Greg5OH

What is a good coils resistance on a 2000 ls400? do you jsut measure resistance across the two blade terminals?

LScowboyLS

$15 and all of your questions shall be answered!

Greg5OH

somebodys gotta know it..

Greg5OH

I got the service manual. Nothing about ignition coil resistance. Every other resistance, no coil resistance.
Good I didnt waste 15 bucks on that

LScowboyLS

it's in the service manual, if you have the genuine article

Yamae

A wise guy wouldn't ask such a question. It is a vain to know the internal resistances for the ignition unit after 98 except the insulation resistance.

LScowboyLS

Yamae can you expand on that comment so that the non-electrical engineers here will understand?

sha4000

iTrader: (1)

Read this, I believe this is what Yamae is talking about. It seems that with coil on plug (COP ) ignition systems ( 98 and up LS400s ) that coils rarely go bad. Most times it's the insulator boot so check that first.

Yamae

Come to think of what's inside of the ignition unit, you will know how it's useless to measure the resistances.

The ignition unit after 98 is not simple coils and the core any more. It's a module and it also contains semiconductors and resistors as well. Coils are connected to the drive circuit and only a secondary winding of the high voltage side is exposed and you have no idea to check the resistance of both end of coils. Other terminals are connected to the drive circuits which can't be judged the goodness only measuring the resistance.

A classic style of mechanics/owners don't know modern engines well enough and waste a lot of time and efforts just trying to measure the resistance. It's not a smart idea to troubleshoot trying to measure only that. A smart guy can check it by a simple, better and quick way. Are you interested in how to do it?

I'm ready to introduce the way to people but I hope you would donate 1 US dollar to those who are still suffering from the Biggest Quake and Tsunami disaster happened 3 years ago in Japan.

sha4000

iTrader: (1)

I didn't see that coming.

python

iTrader: (4)

in this case u would have a specific cylinder # misfire..switch that coil out to another cylinder...clear the codes and see if the code changes.

Greg5OH

problem is there are no codes. its a totally random engine stutter. Feels liek all 8 of them stopped firing for a split second. pretty violent.

LScowboyLS

how often does it happen, and when was the last time you checked for codes?

just because there is no check engine light on, doesn't mean there are no codes

Greg5OH

i checked after i got home from it happeneing once on my little trip to the gym.
happens randomly. happened 6-7 times on my 250 mile trip once, then few days later on the way back it didnt do it at all. sometimes will do it when engine is bone cold, other times at operating temp. no predicting it, no pattern,

LScowboyLS

a crank sensor going out could do this, or even a cam sensor (either the sensors themselves or a short in the wiring) but these situations would typically register a code.