Over the past few days my tach was acting erratic and my car was going into lean spurts. I did not have my laptop with me, so I just tried to go through electrical connections. I was resoldering, checking different things. I thought it was my ECU ground, because when I messed with that the bucking went away.

Well, it came back today, bigtime. I went over to Jimmyv13's to return a socket all the while my car shaking like mad. I was going to try to fix it at his place. He had a hesitation problem and his car died a couple days ago. He pulled his CAS plug and his car started (wasn't before). I hooked his laptop up, and I had an RPM error as well. I pulled my plug, started up, and my car is running perfect.

It's amazing this problem happened to 2 of us in the last few days. I think it must have to be from the humidity and how the temperature is changing.

I hope this helps someone if they experience weird RPMerrors. We are going to be getting new connectors soon.

 

Did you guys re-use the stock conectors, or buy some new ones?

 

stock connectors...but currently looking for new weathertight ones? Any ideas?

 

we both used the stock ones. Oh, and we plugged them back in of course before restarting (shaddup Jim)

 

yea ive had alot of rpm errors and no start situations through no connection to the cas.

 

Known problem for FC's, and I've run into four difference vehicles tracked down back to the CAS plug...

Take it apart.
Shoot it down with some kinda cleaner / degreaser.
If you can find a specific electronics contact clear and enhancer, get it!
We use this stuff called DeOxIt.


-Ted

 

Just out of blatant curiousity, and to educate myself , what kind of symptoms would one get if that were the case? Like a hesitation I'm guessing? If the CAS wasn't sending a clear signal to whatever ECU in the car, then there'd be a break in the firing of the plugs right?

 

Hesitation and an RPM error on the ECU led me to the CAS plug.

I've done some researching for plugs and found some MSD 4 prong weathertight connectors for ~$10 from summit. I will probably get one, I am really happy with the MSD injector plugs I bought, so I'm assuming this plug will have the same results. Then, I can resolder the CAS plug to my stock harness and sell it.

 

These were the symptoms...

*high RPM misfire
*intermittent cranking/starting problems

The high RPM misfire was on a stock ECU kouki NA GTUs.
The intermittent starting problems were on Haltech FC 13BT's.

It's funny that it only affected the Haltech cars at cranking.
If the engine cranked over and started, there was no hint something was wrong.
Initially, the cranking problems was very rare.
The problem got worse to the point it would never crank and fire over.
Watching the engine data page and through datalog showed the intermittent RPM input signal - doh.


-Ted

 

An rpm error will usually be caused by the following things............
CAS problem (usually rare on a turbo 2),wiring to the crank sensor or the most common cause is RFI.
RFI is usually caused by the CAS wire too close to the main alternator wire or by a **** set of plug leads.This is why the wiring for the CAS is shielded.It is EXTREMELY sensetive to any type of electrical interference.
Try running the wire right away from anything that might be capable of having any type of high current running through it & try a good set of leads (i have had the best success with Magnecor & NGK)
Jon