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I generally use some Red or UltraCopper RTV on the ball/socket connection when I hook those up. I honestly don't know if it's necessary, but it's something that I just got in the habit of doing on snowmobiles over the years, as they use a similar ball and socket exhaust connector, and they're *much* more sensitive to exhaust leaks, being 2-strokes.
As did I since it's hard to put them together perfectly.
I'm not sure if the high temp RTV stuff works on exhaust headers to the engine will work as well.
You have done a lot at this point to find common issues.
I'm shooting from the hip but a bad throttle position sensor that stays open continuously will cause a lean condition. Whichever pin in the PCM that regulates the A/F ratio, maybe the HEGO pin can be checked. You can also buy or make a cheap smoke test that will help find a difficult air leak. I am just trying to give you some different things to consider. The smoke is a good way to test for sure.
If it’s a MAF, I’ve had one fail on a differnt brand truck fail and cause a lean condition on both banks. As well as o2 sensors failing causing lean conditions.
The straight piece of air intake hose after the air filter is a little cracked at the connection but I sealed it off with duck tape.
Is yours MAF or SD, do you know the difference?
Originally Posted by 302Ford1994
fuel pressure is within specification.
you never gave #'s
Originally Posted by 302Ford1994
I don't recall off hand but it's running lean on bank 1. I'm not sure if it was upstream or downstream.
Originally Posted by JJF20
If it’s a MAF, I’ve had one fail on a different brand truck fail and cause a lean condition on both banks. As well as o2 sensors failing causing lean conditions.
If it’s a MAF, I’ve had one fail on a differnt brand truck fail and cause a lean condition on both banks. As well as o2 sensors failing causing lean conditions.
I don't fully understand what it means by banks. I know there's two.
Bank 1 is passenger side 4 cylinders bank 2 is the other. The truck fires all four injectors in a bank at a time. I think your bank 1 has the O2 sensor.
Here is what JJF20/sandymane are talking about, Speed Density uses a MAP sensor, and has one O2 sensor, in the exhaust (it is at the y-pipe, and first cat), so you wont/cant know, which bank(1 or 2) is lean(but S.D. uses Bank 1 for lean/rich codes, confused yet? good it gets worse)
MAF(Mass Air Flow) on the other hand has bank 1 and bank 2, because the exhaust has O2 sensor on each bank for lean/rich codes, and can tell you which bank is doing it, unlike S.D. so below is pics of a MAF system, and a Speed Density System, you should be able to look under truck for 1 O2 sensor or 2 O2 sensors, or look under hood.
First is Speed Density has a MAP sensor on passenger side firewall, with a vacuum line, and electrical connector
Second MAF(Mass Air Flow) has one large hose that splits into 2 pipe to connect to throttle body, and electrical connector
No, '97 GM truck. The MAF started reading / giving erratic voltages. the element in got dirty/wore out.... changed it for a new one, worked perfectly. It would lean it out to stalling the engine.
Here is what JJF20/sandymane are talking about, Speed Density uses a MAP sensor, and has one O2 sensor, in the exhaust (it is at the y-pipe, and first cat), so you wont/cant know, which bank(1 or 2) is lean(but S.D. uses Bank 1 for lean/rich codes, confused yet? good it gets worse)
MAF(Mass Air Flow) on the other hand has bank 1 and bank 2, because the exhaust has O2 sensor on each bank for lean/rich codes, and can tell you which bank is doing it, unlike S.D. so below is pics of a MAF system, and a Speed Density System, you should be able to look under truck for 1 O2 sensor or 2 O2 sensors, or look under hood.
First is Speed Density has a MAP sensor on passenger side firewall, with a vacuum line, and electrical connector
Second MAF(Mass Air Flow) has one large hose that splits into 2 pipe to connect to throttle body, and electrical connector
I have non California maf sensor at the air intake hose, but I replaced it as well.
For fuel pressure, ~32 psi at idle with vacuum hose hooked to the regulator is normal. Remove the vacuum line at the regulator, pressure should increase to around 39-40 psi. If that checks out, great, you have a good regulator.
While driving, fuel pressure will depend on engine load (because more load decreases intake manifold vacuum). If you're cruising along under part throttle, low 30's for pressure is normal, but when you go full throttle, manifold vacuum drops, the pressure regulator applies full pressure, and the fuel pressure must rise to 39-40 psi and hold. If it drops, there is a fuel supply issue. This tests the fuel pump.
Does this truck have a single oxygen sensor, or two? There should not be an "downstream" sensors in a 1994, but you may have 1 or 2 upstream sensors.
I checked all the gasket that you have mentioned except for the head gasket and they are new and sealed.
The straight piece of air intake hose after the air filter is a little cracked at the connection but I sealed it off with duck tape.
why the hell are you using duct tape
its not sealing or long fix
use jb weld or a butyl adhesive tape for temporary fix. But those fumes may affect PCv
For fuel pressure, ~32 psi at idle with vacuum hose hooked to the regulator is normal. Remove the vacuum line at the regulator, pressure should increase to around 39-40 psi. If that checks out, great, you have a good regulator.
While driving, fuel pressure will depend on engine load (because more load decreases intake manifold vacuum). If you're cruising along under part throttle, low 30's for pressure is normal, but when you go full throttle, manifold vacuum drops, the pressure regulator applies full pressure, and the fuel pressure must rise to 39-40 psi and hold. If it drops, there is a fuel supply issue. This tests the fuel pump.
Does this truck have a single oxygen sensor, or two? There should not be an "downstream" sensors in a 1994, but you may have 1 or 2 upstream sensors.
use jb weld or a butyl adhesive tape for temporary fix. But those fumes may affect PCv
One: I haven't found new or junkyard part for that was good or available.
Two that's all I have and I'm not paying for a roll of butyl tape for a little piece.
Finally calm answers and questions please
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