Ford Truck Enthusiasts Forums

Ford Truck Enthusiasts Forums (https://www.ford-trucks.com/forums/index.php)
-   1987 - 1996 F150 & Larger F-Series Trucks (https://www.ford-trucks.com/forums/forum28/)
-   -   Signs of a bad catalytic converter (https://www.ford-trucks.com/forums/1010067-signs-of-a-bad-catalytic-converter.html)

teamshadyinc 11-13-2010 02:30 PM

Signs of a bad catalytic converter
 
I had my transmission looked at today and everything thing checked out, so is it possible that my cats are bad, I am experiencing horrible gas mileage as well as hesitation while driving and plus when I let out of the gas it feels like it falls on its face. I have done endless amounts of troubleshooting, did a complete tune up, with no change in performance. So I was thinking it might be the cats are clogged.

danr1 11-13-2010 03:55 PM

Use a vac gauge, see example 14 in the link bellow.

How to Use and Interpret a Vacuum Gauge

teamshadyinc 11-13-2010 04:17 PM

Ok Im lost what?

Jigger2020 11-13-2010 04:28 PM

do you smell any thing burning ? maybe a brake caliper siezed up or a plugged cat smells like rotten eggs.Gigger

danr1 11-13-2010 04:31 PM


Originally Posted by teamshadyinc (Post 9554739)
Ok Im lost what?

Test it with a vacuum gauge, cheap enough to buy one if you don't have one.

Connect it to a vacuum port directly to the intake, see what it tells ya.
If it reads the same as scenario 14 in the link, you very likely have a clogged cat.

teamshadyinc 11-13-2010 06:13 PM

Well I got a vacuum gauge and it all checked good. I had about 21-22in Hg at idle and when I increased engine rpm it slightly decreased but stabilized at 21in Hg and if I rapidly let off the throttle the vacuum increased to about 25-26in Hg and then stabilized at 21-22in HG. So according to all those scenarios it all check out and I don't have any of those issues listed. Thank God, now I just need to look else where, I am still thinking its my transmission or TC since the TC is clicking at idle! I just wish I had that vacuum information along time ago it would have saved so many headaches in troubleshooting!

danr1 11-13-2010 06:29 PM

I am still thinking its my transmission or TC since the TC is clicking at idle

Remove the inspection pan, verify the flex plate isn't cracked/broke around the bolts at the crank shaft, make sure all the TC nuts are tight. Also check the bell housing bolts, make sure they are tight with no gap between it and block.

Even at that it might explain the clicking you hear, but none of that would cause hesitation/failing on its face.

I have done endless amounts of troubleshooting

What exactly?

Mass air or SD?

Could be as simple as a dirty MAF sensor or a EGR valve hung partially open just to throw out a couple quick examples, post what you've done so everyone has as much info as possible to work with.

How about "self test", have you checked for trouble codes? Light doesn't have to be on to have them stored.

If at any point you disconnected the battery, any it might have had stored would have been lost.

If you're not aware how see > Ford Fuel Injection » How To Run a Self-Test

teamshadyinc 11-13-2010 07:30 PM

Well here you go these to links should catch you up!
https://www.ford-trucks.com/forums/1...ight-lope.html
and I kind of high jacked this thread but my info is in there.
https://www.ford-trucks.com/forums/9...f-a-cliff.html
Also I have checked for cracks and security of the flywheel, the clicking didn't start till after I changed the fluid in the TC and pan along with a new filter.

danr1 11-13-2010 08:56 PM

Didn't notice you had more then one thread going, both the links you posted are to the same thread.

Anyway how about the ACT and ECT sensors and O2 sensors, how old are they? original to truck? If you listed any of them as being replace sorry I missed it.

To an extent the symptoms you describe tends to suggest a rich condition, what do the plugs look like after run a few miles? Looking at the plugs will tell you a lot about the conditions in the combustion chambers.

Ruff idle, horrible gas mileage hesitation that goes away under heavy and or full throttle conditions suggest rich condition, all the fuel its getting is consumed under that condition, at idle/part throttle to much loading it up.

The fuel injector you blew compressed air through, did you apply constant power to hold it open it or rapid, fast as you can on/off/on/off/on/off power to it. If you applied constant power holding it open you likely damaged the injector, it could be constantly dribbling fuel as a result.

ACT could be reading wrong as well as ECT telling the computer its running "cooler" then it really is, couple that with an ole dirty carboned up 02 sensor making a bad condition worse. None of them bad enough to trigger a CM code.

Of course some test can be done to see if sensors are within acceptable range.

