# Running too rich



## Lani Pumpkin (Dec 22, 2006)

I'm about to give up. I have a 1997 truck and have replaced just about every sensor on it and I am still having problems.  It's rediculous! Help!


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## dvdswanson (Nov 6, 2005)

MAF, IAC, Temp sensor, and TPS will cause it to run rich, do you have a CEL on? have you checked for codes? what sensor have you replaced? what all is the truck doing? more info you add will help us give suggestions on what to look at. when was the last time a tune up was done?


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## azrocketman (Oct 5, 2005)

dvdswanson said:


> MAF, IAC, Temp sensor, and TPS will cause it to run rich, do you have a CEL on? have you checked for codes? what sensor have you replaced? what all is the truck doing? more info you add will help us give suggestions on what to look at. when was the last time a tune up was done?


In addition to sensors, a cooling system that does not reach normal operating temperatures will cause the truck to run rich. Is your temp guage indicating normal operating temperatures?

Also, check your wiring and connectors to the sensors. 

Steve


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## Lani Pumpkin (Dec 22, 2006)

dvdswanson said:


> MAF, IAC, Temp sensor, and TPS will cause it to run rich, do you have a CEL on? have you checked for codes? what sensor have you replaced? what all is the truck doing? more info you add will help us give suggestions on what to look at. when was the last time a tune up was done?


I've replaced the EGR valve, Front 02 Sensor, MAF and one or two other sensors (don't have the paperwork on those in front of me right now, sorry) . The spark plugs and 02 sensor get lots of black soot on them in a short period of time. It chugs when trying to accelerate and dies when stopped. After cleaning the spark plugs and 02 sensor again, it will run okay for a while. 

The code given is Bank 1.

Sorry for sounding dumb but, what is a CEL?

Nissan and my own mechanic have both worked on it. After they get done, it works for a while and then does this again. My mechanic basically threw up his hands--he just can't figure out what the problem is. 

Thank you!

Lani


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## Lani Pumpkin (Dec 22, 2006)

azrocketman said:


> In addition to sensors, a cooling system that does not reach normal operating temperatures will cause the truck to run rich. Is your temp guage indicating normal operating temperatures?
> 
> Also, check your wiring and connectors to the sensors.
> 
> Steve


The temperature gauge shows average temps, not too high or low. 

Hopefully the mechanics have checked the wires, but who knows???!!!

Thanks,

Lani


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## jerryp58 (Jan 6, 2005)

Lani Pumpkin said:


> I'm about to give up. I have a 1997 truck and have replaced just about every sensor on it and I am still having problems.  It's rediculous! Help!


Is the timing set correctly?

Injectors operating correctly?

Just a couple of thoughts.


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## himilefrontier (Jan 21, 2003)

Does your truck leak oil? If so, it could have damaged the wiring harness and be causing a short. Most people don't realize just how harmful an oil leak can be. I have seen dried out insulation pull back enough to have a quarter inch of exposed wire near a sensor's plug. It's important to see just what readings the ECU is seeing while it runs rich, and for that you need a fairly good scanner. Another possibility is that the engine is burning oil which could cause a false reading at the oxygen sensor if it gets coated with excess soot and oil. Is one of your injectors leaking? If it is failing to close , then it could be running rich and then cause the oxygen sensor to become loaded up which might then give a false lean reading and cause the ECU to richen the mixture. You also failed to mention which engine you have in the truck. Is it a KA24E or a VG30E? Do you have a cold air intake or is your intake stock? CAI's sometimes kill MAF sensors by drawing in excess water or if the filter is over oiled they coat the hot wire with oil and give bad readings.


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## golfer (Aug 21, 2006)

Lani Pumpkin said:


> I've replaced the EGR valve, Front 02 Sensor, MAF and one or two other sensors (don't have the paperwork on those in front of me right now, sorry) . The spark plugs and 02 sensor get lots of black soot on them in a short period of time. It chugs when trying to accelerate and dies when stopped. After cleaning the spark plugs and 02 sensor again, it will run okay for a while.
> 
> Nissan and my own mechanic have both worked on it. After they get done, it works for a while and then does this again. My mechanic basically threw up his hands--he just can't figure out what the problem is.
> 
> ...


You have spent a few dollars to this point.
More information would be helpful ... 4cyl or 6cyl and modifications etc.



> Sorry for sounding dumb but, what is a CEL?


 CEL = *C*heck *E*ngine *L*ight




> The code given is Bank 1.


Need more info such as the actual code ... for example P0172 = System Too Rich ( Bank 1 )

In this case the likely causes would be :
- front heated oxygen sensor
- injectors ( listen to hear each injector is clicking )
- exhaust gas leak ( listen for exhaust air leak before three way catalyst )
- incorrect fuel pressure ( 34 psi at idle - 43 psi not running and key on )
- mass air flow sensor ( listen for an intake air leak after the mass air flow sensor )


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