Thermactor question
09-07-2012, 04:00 PM
#1
Thermactor question
Lol .... i know that smog pump system is like the ugly orphan stepchild with a limp and a lazy eye that nobody wants to know. 
I'm tryin' to get mine straightened out though. It's throwing codes and i think maybe a CEL. If the CEL or any of the other warning lights on the dash are on it won't pass for inspection.
You can't pull the bulbs because they check for that too.
It's gotta be dealt with.
The "94- 351" motor that was originally in the truck used two solonoids. One to control air valve B and one for air valve D.
The 351 that they swapped into it supposedly came out of a 94 as well but it's only got one solonoid and that controls a valve which combines the functions of air B & air D. When it's under a vacuum it sends the air downstream of the O2 sensor to the cat. When not under a vacuum it sends air upstream of the O2 sensor into the exhaust manifold.
The ECU is looking for two solonoids and doesn't know how to run the thermactor system on the motor that was swapped into the truck.
I've got the two solonoids from the old motor but not the air B & air D valves.
There might be a way to re-route the vacuum lines so that the two solonoids work in tandem to operate the new air diverter valve but i can't seem to wrap my head around it.
If anyone is familliar with the two systems some insight would be appreciated.
Thanks
I'm tryin' to get mine straightened out though. It's throwing codes and i think maybe a CEL. If the CEL or any of the other warning lights on the dash are on it won't pass for inspection.
You can't pull the bulbs because they check for that too.
It's gotta be dealt with.
The "94- 351" motor that was originally in the truck used two solonoids. One to control air valve B and one for air valve D.
The 351 that they swapped into it supposedly came out of a 94 as well but it's only got one solonoid and that controls a valve which combines the functions of air B & air D. When it's under a vacuum it sends the air downstream of the O2 sensor to the cat. When not under a vacuum it sends air upstream of the O2 sensor into the exhaust manifold.
The ECU is looking for two solonoids and doesn't know how to run the thermactor system on the motor that was swapped into the truck.
I've got the two solonoids from the old motor but not the air B & air D valves.
There might be a way to re-route the vacuum lines so that the two solonoids work in tandem to operate the new air diverter valve but i can't seem to wrap my head around it.
If anyone is familliar with the two systems some insight would be appreciated.
Thanks
09-07-2012, 08:49 PM
#3
It's been something i've been trying to puzzle out for awhile now.
You see ... that vacuum diagram on the hood is different than the vacuum diagram on the motor. In a case like that you're supposed to go by the diagram on the hood because that's what the computer knows how to run.
It's the right computer for a 94.
I borrowed a copy of the Haynes manual from a friend today. Been going through that for the last couple of hours to see if i could pick up any clues. It was saying that the setups vary by year and even geographic location so you have to use the book more as a general guide.
Overall it seems pretty simple. With a lot of the setups there's a vacuum operated bypass valve (air B) just on the outlet side of the air pump.
After the air B valve you follow the hose up and it eventually comes to the air diverter valve (air D). That's vacuum operated too.
The air bypass valve on my truck is completely missing. At this point i'm thinking that the simplest fix might be to put one in and see if it fixes the problem.
Wish the old motor was around so that i had something to go by.
You see ... that vacuum diagram on the hood is different than the vacuum diagram on the motor. In a case like that you're supposed to go by the diagram on the hood because that's what the computer knows how to run.
It's the right computer for a 94.
I borrowed a copy of the Haynes manual from a friend today. Been going through that for the last couple of hours to see if i could pick up any clues. It was saying that the setups vary by year and even geographic location so you have to use the book more as a general guide.
Overall it seems pretty simple. With a lot of the setups there's a vacuum operated bypass valve (air B) just on the outlet side of the air pump.
After the air B valve you follow the hose up and it eventually comes to the air diverter valve (air D). That's vacuum operated too.
The air bypass valve on my truck is completely missing. At this point i'm thinking that the simplest fix might be to put one in and see if it fixes the problem.
Wish the old motor was around so that i had something to go by.