I installed my Unichip, Harness, and EMI adapter this morning, and after getting it in, I noticed a "shudder" in the throttle after install.

At roughly 2500-3500 RPM with the throttle at about the midpoint (ahven't gotten to a place to do WOT, yet) as the revs are climbing the car will "shudder" and the revs will jump up and down for a bit. Once it gets above 3,500ish, then no more.

Is this the new transition between closed- and open-loop boost (unfamiliar with this principal) or is it something else?

Can I drive it out, or is it something serious?

My car is tuned to the Vishnu Stage 1, but I HAVE NOT installed the boost controller yet because I'm putting in an AVC-R. Still running stock boost.

Thanks
-Etch

 

Transition from closed loop and open loop operation is determined by throttle % and not rpm.

The car switches into open loop mode @ ~55-60% tps.

My TXS Stage 4 Unichip did it *just a bit* when I hit the crossover spot just right (or wrong, as the case may be).

Don't know if the EMI adapter is supposed to help with that.
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Of course hind sight is always 20/20....

What you should or should I saw we? What we should have done was put in the unichip on and drive around with it to make sure you were happy with this. Then let me wire in the EMI adapter after all of that checked out.... Of course we just dove right in didn't we

Put in the bypass for the chip and see if the shudder goes away...

If it's still there, I may have botched the EMI adapter install

For that I'm truely sorry, and I'll fix it ASAP. Call me to let me know.

 

sounds funny ....... kinda like when I used to climb the rope in gym class .....




Is it a "bad" shutter? What about under full throttle acceleration?

and when do you want to do that boost controller install?

 

IS2Scooby Gotcha on the TPS. I figured that out later in the day
teiva-boy The EMI adapter did start to soften out the shudder a little later. What bypass are you talking about? Does it involve the jumper switches? Don't think you botched it. Thanks again for the help
NoLimit I'd like to do the boost controller soon. Possibly tomorrow before the afternoon Auto-X, but I have no idea what your sked looks like. As for the Unichip, full throttle was not a problem. Nice and smooth. I really liked it until...

...the NEW PROBLEM OCCURED

I stopped at the class 6 to pick up some Captain Morgan, and when I came back out I couldn't get my car to start. I had to take the Unichip off in order to get things running, again.

Here's a description of what happened:

The engine just turned over with occasionally one cylinder firing in the 1st second or so of trying to start the car. After that, just the starter.

I figured it might be a lean condition and hazard a guess that it was due to my CAI, so when I got the car home, I removed it and tried to start again... Nothing. Once again, unhooking the Unichip made all the problems go away.

Oh yeah, before giving up and unhooking the ECU, I reset the ECU (unhook battery, stomp on brake repeatedly, rehook-up the battery)

Also, after the Unichip install I was getting a CEL... thought Vishnu wasn't supposed to do that.

On a happy note, my upipe-related CEL never came back. The 2.2k Ohm mod worked.
-Etch

 

uhh, give me more notice than that
do you ever get off work early?

as far as the new problem, ... it sounds like something may not be connected correctly. I think I'd need to take a look at everything and go from there before I start trying to dissect your problem. I don't know enough of the "unichip quirks and problems" to guess.

 

Nolimit I figured about the notice, thought it was worth a shot, though. I'll try to skip out of work early one day this week. I'll call you and talk to you about it.

Anyway, I bypassed the Unichip and still couldn't start the car with the harness attached, so it's either a mis-wired Unichip, or mis-wired EMI adapter. At least the problem is narrowed down a bit...

 

After running my car with the stock ECU, I plugged in the Harness and Unichip and fired it up again. This time it started just fine. However, acting on a hunch, I waited for the car to get warmed up and then shut it down and tried to restart it. It wouldn't restart. I waited for the car to cool down and tried again, and it started. Makes me think that the harness (really thinking the EMI adapter, due to the problems continuing after bypassing the UniChip) is causing a problem, probably a lean condition, with hot starts.

Can anybody tell me if there is a significant difference between the programming for a cold start and a hot-start?

The next step is to remove the EMI adapter and try again. Just need to buy some bullet connectors.

-Etch

 

Greg,

Sorry I couldn't help you out at the track. I didn't understand what it was you wanted me to do. Did you just want the EMI unattached from the unichip? Test the connections?

It was a good thing Josh was there. Josh and Sean are both wizards at that stuff.