Once again...plugged cats? Maybe?

[Spitfire1975]

86 2.9 that is acting like it has a plugged catalytic converter. I have also been trying to fix a "miss" or "stutter" for the last year.

What it is doing:

a) "miss" at 2600 RPM under load.
b) slow and no power in the low rpm's, also no hill climbing power. Feels like it is surging a little as well when accelerating.
c) when first started (warm) will "hunt' for idle (~600-1000 before settling at 850-900)
d) when first started cold RPM's go to about 1500
e) Will stall out (sometimes) when A/C is on.
f) Engine temperature is a little hotter then normal (based on the gauge, not a thermometer)

What has been done to it:

NEW:
Distributor Pick-up sensor
Ignition Control Module
EGR system (all of it)
Radiator, water pump, heater core, thermostat, gauge sender
Ignition switch
Battery
Starter relay/switch
Coolant Temperature sensor
Coil
Cap, rotor, wires, plugs
Valve Cover, Intake Manifold, Throttle Body gaskets
Fuel Injector O-Rings
High Pressure Fuel Pump
Fuel Filter (several times)
Brakes, rotors and bearings
Muffler and tailpipe
Rear Driveshaft
Throttle Position sensor
shocks, sway bar bushings, tie rod ends and drag link

USED:
Charcoal Cannister
Knock Sensor
Air Temperature Sensor
Idle Air Control Valve (and cleaned it real well)
FPR looks new, but I didn't do it.
Catalytic Converter (couldn't see light through it but figure it was because of the dual cat setup)
Transmission (switched from TK5 to FM145)
Hard EGR vacuum lines
MAP Sensor

TESTS:
a) Fuel pressure at idle is about 30-31 lbs
b) Vacuum readings look normal, actually increase a couple of lbs when increasing RPM's? 21 at idle, drop to ~4 on quick accel., increase to 25 under quick decel. and settle back to 21. Run it steady at ~2500 RPM's and it sits at 23-24
c) Compression is about 150 each cylinder
d) NO CODES ARE BEING SHOWN (at the same time I cannot get a stored memory code when running the KOER test, but can when running the KOEO test)
d) all grounds seem to be good. I do not have a grounding strap connecting the hood to the engine compartment. Everything else seems to be in good condition.
e) I have seafoamed the engine, gas and oil (I run conventional 5W30)
f) mileage is about 16 city and 20 freeway on 235 75 15's with a 3.73 ratio.
g) Timing, with SPOUT removed, is set at 10*

I can't think of anything else.

Did I put in a bad Catalytic Converter?? The vacuum readings seem to say no, but the performance seems to say yes.

PLEASE, Ford mechanic guys........what the heck else can I do??????? Sell it?

 

[Spitfire1975]

Bueller??









Bueller??

 

[Ranger Sport Honduras]

a banana is stuck in your cat

 

[Spitfire1975]

Dude. Get your nanners outa my cat.


I drove it to the coast today and all I can say is, No Bueno. It's gotta get fixed.

 

[bronco_lou]

what is your fuel pressure with the vac line pulled from the regulator?

Louis

 

[Spitfire1975]

good question. I don't know.

Will check it here in a few minutes.

EDIT: It goes up to about 40-41 lbs. This is a harbor freight fuel pressure tester so I don't trust the numbers to be 100% accurate, but the pattern for what the FPR is doing seems to be correct.

 

[Psychopete]

That's tough, if you have good spark and compression, that makes me think maybe a fuel delivery problem if the miss is consistent. Seems like you've replaced everything under the sun, but might be worth while to do another vacuum test and particularly look for signs of valve train/spring issues. Other than that, you have quite the gremlin there.. From what I have read doing some searching, you may be able to perform a cylinder balance test, but I am not sure the 1986 computer supports it. I have some injectors you can have that I can ohm out, but they have been setting for quite some time and would need cleaned - they have 98K on the clock.

 

[bronco_lou]

a) "miss" at 2600 RPM under load.
b) slow and no power in the low rpm's, also no hill climbing power. Feels like it is surging a little as well when accelerating.

what about in the upper rpm range? how does it run? I have saw in other posts that the 2.9 will run with the distro 180 out, I just don't know how bad, I do know they say it lacks power

The computer gives you an 11 when you pull the codes?

Louis

 

[Psychopete]

I have saw in other posts that the 2.9 will run with the distro 180 out, I just don't know how bad, I do know they say it lacks power

I've done that before and it will not run with the dist 180 out. It will pop once out of the exhaust and flood out the cylinders w/ gas.

 

[Spitfire1975]

Dizzy is in correct position. I too had to deal with 180 out. No bueno.

Computer gives me an 11 when pulling codes, both KOEO and KOER. The only weird part is not getting ANY type of stored memory code when KOER. It gives an 11 two times and then nothing, like the test ends. Maybe that's normal if there are no stored codes?

It has been giving me the "miss" at 2600 religiously. Lately when it really started bogging down it was missing and surging under any load at any RPM.

I changed the cats today with NEW ones. It is running better, but still not 100%. Still missing under load at 2600. Still not accelerating like my other 86 2.9. I am going to change the plug wires again tonight and the fuel filter if necessary and see if that helps.

Would the low pressure, in-tank pump cause these types of issues?? It is about the only thing that hasn't been changed on this truck.

I also have another set of injectors. Could this be an injector problem??

 

[90B24wd]

How about checking all your ground connections?
Or you might have a vacume leak somewhere around the intake? Try squirting WD40 on the manifold joints & listen for any difference in idle.

 

[Spitfire1975]

Now, I have said this before, but...... I think I got it.

Changed the plug wires last night. No difference.
Changed the fuel filter last night. Slight difference.

As I was re-checking timing and double-checking the TPS it started to idle horribly. I could not get it to idle above 550 rpm and it was surging and missing. It sat there and kept getting worse and worse.

"Could it be the computer?" I ask myself. Naaahhhh. But what the hell, I have an extra so I changed it. Ran like crap for a few minutes while the computer was "re-learning" and then smoothed right out. Idle was nice and smooth at 850. TPS was set at .99 V.
Took it for a drive and for the first time in a year I could not get it to miss. Acceleration was good. I will drive it some more today and hopefully it stays good.

 

[robertc1024]

Excellent. Makes me want to go to the boneyard and get a spare.

 

[Viper Command]

I have a question. once you get it to 2600 rpm's does it fall on its face?
(boggs down like its going to stall but when you lift off its steady but there is a lack of power)


I had this problem in my '97 3.0, some one put dirt in my fuel tank and clogged my crap trap on my pump, preasure test was fine, but under load @ 2400 rpm's the pump could not produce the cfm's my motor needed to make power.

hookup your psi tester and drive it w/ load and I bet your fuel pressure will drop very close to 0 psi.

let me know how it goes.

 

[Spitfire1975]

It doesn't fall flat on it's face. It acts as though the truck turns off for a split second.

And by the way, with the newish computer it is still doing it. Not anywhere near as severe as before, but it is still there. I am really thinking it is some type of electronic/sensor/computer issue. Eventually I will replace EVERYTHING and hopefully the problem will be solved. Hopefully.

Ohh...and now the truck will stall out when coming to a stop, but ONLY when the A/C is engaged. Fires right back up no problems.