dreamer1q

Yes, just those plugs were wet. The other ones were black and sooty. All were clean and new when installed 3 days ago.

stephen18

Just to be sure, to check continuity of a the cam position sensor circuit, you put one lead of your multimeter at pin 1 of drivers cam pos sensor connector (red wire) and the other lead at pin 10(red) of 22 pin ecu connector. should have 0 resistance.

then check between pin 2 at sensor connector (green) and pins 11(green), 17(white), 6(white) at the 22 pin ecu connector, pin 2(white) at the crank sensor and pin 2(light blue) at the other cam pos sensor (all these are spliced together in the harness) these should all have 0 resistance between them.

then pin 1 of the crank position sensor and pin 5 at the 22 pin ecu connector (both black)

these are the circuits involved with the code 13

the attached PDF is from the 1994 ls400 manual, even though it says 95 lol

LScowboyLS

please reread my post #13, it is already narrowed down for you to just a couple of possibilities!

once you have verified the driver's side coil/igniter and visually/electrically inspected its associated cap and rotor, then this pretty much just leaves failing ECU capacitors as the only other possibility, and that problem is fairly common on your year.

think about it logically and look at the wiring diagram I posted in post #13 - you see, to only have just those 4 plugs wet, it can only be a couple of things to result in that scenario!

dreamer1q

Stephen, I have done all of that already. As I stated above, only the #5 line had resistence, all others were zero.

Cowboy, I am getting up and out there this morning and I intend on doing your posted test as shown on Youtube. I will reply with an update shortly, and give you a shout once I have information to give you as a result. However, again, I do have a hard time believing that the ECU decided to just suddenly go bad when I was doing a tune up. I'm more prone to believe that the wiring if screwed from being man handled to get around a valve cover. Especially since I have all dead lines at the ECU coming from both cam sensors and half of the crank sensor.

python

iTrader: (4)

+1

besides there is a test procedure posted by yamae that should be the first thing done instead of pointing to the failed ecu caps thread..if the test by yamae is done,then and only then does the failed ecu caps come into play.

LScowboyLS

ECU caps are suspected and should absolutely be replaced any time any of the following are true:

● Yamae's ripple test is failed
● there is any visible leakage whatsover
● troubleshooting (as in this case) identifies ECU as a potential suspect and ECU caps are original (past service life and the known defective variety) and on a highly affected year model (94 in this case) and especially on a car in a highly affected hot humid southern state. (Tenn)

python

iTrader: (4)

replacing ecu caps when the ecu is "suspect" makes no sense when the test yamae presented is a a way of eliminating the need for the caps to be replaced..so any of the other reasons u stated is null and void

stephen18

To rule out the ecu and settle this just swap ecus between the parts car and the car in question, since it ran not too long ago. Assuming the cars are of the same year range

stephen18

Code 13 is a discrepancy or missing inputs between the two cam signals and the crank signal.

codes 14 or 15 would be in issue in the spark circuits.

if you pull a plug lead (not the coil lead) of one that goes to a wet plug, do you get spark there?

i know you said you have spark, but it wasnt clear to me if it was at the coil or at the plug.

If the plugs are wet, its not getting spark, getting spark at the wrong time(or fuel/air charge at wrong time), or getting WAY too much fuel.

dreamer1q

Ok, I did the ECU bypass on the ignitors tonight. The video on it was unspecific as to which lines to test, but after trial and error I was able to figure out that I had to apply ground to the bottom two wires on the ignitor plugs.

I was able to produce spark at both coils, but I think it was a little weak in my opinion of sparks I have seen on other cars in my experience. I could be wrong, but the video spark was larger and louder than mine.

The driver side coil also seemed to not fire everytime I touched off the ground to the ignitor. It might have been my connection, but it just seemed like it was unreliable. However, there was spark on both coils.

Also, can anyone tell me for certian which ignitor plug, left/rear or right/front should have the 5 wires and which should have 4? I just realized tonight that there were different numbers of wires into each plug. Based on the loom memory, I believe I have it correct, but I would like to verify this too.

As always, I eagerly await your input, and thank you all for any help you provide.

dreamer1q

Stephen, I have not verified at the wire, only at the coil. I will do this tomorrow or later tonight if I can sneak back out to the garage again. But currently it has verified spark at the coil.

stephen18

on my car the 4 wire plug goes to the rear ignitor.

dreamer1q

Thank you, that was what I have too.

stephen18

I dont think a weak coil will cause a code 13. maybe a 14/15 but when my car had an exploded rotor it had no codes, so im thinking something is up with the timing or the cam/crank wiring/sensors

LScowboyLS

I think several of the posters in this thread are still missing this key point, if the only wet plugs are in those cylinders controlled by the driver's side (#1) coil (cylinders 1, 4, 6, 7), then the list of potential culprits is very short, as follows:

● ECU
● #1 coil
● #1 igniter
● #1 cap
● #1 rotor
● the associated wiring for the above items

nothing else will selectively fire the passenger side coil's (#2 coil) cylinders and not the driver's sides!

for example, a bad cam sensor or jumped time would affect an entire bank of cylinders, not selectively the ones on the driver's side coil only.

I am not sure what is still unclear on this, everyone please reread my post #13 and look at the diagrams posted below again

PS - the ECU is strongly suspected due to the code 13, which doesn't make a lot of sense if only the driver's side coil's cylinders are wet, however failing ECU capacitors will make an ECU nonsensical! - have you even physically peaked inside the ECU? - or performed Yamae's test?