13 replies to this topic

[GSRmotor]

Hi guys,

My '93 Lancer GSR doesn't fire on two of the cylinders (2,3) and also won't start. I ruled out the following:

- Fuel pump failure
- Coil Pack failure (bought a replacement one and same problem)

Checked the resistance on the coils and this was in range (12kOhm), so no shorted turns or open circuit. I investigated further and found that the power transistor on the ignitor/coil pack module (J722T) was not triggering on one of the coil packs (but is triggering on the other), even though there is power to the module.

Trigger signal comes from ECU. Opened this up to check for any exploded capacitors that may have shorted bits of the circuit board of the ECU together. It looked as clean as when it left the factory.

Then I looked at what inputs go to the ECU for timing/ignition and examined the Crank Angle Sensor (CAS). It's mounted on the end of the inlet cam, and the module (J822) also contains a TDC sensor and transistor circuit. I checked that there was power to it (rigged up some clip leads and wires to make a test point between connector and plug), which there was. Also 5V signal coming from both TDC and CAS leads of the ECU.

I cranked the engine over (using the starter motor) and checked that the 5V signal was interrupted on both the TDC and CAS sensors, as it should be when the sensor plate passes by the magnetic pickups. Results TDC constant 4.9V, CAS varied voltage between 0, 5V

Conclusion: faulty TDC sensor.

Question: Can anyone sell me another CAS/TDC sensor module (Don't know how to make a post in the classifieds so apologies if in wrong thread etc..)

Hope this is otherwise useful to someone and sorry if it duds an auto-elec/mechanic/lube mobile out of $500 to fix this type of problem

[jack be nimble]

If you are getting spark on 2 cylinders but not the other 2. Umm.
Is the spark at the correct timing point? Ie. 5* with timing connector grounded? This will tell you that tdc sensor is correct. I'm not sure your testing regieme is sufficient for that sensor.
You really need to compare ecu signal outputs for both the coil triggers, then check them at the input to the ignitor. What about if you swap the 2 wires at the ecu and see if you get spark at the other coil, this will test the ecu outputs. Keep swapping wires till you find the fault.
Sounds like a rvr engine to me, maybe you can swap to the evo style cas.

I have a dso oscilloscope for this type of faultfinding. They cheap at around $90 and good enough.
Congrats on your fault finding skills so far. Excellent work.

Check your continuity on your loom too. Maybe a dodgy wire there

[BMGTZ]

just in case you happen to find an evo 123 CAS. although the body is different...the guts is the same and can be fitted to the GSR body. I havent checked any other engines to see if they can be swaped...but it wouldnt surprise me if you found the efi 1.8 was the same.

when these run on two cylinders...it is usually one of two things.....ignitor or cas. see if you can borrow both to confirm tour findings before you buy.

[EVL20T]

Proton M21/GTi 4G93 DOHC are the same, the 4G93 SOHC run off a distributer

[jack be nimble]

2.0 dohc sonata, 93-97 ish also

[EVL20T]

2.0 dohc sonata, 93-97 ish also

Do they use the same module or do they have the wires comin out of them then to a plug like the VR4s have??

[jack be nimble]

Do they use the same module or do they have the wires comin out of them then to a plug like the VR4s have??

Yea, sorry. They have the lead and the plug, so vr4 style.
My oops, and nice pickup

[EVL20T]

^^

[jack be nimble]

cas are around $75 on ebay. i saw a few there tonight

[GSRmotor]

Changed the CAS and now it runs!!! Idled at 4,000 RPM but then I reset the ECU by pulling the battery lead. Idles "normal" at 1,500 as it has always done. Sweet

You really need to compare ecu signal outputs for both the coil triggers, then check them at the input to the ignitor.

Did that - thats how I knew to start looking at the inputs to the ECU.

cas are around $75 on ebay. i saw a few there tonight

I never managed to find any on evil bay... It does pay to shop around though:
-Lube mobile $540 supply/fit ($368 of this is for the part)
-Repco $280
-Burson $173
-Advanced Jap Imports $120. Tick and I didn't even have to wait till monday.

As mentioned by someone, it came off an EVO and I had to extract it ( a bit of a biatch with limited tools )

Btw now the thing's running its' up for sale! If you buy I'll even throw in a spare coil pack for phree!

[jack be nimble]

good work..yep bmgtz and evl20t are 2 of the gurus
new
http://www.ebay.com....=item35bda13248

2nd hand
http://www.ebay.com....=item336f4d87ed

[clone]

when these run on two cylinders...it is usually one of two things.....ignitor or cas. see if you can borrow both to confirm tour findings before you buy.

i hope you mean electrical fault problems cause this can also be caused by a blown headgasket between combustion chambers causing seesaw effect

[BMGTZ]

i hope you mean electrical fault problems cause this can also be caused by a blown headgasket between combustion chambers causing seesaw effect

It would need to be a massive hole to create a seesaw effect that mimics the effect of no spark at all. even with a very badly blown head gasket there is still some combustion taking place

Edited by BMGTZ, 17 July 2012 - 03:14 AM.

[clone]

oh yeah it was lol only know since it happened to me a month ago, the valley between cyl 2 and 3 had 0.004 thou variation after putting a straight edge on it , had head machined and block service new head gasket now good to go