I have other threads up where I struggled for a few summers getting my S4/S5 swap to run in my S4 GXL. Well its finally running and I can get into boost!

1987 S4 GXL with a S5 T2 block swap with S4 sensors and N332 ECU. No emissions components or BAC.

I finally found the main cause of my bogging throttle issue under load to be that the CAS was stabbed incorrectly and was at least 70 degrees off of where it should be. Also, because of so many issues with the sensors on this engine, I took the CAS off my na s4 block and used that. I stabbed it properly and set the timing and everything seems to be running well.

There are still some issues though that need to be addressed, and one is this weird timing issue I can't figure out. I found the issue with the CAS by accident when I was trying to fix the issue that L1 and T1 are firing at the same time, on the same L1 yellow timing mark on the pulley. I can't understand why this is the case. I know you can adjust the CAS to set the timing, but as far as I know you can't set the timing angle in between the L1 and T1 marks.

I don't think the issue is wiring related, because I redid my front and engine harnesses due to melts. I also replaced the trailing coil pack twice, and also the ecu with another N332 ecu.

Can anyone shed some light onto why this would be happening? I don't think the timing light is picking up a reading off the wrong wire, because I'm reading it near the coil pack.

I also don't have any engine codes when checking the green connector near the leading coil pack.

I've also redone all my grounds.

Thanks in advance.

 

dem bad cas got you.

you checked 2? maybe have two plug and visualise to see if that is really what is happening, just let the motor run on one rotor.

 

Doesn't the split between the two happen so fast thats its almost impossible to see? I would at least think so?

 

Yes I would think it would be too fast to see the difference between the two sparks. Can only really see the comparison of the timing marks illuminated with the timing light flash. And they're both showing the L1 leading mark?

 

Yalls eyes suck. :p

 

are u sure your on the right wires?

L1 and L2 are the two next to the battery,( and both leading fire at the same time allways , one is a late waste spark for emissions )

and T1 and T2 are the the pack next to the brake master t2 being closer to the firewall of the two

if warm, and idle is around 750 and the initial set coupler is jumpered they should be visibly different between L1 and T1,

 

Just to add that the Spark plug wires referred to as "L" are LOWER plug wires..and the "T" wires are the TOP plug wires.
Kompressor's statement should actually refer to the COIL Location.
Leading coil (L) is at the front of the Driver's side.
Trailing coil is near the brake booster.

ALSO L1 and L2 Do fire at the SAME TIME so that statement is wrong.

 

crap good catch, I made a typo

the statement "if warm, and idle is around 750 and the initial set coupler is jumpered they should be visibly different between L1 and L2, " should be edited to be L1 and T1... I changed the initial post, but just to clarify

 

Yes I'm definitely checking the correct wires coming off the proper coil packs
L1 L2 and T1 T2 are also labelled on the coil packs (and the spark wires if you install them correctly)
And the're also going to the correct locations on the engine

I didn't jump the initial set coupler, will that really change anything in this case?
and my idle is at about 900. I can drop it to 750 if its really necessary but I would think there should still be a difference in the timing marks between L1 and T1 at 900 RPM.

Has this really never happened to anyone else?

 

take all your plug and lay them out. take your cas out of the front cover( make sure you can know the reinstall procedure) then spin the CAS by hand, you can mimic 200-400 rpm this way, view all plugs firing while slowly turning the CAS and report back.. or make a video and post it. it is possible for the ecu to use 15 degrees of split to make them fire at the same time, i but i have a heard time beleiving the trigger to due that would happen at 900 rpm. im almost certain the stock ecu will use 0-10 split under 1k rpm.