Cam installed, now excessive backfiring and flashing SES???
10-10-2009, 10:58 AM
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Cam installed, now excessive backfiring and flashing SES??? Ok I just got done monday installing my Texas Speed 228/228 .588/.588 112+2 cam. My tuning is bone stock yet besides SES lights turned off for AIR delete and my ORY. In my sig you can see my other mods, ported LS6 heads, longtubes etc. but anyway this is the second cam i have done and didn't have this problem on my first time installing which is why I am a little worried. The car now is extremely rich, it almost burns your eyes standing behind it and smokes like a diesel when I punch it and other problem is after 3000 rpm it starts to backfire while the throttle is DOWN and the SES light will start flashing for about 15 seconds. It never backfires when I let it hang in gear but while i'm pushing it down above 3K it BANGS and the throttle goes temporarily dead when it does this. I put it new plugs and wires during the cam install and checked and rechecked to make sure the plug wires are tight. I am gonna do a full dyno tune pretty soon and my main question here is this all the tuning that will be taken care of or do I have bigger issues?
10-10-2009, 11:01 AM
#2
Awesome I have the same exact problem same cam... good to see im not the only one... damn hopefully one of our posts will get an answer, I searchd for a couple hours last night and came up with not much of anything.
We have almost identical setups, well except i have milled 241 heads.
We have almost identical setups, well except i have milled 241 heads.
10-10-2009, 11:03 AM
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*other than full throttle it runs good, idles decent and drives nice, I can tell a nice power gain too until it starts to back fire and SES flashes at me and I let off at about 4-5K
10-10-2009, 12:38 PM
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haven't gone past 5K but my buddy data logging for me hptuners while we drove showed no knock but it was pulling a lot of timing, full throttle i was in the low 20's and my fuel trims were very rich
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10-10-2009, 12:39 PM
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could it be from running really rich that fuel is possibly pooling in the exhaust and under heavier acceleration it's causing to explode, that was my buddies idea of a possibility?
10-10-2009, 05:15 PM
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Tried calling TSP but not around when I tried, I'll try next week again but i'll wait till after a tune and see if the problem is better then
10-10-2009, 10:02 PM
#12
A Flashing SES light means that the PCM is detecting a MISSFIRE, either you have a ignition issue or since you have a cam now you need to tune the car for the cam and possibly adjust the missfire detection...I wount drive it hard or my opinion at all till you get a tune...if it will be some time before you can get it dyno tuned ...PM frost he offeres very resonable mail order tunes.
10-10-2009, 10:18 PM
#13
Well I just checked my pre load tonight, I now know that the wrong rod lengths can cause a misfire, it was keeping the valves open causing my misfire, I would check your preload, all I did was pulled the valve covers look at each and every valve, I chose the valves that were almost to the top no load on the springs, I then loosened the rocker arm bolt then tightened it finger tight to get zero lash, then went measured ever 1/4 turn, I got 2 and roughly 1/4 turn out of those valves, leaving me at 0.10575 pre load, ideally you should be around the .050-.080 ish range, I know some people say less or more but this is the great debate, I am using an average of the two sides of the fence. I am getting 7.350 length rods and this knocks me down to 0.0556 preload which will put me in the correct range. roughly, at least now I should have a properly running car.
10-10-2009, 10:53 PM
#14
The SES flashes when you are >1.5 times the EPA mandated tailpipe emissions threshold which can cause cat damage(assumining you have cats). Misfires can cause this problem, but that's not the only thing. It can be something as simple as a spark plug connector not seated fully.
10-11-2009, 06:13 PM
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Well I just checked my pre load tonight, I now know that the wrong rod lengths can cause a misfire, it was keeping the valves open causing my misfire, I would check your preload, all I did was pulled the valve covers look at each and every valve, I chose the valves that were almost to the top no load on the springs, I then loosened the rocker arm bolt then tightened it finger tight to get zero lash, then went measured ever 1/4 turn, I got 2 and roughly 1/4 turn out of those valves, leaving me at 0.10575 pre load, ideally you should be around the .050-.080 ish range, I know some people say less or more but this is the great debate, I am using an average of the two sides of the fence. I am getting 7.350 length rods and this knocks me down to 0.0556 preload which will put me in the correct range. roughly, at least now I should have a properly running car.
10-11-2009, 10:12 PM
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well i know when i am trying to tune a carb on my yfz 450 when i punch the throttle and there is a stuttering kind of bog and it does not pick up, it is because it is running too rich, it was fixed by leaning out the midrange, so im guessing you guys are experiencing a very rich mixture so a tune will do the trick
10-12-2009, 01:36 AM
#17
well i know when i am trying to tune a carb on my yfz 450 when i punch the throttle and there is a stuttering kind of bog and it does not pick up, it is because it is running too rich, it was fixed by leaning out the midrange, so im guessing you guys are experiencing a very rich mixture so a tune will do the trick
10-12-2009, 08:55 AM
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Post on here how your tune goes if it fixes everything, we got snow here and i'm putting the car away for winter soon and not tuning till next March or April but i'd like a little piece of mind over the next 6 months if yours gets better. As of right now right when I head to the dyno/performance shop I am taking 7.4 pushrods along, 2 spare 02 sensors, 8 spare plug wires, and 38# injectors to install right before I get on the dyno.
10-12-2009, 10:35 AM
#19
Post on here how your tune goes if it fixes everything, we got snow here and i'm putting the car away for winter soon and not tuning till next March or April but i'd like a little piece of mind over the next 6 months if yours gets better. As of right now right when I head to the dyno/performance shop I am taking 7.4 pushrods along, 2 spare 02 sensors, 8 spare plug wires, and 38# injectors to install right before I get on the dyno.
