Running rough and exhaust is cherry red
 

Well, it has been about a week and a half since i started my car, and I just started it and it idles really rough....like the engine shakes a little and its backfiring like crazy. When I hold the gas down to about 1500 or 2000 RPMs it runs pretty smooth...I did that for a few minutes though and the exhaust was BRIGHT cherry red and the car keeps dying now......how much am I screwed? Can someone help please?

Check your map sensor, the vacum line might have poped off.

You may have trouble with your leading igntion - if the car is only running on trailing it will run like crap and get the exhaust SUPER hot.

Dale

Wow, thats a new one on me! I dont want to steal the thread or anything and if its need i'll start one but, What happens when you do the oposite? run on leadings only.

not much. idle qualtiy will suffer, throttle tip in etc..

cat or mp? if you have a cat, the ceramic brick may have desintigrated (sp?) and that could be causing the exhaust to glow

the whole downpipe was just glowing red....how do i check the map sensor and leading ignition?

the whole downpipe is just glowing bright red....how do i check the map sensor or leading ignition?

The MAP sensor is the little solenoid thats mounted on the firewall on the drivers side. It should have a vacuum line going to the nipple on the bottom side of it from the throttle body area.

do you have a stock dp with a pre-cat or a aftermarket downpipe?

Sounds like a blocked Cat to me...

bought the car with a greddy catback exhaust on it, but its still the stock DP.....guess ill check that out first. there any easy way to do it, or do i pretty much just have to take the whole thing off? Sorry all the noob questions....but we all gotta start somewhere :o) Thanks for all the help.

First, did you check the MAP sensor (has "boost sensor" printed on it) for a disconnected vacuum line? That's a very common occurrence. Also check the other stuff mentioned above.

To check the pre-cat (the one the above posts referenced) you have to pull it off. That's somewhat of a PITA. If pieces fall out, it was trashed. Also some pieces may have clogged the main cat and it may need replacement.

For how to remove the pre-cat, search for posts on downpipe installation - lots of good info here.

BTW, having the exhaust glow red after running at 1500-2000 RPM for a while is not unusual. The pre-cat WILL get that hot.

Yea, the map sensor was the first thing i checked. That line has popped off before, its amazing how much one little line can screw up your car :oP Unfortunately thats not the problem this time......also, I heard that messing with how rich the car runs isnt good at all, so if I get rid of my precat by getting say an HKS downpipe or something of the sort, am I going to have to do something else so that it doesnt run to lean? Or will it not change that much with it?

i think you'll be ok if you have the stock main cat, just watch your boost gauge on transition, if you see it start to spike, let off immideately. as far as i've read (dont' own a 7 yet, trying to learn a shit-ton before i buy) if you have a dp and cb, but no mp/hf cat, and no intake, you should be fine with not running lean (someone PLEASE correct me if i'm wrong ASAP.) drop on a dp and you should be good for having a smooth running engine, but when you drive it for the first time watch your boost gauge and if at transition you start to spike, let off immideatlely.

once you put on the dp, don't do any more performance mods 'til you get: upgraded ratiator, Aluminum AST/AST removal kit, and a PFC. once you get a PFC, personally, i'd get an intake, a medium SMIC (large is too big for the stock twins, and SCC prooved this with their project 7 that the large smic's with stock twins make a little less power than the medium smic), and a mp/hf cat, and install them all at once, along with the PFC, and get it tuned. doing your modifications in chunks will save you costs on tuning.

after these, i'd suggest sequential simplification with silicone to get rid of all your old rubber hoses, and replace your check valves with viton ones (there's a guy on the forum that is selling them at 4/$20, cheaper than stock plastic). viton will hold up MUCH better than the stock plastic ones.

Yup, you should ditch the pre cat, you've seen it glowing.....do say more or is that enough. Down pipe and catback is very much safe on the stock ecu. It will compensate.