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Correction from earlier, my old modulator has a black top
I had P0401 Insufficient Flow. I changed all vacuum lines, cleaned the EGR port in the intake, and then lastly changed the EGR modulator and no more CEL. That was ~3 months ago.
I rebuilt the engine, changed every single piece of rubber/plastic on the engine, every hose in or near the engine bay, nearly every wire incl harness, modulator, cleaned the TB and intake, head rebuilt by pro shop, etc... Im thinking a piece of carbon got loose somewhere I didn't check well enough. It just seemed odd to go from insufficient to excessive. Truck idles great, no change from one modulator to another. Haven't run it through emissions since the change.
Oh yeah, more O2 sensor codes since the change. Prolly related, prolly involves exhaust leaks
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surfpig
The Anti-Tech
- Thread starter
- #26
Well, I found a vacuum hose with this in the end of it... Anyone know the Toyota part number for this? 
So I pulled the upper intake as there is no way to figure out what it is supposed to go to otherwise. Figured I'd have the injectors gone over since I'm in there too. Going to drop them off at a local place "Fuel Injector Specialists" in Wheat Ridge. Hopefully a few days will be enough time to figure out the vacuum lines and test all of the electrical components.
So I pulled the upper intake as there is no way to figure out what it is supposed to go to otherwise. Figured I'd have the injectors gone over since I'm in there too. Going to drop them off at a local place "Fuel Injector Specialists" in Wheat Ridge. Hopefully a few days will be enough time to figure out the vacuum lines and test all of the electrical components.
- Thread starter
- #27
Dropped the injectors off this morning, and started to try and identify the vacuum hose with the wood screw in it. Looked at the diagram under the hood and it does not show it (best I can tell). Under the VSV there is a section of hard line, with one end connected to a bung on the manifold and the other with the section of hose with a screw in it. The bung on the manifold is not plugged as I can blow through it. Where should this be connected?
I also noticed another bung on the maifold that did not have anything attached to it. That is also not plugged. I had noticed what sounded like a vacuum leak right before I tore into her and I am guessing this is where it was coming from. Any ideas on this one too?
I also noticed another bung on the maifold that did not have anything attached to it. That is also not plugged. I had noticed what sounded like a vacuum leak right before I tore into her and I am guessing this is where it was coming from. Any ideas on this one too?
- Thread starter
- #28
Dropped by a dealership to see if they could help find my mystery hose-- no luck. Might end up going back in with a plug in it at this point.
Injectors all tested clean, no leaks all between 13.5 and 13.8 Ω.
Downside is that the TPS and IACV tested bad. TPS wasn't too bad from Amazon. But the IACV is speeeeeendy! Would a malfunctioning IACV cause excessive CO? I'm all for replacing things that need to be replaced, but at present I just want to get the thing smog'd and plated.
Injectors all tested clean, no leaks all between 13.5 and 13.8 Ω.
Downside is that the TPS and IACV tested bad. TPS wasn't too bad from Amazon. But the IACV is speeeeeendy! Would a malfunctioning IACV cause excessive CO? I'm all for replacing things that need to be replaced, but at present I just want to get the thing smog'd and plated.
Is the PAIR system still hooked up?
Where does the hose go, what is it hooked to?
Do you have a vacuum hose diagram?
Where does the hose go, what is it hooked to?
Do you have a vacuum hose diagram?
You can get used 80 parts from http://yotayard.com/
http://www.yodajims.com/ and other salvage yards have 80's.
http://www.yodajims.com/ and other salvage yards have 80's.
- Thread starter
- #31
Yes the PAIR is still hooked up. The hose I highlighted in red in the above pic is not part of the diagram under the hood. :/
On my '97 (your '93 may be different) the port in your second pic attaches to the EGR valve, and the end of the hose with the screw in it attaches to the EGR VSV which is the open black port on darker of the two solenoids.
- Thread starter
- #33
- Thread starter
- #34
So, the saga continues...
