froseph

I thought this thread was going to be my savior, but I just returned from swapping out my spinning, dented engine speed sensor and an unsuccessful test drive. I was the unfortunate victim of some poor dyno testing I had done to get a speedometer calibration for defending a traffic ticket which resulted in a trashed transmission. I got another one installed around last November and the car never got close to the performance levels it was at previously. Another nagging issue that I've dealt with after the fix is the battery dies if it's not turned on every couple days. About 500-1000 miles after the transmisison swap, the stalling problems began. The car starts back up shortly after stalling. The shop I took it to when it first started got the engine speed sensor error, but I don't know that they had the car running, so I did not put much merit in that, though I replaced it anyway. I just did resistance testing on the adjacent G4 sensor and it seems to be in working condition. I've also swapped ECUs, observing no difference with the problem.

Other observations I have are that there's an audible clicking (relay) from the ECU when the car stalls, and the car tends to stall after a few minutes of driving. I am running an RS2 setup with MRC chips and a 1.8t coil conversion.

My gut tells me the next probable causes:

(1) Low voltage from the battery issue is causing the relay in the ECU to throw and stall the car (but this doesn't explain the decreased performance)

(2) In the transmission install, something got connected back wrong and my timing is off. I got a new South Bend clutch installed, but did not get a resurfaced flywheel. Could there be timing issues that are not electronically related? Could the G4 and G28 have been swapped into the wrong connector on the wire harness?


Any thoughts are much appreciated.

froseph

Update: I checked the sensor connections and confirmed they are connected in the right places and there is continuity in the harness from both positions for signal and ground. The battery voltage at idle is about 14V. I haven't driven it and watched the voltage at the point it stalls.

shoppinit

If the G4 and the G28 connections are mixed up the engine won't start. Battery shouldn't be a consideration as long as your alternator is functioning.

I don't think your problem is the G4 because I *believe* that if it fails you'll still be able to run the engine, it just won't start next time you try.

shoppinit

Might be worth running a jumper cable from the battery negative to the engine in case there's a grounding problem somewhere. They might have screwed up the earthing when removing the tranny.

froseph

I bumped into a great write up on another forum site. I'll delay on making a direct link to it until I have admin's blessing to do so. To make things short...the S64 "Thermo-fuse for holding relay" caused the exact same issues I am experiencing for someone else. The clicking relay in the ECU, I suspect, is the holding relay, identified as "J" in the ECU wiring schematic. I'll report back on success or failure.

froseph

Eureka! After roughly $400 in investments to remedy the situation, the eventual cure to my dilemma is a $.10 15amp fuse. This whole process has taken an agonizing 5 months. Lesson learned: read, read, read the forums before making assumptions or taking your mechanic's opinion as truth.

I've attached a picture of the suspect thermally switching fuse.

moniq77

hi. i have similar problem where the engine stalls in idle or drive(when coming to a stop). it dies then starts perfect but it will stall again at random time.
i've replaced fuel filter, maf sensor, changed all the hoses incase there was an air leak, changed ecu, and ignition switch.
nothing helped..
can u tell me where i can find this j fuse? or is mine a different issue? please help me...

scarman

Remove and thoroughly clean the Idle Stabilization Valve with a solvent such as carburetor cleaner and lubricate with WD40 or a light oil. You can check the function of valve using the troubleshooting section of Scott Mockerys
web site.



http://www.sjmautotechnik.com/troubl...ng/ecu20v.html