New member with Thermactor trouble
New member with Thermactor trouble
Just got a 1984 Bronco II for my 16 yr old son. Bought it in a county that doesn't have emission testing, but my county requires it. Failed testing on high CO , started troubleshooting. Pulled codes, came back with EGR and Thermactor system problems.The air pump is working, found I wasn't getting vacuum to the 2 air diverter valves. Found the solenoids for them on the passenger side fender. Checked for voltage on the plug, had voltage. Used jumper wires straight from the battery, and the solenoids worked. Plugged back in, soleniods didn't work. Checked the other 3 soleniods near by, 2 of wich are for the EGR,same situation. Could work them straight off the battery,but they would not work when plugged in. I have the wiring diagram, all 5 of these solenoids have constant hot when the ignition is on, and they work when the computer gives them a ground. It is funny I can get 13 volts across the plug connectors, but it won't operate the valves. Since the computer gives the ground to the solenoids, I measured the resistance from ground to negative terminal of the plug, expecting to see something close to zero, but read very high resistance instead. I pulled the computer, and checked all the wiring, it all checked out. Checked the ground and voltage for the computer itself, all OK.The only thing in common for all 5 valves is the computer..are computer problems common for these trucks? I am leaning to a bad output driver in the computer...anyone else have a similar problem?
Sounds like you are pretty knowledgeable is area. I definately wouldn't rule out the computer. I would think you could pick one up for next to nothing on the net. Post in the wanted forum.
One common problem on the 2.8's is the EGR passages in the intake get completely plugged with carbon. That wouldn't explain relay problems, but it's definatley something to look into.
In Washington state, you can get a waiver if you spend $150 at licensed repair shop and still fail the test. Might want look into something similar in your state. One thing I've found with emissions systems on older vehicles is the repair cost can quickly pass the value of the vehicle so you don't want to get too carried away.
If you don't mind the work, swapping in a fuel injected 4.0L is pretty easy. It's a popular swap with lots of info on the net.
One common problem on the 2.8's is the EGR passages in the intake get completely plugged with carbon. That wouldn't explain relay problems, but it's definatley something to look into.
In Washington state, you can get a waiver if you spend $150 at licensed repair shop and still fail the test. Might want look into something similar in your state. One thing I've found with emissions systems on older vehicles is the repair cost can quickly pass the value of the vehicle so you don't want to get too carried away.
If you don't mind the work, swapping in a fuel injected 4.0L is pretty easy. It's a popular swap with lots of info on the net.
yoyodyne
I don't have any specific fix-it suggestions either. But . . .
I have disconnected my EGR system. The tube from the pump to the exhaust manifold was rusted out and leaking (you might want to check that). I just capped the manifold end with a pipe fitting cap and sealed up the pump side. Once I got an unrelated issue resolved (bad O2 sensor - no bad sensor code, just a bad sensor), the vehicle was easily able to pass the MD emissions test - the tailpipe version.
I don't know if it is the same in WA and MD (you mention failing a county test?), but if you intend to just pony up the $$$ for non-compliance with state emissions testing, check to see if you should have the vehicle tested and fail first. (I found out the hard way, only $$$ spent AFTER you fail count!)
Good Luck!
CraigK
I don't have any specific fix-it suggestions either. But . . .
I have disconnected my EGR system. The tube from the pump to the exhaust manifold was rusted out and leaking (you might want to check that). I just capped the manifold end with a pipe fitting cap and sealed up the pump side. Once I got an unrelated issue resolved (bad O2 sensor - no bad sensor code, just a bad sensor), the vehicle was easily able to pass the MD emissions test - the tailpipe version.
I don't know if it is the same in WA and MD (you mention failing a county test?), but if you intend to just pony up the $$$ for non-compliance with state emissions testing, check to see if you should have the vehicle tested and fail first. (I found out the hard way, only $$$ spent AFTER you fail count!)
Good Luck!
CraigK
Checking the other trouble codes I got, I noticed they were all sensor related...things like sensor voltage out of range, no voltage from sensor, ect. All this just furthered my belief that is it computer related, so I wrote down the number stamped on the computer case: E43F-CA. Did a little web searching, found that a 1984 Bronco II should have a computer with the code E47F-CA. I later found the actual Ford sticker with the full part number that had fallen off in the kick panel. It had the number E47F-12A650-M1A, which cross references with the E47F-CA computer. So, I think someone in the past had computer trouble, and bought the incorrect replacement. They put it in, and the truck would run, so I guess they figured they had the right one.Which would explain why none of my emission control systems, the idle speed solenoid, and a few other things don't work. When I cross referenced the E43F number, it appears Ford used them on 1984 full sized vans, full sized trucks, and full sized Broncos. I ordered a rebuilt E47F-CA , I will have it in the morning. I am hoping this will fix what ails my truck !
I just ran across this bit. Makes me think the computer and relays are working, but throwing a code because the system is not responding as the computer expects.....possibly due to leaking thermactor tubes, plugged EGR, cracked broken vacuum lines etc.
During the KOER, the computer tries to divert air into the exhaust manifolds. Doing so with a functioning AIR system will result in a lean condition from the O2 sensors. If a lean condition is not seen, the EEC will throw the 94/44 codes. If a lean condition is sensed, the EEC will then vary the valve actuations to make sure the AIRB/AIRD valves are working.