First up, that nipple I had high lighted in post 27 does not go to the EGR. That comes from the EGR VSV in the intake clam-shell. I have no idea what it should go to as it is not in the diagram under the hood. Also, the vacuum hose that had the screw in it from the first picture in post 27 is not in the diagram. Since I am not able to find anything about either one of these, I have simply connected them together with a vacuum hose.
So, I have replaced the following (thanks to @beno!):
TPS - and set / aligned to FSM specs
O2 sensors
All vacuum hoses and check valves
PCV, hose and grommet
Breather hose
I have tested the following according to FSM:
VAF (FSM has a major typo in the pin out labels between EG-290 and EG-292 on the 93 FSM, looks like 290 is the correct one)
IAC
All 4 VSV's
This morning when I got her back together I took the pups and her for a drive from Kippling and 70 up 70 to the Dino lot exit and back home, dropped off the pups and then to the emissions station on Wads and 52nd. Left her idling until I got to the emissions place.
Results:
HC - 1.0401 (2.500 max)
CO - 37.7445 (25.00 max)
CO2 - 754,9342
NOx - 1.9880 (4.500 max)
Decent improvement from my first two attempts... I had never checked the timing, so I ran up to a buddies house to get his timing light (144th and 25) and came home. Checked the timing and it was around 5-6*, maybe even 7.
Dialed it back to 3* on the money and hoped that would get me below the magic number. Blasted up to the Lookout Mountain exit and back, but got caught up in 5 o'clock traffic. So hoped off 70 and went to the emissions check in Golden. I had high hopes (no Colorado marijuana pun intended). But when the test flashed and reset for a second attempt I knew I had bombed again. But maybe even closer...?
Results:
HC - 2.1691
CO - 72.5947 (@$%@$%#$!!!!)
CO2 - 679.3595
NOx - 2.0799
Completely wrong direction!
Couple of questions:
First up, that nipple I had high lighted in post 27 does not go to the EGR. That comes from the EGR VSV in the intake clam-shell. I have no idea what it should go to as it is not in the diagram under the hood. Also, the vacuum hose that had the screw in it from the first picture in post 27 is not in the diagram. Since I am not able to find anything about either one of these, I have simply connected them together with a vacuum hose.
So, I have replaced the following (thanks to @beno!):
TPS - and set / aligned to FSM specs
O2 sensors
All vacuum hoses and check valves
PCV, hose and grommet
Breather hose
I have tested the following according to FSM:
VAF (FSM has a major typo in the pin out labels between EG-290 and EG-292 on the 93 FSM, looks like 290 is the correct one)
IAC
All 4 VSV's
This morning when I got her back together I took the pups and her for a drive from Kippling and 70 up 70 to the Dino lot exit and back home, dropped off the pups and then to the emissions station on Wads and 52nd. Left her idling until I got to the emissions place.
Results:
HC - 1.0401 (2.500 max)
CO - 37.7445 (25.00 max)
CO2 - 754,9342
NOx - 1.9880 (4.500 max)
Decent improvement from my first two attempts... I had never checked the timing, so I ran up to a buddies house to get his timing light (144th and 25) and came home. Checked the timing and it was around 5-6*, maybe even 7.
Dialed it back to 3* on the money and hoped that would get me below the magic number. Blasted up to the Lookout Mountain exit and back, but got caught up in 5 o'clock traffic. So hoped off 70 and went to the emissions check in Golden. I had high hopes (no Colorado marijuana pun intended). But when the test flashed and reset for a second attempt I knew I had bombed again. But maybe even closer...?
Results:
HC - 2.1691
CO - 72.5947 (@$%@$%#$!!!!)
CO2 - 679.3595
NOx - 2.0799
Completely wrong direction!
Couple of questions:
- I saw that Mobile 1 0w40 was recommended here. So I went with it. The oil pressure at 1500RPM+ is near max, even when hot. Could this have anything to do with it? (totally grasping at straws here) I think I am going to switch to 10w30 either way, but if it is possibly contributing to the high CO then I will do that tomorrow as well versus doing it later.
- I think the last think I have not tested is the TVV, which I will do tomorrow as well. If it is bad it will be replaced, but could this be contributing?
