Hello all,

I just bought a 1997 Infiniti I30, but it failed emissions with the following 6 problems:

On-Board Computer:
Vehicle's Malfunction Indicator Light (MIL) does not illuminate under key on engine off conditions
Vehicle's Malfunction Indicator Light (MIL) commanded on

Trouble Codes Present:
P0400: EGR Flow
P0325: Knock Sensor 1 Circuit (Bank 1 or Single Sensor)
P0110: Intake Air Temperature Circuit
P0141: O2 Sensor Heater Circuit

I am completely lost and any and all help would be greatly appreciated. Thank you.

Hi there congrats and Welcome to our little group.

Ok so here is the deal with these codes.

P0400- Means the computer is not seeing the EGR system reintroducing exhaust into the engine when commanded. Typically means there is a resrtiction in the system and it will need to be removed, inspected and cleaned.

P0325- Pretty straight forward failure of the knock sensor. That will not set a MIL but might effect your ability to pass emissions.
P0110 There is a sensor in the airbox that tell the computer what the intake air temperature is. This has an error, what type of error I cannot tell from the code and without looking at it.
P0141- One of the heating elements in the oxygen sensor is no longer functional and will require replacement.

So your new shopping list will now need to include;
at least 1 oxygen sensor
a knock sensor
and several cans of engine degreaser for the egr lines.

Good Luck.

Engine degreaser? I've never thought of that... do you like it better than brake parts cleaner? I think I would kill fewer brain cells that way for sure!

Heath

The sludge that builds up in there is like no dirty brakes I've seen.

The only thing I can liken it to is a cholesterol filled artery. But instead of plaque you are dealing with carbon rich exhaust fumes, over a period of 14 years it has collected probably a solid two inches on either side of the plenum. It will take some elbow grease and maybe some <environmentally friendly solvents to break up the some of the carbon.

I tend to see many techs recommend the entire pipe and EGRT sensor and even sometimes the entire valve to resolve this. I have always gone the route of a thorough cleaning and I have never had a return for that.

Steve, thanks for the help. I am going to start cleaning soon. I bought some of the parts and got a repair manual so lets see where that leads to.

One question though, the part that says MIL does not illuminate when the key is turned and the engine is off.. how do I fix that?

I know BG makes a product called "throttle body cleaner" that works wonders on carbon - and my impression is that it's like brake parts cleaner on crack. I cleaned my plenum and EGR port with a lot of brake parts cleaner and it works pretty well. The good thing was that I could leave the bucket of dirty cleaner sitting outside for a day or so and it all evaporate off, leaving a nice carbon sludge in the bottom that was easy to wipe up.

I have also tried oven cleaner, but liked the lack of any residue with the brake cleaner better. Both are pretty caustic and fume-tastic though. Maybe I'll try degreaser next time.

WMC - The lack of an illuminated MIL is probably due to a prior owner removing the bulb or disabling it somehow... or maybe it's just burnt out. The MIL should come on with all of the other dash bulbs during the "bulb check" when you first turn the key to the on position.

Heath

wmc wrote:Steve, thanks for the help. I am going to start cleaning soon. I bought some of the parts and got a repair manual so lets see where that leads to.

One question though, the part that says MIL does not illuminate when the key is turned and the engine is off.. how do I fix that?

Here is the book I am using page EC-209
http://www.nicoclub.com/FSM/i30/1997_I30/ec.pdf


You will need to remove the tube that contains the EGR temperature sensor is the one that will need to be cleaned.

BGs throttle cleaner would be a waste here. I have tried that and the amount required would be surprisingly expensive.

To replace the MIL you will have to remove the gauge cluster and see what the situation is back there.



4 and 5 will need to come out before you can get access to 6.




Here is what to expect back there.