Stalling out wont idle have to stay on throttle
#21
05-05-2023, 12:48 PM
That's how I understand it also. And I agree he should be getting a code if it is not going into closed loop. He should also be getting a code (P0172) with the really rich mixture that his scan tool is showing. I think the ECM is not playing nicely.
If the O2 sensor is not providing a varied output -- bad sensor, or, as you pointed out, not able to accurately sample the exhaust gas because of missing cat -- the ECM may not be going into closed loop. OP should be able to see which mode the engine is in on his scan tool, open loop or closed loop.
If the O2 sensor is not providing a varied output -- bad sensor, or, as you pointed out, not able to accurately sample the exhaust gas because of missing cat -- the ECM may not be going into closed loop. OP should be able to see which mode the engine is in on his scan tool, open loop or closed loop.
#22
05-05-2023, 10:08 PM
The car doesn’t care about the cat until it does a cat efficiency test. The first oxygen sensor controls the mixture, the second sensor looks at the cat efficiency only.
It sounds like this car has not run right since the head has been off. But it ran well before the repairs other than the water use. Quit throwing parts at it.
It could easily be anything at this point. Start by looking at what was changed. The valve grind, the head surface was shaved, the main chain and kit? was replaced, guides?, tensioner?, torque to yield bolts replaced?
Is the ground wire that goes between the valve cover and the head back where it goes? This grounds the icm since the valve cover is rubber mounted.
I agree this is a pain to diagnose but I cannot see your car. Have you checked the compression yet?
It sounds like this car has not run right since the head has been off. But it ran well before the repairs other than the water use. Quit throwing parts at it.
It could easily be anything at this point. Start by looking at what was changed. The valve grind, the head surface was shaved, the main chain and kit? was replaced, guides?, tensioner?, torque to yield bolts replaced?
Is the ground wire that goes between the valve cover and the head back where it goes? This grounds the icm since the valve cover is rubber mounted.
I agree this is a pain to diagnose but I cannot see your car. Have you checked the compression yet?
#23
05-10-2023, 04:48 PM
I'm sorry, but the air-to-fuel mix must also depend on the front O2 sensor. If the sensor is there, it doesn't seem to be sensing any oxygen so I would get the reading off that. I'm thinking it's near zero. That would tell the ECM to richen the mixture.
If you don't have a cat, you probably don't have any back pressure either in the exhaust, which means the exhaust will not spend enough time around the front O2 sensor for it to read properly.
Did you have a cat before you started the rebuild?
Suspect the ECM as the last option.
Andy's comment about the fuel regulator is something you must check. There is a Schrader valve on The fuel line leading to the fuel rail. Hook up a fuel pressure gauge. The average fuel pump will put out 90 to 100 PSI into the regulator which brings it down to the 40s or '50s. The regulator for these third gen cars is integral to the fuel filter. So checking fuel up by the engine will tell you if it has failed.
Is there anything else about this build, component-wise not on the car extra on the car etc, that you have not told us about? Does it have a muffler or is it straight piped? Are you bypassing anything? Have you adjusted anything on the throttle body?
Please share the information now so that we may help you. Otherwise we're chasing a ghost with three arms, two heads, and an ****
If you don't have a cat, you probably don't have any back pressure either in the exhaust, which means the exhaust will not spend enough time around the front O2 sensor for it to read properly.
Did you have a cat before you started the rebuild?
Suspect the ECM as the last option.
Andy's comment about the fuel regulator is something you must check. There is a Schrader valve on The fuel line leading to the fuel rail. Hook up a fuel pressure gauge. The average fuel pump will put out 90 to 100 PSI into the regulator which brings it down to the 40s or '50s. The regulator for these third gen cars is integral to the fuel filter. So checking fuel up by the engine will tell you if it has failed.
Is there anything else about this build, component-wise not on the car extra on the car etc, that you have not told us about? Does it have a muffler or is it straight piped? Are you bypassing anything? Have you adjusted anything on the throttle body?
Please share the information now so that we may help you. Otherwise we're chasing a ghost with three arms, two heads, and an ****
#24
05-10-2023, 05:09 PM
The car doesn’t care about the cat until it does a cat efficiency test. The first oxygen sensor controls the mixture, the second sensor looks at the cat efficiency only.
