Standalone ECU The right Standalone ECU for me

[och]

Guy, I will try to make this one as short as possible, so bare with me.

If anyone remembers my old posts, you will know that I own a 1994 LS400 since 2006, and all this time it's been awfuly low on power. It takes off like a 3 cylinder Geo Metro, pings around 2500-3000rpms, and sounds trashy after that.

I've replaced everything that has to do with A/F - MAF, O2, ECT. Did full maintenance including plugs, ignition coils, distributor caps, rotors, wires, pcv, fuel filter. New timing belt and water pump as well. A bunch of other stuff as well - seafoam, clean throttle body, ran fuel injector cleaners - all to no avail.

I'm confident that my engine is in good shape mechanically. It run brilliant if I disconnect the MAF - much stronger pull and sounds healthy. I would run with MAF disconnected, however once in a while it would ping, after which the ECU will retard timing, and it starts performing eratic until I reset the ECU.

I havent replaced the ECU, but I did sent it for a repair service, which did nothing. I bought an Apexi Neo piggyback, but quite frankly thats a piece of junk.

So basically I'm confident my problem is A/F ratio, and since the ECU is the only part I havent replaced. I believe for some reason the ECU is leaning out the mixture (I will do the diagnostics described in this post in the near future - http://us.lexusownersclub.com/forums/index.php?showtopic=20851&mode=threaded)

But basically I've been quoted $900 for a new OEM ECU. I'm almost ready to buy it, but then if I'm going to spend that much, maybe I should opt for an aftermarket ECU? Can anything be had for not much more than that?

Now, let me say that I have no experience with aftermarket ECU's at all. I do have a friend whoever who programs GM ecus all the time, he's very talented and will help me. Of course I'm counting on this forum as well.

I've been reading this forum for a while now, and here's how I understand it. If I do get an aftermarket ECU, I will still retain the factory ECU. The factory ECU will control functions of interior - lights, seats, etc, which the aftermarket ECU will take over the ignition, transmission and fuel management. Is that so? Also, am I gonna have a bunch of errors on my cluster if the factory ecu is no longer controlling the drivetrain?

And now to the requirements. This new ECU that I'm looking for needs to be reasonably priced, as easy to install as possible, and provide decent capability. I dont have modding plans for this car, I'll be happy if it just ran as well as it should from factory. I'll be happy to just get my 250 factory prescribed horses, so make your recommendations based on that. And of course I'd like to get rid of the horrible Karman maf, so I'd like an ECU that will allow me to do that as well.

However, as an alternative, I need another recommendation. It is highly unlikely, but I might be stupid enough to decide and super charge this car sometime in the future. If anything its going to be a mild supercharge, wont rebuilt internals at all. Maybe 5 PSI and maybe upgraded injectors. So please recommend another ECU that can handle this screnario as well.

 

[stevechumo]

I remember you had an issue with your car awhile ago. I thought the issues were resolved. I strongly believe only Toyota factory has the tool to retune the stock ECU. If you sent it to somewhere, you're more likely 99% cheated.

Running an aftermarket ECU that can control the ignition, fuel, and transmission will be quite more expensive than $900.

Here're a few types of ECU:

Low End Piggyback ECU: costs around $300 such as Apexi, Greddy E-Manage Blue, Map-ECU....etc. It can only control the fuel, mostly used to trim bigger fuel injectors. It's used for low boost FI system with 30-40% bigger injectors.

Mid End Piggyback ECU: costs around $500-$700 such as Greddy E-Manage Ultimate, Map-ECU II, AEM FIC...It can control fuel and the ignition retard.

Standalone ECU: costs around $1000-$2000 such as AEM, Adaptronic, Wolf EFI...etc. It replaces the stock ECU with full control from fuel, ignition advance/retard, transmission, and accessories.

The more advanced ECU it is, the harder to wire it to the existing harness and to tune to it correctly. On average, it costs about $600 to wire a standalone ECU and another $500 or more to tune it. This tuning might not include the dyno rental, which costs about $150/hr. The session might include 3-4 hrs.

Unfortunately, I don't think there's any plug & play standalone ECU for the LS.

Your friend must have a wiring diagram for the LS in order to wire the ECU correctly. Tuning a pre-programmed/reflashed ECU for the American cars is easier than tuning a piggyback or standalone ECU on a car that requires special tools to read the exact condition of the car. Make sure your friend had tuned something like I mentioned earlier.

The cheapest ECU solution for you is to get a good used OEM ECU for your specific make/model.

 

[cribbj]

If I'm reading between the lines correctly, you're hoping a standalone ECU will sort out some fundamental problems you're having with the car?

I would strongly suggest you get the problems sorted out before you plunk down a chunk of money for a standalone.

If you truly suspect your AFR's are off, invest in a WBAFR controller, or bring the car to someone who has one, and see what they are, then figure out why they're off.

Also talk to Aliga or one of the other guys who have loads of parts to see if someone can't get you a replacement MAF and ECU, perhaps on a loaner basis.

You'll be opening up a new can of worms with the standalone, before you've sorted out the existing can of worms

 

[gloverman]

Chances are that if you replace the ECU with an aftermarket one you will still have problems unless the ecu if the issue. My suggestion is get it onto a dyno and monitor everything that is happening. Get a scan tool attached when the car is on the dyno along with mixture and timing checking. Another suggestion is rebuild the alternator. They can cause strange problems similar to the ones you are having. Cheers

 

[och]

Well guys like I was saying, I've replaced everything that has to do with A/F, but the ECU. I believe for some reason the fuel trim functions of the ECU are leaning the mixture out. I will test it and know for sure.

