CCobraW

I put in a new fuel filter in my 96 Cobra last week and I've noticed it takes 4-5 second for the car to start in the morning now. What the heck could cause that??

Also on my way home today I got a check engine light, code P0420. Which appears to be a bad cat or 02 sensor. I had a BBK catted X installed 300-400 miles ago, along with some BBK LT Headers. So I don't think the cats are bad. I tried to get a look at the 02 sensors, I only saw the 2 on collectors of the headers. Isn't there supposed to be 2 pairs of 02 sensors??

What are the odds the 2 are related or is it probably just coincidence these both started around the same time??

Bman2000

couple things, this may sound dumb but did you install the fuel filter the right direction? on to the other stuff. There should be 4 02 sensors if your getting that code, 2 right after the manifold, in your case, probably in the lt headers. and 2 right after the cats. So heres where things get interesting. Extended crank and possible power loss could be a cat issue, either plugged or broken reducing exhaust flow, but since they are new i kind of find that unlikly but not impossible. Have you hit anything recently? lik a speed bump that might have whacked one of the cats? Outside of that, i dont see the 2 being related, because typically if you have a bad post cat sensor its just that a bad sensor, it wont affect the way the car runs unless the cat itself is bad. The only other thing i can think of is did you run the tank dry? maybe you plugged that brand new fuel filter? This is also assuming that it didnt take 4-5 seconds to start before you changed the filter...haha

CCobraW

I'm pretty sure I got the fuel filter back in the correct way, I reinstalled it the same way I took it out. the old one didn't have anything markings so probably a cheap one the previous owner had put on, but I did put the new one in the same orientation.

It was installed where the fuel flow arrow was pointing to the passenger side is that the correct direction??

Bman2000

honestly i cant remember. im pretty sure you want flow arrow pointing to the line that goes to the motor not the tank.

CCobraW

I got up under there and the filter is in the correct way. I tried turning the key to the On position and letting it sit there for a minute to prime the fuel pump, but that didn't help any. I haven't run the tank dry, I tried to fill back up at a 1/4 tank usually.

I got another code the 0430 which is the other bank, I haven't bottomed out on anything and I went under and tapped the cats and didn't hear anything rattling around in there.

uberstang1

There are 4 02 sensors on the car, two pre cats, two post cats. The post cat sensors (bank 1 sensor 2 and bank 2 sensor 2) just ensure the cats are working properly, they in no way can effect and engine managment controls. If you replace a rear 02 sensor and the code comes back then there is an issue with the cat. A clogged cat can make a car hard to start.

wrihar

I had the same problem on my 2000 mustang 3.8. I did the usual things like change the plugs and fuel filter but that did not help. It always cranked for 5 to 8 seconds before starting after it had been sitting a while.
The problem excessive cranking, long cranking or hard starting turned out to be a leak in the hose going from the fuel pump to the fuel tank flange (in the tank). This is a special flex hose that had a pin hole in it. It allowed the pressure to bleed down after a few minutes. You need to drop the tank and remove the flange on the top of the tank to get access to it. I simply replaced the hose with a high quality fuel injector rubber hose and 2 worm screw clamps.
To verify this is the problem put a fuel pressure gauge on the Schrader valve (tire valve stem type of valve) on the fuel rail. (front left corner of the engine on a 3.8 Liter engine). The pressure should be about 30 psi and 40 when just turn the key on. Newer engines do not have this Schrader valve and you will need to put an adapter in the line somewhere by opening one of the spring clamp fittings... maybe at the fuel filter or on the engine somewhere so you can measure the pressure. You need a special tool to release the spring clamp fittings available at most auto parts stores for a few bucks. I suggest undoing the output line of the fuel filter and slide your pressure gauge onto the fuel filter outlet and then turn the key on to test the pressure. It should remain at 30 psi after you turn the key off.
If you have a problem you will note the pressure will bleed down after you turn the key off.
If it bleeds down it could only be 3 things. A leaky injector, a bad check valve in the fuel pump or a leak in the hose ... which was my problem. The pressure should be maintained for a long time (in the order of days) after turning the key off.
As a work around to keep from cranking so long and killing your starter and battery you can cycle the key on and off a few times to charge the rail before starting. This will give you time to prepare.... and get the tank empty so you can drop the tank easily.
If you need to replace the fuel pump Napa sells the fuel pump by itself for $152. Most other auto parts do not stock it.
Good Luck.

ctgreddy

the arrow should be pointing torwards the drivers side. the fuel line comes out the tank on the passenger side, goes to the filter, then connects on a line on the drivers side that runs up over the axle and then goes back to the passenger side and goes up, confusing i know, but the arrow must be pointing torwards the drivers side.