- I have a fuel pump on order, but it is not here yet. More of a preventative thing, but could this be contributing as well?
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Maybe this will help.
"When you fail because your CO or carbon monoxide is too high, that means the fuel and air ratio is way off and there is evidence of incomplete combustion or burning of the air/fuel mixture. Most of the common causes relate to the carburetor or the fuel delivery system."
CO Failures (vehicles with carbs)
1. Engine not at operating temperature. Example, engine/cat cooled off while waiting in test line or has a stuck open or missing t-stat.
2. Bad or misadjusted float level.
3. Plugged air bleed passages or misadjusted main metering system, leaking fuel passages or gaskets.
4. Maladjusted idle air/fuel mixture screws.
5. Ruptured or sticking canister purge valve.
6. PCV plugged or drawing in fuel contaminated oil vapors.
7. Malfunctioning mixture control device.
8. Malfunctioning computer inputs. Example: O2 sensor defective, reading lean all the time. MAP sensor vacuum hose being clogged or broken (reading a heavy load all the time). Coolant temperature sensor having high resistance or open circuit (reading "cold engine" all the time). Throttle position sensor stuck or open ground, (reading wide open throttle).
9. Contaminated, restricted or bad catalytic converter.
CO Failures (fuel injected vehicles)
1. Any of the computer components listed above.
2. Leaking or bad injectors.
3. Mass air flow sensors (voltage or frequency being too high).
4. Fuel pressure too high (restricted fuel return line or stuck fuel regulator)
5. Ruptured fuel regulator (fuel leaking directly into intake)
"When you fail because your CO or carbon monoxide is too high, that means the fuel and air ratio is way off and there is evidence of incomplete combustion or burning of the air/fuel mixture. Most of the common causes relate to the carburetor or the fuel delivery system."
CO Failures (vehicles with carbs)
1. Engine not at operating temperature. Example, engine/cat cooled off while waiting in test line or has a stuck open or missing t-stat.
2. Bad or misadjusted float level.
3. Plugged air bleed passages or misadjusted main metering system, leaking fuel passages or gaskets.
4. Maladjusted idle air/fuel mixture screws.
5. Ruptured or sticking canister purge valve.
6. PCV plugged or drawing in fuel contaminated oil vapors.
7. Malfunctioning mixture control device.
8. Malfunctioning computer inputs. Example: O2 sensor defective, reading lean all the time. MAP sensor vacuum hose being clogged or broken (reading a heavy load all the time). Coolant temperature sensor having high resistance or open circuit (reading "cold engine" all the time). Throttle position sensor stuck or open ground, (reading wide open throttle).
9. Contaminated, restricted or bad catalytic converter.
CO Failures (fuel injected vehicles)
1. Any of the computer components listed above.
2. Leaking or bad injectors.
3. Mass air flow sensors (voltage or frequency being too high).
4. Fuel pressure too high (restricted fuel return line or stuck fuel regulator)
5. Ruptured fuel regulator (fuel leaking directly into intake)
- Thread starter
- #37
Yeah, I am questioning the validity and thoroughness of the shop I had check them. I am really trying to NOT think about that since I had to install and then remove the upper intake twice due to bunging up #3 injector o-ring and not checking that it didn't leak BEFORE I put everything back together.
I use an automotive stethoscope to check the function of my injectors. You put the probe on the injector and listen for the clicking.
IF you have an inferred thermometer you can check the temp of each exhaust manifold port to see if there is a change in temps between the cylinders. If one is colder than others, then you would know there is a problem there.
IF you have an inferred thermometer you can check the temp of each exhaust manifold port to see if there is a change in temps between the cylinders. If one is colder than others, then you would know there is a problem there.
ppc
M Go Blue
Well... I might have a reason for the crazy jump. Someone left the diagnostic jumper in place.
Still open to feedback though if anyone has ideas (even just a
If the jumper was left in place the check engine light should have been flashing. If it wasn't, the light is either burnt out, been disabled or the jumper was not making proper contact. In any case there could a malfunction code like a bad O2 sensor causing a rich condition.
