I've just had a secondhand Unichip A installed and tuned in my TL VRX AWD. Apart from some reasonable power increases, it now has a rough idle. I spoke to the tuner and he said that Unichip A's don't affect the idle tune and that there was a batch of older units that had a problem with the idle "pass through" (whether that is sensor electrical or a logical pass through I don't know). I know that there is a post around about this problem, barring removing the Unichip, has anyone managed to fix this?

Otherwise, because Unichip A's are an old model, my other option is to have them supply, install and tune a new Unichip model Q, and, because they don't share the map, I'd have to just throw away the A's tune (and $660).


Thanks

Ken

it may just be a coincidence....

try checking all the normal signs, like the maf is plugged in properly etc..

also.. wat do u mean by rough idle exactly? elaborate on this and we may be able to help a bit better..

When I say rough idle, I mean that both when cold and when warm, when you let the car sit, the engine RPM changes (nominally RPM is at ~750RPM and it drops from this) and it sounds and feels like the engine will stall. This is, of course, much more noticable when the car is in drive, it is stopped and your foot is on the brake. Putting it in neutral reduces the roughness of the idle, but it is still rough. It was only tuned yesterday and idled roughly from the first time I stopped after picking it up from the tuners. The "roughness" can be heard, but it is most noticable as a vibration through the car.

Thanks

Ken

sounds to me like the maf plug isn't in quite properly...
its in enough to run.. but u gotta squeeze this mofo like there is no tomorrow..

also might be worth adjusting your idle screw on the throttle body... up the idle a little bit and it might solve the problem..

aiight thats plan a.. if plan a fails.. we go to plan b. reset the d/c battery and reset ecu, leave d/c for hours.. then when you start the car let it idle for about 10min.. if it won't idle, just rest your foot so it idles around 1000rpm.

Call me silly but are we missing the obvious??,i dare they disconnect the battery or unplug the harness out of the ECU while wiring in the unichip to avoid shorts etc,so isnt it common that they idle like a wooly goat until the thing "re-learns " propper idle settings?,i would give it a few days and see how it goes,if it doesn`t settle by then,take it back,but as the tuner said,unichips do not alter closed loop operation such as idle etc,but his other statement sounds a bit fishy,if in doubt,get onto APS and ask if this is the case with certain type "A" unichips

FYI,i had a Unichip fitted to another vehicle (V6 camry) and it didnt alter idle at all

Steve

I've disconnected the battery to reset the TCU and ECU a few times before and it didn't behave like it is now. However, I'm still looking at this with an open mind, so I won't discount it. Thanks for the suggestion.

Ken