I have a 1994 F150 4.9. I have the silly preheater/cat assembly with a single HEGO sensor. I am wondering how to tell if the Cats are plugged without removing the exhaust, as most of the components will need to be replaced if I do, and it just isn't in the budget right now?

 

I'm sorry . . . this has nothing to do with this thread, i havent even read it yet but when i saw the title i was like "WHAT? what kind of testing do you need to do on cats? I hope he isn't hurting them . . I'm allergic and don't really like them but still, its not nice to see people hurting cats for fun."


hahahahahahahahaha sorry man i couldnt resist posting that. lol ok ok, now i'll read lol

*hold music*
("You comment is very important to us, please remain on the line while we review what the heck it is you are really talking about. A post will be with you in aproximately . . . 1 min-ute . . . ")


Ok well after reading i see we have the same exact truck/year etc. . . im not too experienced with this so i will just have to wait along with you and see what is said by the more experienced as i am now curious about this as well. a backyard mechanic's suggestion: just yank it all off and run the pipes out the side and paint some nascar logos on er!!! get'r done! lol. it would definitely clear up an clog if it had it.

what symptoms are you having that you think you have "clogagge"?

 

you use a vacuum gauge to check exhaust.

 

man you guys have no sense of humor whatsoever around here huh?

 

can anyone give this guy some real help? not just say something like "you use a key to unlock the door" . . where's the eyeroll smiley around here?

 

felixr, what are you talking about?

i gave an answer as to how to check exhaust.

that was real help.

 

sorry its just that it seems that most of your posts are one liners. what if he uses a certain brand that explodes when you use it on 300's for instance and you knew that and didnt tell him. . . see what i mean? it just seems that a one line answer, although it answers the question, is missing that extra mile type of help that we come to forums for. sorry if it was offensive. im not looking to make waves nor am i in the mood for an internet fight lol

 

everyone has thier own style of posting.

i did not think you were being offensive.

 

good to hear you have tough skin and realize that people can be stupid if they happen to be in a stupid or bad mood. 'ppreciate it

 

HEY! two lines that time! NICE! lol jfwy

 

OK. how do you use the vacuum guage to test a cat? what am I looking for on the guage?

The reason I am suspecting my cats is my truck is getting more and more gutless by the week, and although my timing is off, it's not enough to be causing this. Also, they are original and I have 270K km on the truck. I will be replacing the fuel filter this week to see if that has anything to do with it, but it seems to me, there has been a lot of exhaust pushed through those things, and it could very well have been bad exhaust at some point in time. I wanna make sure it isn't cats before I go off and test injectors and that stuff

thanks,
Dave

 

you warm up truck, than shut off, hook up gauge, start and let truck idle, the gauge should stay steady near average than drop slowly down to very low.

gauge will have instructions or most manuals have a write up on how to use them.

 

This will help you with your gauge analysis........

https://www.ford-trucks.com/lc/lc.ph...off%2Fvac1.htm


Cut and paste if you can't click....

 

Ooops,

I clicked on the link myself and didn't see anything about exhausts....sorry.

 

For exhaust restriction analysis, use a vacuum gauge. On the 4.9, if you look to the left of where if says "electron fuel injection"(written sideways) you'll see a cluster of hoses running off, one of the nozzles will just be plugged with a rubber stopper. Remove that rubber stopper and place the vacuum gauge of it. Have a friend rev the engine up to 2500, allow the gauage to settle for a second or too, then make sure the reader stays fairly constant. If it changes more than just trivial amounts, your exhaust system is most likely restrictive.

There, more than a one liner for you, hah