Replacing Cats

[tommy33]

Well, after changing all of the temp sensors, fuel filter, plugs, wires etc. and with the hesitation and hard starting (after the engine warms up) getting worse, it seems that either one or both of the CATs are bad. I read up on the symptoms and my 97 SE7 with 104k miles is a poster child for replacing the CATS.

Joey, is this something I should leave to the muffler shop? Should I buy the CATS and have the shop do the labor?

What do you think?

Thanks,

 

[joey]

Depends if they are actually bad first, and second if the shop will allow you to bring parts in and have them do the work.

First thing I would do is check fuel pressure... then the battery... after that it may be the cats... most shops can test them for free.

 

[99d2]

take it to a muffler shop (Midas is pretty good) and ask them to test the cats. They can tell you if they are both bad, only one bad, or not bad at all....it could save you $$$.

 

[tommy33]

Midas will test for free and replace each side with a universal CAT for $200-$250 each side.

Since I don't have to order CATs and pay shipping I did not think this was too bad a price?

Thoughts?

 

[tommy33]

CATS NOT BAD! Now What??

1997 Disco
104k miles
Runs rough, will miss and sputter after it warms up. Problems going through the 20-30 mph range. After that runs ok.

If you shut it off after it warms up it is very VERY hard to re-start. have to wait 15-20 minutes. Then it will run terribly, miss and chug from 0 mph to 20-30 mph.

When it is cold it runs beautifully.

Changed fuel filter, fuel temp sensor, vehicle temp sensor, VSS.
Changed plugs and wires in the past 6 months.
Seafoamed the heck out of the intake twice in the past month.

Took to Midas. Checked CATS and they are not restricted. Honest guy. No charge. Told me he thought it was a fuel problem.

What's next? Fuel pressure regulator?

Thanks for any and all suggestions.

 

[joey]

Depends on the fuel pressure at the rail. Check the pressure.

 

[tommy33]

Joey, how do you check the pressure?

Thanks,

 

[joey]

You will need a fuel pressure gauge or ouch... take to a shop that will check it for you. For the price of taking it to the shop you can buy a very nice gauge... I bought a cheap $15 dollar one and it work pretty good.

There is a shredder valve on the passenger side of the fuel rail... attach the fuel pressure gauge to the valve.. turn on the key. Read gauge. If it is sealed correctly it should not leak down for a while. Time the leak down. This will assist in finding a bad injector or fuel pump or regulator...

 

[tommy33]

Thanks Joey:

I'll go buy the guage.

What are the possibilities here? Injectors? Fuel Pressure Regulator? Fuel Pump?

Probably any and all.

Thanks again,

 

[joey]

yep... I am guessing the fuel filter or pump... these are the normal items to go... the injectors are next on the list... regulator not too often.