opntrk86

I think my chipped p28 has reverted to the stock tune without cutting the J1 jumper.

Car is a '94 CX w/ a stock B16A.

I did the swap last summer and installed a chipping kit and stock B16 basemap from xenocron. It ran great until about a week ago, when running it a little harder that usual (this is my daily driver / gas saver so it's usually babied) it hit the rev limiter at aprox 7400 where I was able to rev it to 8k previously without any issues.

I also noticed that that VTEC is now engaging at aprox 5K when before it would not engage until about 5500. If I assume that the stock tack reads a few hundred rpm's high, so that puts me near the stock P28 specs.

So I removed to ECU to inspect the J1 jumper and it was not broken, I also double checked all of my solder joints using the chart that I found here http://qcwo.com/technicaldomain/trou...8-installation and they all checked out.

I thought that maybe J1 was broken somewhere in the traces of the board so
I tried starting the car with out the chip in place and I got a solid CEL and it started in limp mode. I believe this tells me that J1 is completing the circuit because opening it will bypass the chip all together and that it would run the stock program regardless if the chip was in place or not (correct me if I'm wrong).

I then put the chip back in and reset the ecu and test drove the car and the lowered rev-limit and vtec actuation are still there.

I have read that a bad temp sensor could cause ecu to stay in the cold start strategy and lower the rev-limit, so that is my next thing to check. It has never thrown any codes at all since the swap has been done, so I have my doubts.

Has anyone had a similar problem or have any suggestions?

mouab18c1

iTrader: (5)

Can you reburn the map? Just to verify that the file is not corrupted.

opntrk86

I don't have the hardware to reburn, but I do have a new basemap on the way to try out.

Update: On the way home from work last night I made a pull through first and second gear and the vtec engagement and rev-limit were back to normal. It was unseasonably warm yesterday (low 60's) so I am now thinking it may be the temp sensor after all.

According to the idiot gauge, the temp has always been a constant 1/3 to 1/2 way up and gets to that point within a couple minutes of driving. This always seemed low to me, but it was that way with the stock engine and the d16y8 that I was running before. I know the gauge uses a separate sensor than the ecu, but this tells me that the fan has been cycling as it should.

I will swap out the temp sensor tonight with a spare one I have and see what happens.

opntrk86

Bringing this back up,

After repacing the temp sensor & t-stat, as well as trying a different base map and eventualy a different chipped ecu, the problem continued.

Then after a brake light switch issue forced me to stick my head up under the dash, I discovered that the rubber stopper piece on the clutch pedal that contacts the clutch engagement switch was missing causing the switch to be constant open (clutch depressed). I fixed the problem so the switch works like normal and the rev-limit issue when away also. I never gave it a second though until the problem came back a week ago.

I checked the clutch switch again and it is still working as it should, I also tested the switch off the car and it is fuctioning. After some research here and on pgmfi.org, I learned about the FTS function and how it lowers the rev-limit when the clutch is depressed. It is mostly talked about for drag race shifting purposes, which I could care less about in this car.

Could this be the issue I am having, and why would the problem randomly appear with an "apparently" functioning clutch switch?

My next plan of action is to check the the wiring from the clutch switch to the ecu.

opntrk86

Maybe it's not a FTS issue after all.

So last night after looking at the FSM, I concluded that the clutch switch is nothing but a NC switch (closed when the clutch is pressed) from ecu pin B7 to ground.

I then unpluged the switch to open the circuit and replicate a clutch out and also remove the switch from the equation, test drove and the problem persisted. I then checked B7 @ the ecu to see if there was a short to ground some where in the circuit, all was good there.

Finally I jumped the clutch switch connector and checked for ground @ B7, it was there so I test drove again just to see and the lowered rev limit is still there.

I'm now back to square one.

WTF?

SQ is the SQUAD

try hooking up an aftermarket tech to see if your tach is off...................

opntrk86

That's not a bad idea, and something I haven't offically ruled out.

I have my doubts though because I have seen the problem come and go with the same cluster.

I guess my next step will be to start datalogging and find out whats really going on with the map

SQ is the SQUAD

you, your tach signal could be getting interference somewhere. best bet is to datalog and use an external guage wideband