CEL on, scanner reads PASS??

[msgrape]

:dizzy: Did an engine install on Vue, all went well. Then we had black smoke coming out of back and check engine light on. Purchased a scanner from autozone and once scanned came back PASS...no codes returned. The black smoke is gone, but only upon acceleration a little black smoke comes out. Any ideas what to do next? Cant get the CEL to turn off??? Thanks. Kat

[msgrape]

Took Vue for hour long drive and sucked through gas....black smoke out back again. CEL still on.

[fdryer]

What's the history on the Chevy-Cobalt engine? The excess gas (black) burning can come from one or more sensors. The sensors that come to mind are the intake air temperature, coolant temperature, and O2 sensors. Then there's the possibility of a fuel pressure regulator rupture, feeding fuel into the vacuum side. Have the fuel pressure checked for possible injector leaking although I doubt it since there wasn't any mention of driveability problems other than using more gas than normal. Is the fuel pressure regulator from the original engine or from the replacement one? Is the pressure the right one or wrong for the engine? This little problem may require troubleshooting one step at a time. To begin, you should post the history of the engine transplant followed by the engine starting and running sequence such as cold starting and hot starting. In a cold start does the engine idle higher until it warms up then returns the idle to normal? Does the Vue drive ok during this warm up? In a hot start does the engine run at normal idle, below, or high? Does it run rough at all? Just a few questions for you to think about that may give you some clue of which way to go.

[burnout]

If I'm right, theres two different "CEL" lights. One that throws codes you can read with the autozone scanner, and another that throws codes the dealer can only read.


...I think.

[msgrape]

If I'm right, theres two different "CEL" lights. One that throws codes you can read with the autozone scanner, and another that throws codes the dealer can only read.


...I think.

Saturn tech told us what to do to get CEL off...unplug this , plug in this, etc.....hubby did it, so not sure exactly..BUT CEL did turn off. Now, we have to figure out why Vue is running so rich, with black smoke??? Thanks for all the help.

[msgrape]

What's the history on the Chevy-Cobalt engine? The excess gas (black) burning can come from one or more sensors. The sensors that come to mind are the intake air temperature, coolant temperature, and O2 sensors. Then there's the possibility of a fuel pressure regulator rupture, feeding fuel into the vacuum side. Have the fuel pressure checked for possible injector leaking although I doubt it since there wasn't any mention of driveability problems other than using more gas than normal. Is the fuel pressure regulator from the original engine or from the replacement one? Is the pressure the right one or wrong for the engine? This little problem may require troubleshooting one step at a time. To begin, you should post the history of the engine transplant followed by the engine starting and running sequence such as cold starting and hot starting. In a cold start does the engine idle higher until it warms up then returns the idle to normal? Does the Vue drive ok during this warm up? In a hot start does the engine run at normal idle, below, or high? Does it run rough at all? Just a few questions for you to think about that may give you some clue of which way to go.


Idles fine.Cold starts at 1500rpm, desends down to 1000rpm. Warm start at 1000rpm does fine. All sensors and pressuer regulator and fuel rail from original engine. Even switched over sparke plugs from original. Only time there is black smoke is when you goose it or when you are clilmbing or on interstate. Fuel consumption drank 1/4 tank in 15 miles. Thanks for your help. Let me know if you can think of anything that would fix this problem. Thanks!

[fdryer]

Unlike past engines with carburetors, transplanting another engine would require matching bolt holes, engine mounts, and some miscellaneous items but EFI systems can complicate things. Sensors, regulator, fuel rail, and spark plugs from the old engine to the replacement one may create something not expected. Is the Cobalt engine a direct drop-in replacement that will work with the transplanted parts or is there a possibility of a conflict where one or more sensors, injectors or regulator may not be an exact fit? Is the Cobalt fuel pressure spec the same as the Vue? Are the injectors the same also? I would imagine a higher than specified pressure and/or injector for the Cobalt could allow more fuel than necessary that the O2 sensor won't correct for if the ECM/PCM can't account for if its out of range. This is all hypothetical at this point so parts comparison is necessary to isolate which component is contributing to the extra fuel mixture. A higher than normal regulated fuel pressure can do this and so can an oversize(?) injector or injector specified for greater flow than needed. I'm wondering about the 1,000 rpm idle; did the old engine idle this high? I would think that the engine idle should be around 800 or so but 1,000? Possibly a bad coolant sensor?

[msgrape]

Unlike past engines with carburetors, transplanting another engine would require matching bolt holes, engine mounts, and some miscellaneous items but EFI systems can complicate things. Sensors, regulator, fuel rail, and spark plugs from the old engine to the replacement one may create something not expected. Is the Cobalt engine a direct drop-in replacement that will work with the transplanted parts or is there a possibility of a conflict where one or more sensors, injectors or regulator may not be an exact fit? Is the Cobalt fuel pressure spec the same as the Vue? Are the injectors the same also? I would imagine a higher than specified pressure and/or injector for the Cobalt could allow more fuel than necessary that the O2 sensor won't correct for if the ECM/PCM can't account for if its out of range. This is all hypothetical at this point so parts comparison is necessary to isolate which component is contributing to the extra fuel mixture. A higher than normal regulated fuel pressure can do this and so can an oversize(?) injector or injector specified for greater flow than needed. I'm wondering about the 1,000 rpm idle; did the old engine idle this high? I would think that the engine idle should be around 800 or so but 1,000? Possibly a bad coolant sensor?

Vue now idling at 800, black smoke seems to be gone, but CEL back on:upset:
So something is not right. Only Cobalt sensor not direct match to Saturn was the O2 sensor in the exhaust manifold. Also, the Cobalt fuel rail was totally different and could not hook up with Saturn, so Saturn fuel rail, spark plugs and injectors were put back in. We will have to do a parts comparision. Thanks for all your knowledge.

[msgrape]

Found problem....fuel pulse dampener regulator. Ordered new one from Saturn, should be here Thurs, so hopefully this will solve problem.

[burnout]

Wow, thats off the wall...:ugh:

Hope it fixes everything!

[kodak_jack]

Found problem....fuel pulse dampener regulator. Ordered new one from Saturn, should be here Thurs, so hopefully this will solve problem.
How in the world did you find that?:dizzy: Do you have a manual?

[Bigdaddy94sc2]

It is about the only thing that would continue to let it run rich enough to spit smoke and cause that kind of fuel consumption. It was dumping full throttle fuel for idle spark. RICH as a mofo = smoke like a mofo.

Good find though if it fixes it.... let us know.

[msgrape]

Dont have manual...Alldata DIY had some usedful info. Fuel pulse dampner replaced and all is well with the Saturn:):) Its been a long road to this place and gas mileage is better than ever!!! Thanks again to all who posted. We were really fortunate with the Cobalt engine because it is a real peach!