We have a 1999 F150. Truck was running fine Thursday evening got 20 bucks in gas went and parked it. Started to my brothers house in Malden lost power. Codes said it was the cats. Cut holes in exhaust before cats mad no difference no codes are showing up at all. What is wrong still in shop mechaninc cant find nothing wrong. Only means of transportation. Just got back from mechanic. Tried hooking up scanner to truck again. Keeps shutting down.. Desperate for help.

 

Allen, don't go about trying to repair like that please.
What were the codes? Did you interpet them correctly?
Where are the codes now? They should have come back if the fault is a hard fault.
What is the state of the engine now? Any new codes etc.
We need some concrete info to even begin seeing what the issue is.
Good luck.

 

Bad gas fill?--- Water in fuel? Somebody put diesel in by mistake?

 

There are no codes showing up at this time. Idols great. Really loud though from cutting exhaust due to cats. The only codes was showing the cats was bad. But still no power under load. Been getting gas from same place for years.

 

Allen, again what was the codes?
You mention codes then you said no codes. How is that?
The rear OX sensors usually will throw a code with holes ahead of the cats, at some point in time if the cats are good but will still throw a code if the cats are no longer working within limits, either way.
Cats that are no longer working within limits is different than plugged cats but will cause the same code numbers because the PCM cannot tell ,one issue from the other.
The front sensors are at the manifold outlets and may not be affected by your holes down stream of them.
You have nothing to go on yet.
Time to get a scanner on the DTC port and look at the live operating parameters or you need a lot of luck.

 

I dont know what the codes were. The mechanic is the ones that told us that it was the codes for bad cats. We took it to another place this morning. Hopefully to know more by tomorrow. But just as soon as the exhust man cut the holes into the exhust the light went off. There are no service engine light on as of right now.You can hear the cats rattle when u hit them.

 

Well I can tell with absolute certainty that CEL and codes don't go away by cutting holes in pipes.
That guy should be 'hung' for such an action if I understand what you said, correctly.
No wonder you don't know what's going on.
He apparently did not know what the code actually meant as well and cleared them with a reader/scanner and not tell you, trying to get the job.
Cutting holes is absolute damage unless he was going to replace them with your permission.
Now you have to replace both cats 'assemblies at great cost, in any event.
Your looking at at least $600 +/- for aftermarket cats plus labor. You do not replace individual cat units unless a good muffler shop is used that can cut out and reweld a good job. Your pipes are now runioned.
FYI, both cats plugged at the (same time) is dam near an impossibility unless the engine had cylinders out on both banks, passed raw gas that burned in the cats and you ran it long enough..
Any of this sound familar?
The last time I saw this happen, the PCM failed on several cylinders, several coils faulty, lost cats on one side and cost a big pile of money.

Here is what you need to do now.
Replace both cat assemblies AND make sure there are no missfires on the engine.
If there are missfires and you run the truck you risk burning the new cats out.
And I am still not sure of all the issues you might have.
Alway give the correct info here if you want to get the most accurate replies and possible help.
I sensed all the info was not being presented previously..

Good luck

 

I found both sides direct fit cats for right at 600.00 with free shipping. I didnt want to order them on until I got the power back to the truck. I did take it to another shop yesterday. The exhaust man did say that where he cut the hole into the pipes he could repair. U can hear the cats rattle when u hit them. I had been hearing this little rattle for a few months. The exhaust man said that they had been going out for a while. And I know how the warranty is on the new ones. Maybe the old truck is about dead. Just find that hard to believe though. Always ran great. Still starts and idols great.

