2.5 running lean when cold, super rich when hot.

[MontanaManche]

So the other day I got a renix engine monitor from @NickInTimeFilms and its telling me my fuel mixture is super janky. when cold its very lean and warm its very rich. I forgot what the reading was when cold but it read 900-1000(mV?) from his website it seems like it should be closer to 500. I have a suspicion my rings are wasted so I'm not sure if that could cause the problem or i have something else going on. My tps and idle stepper motor seem to be adjusted right and I have a brand new o2 sensor. Not sure where to go from here.

[zomeizter]

Coolant temp sensor issue maybe...

[scaleless]

First I would start by cleaning the sensor grounds if you haven't, and completing Cruiser's relevant Renix tips while you're at it. 

http://cruiser54.com/

 

If you've already done so, I would start by testing your IAT, then checking for a MAP line leak.  The data from these is used to calculate air density, of which a wrong reading would lead to the issue you're describing.

 

[ghetdjc320]

How does it run? 

[MiNi Beast]

exhaust gasket head gasket

[MontanaManche]

On 4/20/2021 at 7:26 PM, ghetdjc320 said:

How does it run? 

seems to run ok, it shakes quite a bit and it backfires around 2500 when cold. starts super well.

[MontanaManche]

I looked into the vaccum system and its super clogged with carbon. I'm gonna try and clean the vaccum lines out and see if that helps.

[MontanaManche]

I'm also now getting a "Loop Fault Rich" code through my REM. according to his website that means the system is too rich to correct. Maybe fuel injector issue?

[scaleless]

7 hours ago, MontanaManche said:

Maybe fuel injector issue?

Possibly.  But start with the cheapest and easiest checks first: block one side of the hose that goes to the MAP and suck on the other.  Holds suction?  If not, replace it.  Common failure point.  Make sure there's no leaks anywhere on the line.

[cruiser54]

Intake manifold bolts are VERY prone to loosening, and the 2 hoses under the throttle body prone to disintegrating. Check those first, along with MAP vacuum line. 

 

Remove and clean the firewall ground mounting point. 

 

 

[MontanaManche]

19 hours ago, scaleless said:

Possibly.  But start with the cheapest and easiest checks first: block one side of the hose that goes to the MAP and suck on the other.  Holds suction?  If not, replace it.  Common failure point.  Make sure there's no leaks anywhere on the line.

seems to hold suction pretty good, also has a new ntk MAP.

 

14 hours ago, cruiser54 said:

Intake manifold bolts are VERY prone to loosening, and the 2 hoses under the throttle body prone to disintegrating. Check those first, along with MAP vacuum line. 

 

Remove and clean the firewall ground mounting point. 

 

 

How should I go about checking those? brake cleaner while running?

[cruiser54]

Me, I'd put a wrench on the bolts and tighten them all up, starting in the middle and working toward the ends.

 

As for the hoses, you could use carb cleaner or brake cleaner. Just look at em and see how they are. They're usually bad. 

[MontanaManche]

I kinda feel like an idiot for not checking this but it was that ground at the firewall, I put it off since I thought I already cleaned it up but I tried again and now its running super well. Thanks everyone for the help! I should probably start on your tips @cruiser54 haha 

[cruiser54]

For some reason, that ground strap is much more critical on the 4 cylinder.

 

Yeah, do the Tips.

 

Did you inspect the intake bolts and those hoses though? 

[MontanaManche]

10 hours ago, cruiser54 said:

For some reason, that ground strap is much more critical on the 4 cylinder.

 

Yeah, do the Tips.

 

Did you inspect the intake bolts and those hoses though? 

yeah the intake bolts were kinda loose but not much, the hoses seemed fine.

[cruiser54]

Spray with carb cleaner along intake and those hoses.