As far as why its doing it, I have no clue. The only other thing that has to do with A/F is the HAC sensor (high altiture sensor which is also called MAP or Barometric pressure sensor). Maybe that one isnt working correctly, but its a part of the ECU.

At this point I've dumped so much money into the car, and this is becoming the only thing stopping me from crashing it into a tree so I dont have to drive it no more

But in any case, if I do get a standalone ECU, I'll have someone who will help me wire and program it for free. I do have all the wiring diagrams. Dyno tuning it is another story, but I'm not looking to have it tuned to the point where I'm squeezing every possible drop of power. If theres a standalone that has LS400 fuel maps pre-programmed and they work OK, I'll be fine with that and just do some light tuning.

 

[gennro]

Your ECU is bad. It is running in Back-up mode which usally means the ECU is shot. How I know this is if you can disconnect the MAF and the engine still runs and revs means it is running in backup mode. Also the timing will be set at 5 degrees BTDC and will not advance. I had the same problem when I was doing my engine swap. The engine would run and rev but it ran like crap. Also will the ECU put out check engine codes at all? Replaced the ECU and it fixed the problem instantly.

 

[-Nemesis-]

I can unplug my MAF and mine still runs good, but the CEL comes on. Nothing wrong with my ECU. Not saying your conclusion isn't right, but being able to run without the MAF doesn't mean the ECU is dead, it can mean the ECU is running it's basemap because there's no maf


Having said that. If you're engine runs like crap with the MAF, and you are certain the MAF is fine, then it sounds like the ECU is shot yeah. Normally a shot MAF will mean a better running engine when you disconnect it, but if your maf is good it must be the opposite.

Any chance you know someone, or can find someone with the same ECU to plug in and test och?

 

[sideshow]

ive had 3 or 4 bad mafs lately
yr ecu might not be stuffed
just its in limp mode
ive never had to replace a 1uz ecu and ive done 60 to 70 of them
afew guys recon the car still runs ok after unplugging maf but ive never had the change to research this so i cant say its a maf or ecu prob

 

[gennro]

There is a difference between Limp Mode and Backup mode.

Limp mode is a set of codes that will cause the computer to into a limp mode till the problem is fixed.

Backup mode is where the computer will run on pre determined settings and will let the engine run but at 5 degrees BTDC and will not output any check engine codes. Backup mode only happens when there is a MAJOR malfunction in the ECU itself.

Also you can check your grounds going to the ECU and check to make sure all of your shift selonoids in the transmission are good.

 

[och]

Unfortunately I dont know anyone who can swap ECUs with me.

My MAF is new, or rather was new in 2007 when I purchased it. Took a big plunge and no improvement was made.

The ECU seems to be able to put out codes. If I disconnect anything (maf, ECT, O2) it will throw a CEL, and turn off TRAC as well. But when everything is connected there are no codes or CEL.

I understand the ECU calculates fuel ratio based on MAF sensor input, but then it reads other sensors and uses long and short term fuel trim functions to make further adjustments. The fuel trim function has five settings - max lean, min lean, no adjustment, min rich, max rich. I believe its gets stuck in max lean, for whatever reason. I will run diagnostics to find out exactly which setting its stuck in.

I've replaced pretty much all the sensors that are responsible for this adjustment. O2, MAF/IAT, ECT, did all the possible maintenance all to no avail.

Theres also a HAC sensor which can adjust fuel trim, but thats internal to the ECU.

The other posibility is that my ECU isnt leaning out the mixture but rather retards timing to the max. I read that our ECUs retard timing during transmission shifts, and maybe its stuck in that mode. Unfortunately our stock ECUs have no way of adjusting either timing or fuel, and I've already spent thousands trying to repair this car, and I really don't wanna plung $900 for a stock crappy ECU if I could get a nice standalone for not too much more.

 

[greybeard]

An adaptronic e420c is A$990

 

[och]

I'm thinking Adaptronics too...

But I understand it only does semi-sequental injection and ignition on 8 cylinder? I'm not sure what the disadvantage of this would be.

Also, is my cluster going to look like a Christmas tree with all the warning lights?

And whats going to control the transmission?

 

[greybeard]

early 1uz's are 4x2 injectors, so that's the same.
ignition is via a distributor on each bank so sequential and also no change. the only other issue is single O2 sensor, but that's not much of a drama.
you can leave the OE ecu controlling the transmission. there's wirring info in the technical section here on how to wire adaptronic both ways.
the other option is to get a standalone TCU too, e.g. the PCS unit.
you should be able to do standalone ECU & TCU for under $2k
edit: no idea about dash/cluster implications

 

[och]

early 1uz's are 4x2 injectors, so that's the same.
ignition is via a distributor on each bank so sequential and also no change. the only other issue is single O2 sensor, but that's not much of a drama.
you can leave the OE ecu controlling the transmission. there's wirring info in the technical section here on how to wire adaptronic both ways.
the other option is to get a standalone TCU too, e.g. the PCS unit.
you should be able to do standalone ECU & TCU for under $2k
edit: no idea about dash/cluster implications

This is good information!!! I just briefly read through the article, and it seems like I will be able to defeat any error codes, and can get rid of the stock MAF.

And yes, I'd like to keep the stock ECU to control my transmission. I will review the tech article in full detail before I make up my mind whether or not to buy it.

 

[och]

Few more questions. With the adaptronic, is it able to control EGR valve and IAC valve?

 

[gennro]

You know throwing money at problems won't fix anything. I would take the car to a reputable dealership and get the problem fixed before dumping any more money into an unkown problem.

 

[Riaan810]

I would like to find out Iam building a truck with a 1uzfe vvti engine and have its original ecu if its possible to wire it up?