GSR, Running on two Cylinders, Not your Usual...

[to4garret]

Hi guys,

i got a pretty big issue with a mates CD5A GSR i've been working on.

Its only running on cylinders 1/4.

i'll start with what i have checked, all of these checks i am 99% happy are correct.

spark plugs, new ones used, swapped between firing cylinders, perfect!

leads, checked for continuity, resistance and swapped between firing cylinders, perfect!

coil packs, swapped for known good set, still didnt fire on one side, swapped coil pack wiring non-firing coil fired fine.

PTR, switched I1/OB1 with I2/OB2, non working side of the PTR worked correctly, also swapped PTR with a known good one.

checked all wiring for continuity, resistance, even ran a whole patch wiring harness direct from the ecu to the PTR, nothing is showing up and it will not fire on 2/3.

2/3 is the ECU ignition output channel two, which from what i could gather was not working. i dont have an oscilloscope to check for sure, but i could never get that channel to work.

suspected faulty ECU. swapped for a known good ecu, still no luck, no firing on 2/3.

the car was running fine, stopped it, started ran on two, stopped it, started ran on four, fueled up, started ran on two, stop then started, ran on four, drove home then never ran on four again.

i've practically checked everything in the ignition circuit, things i havent checked but will tomorrow are injectors (smells like unburnt fuel though) compression (pretty sure it isnt a head gasket) i also havent specifically visually checked for spark on 2/3.

its just odd how one ignition channel on the ecu will not work at all, not matter what i try.

*lost*

 

[CLuTZ]

One of those ones aye.


Longshot, but what about a C.A.S!?

 

[to4garret]

i had thought about the CAS, but from a electrical/circuit perspective if the CAS was not working it wouldnt even fire on 1/4.

however, i was thinking that may not be entirely correct, as the CAS has a TDC and Cam position sensor built in. perhaps, possibly the ECU is seeing *maybe* only the TDC signal, firing the first batch fire, waiting for the next signal from the Cam position, not receiving it, hence never firing cylinders 2/3.

another thing...

right now as the car sits, if we start it, it runs on cylinders 1/4 for about 10secs, chucks a check engine light then turns off.

i can pull ecu codes as i dont have a logger for a GSR

 

[CLuTZ]

right now as the car sits, if we start it, it runs on cylinders 1/4 for about 10secs, chucks a check engine light then turns off.

i can pull ecu codes as i dont have a logger for a GSR

I can express mine over if you want bro

 

[to4garret]

i will try the buzzer trick to get the codes tomorrow if i can.

if that doesnt work may have to take you up on that dre

farken thing, has me stumped.

apparently Liberoz may have a similar issue...

 

[Liberoz]

i will try the buzzer trick to get the codes tomorrow if i can.

if that doesnt work may have to take you up on that dre

farken thing, has me stumped.

apparently Liberoz may have a similar issue...

Make that exactly the same issue :x

It may be relay under centre console under radio as this has links to ignition circuit .....
Of all the looms and parts I have in the workshop do you think Ive got just one of those spare relays to try out NO :x

 

[bazeng]

to confirm that the cas / ignition system is working you could pull out the CAS, pull out the spark plugs and leads, sit them on the rocker cover and turn the CAS by hand, the plugs should fire in sequence... this can be done slowly to confirm ignition sequence..

injection sequence can be tested thsi way too.. do you have the LED's that plug into the injector plugs?

 

[Liberoz]

Cas has been check already and is operational, But the Cas was a faulty one now swapped out with a known working one and presto

 

[JayRome]

ground connections nere the ECU and engine bay?

i'v had that problem, but for your sake hope its not the head gasket......

 

[to4garret]

alright,

finally found a analog multimeter today, i cant believe how hard they are to find now.

anyway, a fault code 23 came up, which is the TDC sensor.

so off to find a new CAS.

 

[EVO-00X]

Yep, the CAS would have been the first thing to check :lol: Always pays to have a spare handy in the garage :wink:

 

[to4garret]

to be honest,

why would you check the CAS as the first thing?

remember the issue was 2/3 cylinders not firing, which coincidentally is one coil, which is one channel on the ecu.

biggest issue was not having access to away of reading the error codes and having to diagnose a problem the old fashion way

 

[EVO-00X]

Because the CAS controls when the coils fire and if the wiring is dodgey or the electronics in it are stuffed it wont pick up when to send the signal. The design of the EVO and GSR CAS isnt the best IMO, nor is the plug on top of the unit. Too many times I see peoples wiring bent over with wires corroded and poking through the insulation :roll: Plus the amount of times I've had to change faulty CAS's on people's cars is probably the same amount of times I've had to change faulty ISC's too (too many) :lol: This is why I always keep spare CAS's and ISC's in the garage for when guys bring their car over I can check straight away. I have never had to change a dead coil ever and thats testament to the quality of them now some 15 years later and still going strong.

I have MMCD and a palm pilot but I have not yet had a car I can use it on as it just wont reigster on any of the GSR's and EVO setups I've had over :roll: I can see the benefit in it but I still havent had a chance to use the buggar :roll: Therefore just like you, I've been locating most electrical problems from past experiences and a general understanding of how things work as well

One of my pet hates though is when a shop is guilty of reaching for the diagnostics computer straight away to test things and when the computer cant locate the problem the guy operating it shrugs his shoulders and says he has no fkn idea, blames it on the ECU, charges you $300-500 and you're still no better off from when you walked in the door :lol: Just like a doctor when you know the symptoms you can usually know where to look right away... you may not always get it right 100% of the time, but when you're broken down on the side of the road in the middle of the night or at the drag strip you're gonna wish you had a fair idea of what the problem was then and there so you can get your ass back home :lol:

 

[Mr Gears]

the out come was old CAS had grainy feel when turning the guide which sits in the end of cam, threw a vr4 one in for now and reset timing with T/Light

 

[to4garret]

well finally got a analog multimeter so i could read the error code.

it was 23, which it the CAS, so a huge thanks to Mr Gears overnight express posting a replacement and now everything is happy.

what a head fuck though.

 

[Liberoz]

:lol: that was me actually at the workshop in Brett's laptop, I forgot to sign him out and me in :lol: