: Rough Idle and smokle when electric fans are running



Powermall
02-17-13, 09:39 PM
Hey guys,

Thanks in advance for any help. I was having an issue with the electric fans on the radiator constantly spinning (even after the car was turned off and key removed) until the battery would die. I did some research, replaced the resistor for the blower motor and reprogramed the blower control module. Now the fan comes on when the engine warms up, and goes off when the engine is cool just like it should. However, now every time the fans are running, the engine idles rough, and white smoke pours out the exhaust. As soon as the engine cools down again, the fans stop spinning, and the engine idles as it should. Let it idle for a bit longer and it warms up again, fans spin, the engine idles rough and smoke. This cycle repeats over and over again. Any ideas are appreciated

Thanks,
Isaac

the cadillac man
02-18-13, 12:09 AM
Hey guys,

Thanks in advance for any help. I was having an issue with the electric fans on the radiator constantly spinning (even after the car was turned off and key removed) until the battery would die. I did some research, replaced the resistor for the blower motor and reprogramed the blower control module. Now the fan comes on when the engine warms up, and goes off when the engine is cool just like it should. However, now every time the fans are running, the engine idles rough, and white smoke pours out the exhaust. As soon as the engine cools down again, the fans stop spinning, and the engine idles as it should. Let it idle for a bit longer and it warms up again, fans spin, the engine idles rough and smoke. This cycle repeats over and over again. Any ideas are appreciated

Thanks,
Isaac

Sounds like the thermostat

Powermall
02-18-13, 01:09 AM
Can you elaborate on this? By using Tech2 I am able to manually run the coolant fan at different speeds. There are three different options; 1, 2 and 3, and 1,2 and three. When I manually run 1, the slow speed fans sick in, and the engine idles rough. When I run 2 and 3, the high spoeed fans run and the engine idles fine. When I run 1,2 and 3, the engine idles rough. The common element for when the engine is idling rough is whenever the relay for coolant fan 1 (slow speed I am assuming). The thermostat is incharge of telling the radiator when to circulate coolant, and when to run the fans, which seem to be running as they should.

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Sorry for the spelling errors. Basically, when the PCM tells the low speed fan relay to run, the engine idles roughly. I pulled a variety of codes, amoung them was 0300- random misfire. Further ivestigations shows that cyl. 7 is the misfiring cilynder. Based on the smoke, and gas smell, Im guessing the fuel/ air is fine, and that spark is not producing fire when the low speed cooland fan is opperational. When it isnt, the spark plug produces fire just as it should, and the engine idles fine. What is the correlation between the coolant fan relay and the spark circut?

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Pcm?

the cadillac man
02-18-13, 01:51 AM
Can you elaborate on this? By using Tech2 I am able to manually run the coolant fan at different speeds. There are three different options; 1, 2 and 3, and 1,2 and three. When I manually run 1, the slow speed fans sick in, and the engine idles rough. When I run 2 and 3, the high spoeed fans run and the engine idles fine. When I run 1,2 and 3, the engine idles rough. The common element for when the engine is idling rough is whenever the relay for coolant fan 1 (slow speed I am assuming). The thermostat is incharge of telling the radiator when to circulate coolant, and when to run the fans, which seem to be running as they should.

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Sorry for the spelling errors. Basically, when the PCM tells the low speed fan relay to run, the engine idles roughly. I pulled a variety of codes, amoung them was 0300- random misfire. Further ivestigations shows that cyl. 7 is the misfiring cilynder. Based on the smoke, and gas smell, Im guessing the fuel/ air is fine, and that spark is not producing fire when the low speed cooland fan is opperational. When it isnt, the spark plug produces fire just as it should, and the engine idles fine. What is the correlation between the coolant fan relay and the spark circut?

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Pcm?

Since you have went into more detail with the info and since the fans are controlled by the PCM along with the coil packs it seems to be because of a possible issue in the PCM

In order to be sure I need to know the codes as it can help me in pinpointing the source of problem and verify if it is in fact the PCM
The tech-2 can access quite a lot more then a regular code reader

Powermall
02-18-13, 05:14 AM
Yes I was adding informaiton as I worked on the car. There were a number of DTCs coming on and off, the two which have remained constant the whole time are:

p0300: Random misfire
p0480: Coolant fan relay 1 control system

Are the 6.0L and 5.3L PCMs compatible if they are both for the same year? I think I have or can find a spare 6.0L one somewhere to try on this car which is a 5.3L, but couldn`t find part #`s which tied the two together.

the cadillac man
02-18-13, 11:09 AM
Yes I was adding informaiton as I worked on the car. There were a number of DTCs coming on and off, the two which have remained constant the whole time are:

p0300: Random misfire
p0480: Coolant fan relay 1 control system

Are the 6.0L and 5.3L PCMs compatible if they are both for the same year? I think I have or can find a spare 6.0L one somewhere to try on this car which is a 5.3L, but couldn`t find part #`s which tied the two together.

The PCM is the same regardless of engine or the brand(gm uses the same parts on the power train of the truck and suv lines) but it will have to be programmed to the truck not sure if the tech-2 can do that without the dealer's gm connection

Also if you don't have the gm service manual let me know as it covers reprogramming modules

Powermall
02-18-13, 08:19 PM
Thanks for confirming that, I still hadnt been able to spot that. I use the GM MDI with Tis2web to program the PCM so that should be no issue. We don`t have a manual for the Escalade but do have one for the Hummer. I think we should be able to figure it out, I did a new ECM into a Duramax swapped H2 a few weeks ago with no issues. I`ll let you know if we need some more info though, thanks for the help though! You know alot it seems, do you work at a dealer or something?

the cadillac man
02-18-13, 08:21 PM
Thanks for confirming that, I still hadnt been able to spot that. I use the GM MDI with Tis2web to program the PCM so that should be no issue. We don`t have a manual for the Escalade but do have one for the Hummer. I think we should be able to figure it out, I did a new ECM into a Duramax swapped H2 a few weeks ago with no issues. I`ll let you know if we need some more info though, thanks for the help though! You know alot it seems, do you work at a dealer or something?

Let me know if you need the reprogramming section I have of the gm dealer service manual

Cadillac Cust Svc
02-19-13, 05:13 PM
Powermall, I know you're in the middle of DIY repairs, so I just wanted to pop into say I'm sorry to hear you've been experiencing these concerns. If you ever do decide to involve a dealer and would like further assistance, contact me anytime via email at Katie_Lucille@gmexpert.com.

Best,

Katie
Cadillac Customer Service

Powermall
02-21-13, 09:32 PM
contact me anytime via email at Katie_Lucille@gmexpert.com.

Best,

Katie
Cadillac Customer Service

Hello Katie,

Thank you for the offer, I will probably take you up on that at some point.

Isaac

Powermall
02-25-13, 07:39 AM
I just put a new ECM in this afternoon, reprogrammed it using MDI and Tis2web, and now it wont start. It cranks and the immobilizer light flashes, but wont fire. Im assuming there is sokething else I need to reset? I recalibrated VTD as well and no change. Any advice?

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I feel dumb now, just put some gas in and it started right up, haha.

the cadillac man
02-25-13, 07:50 AM
I just put a new ECM in this afternoon, reprogrammed it using MDI and Tis2web, and now it wont start. It cranks and the immobilizer light flashes, but wont fire. Im assuming there is sokething else I need to reset? I recalibrated VTD as well and no change. Any advice?

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I feel dumb now, just put some gas in and it started right up, haha.

If you have any more problems let me know