Tricks to get more out of the factory L28e ECU

[hunterzed]

Hey guys. I've seen a few guys say that there are tricks to get more out of the factory ECU. I'm just curious to find out some of the things that you can do with them. I understand that the easiest but not always the cheapest thing to do would be to get an aftermarket ECU. I can't remember where it was written but I think someone wrote in a post that you can get the injectors to double pulse. Like I said I'd like to find out a bit more on how the ECU can be tweeked.

 

Cheers

 

[Mr Camouflage]

It's like tweaking a Commodore Vic 20. Lets face it, its late 1970's tech, and not designed to be modified. Any mods will have little effect unless combined with engine mods anyway.

 

90's ecus (Z32, R32 and later) can be modified with the nistune  board to make them programmable. http://nistune.com/

[Zedman240®]

With some ECU's that cannot be modified internally, one way to "trick" the ECU is to modify the signal from an input. For example, modifying the signal from the air flow meter could make it run leaner or rich. There's a fair bit of info available, just have to do alot of searching.

[hunterzed]

Thanks zedman, this is the sort of thing that I'm looking for. I know there are better ways and more up to date hardware to get better tuning but I'm interested in the history of the way people have modded these cars in the past. Not that I'm looking to do these mods. Like I said. I'm chasing the history.

[PZG302]

With my first Z, an ex PRC Rally car, we found that the standard Bosch L28 computer was the same as a Jag V12 computer and was able to trick the computer into thinking it was running a V12, therefore able to get moe fuel into the engine. We also used this on my current Z until we got the Haltech F9 for it, quite a few years ago now.

 

I can't tell how it was done as my engine builder at the time did all the white man magic to get the computer thinking it was running a pommie car, but without the usual Lucas Prince of Darkness reliability 

 

Jason, Dat2kman, has to run the standard computer in his Sc car and has been playing with the injectors, changing the in line reistance to get them to pump more fuel in. If he sees this thread I'm sure he'll be more than happy to explain what he did a lot better than I ever could.

[hunterzed]

Thats pretty cool. I never would have thought of something like that. 

[thehelix112]

My L28E computer at the moment is running ridiculously rich, so much so that when the car is warmed up it won't run.  Current theory I have (from RTz over at hybridz) is that the water temp sensor is bogus so the car isn't backing off from its warmup enrichment mode.

 

Other possibilities are that whatever it is that switches the ECU from cranking to post-start to warmup to running modes is broken.

 

Stands to reason that if you can control or modify both of those things, you can replicate the same behaviour but have a good effect.

 

Dave

[Zedman240®]

As with all ECU's, it only runs the engine the way the sensors "tell" it to!

[hunterzed]

As with all ECU's, it only runs the engine the way the sensors "tell" it to!

Yeah I agree. Thats why you really need to go to an aftermarket ECU to get any decent results as there is only so much you can tell this ECU. Like I said this was more an exercise in history. I was just interested in some of the cool tricks that people have done in the past. Sometimes it pops up some cool results that have been forgotten in the past that can still be applied today. This obviously applies to much more than just the ECU.

[.]

The problem is these ECUs have an established curve. You can trick them into moving the whole curve up or down but you can't change the curve. In other words you can't target a particular rev range to address a problem there.

[pauly_adams]

http://atlanticz.ca/zclub/techtips/afm/index.html

 

heres a link that does help alot, it helps with richening and leaning out of the system.

 

cheers pauly

[hunterzed]

Thanks for the extra info Pauly. 

[garvice]

Current theory I have (from RTz over at hybridz) is that the water temp sensor is bogus so the car isn't backing off from its warmup enrichment mode.

I'm going off topic here, but that should be pretty easy to check mate. Most temperature sensors are just resistive devices that increase with temperature. Just measure the resistance of the sensor at different temperatures, I.E. chuck it in ice water, then boiling water. That will tell you if the sensor has open or short circuited.

[Ben]

I'd say the easiest way of tweaking the ECU (if you must) would be to use something like a Jaycar Digital Fuel Adjuster to 'bend' the AFM voltage. But modifying these ECU's is become a lost art - and that is partly due to the fact that a fully programmable digital system can be had for such a low price these days.

[pauly_adams]

if you wish to increase the fuel through rev range just do the air flow meter trick the only problem is it will only go so rich other than that up the fuel pressure a tiny bit this will also increase fuel it can be done by a adjustable fuel pressure regulator.

 

cheers pauly

[Sirpent]

Just a reference to a guy I know who does a lot of older ECU mods.

 

Ivan at T.I.K. Motors in St Albans Vic.

 

 

[DatPilot]

I have played with the AFM spring tension a fair bit, im now getting a constant 600km to a tank instead of the usual 400 or LESS

my dyno sheet before hand was showing MUCH richness through the whole range, a guy said if i put 6psi turbo setup through it it would run better and more economy!

 

car is a bit boggey in the revs up to 2500, then after that a nice kick in the back and woosh! can sit at 110km/h without hitting the 'sweet spot' and have that reserved for overtaking or switch the overdrive off

[Zeddophile]

if you wish to increase the fuel through rev range just do the air flow meter trick the only problem is it will only go so rich other than that up the fuel pressure a tiny bit this will also increase fuel it can be done by a adjustable fuel pressure regulator.

 

cheers pauly

 

Another trick for upping the fuel pressure is to grab a socket, place it over the top of the fuel reg (out of the car obviously!), and give it a little squish in the vise to increase the preload on the spring inside.  Can't go to far obviously, but I HAVE had a 2.5 bar reg running at 3.25 bar with stable pressure.  3.0 bar would be a more sensible maximum though, which I have running on my Rangie with no issues.