clarkmtc

Hey all, just got the bumblebee out of the shop for three days, did a performance cam install from MTI Racing. I specifically asked MTI to give me a cam that was light/aggresive, yet subtle, since I am a commuter as well. They suggested a new cam release called a Stage 1.5 "ish" cam package. I bought the cam with springs, the works to be safe. Well, the cam install was good, no issues, but one thing they didnt tell me was that this cam, after install would have to be "tuned" with a specific build which would prevent the automatic timing adjustment from kicking in at startup. Basically, it prevents the car from trying to adjust the timing right when the key is turned and realizes the cam is "not stock". Well, I have the Diablo tuner, but I didnt buy the PC download kit, so he couldnt upload and customize the tune to try and block this problem out", I had to have the thing sent from Amazon; wont arrive until next week. Anyway, the car drives fine now, but it wont start most of the time without a few cranks, and it backfires at startup as well. My 2010 Camaro sounds like my old Apache 100 fleetside I learned to drive on in the 70's.... Needless to say, I am dissapointed that MTI didnt warn me of this issue beforehand so I could have adjusted it right after install. Now I have a mess. When the engine is warm, restarting it is almost impossible.

So, people, be ready for this when you buy a cam, sont be a dummy and listen to the "sales guy" (like I did), because they just want to "sell". Despite him telling me several times the cam was a "medium" performance cam and would require "no tuning after install", it was false. Hence, my backfiring jalopy....I should make a video of this backfiring and upload it to YouTube.

In closing, if you buy a cam and have a set budget, be ready to drop several hundred more dollars for a tuner and cable and mechanics time to go and "tweak it" after install. Set me back an additional 500 bucks now that I wasnt ready for.....

JasonD

I am surprised that they basically told you it was "plug and play". I believe that just about every cam needs a tune for the most part, especially for an L99.

2010_5thgen

why would you think the car didnt need to be tuned after installing a new cam? these cars need retuned after putting an intake on. i had mine installed at backstreet performance. they tuned it and made it run perfect. in all i had about 2k with install, tune,cam and all the parts with it.


so what kind of numbers are you putting down with it?!

clarkmtc

Well, I need your help please. My mechanic is having HUGE problems with the tune, using the Diablo. He downloaded the latest software, but I still have startup and backfiring problems. The car (according to him), is loading up on fuel becaus ehe took something out (phaser?), when he installed the cam and it backfires. Also, the damned engine light remains on. I really need some advice. MTI wont help, my guy is stumped, the folks at Diablo have no clue....how do I tune this so this awful startup backfiring and fuel loading stop !!!! HELP !!!!!

JasonD

Okay, let me see if I can help here.

First of all, why won't MTI help? They sold you the camshaft, they should tell you what you need to do in order to make it work.

Second, is this camshaft ground specific for the L99 engine application? If it is, you shouldn't need to remove the cam phaser. I would find out.

There are a lot of things at play here.

What I think the problem is lies in is the removal of the cam phaser. If you remove that, I think you also need to remove the timing chain, front cover, lifters, valve springs, etc. because they are integral to the AFM and VVT which is probably trying to activate. All that needs to be replaced with LS3 parts because that is essentially what you are converting the engine to...again, IF the cam is not a specific grind for an L99 engine.

My advice before you or your mechanic goes any further is to make sure that what is being done is correct. You should call up Vector Motorsports and explain your situation. 586-790-2970. Speak with Kirk if you can. Tell them I sent you and give them all of the details, including the cam specs (this is important, they will need to know this info). Once they set you straight on your required mechanics, order one of their custom tunes and send the Diablo back if that still doesn't work for you.

2010_5thgen

i would take the car to another shop. someone who knows what they are doing.

clarkmtc

Stephen from MTI racing called and as it turns out, the wrong timing cover was shipped with the cam, the thick one, which causes the phaser to "not read" the cam, so the computer never knows where it is. The shalloe cover will fix this (I hope) on Monday and I will lose the backfire and flooding issuse. THe engine light problem though is due to the catalytic converters being removed with the Borla system, not sure how to tune that out to remove the annoying light. Also, found a new shop that uses EFI Live, and realized how insignificant this little silly diablo predator is. The guy laughed at me when he saw it....crossing my fingers....

By the way, the MTI cams are actually comp cams, which made me feel better. I wish now though I would have went with kooks headers and not the Borla, its a bitlouder than I wanted...

JasonD

Okay...so is the cam phaser supposed to be installed or not? If so, I am unsure why you need a different timing cover. Then again, I always think that I have a lot to learn.

Your tuner should be able to tune out the lack of cats.

Most aftermarket cams are ground by Comp Cams, just to their specific grind specs.

jay_lt4

most L99 cam installs will require you to remove the VVt(unless you purchases a L99 VVT specific camshaft) , if your are removing the vvt(standard 3bolt 4x cam gear and ls3 front cover) on the L99 you should also remove the heads and replace the AFM lifters with standard Ls3/7 lifters and also a standard LS3 valley cover to remove the AFM/DOD