Replacing Catalytic converters

[duckdog27]

Finally found out the long time problem with my 94xlt. The car had been stalling and had no accelaration when hot/warm. Today I started the car and it stalled after about three seconds. I unhooked the EGR tube that runs from the exhaust manifold to the EGR valve and started it up and it ran fine (except for the obvious sputtering from the unhooked pipe). I need to know if it is possible for me to replace the catalytic converters myself. Is it difficult and do I need any special tools? I need this fixed asap to be able to travel outside of town. Thanks.

 

[Glacier991]

Your problem is not a catalytic converter, it is a faulty EGR solenoid in all liklihood. Stay focused on the problem system...EGR... which has nothing to do with the CAT.

 

[duckdog27]

I have replaced the EGR sensor and EGR valve but the problem still persists.

 

[Moyer]

I had a 92 once that I thought it was the cat but after changing the the whole exhaust system found that it was really bad plugs. The point is start with the easy stuff first because it was a Bit$$ to change out the exhaust he is probally right it is something to do with the EGR or mass air flow sensor. Here is what you can do to test your cat give it a few hits with a hammer and start the truck if it is pluged you might be able to loosen the carb up enough to blow it out the exhaust but on a 94 I dont see it being a bad cat depending on how it has been driven and the gas you are using.

 

[duckdog27]

Here are the symptoms and my attempts to fix it. The truck runs fine cold (say within the first 10 minutes of driving). If I shut it off while the engine is warm/hot for over a minute and start it back up the truck shutters and most of the time I experience no acceleration even when I push the gas pedal all the way to the floor (while in park). If I drive for extended periods of time I do not turn off the truck but if it idles when it is hot for over five minutes I get the same symptoms; shuttering, hesitation, no acceleration. Recently the truck has been shuttering when accelerating uphill, actually like it is jerking (the same feeling when you are in a boat while pulling a skier). If I press on the accelerator the jerking stops. It is just a pain. I have installed new spark plugs, new spark plug wires, fuel pressure regulator, cleaned the MAS, new EGR valve, new EGR sensor, new coolant temp sensor, and a new temp sending unit. When I attempted to remove the EGR valve awhile back I broke the pipe leading from the EGR valve to the exhaust manifold. I did not experience any of these symptoms while it was broken. After installing a new EGR valve, EGR sensor, and new pipe the truck ran great for about four days and then the symptoms returned. I believe I have narrowed it down to an exhaust problem. Could the sensor be bad?!!? This only occurs when it is hot.

 

[Glacier991]

Are you getting any codes from this? A Check Engine Light?

 

[duckdog27]

Yes, the CEL remains on pretty much the entire time the engine is hot. I have not pulled any codes yet but hope to do soon.

 

[boominXplorer]

does the cat glow red?

 

[DeRocha]

If the CAT was plugged you would have poor problems all the time (hot and cold). Because you indicate you have no problem when the engine is cold you have eliminated the CAT as the source of your problem.

 

[duckdog27]

Just went out to start the engine and it started up fine but it now stalls after a few moments. The CEL is on all the time. I went under the truck and the exhaust pipe before the catalytic converters is hot and the pipe after them is cool. What could the problem be now!??!

 

[Billy177]

just unbolt them and try it then you will know for sure

 

[liqhx2]

i would get the cel codes then check fuel pressure get the CEL codes and post em up here we will be able to help you better narrow it down

 

[duckdog27]

I will get those CEL codes as soon as possible. Drove the truck a bit around and CEL remains lit the whole time and if I press the accelerator all the way down there is absolutely NO power. If I lightly press the pedal the car will accelerate. When I slow down and try to accelerate the truck will hesitate a moment and then respond. What is the problem if it is not the catalytic converters?

 

[liqhx2]

it sounds like your not getting enough fuel that's why i would get a fuel pressure gauge and that will tell you what your fuel pressure is it should read between 30-40 PSI if it is above or below that then you have a problem with the fuel supply

 

[BuffaloXplorer]

I've got a similar problem - no acceleration, occasional shuddering, CEL (code 402 - EGR Flow Excessive(?)), but i KNOW my muffler is bad and likely plugged, causing the lack fo accel. (Hopefully) Having Flowmaster installed this weekend - we'll see how it changes things. I've read on here that if you suck on the egr vacuum tube and the truck responds by boggind down, then it's fine, if not there's a problem...you guys agree?

 

[4544x4]

yes

 

[duckdog27]

I took my truck to a ford stealership and they found that the problem was the fuel modulator/sender (I believe the same thing?) was burning itself out when it got hot. They also found that I needed a new gas tank and since NO ONE makes aftermarket gas tanks for explorer's I had to dish out almost 500 on a new tank! Absolutely ridiculous if you ask me. Problem is fixed though...for the time being.

 

[DeRocha]

Exactly why did you "need" a new gas tank?

 

[Nick26]

you could have just gone to autozone and got the codes scanned for free instead... couldn't he have? or is there problem with doing those years because of ODB1 or something?

 

[duckdog27]

I did go to autozone once and their incompetence made me feel insecure with them dealing with my car. I needed a new tank because the upper half of the tank was rusted out pretty bad when I saw it. It is a ten year old aluminum tank. It was nearly rusted through where the fuel pump assembly attaches to the tank.