benefits with other ecus

[triggerx]

I have a 90 tsi awd, right now im running a 92 gst ecu i believe.
Are there any benefits to using another ecu?
Does drivetrain matter when using a different ecu?

Im asking this ### I really need to pick up another ecu for diagnostics

 

[Tyeler18]

All 1g ecu's are the same minus the 90's and Auto/Manual. No real benefit to either unless you're an auto and switching out to a manual ecu.

 

[triggerx]

so anything newer than 90 it doesnt matter whether or not its manual or auto?
The only thing is if its turbo correct?

 

[Tyeler18]

Anything 91-94 is the same in a 1g, the 90's are slightly different and only require swapping pins 6 and 14 to run in a 91+ or vice versa to run a 91-94 in a 90.

As long as it's a turbo ecu there's no difference between them, only difference is if it's an auto ecu or manual ecu and Eprom or non eprom, however, they all can be run in either interchangeably. Lots of people with autos swap to the manual ecu because it eliminates ignition retard when brake boosting, but there's no benefit to running an auto ecu in a manual.

Hope that clears some up?

 

[taz4432]

Edit: Got beat to the post with a better explanation. See Above Post for answer.

Let's clarify, newer than '90 but older than '95. I.e., you can use any 1G Turbo ECU with any 1G Turbo vehicle, and same goes for 2G, but you can't use a 1G ECU with a 2G or vice versa.

Someone please correct me if I'm mistaken or add additional clarification if necessary.

 

[triggerx]

Awesome good info, yea I knew about the whole pin thing. However what about reliability?
Do the newer ecus tend to hold up better?

 

[Tyeler18]

Awesome good info, yea I knew about the whole pin thing. However what about reliability?
Do the newer ecus tend to hold up better?

They all hold up about the same, I've never had one that was more prone to leaking than another. As long as the caps are fresh and the circuit board has been repaired properly you should have no problem with it for a long time.

 

[steve]

Lets' try to make this clearer or at least more precise.

There is difference between the automatic and manual transmission turbo ECUs but they are close enough to work in a pinch. The software for automatics understand the load an ATX transmission puts on the engine when it's in gear vs in neutral/park and the idle code accounts for this. The software for automatics understands that the injectors, turbo, and cams are different from the manual cars and the tuning accounts for this. You really want to have the correct ECU for your car.

The 90 ECUs have two pins (6 and 14) that changed position on the connector between 90 and 91. Anytime you mix the 90/91+ years you have to swap 6 and 14. There are also important differences in the cars, the 90 cars have problems with the tach operation if you put a 91+ ECU in them.

The Federal and California ECUs are different due to the EGR implementation from 90 to 93. In 94 all turbo ECUs share the California EGR. Putting a California ECU in a Federal car will throw a EGR CEL. Federal ECUs in a California car will work fine but may fail smog checks. Putting a 94 turbo ECU in a 90-93 Federal car will throw a EGR CEL. On 91-93 turbo ECUs you can change one resistor to convert from California to Federal operation.

There are differences between AWD and FWD ECUs but they are more minor than the ATX/MTX differences making the ECUs largely interchangeable. Again a single resistor change on the 91-94 ECUs will switch their operation.

The 1K R129 and R130 resistors select the ECU's operational mode. The software in the 90 cars don't have all the modes so changing the resistors doesn't work, you have to change the software too which can only be done on EPROM versions or.

 

[Tyeler18]

^^ What he said.

Also as he mentioned, the auto's used 390cc injectors not 450cc injectors like the manuals, so that will also alter which you use.

 

[And_44]

I was looking into this in past. Read some where that the fuel trims are slighty different between the two (fwd/awd). One being more aggressive then the other.

Also that the 90's have more flexible fuel trims for 87/89/91/93 octane fuel.

But all the above are true.

Hope this helps at all.

 

[Bud92gsx]

On an auto, it's a good stock upgrade to run 450's, manual fpr, and manual ecu.

Besides having an auto car.Steve and tyler already stated the correct onformation..

 

[steve]

I was looking into this in past. Read some where that the fuel trims are slighty different between the two (fwd/awd). One being more aggressive then the other.

Also that the 90's have more flexible fuel trims for 87/89/91/93 octane fuel..

I'm not sure what you mean by more flexible fuel trims but the fuel trim range is smaller for 90 ECUs than the 91+ ECUs.

 

[And_44]

Sorry didn't mean flexible that way. 90's fuel trims are +/- 20% opposed to the later models which had a larger span. Was supposed to be that the manufacture had different fuel maps for the different octane ratings of fuel.

You could use a lesser octane fuel and the ecu would compensate for it.

 

[Heavy_Arms]

Evo 8 ecu ftw!