Help! Trouble idle, cam, maf tune
05-23-2016, 05:03 AM
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Help! Trouble idle, cam, maf tune Hi, I purchased a vt ss commodore 2000, Only had it 4 days and ready to burn it. It has a maffless tune, muthr thumper cam 227/241 109 lsa, double valve springs ect. Problem I have it will idle nice for about a minute or two than starts snuffing out. fuel can be seen coming out the exhaust, threw a fault code which was the TPS. just replaced this today also the oxy sensors. still the same problem. Throttle body has been cleaned, has the hole drilled into flapper.. Idles good than goes to ****. now have another engine light but I am miles away from a garage. Has anybody had this problem? or any ideas on what to look at next?
05-23-2016, 09:49 AM
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A moderator will likely move the thread to a different spot. It's very difficult with the info provided to make too much progress. Most of the guys in here are going to want to see log files, etc or a copy of the tune to be able to help as well as a comprehensive list of the mods to the car - For example, which intake, headers, what exhaust, catted or not, which heads, how much compression, which injectors, which throttle, etc. A pretty comprehensive list.
That said, very quick stab at it, it sounds like when your car goes from open loop to closed loop during warm up, it starts adding fuel via fuel trims and going stark-raving rich.
So, you will need at least one of the following very basic things to fix this:
1. A highly competent tuner
2. A copy of HPTuners and plenty of time to study and learn, etc
3. A better cam with less overlap. 16 degrees of overlap is quite a lot. You'd do much better with a cam like the Titan 4 from cam motion, 227/232-113+4, with only three degrees of overlap and much better lobes. Without going too much into it, high overlap cams tend to cause oxygen sensors to read false lean and dump fuel.
That said, very quick stab at it, it sounds like when your car goes from open loop to closed loop during warm up, it starts adding fuel via fuel trims and going stark-raving rich.
So, you will need at least one of the following very basic things to fix this:
1. A highly competent tuner
2. A copy of HPTuners and plenty of time to study and learn, etc
3. A better cam with less overlap. 16 degrees of overlap is quite a lot. You'd do much better with a cam like the Titan 4 from cam motion, 227/232-113+4, with only three degrees of overlap and much better lobes. Without going too much into it, high overlap cams tend to cause oxygen sensors to read false lean and dump fuel.