said for the tune, but it will always have a lope to it more so than a stock car to be sure.

Some of the issues that you are speaking of, such as having to use the gas pedal to start the car should not be.

Please contact me here at the shop. I will be more than happy to help in any way that I can. Check your PM's.

Y2KC5NBM

I can understand the lope, that's not what I'm complaining about. My problem is the car is stalling when coming to a stop. If it does not stall, then it will choke down so low on RPM's it almost dies....then recovers. That and using my foot on the gas pedal to start it are my 2 MAIN issues. In fact, if I can get rid of those two problems....I would be happier than 2 pigs in ****!

Y2KC5NBM

The guy that installed my cam has HP Tuners. But it was most recently tuned with EFI Live.

SoldSyclone

You could get/buy a tune known to work with the cam then tweek it for your car.

The G5x3 is not a big cam, I dont like big cams, IMO it is a good med cam but tunning is needed.

Y2KC5NBM

That's kind of what I'm hoping for. Something I can slap in there and have the basics done. Then take it and have it tuned on the dyno for power.

If you know someone that's got a GOOD tune they would like to help a guy out with, I'd be glad to compensate them.

Thanks

johnodrake

Brian,

Give Phil Rickard at DTE Powertrain (forum vendor) a call. He is in Ft. Wayne.

Gotcha

Hey Brian

You might give Ed Potter a call at Modern Day Muscle Cars in Decatur IN, just a couple miles from LPE. Ed was with Lingenfelter for a long time and knows his stuff.

MDMC 260-724-7792

Y2KC5NBM

Thanks for the info guys. I've talked with Anthony with LG, and they are going to try and get me going in the right direction. I'll post with my results when I get things squared away.

Thanks again for your replies.

Brian

Joe_G

I daily drive (mostly city stop and go) my g5x3 and it is perfect. Never dies hot or cold, hot starts just fine and only bucks a little before warmup. Idles at 750 all day long and I never have to keep my foot on the gas. And no po106 issue after I tweaked the ve table. Anyone can pop in my car and drive it, it really is like stock.

If you buy hptuners I'll send you my tune, i spent some time tweaking it but its great. And hptuners is worth every penny for logging if you drag race.

If you buy HP Tuners (and I recommend you do) shoot me a note at joegut at gmail .com

here, listen for yourself.

jcosta79

I've actually had 2 bigger cams in my car from LG - I used to run the G7X4 and now I have the G6X3. Both of these cams ran like crap until we tuned them right. Now it drives like a dream. But even when it was running like crap it NEVER died, never gave a code and surging was only a problem below 1500 RPM. It sounds like you either have something else wrong with the car or you are WAY off on the tune. Call LG and I am sure that they can get you back on the right track. I drive my car every day in traffic and I don't have any problems. It's by no means stock, but it's not anything close to what I would consider a bad driving car... I love it!