serious help need... search cant save me now

[91expy]

Hello people I have mostly been a lurker, and enjoying all the great threads to search and find information. My problem starts as this..... 91 EB 4x4 auto. The truck has a rough idle enough to cause the whole drivetrain to shake like there is a mild cam installed. It seems like a vacuum leak so I replaced most of the vacuum lines. I also changed the coil pack out due to secondary resistance failed. The problem contiunes..... I pull the plugs all the pass. side plugs smelled of raw fuel and had a film on them. My exhaust is hotter than normal and the cat will glow if i drive over a mile. The truck also has a total lack of power. I know Im getting spark and more than enough fuel. My thoughts are leaning towards stuck injectors, but could all 3 go out at once? I keep thinking the head gasket could have went due to all 3 cyl having issues, and if thats the case it could spell RIP for this rig. I did change the cooling system except the water pump 4 months ago. any thoughts.... thanks alot for your help guys.


BTW.... i tried getting codes using the MIL koeo came back 111, but the koer I cant figure it out, only code i got was 312 which i dont know how the AIR system is related.

 

[X6StringerX]

A glowing cat is most likely a clogged cat.

 

[Jd0gg919]

Wouldn't the cat being clogged cause it to glow/ run rough? But that would throw a code i think.

 

[Tbars4]

...I'm not sure if you read your KOEO correctly and did not wait long enough for stored codes...

...My first thought would be a plugged cat and a bad HO2 Sensor...:scratch:..You might have a FPR problem and a bad cat due to the rich fuel mixture...Try reading the KOEO again and wait a bit while doing the test to see if something pop's up...

 

[91expy]

on a side note the cat back exhaust was just done yesterday due to rust at the muffler. Im assuming the fuel rich mixture is burning in the cat and futher down the line due to excess fuel. I also thought that the FPR failing would dump fuel like crazy in all the cylinders. I pulled the vac hose off of the regulator and there is to sign of fuel leaking out of the FPR..... i should get a fuel pressure gauge tomorrow.

also when I do a koeo or even a koer how do i know when the test is complete and no more codes will be displayed. Im new to the OBD IV world.... when i do a koer i tap the brake after 3 blinks, and then wait for the single blink then blip the throttle to 3k then wait for codes..... am i doing something wrong

 

[Tbars4]

...Your catback exhaust doesn't mean you got a new cat...Did you in fact get new cats???

...For reading codes on a 91-94 X, this thread can answer your questions...Read all the post too...
http://www.explorerforum.com/forums/showthread.php?t=147734

 

[91expy]

still stock cats i just find it hard to believe that the cats could be the root of the problem.... BTW what should my fuel pressures be at key on and running. also will stuck injectors throw a code or could a noid light prove the injector to work or would that only prove what the ecm is telling the injectors to do?

 

[Lacky01]

start at the cats dude, seems to be like a definite problem

pull the cat off and see how it runs, and look in it to see if its clogged. eliminate this as a problem, don't dismiss it!

 

[Tbars4]

...When the cats go bad they clog the hole and in turn make the cat red hot...This results in no power and variable power...IIRC, your FPR should read between 40-60...Any higher and it's a problem...

...This thread should help in testing for fuel related problems..
http://www.explorerforum.com/forums/showthread.php?t=221335

...These might be worth a read while we wait for your new codes...

..For the cats read post #5 of this thread
http://www.explorerforum.com/forums/showthread.php?t=240407&highlight=injector
///This is fuel pressure 101...
http://www.explorerforum.com/forums/showthread.php?t=142801

 

[Maniak]

I 2nd fuel pressure. . What your describing is what we got a week or so after an engine rebuild.. What finally tipped me off was in smoke I was seeing at idle as it got rough. Our fuel puressure had jumped to 60+ when the FPR went bad.

~Mark

 

[91expy]

I'm at work right now.... So my plan of action is to unbolt the exhuast and look at the cat. I'm thinking I should just gut it to see if it makes a difference is so ill replace it with a new cat. I'm also going to pick up a fuel pres gauge and check oit the fpr. How hard is it to replace the reg... I see I need my metal fuel line tool any othe tips..... Thanks alot guys for being so fast to respond and giving me solid information..... The total goal is to get two more years out of this rig till my sister can buy a new truck. Does autozone etc carry the gauge?

 

[zukman]

I had a 89 F350 that lost power to the point she wouldn't move the cat was totally clogged pulled it off ran great rather loud but great so change the cat

 

[Joe Dirt]

If you have a laser temp gun, run it until the cat gets warm, and gun the pipe at the front and also the rear of the cat...

 

[410Fortune]

check the fuel pressure BEFORE you look inside your cat converter.

However I have had a clogged cat before on my BII< you want to talk about loss of power? The 4.0L would fall flat on its face, poor idle, and glowing red.

On my truck I went 4x4ing and apparently slammed the cat pretty hard, the interior catalyst had come loose in chunks and was getting pushed back inside the cat clogging the exhaust.... it was very difficult to diagnose, the truck would idle smooth, run for a few miles, then FLAT ON ITS FACE

Your dumping raw fuel most likely, this is what kills a cat converter... so check the fuel pressure first.....

 

[nitro71]

CAT's are spendy, $190+. I wouldn't just gut it.. I'd slowly and methodicaly troubleshoot this as best you can. I like the remove it and try it idea. you can probably blow some air through it with a air compressor and see if it seems plugged?

You said one bank was rich and the other wasn't? I'd swap out the O2 sensor on that side. Is there any other sensor that affects just one side?

 

[91expy]

So far 42 psi all day on the rail I took off the pipe after the cat and the cat itself looks imaculate on the inside hard to beilve its cloged every hole looks clear any thoughts

 

[91expy]

Just did a vacuum test I'm pulling 9 inches at idle and 14 at 2k rpm.... I know that can't ber right well I'm out of daylight time to try again tomorrow

 

[CDW6212R]

The vacuum is very low, and the fuel pressure is too high. Check the pressure at idle with the FPR vacuum line attached, and off. You should see something around 32-35psi normally, and maybe 40psi with the FPR disconnected. If it's near those specs, then it's likely not the FPR.

With the low vacuum it sounds more like a leak of air into the intake. A small hose off shouldn't do that, but check it all again. look carefully at the vacuum "T" on the back of the intake, there should be one or two steel nipples which have rubber caps on them. Make sure none of the ends are not open.

How many miles are on the truck, does it show any signs of oil leaking around the top, intake or valve covers?

 

[Tbars4]

...Yes, I was a little tired last night but want to make my previous post clear...The FPR should read below 40 on the first gen and above 60 on a second gen IIRC...

...I second that the reading of 42 is a little high but did you also keep the tester on and watch the pressure after you turned the vehicle off, as stated in the thread I had posted???

...I do notice you keep saying "The" cat....You should have 2 cats to look at on your X...

 

[CDW6212R]

From 1999 on the fuel pressure should run 55-62psi at any time.