 

Ok Allen.
It was difficult getting to this point.
The cats likely are melted from overheating and blocking good flow. That will kill power.
Look at the rear cat position on the new units.
The OX sensors must be positioned at an angle like the originals to prevent interference with the floor of the cab.
The shields may even have to be clearenced if the cat has a different for/aft position and are smaller/shorter than the originals.
The OEM cats uses strap clamps that are spot welded to the original pipes.
Try to re-use them where possible by using new bolts.
You can't buy them from Ford last time I looked because they are not listed as a seperate part number, that I had found.
If you look closely at how the pipes are made on the ends, they are made to both go togather quickly on the assembly line and provide a superior seal so watch that part of it on assembly.
Last comment about the size of the rear cats vs OEM is the OEM is oversized to ensure long life barring a failure from outside cause.
The smaller replacement will work fine as they won't be called on to last as long as the original before the truck is beyond normal life expectancy and your ownership/use.
Replace all 4 OX sensors.

Good luck with the job.

 

Trying to just get it running before I replace the cats. Mechanic called me yesterday. He put on new plug wires, fuel filter couldnt blow through it. Was only carrying 35lbs fuel pressure. Also replaced fuel pump. Started ran great for 10 minutes. Died and it hasent hit again. Gonna bring it home Monday. Could the problem b in the PCM

 

Your at a point that it needs to be looked at with a scanner full time to see what happens when it dies.
The scanner should trap the conditions at time of failure and offer a lead as to what the failure involved.
It's hard to help much more from afar behind a key board.
I did this for 30+ years from drawings and telephone, helping techs who had the same info to look at, out of a jam with other types of very large systems, so that is what I try to do here as the only way I might be of assistance.
Only difference here is the owners usually are not techs so I have to steer them in the most basic ways by suggestion and example. Sometime it works sometime not.
The help depends very greatly on accurate discription and honest feedback otherwise it's the old saying 'garbage in garbage out' result.
Good luck to you.

 

Im just going to go and get it. Not going to let them put anymore time in it. I do know what it cant be now. Just gonna go from there by myself.

 

It wont even start now. Had it towed to my house this AM. U can smell gas what u try to start it. The guy says that it he got it narrowed down to the cylinder head temp sensor ot the ECM. It really tried to start. Where is the cylinder head temp sencor located at on this 99 F150 4.2 V6

 

The cylinder head temp sensor won't be a cause of not starting or at least 'firing' on cold start.
What you need now is to understand the start sequence of events and look at each area for malfunction.
Overview:
Key to 'run' starts the fuel pump running for about 1 second +/- to begin fuel rail pressure. At this point the head temp sensor and the intake air temp sensor tells the PCM what the relitive ambient temp is for fuel richness, ignition timeing advance and what to do with the IAC opening point.
.
Advance to the the start/cranking position;
As the crank begins to rotate the crank sensor returns a rotation signal to the PCM that re-starts the fuel pump full time and brings the rail pressure up against the regulator setting.
At the same time begins the reference timing for ignition and fuel injection timing off the cam position sensor.
Once all this info and other data are registered the engine fires {as long as the PATS has set the start bit in the ID word in program}.
There are a lot of other things going on at the same time.
So you see the progression that goes on.
It help to know what happens and at what points to look into.
.
1. is the crank sensor plug on tight?
2. is fuel pressure being developed?
3. is there ignition?
4. are the injectors fireing?
Locate what is not happening first then look for the cause.
5.other problems can be the PCM relay or a fuse issue powering these circuits.
6. in extreme cases the PCM could be faulty but you would need to look at signal grounds from the PCM to see any faults.
The coils and injectors are all powered from single fuses such that all are 'signal' grounded in a fire order sequence 'from' the PCM.
7. is the engine being flooded and fouling the plugs?
8. is there no fuel thru the injectors?
9. is the PATS system allowing a start to occurr?
10. is the trans neutral switch circuit open for the Park or N position?
11. any harness or plugup problems?
Like a doctor you need to know what's in the body and how it works in order to have a chance beyond luck to correct the ills.
Good luck with it.

 

Everything has been checked according to the mechanic. Only thing he was saying it could b was that temp head censor or the ECM. It does try to start then floods out. Thats why he is thinking it may b the ECM. Its getting way to much fuel. This truck is actually my sisters. But its at my house now. I really don't know that much about them myself. I just know what this mechanic is saying that had it at his shop. He is very well liked here an town and is always busy. Really nice man.