View Full Version : 96' Cobra ptc 0171 system lean bank 1

08-06-2010, 10:04 PM
recently my 96' cobra started having some issues. the radiator cracked and while it was down I decided to clean the imrc's and do a tune up new plugs new wires new coil packs. when I put it all back together the car ran rough for a little while and then smoothed out it continued to do this back and fourth and then threw a code "secondary air pump flow insufficient" I reset the computer and then it threw a code "cylinder 1 misfire" I took out the plugs and they all looked fine they are ngk irridium but just to be sure I put the old wore out plugs back in that didnt really look all that bad. did not fix the problem I would still get the same 2 codes but not at the same time. I ordered a new secondary air pump and put it in and put the irridium plugs back now I get a pending code "p0171 system too lean bank 1" the check engine light never turns on but the pending code is always there. my gas mileage is worse than usual but not by much only about 20-40 miles per tank. when my car is cold it seems to run fine when it warms up it runs rough for a little while then smooths out but feels like it is lacking a little power especially in 4th and 5th gear. when the car is cold it feels great and has lots of power through all gears. Also the car always idles seems to idle great very smooth. the code confuses me because the car has 4 oxygen sensors and it just says lean bank 1 it doesnt specify either o2 sensor so I am not sure where to look especially since before the secondary air pump went out the car ran great and even after it went out it ran fine for a little while until it started throwing the misfire code. so just to recap I have replaced fuel injectors, cleaned imrc's, replaced spark plugs (ngk irridium), wires(msd), coil packs (stock replacements) and secondary air pump. I also cleaned the maf with maf cleaner not break clean or a brush or anything like that and cleaned the intake and throttle plate and idle air control all out with carb cleaner while I was cleaning the imrc's. I also had one of the hard plastic vacuum lines break and just put a small rubber junction on to fix the break. if anyone can help with this code and this problem I would really appreciate it.


08-11-2010, 09:04 PM
first check fuel pressure, but it could be a vacuum leak. it could be an o2 sensor sayin its lean and its really not. but since its only bank one i tend to think it wouldnt be a fuel pressure problem. if i had a scanner hooked up to your car i would be able to help you alot more. ill do some research but in the mean time try to see if you have a vacuum leak. if the P0171 bank one code started after you broke the vacuum line i would check there to make sure its not leaking, if you cant tell then try to replace that line, they are not expensive at all. but i will try to think of more possibilities.

08-13-2010, 06:19 PM
i was thinking and, it could be the EGR stuck open but then it would most likely cause bank 1 and 2 to be lean. so thats just a shot in the dark.

08-19-2010, 02:04 PM
thanks I will check the vacuum and the egr today and let you know if it helps.
also when my secondary air pump or smog pump or whatever went out I found info on the internet that said if I drive the car without fixing that it could cause the cats to melt. I didnt completely stop driving the car but I barely drove and only short distances until i got the new part except for one road trip when I was moving to my new house which took me about an hour but then the car was parked on ramps until I got the part. should I even be worried about the cats or does anyone know how long it would take to melt them? the exhaust does sound different but I don't think it is any quieter so I am not sure if it is being muffled or what.

08-19-2010, 04:52 PM
drive the car around, to get it nice and warm, when it is warm, look under the car, at the cats, if they are glowing red, they are clogged.

08-20-2010, 03:07 PM
If i were you i would just take the cats off. i dont have cats on mine. it sounds alot better. but thats just me. But yea do what he said look under the car and see if they are glowing. but if they are bad they it will throw a code eventually.

08-22-2010, 08:16 AM
some states are strict on the having cats thing. I know NC is. So, that may not be an option for the OP. Taking cats off you lose torque, too.

08-22-2010, 12:06 PM
yea some states are. Georgia is strict I guess but I just put on cats to pass emissions then take them off. never got pulled over for it or anything. and I cannot tell a difference in torque with or without cats. and i have read extensively on the subject and everything i have read say that is not true the only thing that loses torque is if you put bigger pipes without forced induction because it messes up the flow. according to what ive read no back pressure and high flow is the best way to go. around the same size as stock pipes and no cats and no muffler. but at the same time taking cats off for street use is not worth the very small difference. I just dont like the way cats make it sound. and i could be wrong a bout the torque thing I have never tested it on a dyno or have any proof ether way im just speaking from what i have read about it.

08-23-2010, 01:15 PM
Thanks, I went ahead and bought the cat eliminator and the wire harness' that turn off the check engine light. in my state if you do that it will pass emissions the only thing they test for is the computer codes if you have no codes then you pass so i am not worried about that. I checked the vacuum and it seemed great steady at about 22 in. i took the car for a drive after putting on the cat eliminator the exhaust has kind of a tin sound now at around 2500-3000 rpm and I don't like it, but only when driving when I am stopped in neutral and rev it, it sounds awesome. I have flowmaster 40 series original flow mufflers. other than that for now it seems the problems I was having have stopped the engine seems to be staying a lot cooler now also.

08-23-2010, 03:42 PM
glad to hear you got things worked out.

08-23-2010, 06:24 PM
yea glad to hear you got it fixed. and i have borla xr-1 mufflers and an offroad x pipe and mine does the same thing between 2500-3000. but i love it. I think it sounds good.

08-24-2010, 06:06 PM
can anyone tell me how the imrc's work what makes them open? even though I no longer have the check engine light on and it seems to be much more smooth now it still doesn't quite feel right and there is a lot of lean popping in hard acceleration that I didn't hardly used to get before. will the imrc's not opening throw a code? I took them out and cleaned them they move freely but I still cant tell if they are opening like they are supposed to or not?

08-24-2010, 06:19 PM
they are supposed to open around 3200 rpm's, or somewhere close to that. I can't remember the exact #. They do it on their own. The carbon build up can make them stick open, or not open properly. I see a lot of guys do a imrc delete on their cars. I do not know if that will throw a code. Have you cleaned your MAF sensor lately? Do you run a K&N style filter, the ones that you oil? If so, the MAF sensor could be dirty. CRC makes a MAF sensor cleaner for that job, very easy to do.

09-12-2010, 08:37 PM
the problem that I thought was fixed came back so it seems the cats were not the cause. the check engine light came back saying the same lean bank one condition. I ran a compression test and this is what I came up with
cyl.#: psi.
1: 150
2: 130
3: 140
4: 150
5: 150
6: 155
7: 150
8: 150

then I put it back together and started pulling plugwires with the engine running and cyl. no. 1 was dead there is spark. I thought my injector that I just bought is bad so I started to pull the rail again and found one wire exposed and the connector seems damaged so I am going to buy a new injector harness and solder it in and see if that fixes my problem.