How about fuel pressure test results including the static pressure leakage check results?

frankyford 11-13-2010 09:08 PM

Check your timing, if the mark on the balancer is not visible, your balancer has slipped causing timing scatter and you will have to get a new one. Happened to mine and a new balancer cured my problem. Mine was also running rich or lean which ever way you want to call it.

teamshadyinc 11-13-2010 09:33 PM

For the fuel the injector I did apply power on/off. Also the plugs only have about 500miles on them and they look brand new. The O2 sensor looked good but I swapped it with a known good one and still no change. As for the ACT it checks good in resistance and voltage, as for the ECT which I also had a spare and again no change. The truck definitely doesnt smell like it's running rich. The trans shop said they pulled an EGR code but not sure which one it was so they cleared it and I will check it in a few days, however I think the code was due to troubleshooting because I did the penny trick as refered in the previous thread and it never changed the performance, however at the solenoid for the EGR there seems to have a slight vacuum and according to the manual there is not supposed to be vacuum at idle. Also when I turn the engine off the valve purges, is that normal. I will put a vacuum gauge and pump on it tomorrow. As for the fuel pressure I haven't done a static but I checked it with the motor running and off and it was in specs. And about the two threads thing, I kind of took over someones thread and I seemed to get different solutions from both!

The above links were fixed, but he is the other one I hi jacked. https://www.ford-trucks.com/forums/9...f-a-cliff.html
Also the timing has been check as well.

danr1 11-13-2010 10:07 PM

Also the plugs only have about 500miles on them and they look brand new.

What do you mean "look brand new", did you pull a couple out and look at the business end after it had ran a few miles? What the electrode and insulator look like on em?

As for the ACT it checks good in resistance and voltage

Safe to assume you tested it cold as well as when up to running temp, resistance value changed following spec's?

The truck definitely doesnt smell like it's running rich

Might not smell it, if the cat is burning it off enough to mask a heavy fuel odor. Inside tail pipe, coated kinda soot black or just black or a dark deep tan color?

The trans shop said the pulled an EGR code but not sure which one it was so they cleared it and I will check it in a few days, however I think the code was due to troubleshooting because I did the penny trick as refered in the previous thread

Penny test wouldn't have triggered a code, system doesn't monitor egr flow, EVP still functions provided you left it otherwise intact, only inserting the penny in the tube.

Yea gonna get different solutions from different posters, not necessary a bad thing. Harder to trouble shoot via long distance, not getting the hands on experience. Listen, drive, see first hand, well you know.

teamshadyinc 11-13-2010 10:42 PM

The plugs look really good, the electrodes looked very clean, insulators are still white and I pulled all of them and they all looked the same. Also the tail pipe is black, you can still make out the tan part of the pipe. Also I just installed the penny, I never disconnected any connectors except for troubleshooting wires. As for the ACT I checked it at about 65 degrees and warmed it up and the resistance went down. The only thing I saw that might be whacked is the book say the voltage is supposed to 5v at the act and it was 4.89v. I will run the truck to operating temp and recheck the resistance. I am thinking of eliminating my EGR sys but not sure what problems that would cause. Also the would the Thermactor system cause any of the issues I have? The only thing that seems bug me about that is there seems to be a whistling noise coming from black canister that has to hose connected to the AIR pump(its fwd of the coffee can)

teamshadyinc 11-15-2010 11:07 PM

Well took the truck to another trans shop today and everything seem to check out some what! The trans shop was able to run a KOEO test and got code 334 also I was told that the clicking from my trans was the EPC solenoid. He told me to fix that I was looking at about $300! I found the solenoid for $30, and for $50 bucks more I get the improved TCC solenoid and Shift Solenoid. So I will be looking into that. What gets me is the clicking didn't start till after I changed my fluid and the noise is coming from my TC not my pan! Well back to this code 334, its something to do with the EGR but I can seem to find any solutions what the heck does that mean for me! I was think of getting rid of my egr system! Anyone got any solutions for code 334. Also like I didn't all ready know this but he said my truck is missing/idling bad! I wonder if he knows thats what I am trying to figure out!

frankyford 11-16-2010 05:08 AM

Not trying to sound like an idiot, but please check your timing. Mine did almost the same thing and it was the harmonic balancer had slipped. A code 334 is for the DPFE sensor or EVP colenoid circuit closed ot the limit of 0.67. Your EVP soleniod sits on top of your EGR. I don't think that is your problem, mine was throwing codes like that too and it ended up being timing scatter. If anything just rule it out, if I'm wrong I'm sorry. With the timing off you will get codes that you shouldn't under normal circumstances, because the computers reading what the engine is telling it and vice/versa.


All times are GMT -5. The time now is 11:11 PM.


© 2024 MH Sub I, LLC dba Internet Brands