It sounds like this car has not run right since the head has been off. But it ran well before the repairs other than the water use. Quit throwing parts at it.
It could easily be anything at this point. Start by looking at what was changed. The valve grind, the head surface was shaved, the main chain and kit? was replaced, guides?, tensioner?, torque to yield bolts replaced?
Is the ground wire that goes between the valve cover and the head back where it goes? This grounds the icm since the valve cover is rubber mounted.
I agree this is a pain to diagnose but I cannot see your car. Have you checked the compression yet?
It sounds like this car has not run right since the head has been off. But it ran well before the repairs other than the water use. Quit throwing parts at it.
It could easily be anything at this point. Start by looking at what was changed. The valve grind, the head surface was shaved, the main chain and kit? was replaced, guides?, tensioner?, torque to yield bolts replaced?
Is the ground wire that goes between the valve cover and the head back where it goes? This grounds the icm since the valve cover is rubber mounted.
I agree this is a pain to diagnose but I cannot see your car. Have you checked the compression yet?
#25
05-10-2023, 07:51 PM
For all wondering this is a completely stock motor no cat, has a muffler, both functioning O2 sensors, TB hasnt been adjusted, running 87 octane with fuel system cleaner, all new injectors, new ignition module, head had a valve job and resurfaced, new rockers all around the old ones were loose, new timing set, didnt touch the water pump and balance shaft as those were replaced in the last 30k, no fuel pressure test but will get one soon, even compression all around, new oil pump and all new seals. All sensors are the same a pre rebuild nothing has changed except injectors.
#26
05-10-2023, 10:34 PM
Preexisting rich car, please check pressure when you can. Starting to make sense. The pumps put out 90+ psi, the regulator is the saving grace. If the pressure is where it needs to be, unplug the front oxygen sensor and see how it runs.
#27
05-10-2023, 11:08 PM
So running rich was an issue before the rebuild?
(Sigh.....)
AutoZone or similar will do loan a tool for just putting down a security deposit so that you return the tool. Total cost equals amount of gas to get to store.
(Sigh.....)
AutoZone or similar will do loan a tool for just putting down a security deposit so that you return the tool. Total cost equals amount of gas to get to store.
#28
05-14-2023, 01:02 PM
Update
Replaced the fuel filter that allegedly has the regulator in it and no dice still running the same. The fuel pressure tester didnt fit the valve and i have to go clear across town to get a different one. Im genuinly at a loss is there anything between the pump and the rail aside from the filter???
(Edit) Im wondering if the little nub at the end of the fuel rail is a sensor or regulator of some sort idk what it does or if its literally an end cap but at this point im open to try anything.
(Edit) Im wondering if the little nub at the end of the fuel rail is a sensor or regulator of some sort idk what it does or if its literally an end cap but at this point im open to try anything.
Last edited by Clapped.out.ion.9; 05-14-2023 at 01:12 PM.
#29
05-14-2023, 07:17 PM
That's how I understand it also. And I agree he should be getting a code if it is not going into closed loop. He should also be getting a code (P0172) with the really rich mixture that his scan tool is showing. I think the ECM is not playing nicely.
If the O2 sensor is not providing a varied output -- bad sensor, or, as you pointed out, not able to accurately sample the exhaust gas because of missing cat -- the ECM may not be going into closed loop. OP should be able to see which mode the engine is in on his scan tool, open loop or closed loop.
If the O2 sensor is not providing a varied output -- bad sensor, or, as you pointed out, not able to accurately sample the exhaust gas because of missing cat -- the ECM may not be going into closed loop. OP should be able to see which mode the engine is in on his scan tool, open loop or closed loop.
#30
05-14-2023, 09:05 PM
I wish I had a set of factory manuals for an Ion. I suspect that you can marry a used pcm to this bcm with three learning cycles like the other cars. I have learned that the airbag module and bcm have to come from the same car when working on L series cars. Do not buy any computers from a car without major accident damage at the wrecking yard. Sometimes that is why they are there.