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AFRs going crazy !

LeedomtoFreedom

LeedomtoFreedom

New member
Joined
Oct 11, 2017
Location
Ingleside
Alright guys, here's another one to throw at ya

The Issue
My AFRs are are actually going crazy, it tends to stay very rich and sputters while driving. undriveable

Things to Note
-Stays around 10-11 and can dip to 8-9 which the engine really doesn't like
-Just relocated the maf to cold side, used pretty thick wires when lengthening them regardless of what they were before.
-Boost leak tested and comes out clear
-Maf in a 3" pipe that's about 7" long and adapts to 2.5" immediately after
-Codes are all 1-1-1

I'm searching other threads as well but felt like asking
 
I just drove it and the afrs stay rich but sometimes jump to 15s but go back down. Just jumpin' everywhere.

car doesn't idle with maf unplugged
 
First question is why did you move the AMM? It works just fine where it was placed by the factory?

Second picture of engine bay and picture of amm in pipe? You might be surprised how much data can be gathered from a good picture or two.

Also can you list your setup so we have an idea on what parts you have? Injector size? Stock fpr? What turbo? How much boost? Any other aftermarket parts?

What are idle afrs if you start the car and let it idle up to temp? What are cruise afrs?
 
https://ibb.co/hcDeMx
https://ibb.co/hcDeMxhttps://ibb.co/kZZrZH

Alright so...
HX35 on 90+
Stock fpr
43 lb/hr injectors (s60r injectors)
the boost is around 20lb but I haven't really gotten into boost since I installed it (since I have no bov or recirc valve)
ran fine after HX35 swap, suddenly not
Moved the maf over to cold side to remedy stalling at idle
no blow of valve so to speak(working on this)
stock 940 intercooler

Sits around 12s at idle, bounces around cruising but tends to bump around 10-11

Can't think of anything else atm
 
Ok so first thing, a larger amm (3" pipe with stock AMM in it) is wrong for injectors that small, The scaling is wrong.

Second, if the idle.and cruise afrs are not 14.7:1 then the basics are the problem.. put the amm back where it goes with the the stock housing and or get another amm as that unit might be bad. Check the ect and make sure it checks out. Also what wideband are you using ? Are you using it to feed the signal to LH or are you still using a narrowband to feed LH? Check the 02 voltage and make sure it is in spec.
 
Interesting what you said about injector matching because I've been using these injectors for a year or so with no issues, good afr all round. It's only been recently that things have been off.

Also, I've got two o2 sensors in, one for lh2.4 and one for the wideband. I'm still using the narrowband for lh2.4
 
Sounds like either amm has gone bad , ect or 02 is going bad for idles to start running that far off. Or there is a big leak.

Many had had luck with the 012 with 42lb injectors and many have not. Myself I prefer 46lb with the 012amm but that was a long time ago. I just recently went to 65lb with the 012 and have been tuning around it.
 
There shouldn't be a leak that big. I patched some spots today and it didn't help

I have had no issues with 42lb with my setup so far but in a different thread, I remember being told that I might run out of injector pretty quickly with the HX35

Can I wire the wideband to output for LH2.4 ? does this improve the running in any way? I'm guessing you can because it's essentially just another o2 sensor.
 
I moved the maf back to before the turbo, no change... but

I did a test and unplugged the o2 sensor while the car was running... no change. The engine didn't even flinch, which leads me to believe it's the o2 sensor that has failed.

Any thoughts? Maybe this is to be expected and the o2 sensor hasn't failed.
 
With the new 02 did you reset LH and let it relearn?

Yes you can feed a narrowband signal from a wideband to LH. Many of us have done it but for whatever reason LH always seem to run better with it's own 02 signal over one from a wideband.
 
Alright so I've continued to diagnose. It seems to run significantly better with the MAF on the hotside. It doesn't run perfect, but it stays around 14-15 in a cruise with a lot of wandering. It'll still drop to some low numbers like 10-11 but it's significantly better than before.

When you let off the gas it should go to full oxygen where the wideband would show the text " - - - " but in my case it doesn't, it'll slowly climb back up to lean numbers... very slowly.

I did some tests on the LH pinout comparing to this chart
http://ipdown.net/jetronic.info/tiki-index.php?page=LH2.4+Pinouts+and+Diagrams

pin 24 (o2 sensor) is in range at idle
pin 13 (ECT) is in range at idle but when checking resistance from 13 to 5(ground) with the connector disconnected, it shows some resistance when I'm sure it should be an open circuit.
pin 7 (maf) is also in range
 
If during cruise or idle the afrs are correct and then will randomly go rich like that something is wrong. Be it a spark issue or a leak causing some kind of issue.
 
There is some REAL freaky stuff going on.

I boost leak tested it, and I pushed it pretty hard, there were bubbles coming from the the compressor housing seal? Like it was coming from coolant, because oil doesn't really bubble. But there's only an oil feed to the turbo.

THEN it popped, the intake hose popped off and coolant started coming out of places (multiple). The coolant overflow hose (little one) popped off as well.

I think I'll be needing a priest or a vicar to cleanse my car of this curse.
 
So I shut the car off and noticed the afr stay at 12... With the car off? it stayed present for a minute or so. Usually it goes straight to lean, maybe residual gas in the exhaust?
 
Ok so where did you pressure test from? In front of the turbo? What intake hose popped off? If pressure into your compressor housing is putting pressure on your cooling system sounds like you might have a leaked gasket.
 
It was the turbo inlet, blew right off. I think when it blew off it snagged the overflow hose which created the illusion that it blew off, but possibly was tugged off.

I had a look at a look at everything again and I noticed that with the maf unplugged, the car was unbelievably rich, which in a regular scenario, LH2.4 would go into limp mode, but not be that rich. So because of this, I have less of a suspicion that it's the maf

I then looked again at the o2 sensor, and found that with the car running at idle, it stayed at 4.7 volts constantly. I read that the o2 sensor fluctuates because it's constantly compensating and reading new mixtures and should pass over 5 volts many times. Even revving the car shows no change to voltage. It's also around that voltage with the ignition on without the car started. This leads me to believe that both of my o2 sensors are dead.
 
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