okay, a few weeks ago i decided to try brake boost on my em1 and dtc 4 ckp sensor came on. test resistance on dizzy plug and it shows 379 ohms. i swap ckp sensor from another dizzy and car wont's start. test that ckp and it shows nothing. switched to original ckp and car starts right up.

i put in a new aftermarket dizzy today and still code 4. the original dizzy was an aftermarket too. but it been step/run with msd box and ext coil.
a few months ago i had dtc 8 for cyp and swap the one from that same dizzy that i tried for the ckp and it works, no cel.

here's what i've done so far.

*test ckp resistance on dizzy plug, jumper hardness, and stock wire hardness, and ecu pins itself...all showing 379-450 ohms.

*install new dizzy

*test for short but got no reading...even on cyp/tdc pins.

* set timing belt to tdc and up arrows and dots lined up

what kind of reading should i get if there's a short? what's the proper way of testing it? red probe to b15/b16 and black probe to ground, right?

also, on smanager it shows *59/60 for igintion...i'm guessing that's iginition timing. is it possible my timing is off? it should be *16.5 or close to it at idle, right?

hopeful, i didn't fried or mess up the ecu when i tried brake boosting. i know i rev the car high when i tried it...like 7/7.5k.

any inputs/suggestions would be great.

 

Try another ECU - even if it's not an s300 as long as it has a similar tune.

 

don't know anyone that has a tuned ecu. been searching and lots of people are saying that aftermarket dizzy still triggered cel. might have to look for an oem one.

how would i test for short/open ground wire? thanks

 

99% of the time it's a wiring issue, or a corroded pin terminal. Look closely, and clean everything.
The correct way to test crank sensors is with an oscilliscope; I doubt you have one laying around, but for the record some advanced digital multimeters can also measure frequency which can be effective.
I digress, you've ruled out a distributor problem. If I'm wrong then 7riverra7 is right, you might have just accidentally roasted the ecu. Or you have a bad S300, which is increasingly likely.

 

i just ordered an oem dizzy. i'll try that first. if that still doesn't solved the cel issue, then i might have to look/test the wiring more closely.
what's weird is i had a cel for cyp sensor and got that issue fixed. so, just curious i unplug one of the cyp pin from dizzy plug and no code for cyp sensor.

tested resistance at ecu/hardness plug and got good resistance. i'm thinking it might be short to ground somewhere. continuity is good, otherwise i wouldn't get a good resistance from dizzy sensors.

car fires right up but the timing is way off. but, like i said, on smanager it's showing 60 degree ignition timing.

 

You can still get resistance if the wire or connection is deteriorated, checking for continuity between two nodes is not reliable at all. check continuity from one end of the wire to the other end, use an extension if your meter wires aren't long enough, then check for resistance to ground AND positive. Then replace your ECU. With Neptune.

 

tested for continuity from plug that connects to dizzy plug with extension wires to other end of plug that connects to ecu. got continuity. also wired wires straight from dizzy to ecu pins and still cel.
tested/clean the three main grounds in engine bay and by thermostat and they're all good.

will try oem dizzy tomorrow when it arrived. we'll see what happens.

 

pretty sure you ruled out a distributor issue. if your wire readings are correct and your grounds are all solid, 99% sure it's your ECU.

 

after 3 different dizzys and lots of retest of wires, still issue. finally took ecu to try it on friends's car. same code came on as soon as it fires up.
ecu is the culprit for sure now. just wondering whether to have it send to xenocron for repair if it's even worth it or repairable. or just get a new ecu.

 

Just about any ECU can be repaired, the HC1 board runs CKP and it can be swapped out, I've done it several times. There's no reason to pay more and buy a new one unless you're in a rush. However it's very possible it may just be the S300 unit, they're not really that reliable. If that's the case, upgrade to Neptune since they'll already have your ECU anyway.

 

well, decided to send the ecu to have it repaired. hopefully, no more cel when it comes back.