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b230+t LH2.4 running rich, ECU learning backwards

H

HELLOW

Member
Joined
Jan 16, 2022
b230+T, white top injectors, chipped ECUs. If I reset the computer by unplugging the battery the car runs perfect for like a tank of gas (12 AFR at WOT), then gradually gets richer and richer at WOT until its running horrible (9 AFR at WOT), (idle and cruising at 14.7).

I've already tried a few different MAFs, tried a 5xx ECU, pressure tested intercooler, Ohm tested coolant temp sensor, tried another FPR. What could cause the ECU to gradually make the car run worse after reseting it?
 
Are you running premium gas? An engine knocking where only the knock sensor can hear it may cause the ecu to richen up to protect the engine. The richening may also be because the ignition computer is pulling timing to stop knock.

What ecu is this happening with? You may be better with a 9xx version of the ecu for a turbo. Also what ignition computer is it a turbo ignition computer?
 
im running 93 gas. Im using a 9xx computer right now but I did try with a 5xx and the same thing happens. And yes it is a turbo EZK
 
HELLOW said:
b230+T, white top injectors, chipped ECUs. If I reset the computer by unplugging the battery the car runs perfect for like a tank of gas (12 AFR at WOT), then gradually gets richer and richer at WOT until its running horrible (9 AFR at WOT), (idle and cruising at 14.7).
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Sounds exactly like every other lh2.4 experience I’ve seen.
 
Im really pretty sure there's no boost leak I've taken it all apart and put it back together a few times. There is a VERY small leak in the intercooler but it holds pressure for a few minutes so that's not the issue. The 02 sensor is just over a year old. And no codes.
 
How does LH 2.4 know its running rich at WOT doesn't the 02 sensor just tell it yes/no and not by how much? Could it just be an issue of the chips expecting lower cc injectors and the map being off?
 
HELLOW said:
Im really pretty sure there's no boost leak I've taken it all apart and put it back together a few times. There is a VERY small leak in the intercooler but it holds pressure for a few minutes so that's not the issue. The 02 sensor is just over a year old. And no codes.
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Have you actually pressurized the entire intake? There's a few dozen places it can leak between AMM to turbo.

Are the chips from a reputable supplier? Have you asked them about it?
 
shoestring said:
threewagons said:
Lol wut

LH2.4 is solid on a sorted car
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Ok. Let's do it this way. I realize I don't have the evidence to support my claim... party foul on my part. I gave up on LH2.4 20 years ago and the data I accrued was stored five laptops ago. I also don't have a dog in this fight... I don't own an lh2.4 equipped turbo Volvo (nor do I plan to in the future).

So what kind of evidence could you provide to support your claim that LH2.4 is solid on a sorted car? I can handle being shown to be incorrect in my thinking.

First, I don't expect you (the LH2.4 apologists) to have back to back dyno pull printouts with boost and afr... That's a hard rabbit to pull out of a hat...

What would suffice as sufficient evidence would be something like the datalogs (or plots) of three back to back WOT street pulls of an lh2.4 equipped turbo car... must have boost and afr logged as well to count. If the datalogs (or plots) show a constant (and sane) AFR sweep as a function of RPM and load I'd consider that to be good evidence to support your claim. I suppose plots of AFR vs RPM would work provided you also tell me the boost the car is running.

Granted... this is assuming you log your lh2.4 data and/or use a wideband at all as part of your data collection system instead of relying on looking at what the flashy lights on the afr gauge say as you blast down the street in traffic.... which is kindof another way of saying you have zero data of what your car is doing or whether it's even the slightest bit repeatable.

Alternatively, provided you don't have the data, and I get that not everyone has the data...(see flashy lights above) What's the one thing the OP could do (provided he doesn't have any mechanical issues, boost leaks, etc) to fix his problem (namely AFR going massively rich during boost)? without requiring him to:
1. change has boost and or wastegate settings (MBC, etc)
2. swap injectors,
3. change out an air mass meter,
4. pull out his aftermarket chips, blow them off then reinsert,
5. unplug the battery for 10 minutes.
these by the way being the standard "fixes" for lh2.4 turbo issues.... chipped or unchipped.

What's the one thing he could do to fix his issue? Surely on a 'well sorted' lh2.4 system you could suggest the one crucial change he could make to rectify the issue once and for all?

I await the evidence to support your claim. Convince me that a well-sorted moderately boosted (read more than 7psi) lh2.4 system exists.
 
To the OP, this sounds kinda like a bad O2, where the LH is learning to add fuel over time. Provided YOU ABSOLUTELY KNOW you don't have some fundamental problem like a boost leak or such, I would try that. The service life on an O2 sensor is not indefinite, despite the fact that it's not a maintenance schedule item.

Personally, I am only aware of turbocharged LH2.4 cars that are both modified and sorted and that operate as you defined. Neither of them are mine. I don't really want to make a thing about this, it makes it less fun here. If you gave up on LH 20 years ago, you have to admit that the possibility exists that people who didn't figured some stuff out.
 
OP post a picture or 2 of the setup pls. It is a bog standard OEM like +t? does it have anything non standard like a blow thru AMM, or a blow off valve?? Reading this and your 4 other threads with seemingly the same issue really make it seem like a massive boost/vaccum leak.
 
You're still using a narrowband O2 sensor for LH, correct? Using a WBO2 with an emulated narrowband output may not work well.
Have you checked that you're getting +13v (or whatever your idle voltage is) to the O2 heater wire?
 
The amount of people in this thread who feel the narrowband O2 data is affecting WOT is far too high. As soon as that TPS switch activates at WOT, that O2 data gets ignored for the pre-programmed fuel maps. A 30+ year old 8-bit (?) ECU is NOT going to be able to do closed loop WOT...especially not with a 0-1v sensor...

This is a mechanical issue, or the ECU is stock and it's going pig rich with added boost beyond it's stock mapping.
 
Broke4speed said:
The amount of people in this thread who feel the narrowband O2 data is affecting WOT is far too high. As soon as that TPS switch activates at WOT, that O2 data gets ignored for the pre-programmed fuel maps. A 30+ year old 8-bit (?) ECU is NOT going to be able to do closed loop WOT...especially not with a 0-1v sensor...

This is a mechanical issue, or the ECU is stock and it's going pig rich with added boost beyond it's stock mapping.
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The reason I'm leaning toward the O2 is that this is being presented as a learned problem, where it's fine for a while and then progressively gets worse over time, not over the course of a few WOT rips or whatever. I guess that could also point toward an unmetered air leak too, it helps when you write stuff out sometimes. Anyway, it looks like the LH is adjusting long term trim to add fuel. Others who are more well versed in the intricacies of 2.4 would be better able to tell you if that affects WOT operation as well.
 
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