HELP Aem Series 1 EMS Crank No Start Has Spark and Fuel Stumped.

[Tjk2world]

Had a built ka24det running on aem ems series one. It blew so i swapped in a stock motor, time comes around to start it, and the ecu wont connect. So after a while i source a stock uncut harness, wire in the map and iat sensor, and put it in. Couldnt get it to start so i brought it to a shop. They put in a new distributor and messed with the tune a bit and got it to the point where it could be kept alive with throttle, but barely. They tell me AEM is over their heads, call the guy who tunes all the cars around here. So the tuner comes out and tries to tune it but it wont start for him. Car dumps a ton of fuel even at 1% fuel. We couldnt monitor the injector pulse or anything because during cranking everything would freeze, like you couldnt see the engine cranking, but when not cranking everything on screen worked like depressing the throttle showed up for example.
After the tuner said he couldnt tune it, i narrowed down the problem. Wiring is good, grounds are good, ecu seems good, ignition components have tested to be good, timing is good all around, compression is good. The old distributor turned out to have the aem trigger disc in it. Upon swapping the disk over to the dizzy in the motor now, it loses both spark and fuel. If i switch back to the stock disk spark and fuel come back. Everyone is stumped. Everything worked when the car came apart 8 months ago. The best we have gotten from it is some pops and gurgling but nothing close to running.
I have been searching for weeks.

[hanzbrady]

When you say timing is good do you mean mechanical timing or ignition timing, cause it sounds like you have the ignition timing way off. Also put the AEM trigger wheel back in if this is the case, the Nissan disc isn't accurate at high RPM and the AEM will lose sync with it.

[brndck]

have you tried contacting aem? I know henry schelley (sp?) is pretty damn sharp when it comes to this stuff.

[Tjk2world]

Originally Posted by hanzbrady

When you say timing is good do you mean mechanical timing or ignition timing, cause it sounds like you have the ignition timing way off. Also put the AEM trigger wheel back in if this is the case, the Nissan disc isn't accurate at high RPM and the AEM will lose sync with it.

Isnt it odd though how the aem disk i was previously running produces no fuel or spark? If I had the slightest clue how to tune i would be messing around with that.
Mechanincal timing is sound (both chains were found to be out of time when i bought the used motor and were corrected by a shop that i trust). As for ignition timing do you mean in the software or at the distributor? Distributor is for sure in properly and not 180 out, but as far as in the map i dont think the tuner touched ignition much in the software.

[Tjk2world]

Originally Posted by brndck

have you tried contacting aem? I know henry schelley (sp?) is pretty damn sharp when it comes to this stuff.

Should i contact them by email or forum? Series 1 doesnt get tech support anymore so i thought they wouldnt help me. How could i get in touch with henry?

[hanzbrady]

Originally Posted by Tjk2world

Isnt it odd though how the aem disk i was previously running produces no fuel or spark? If I had the slightest clue how to tune i would be messing around with that.
Mechanincal timing is sound (both chains were found to be out of time when i bought the used motor and were corrected by a shop that i trust). As for ignition timing do you mean in the software or at the distributor? Distributor is for sure in properly and not 180 out, but as far as in the map i dont think the tuner touched ignition much in the software.

I was referring to the software. You have to match what the ECU is outputting to the what the engine is set to.

For example you can install the CAS on an SR20det 180* off but correct it in a Megasquirt ECU by changing the tooth #1 angle setting in your ignition settings.

So look around your ignition settings and see if you have anything close to "tooth angle" this tells the ECU when to actually fire a spark.

Also you said that changing the discs gets rid of your fuel and spark, well last I checked the distributor isn't hooked to your fuel pump so fuel shouldn't be effected, unless you're only changing the disc and not setting it in the ECU. The ECU doesn't know what physical components you change, so if you swap discs you have to tell it that you did or else it'll try to fire on the stock Nissan pattern and wont.

[Tjk2world]

Originally Posted by hanzbrady

I was referring to the software. You have to match what the ECU is outputting to the what the engine is set to.

For example you can install the CAS on an SR20det 180* off but correct it in a Megasquirt ECU by changing the tooth #1 angle setting in your ignition settings.

So look around your ignition settings and see if you have anything close to "tooth angle" this tells the ECU when to actually fire a spark.

Also you said that changing the discs gets rid of your fuel and spark, well last I checked the distributor isn't hooked to your fuel pump so fuel shouldn't be effected, unless you're only changing the disc and not setting it in the ECU. The ECU doesn't know what physical components you change, so if you swap discs you have to tell it that you did or else it'll try to fire on the stock Nissan pattern and wont.

Thank you so much for helping! I should have been a little more clear, pump still primes the same way, but with the stock nissan disc i get pops and the plugs are drenched, but with the aem disc they are bone dry. I'll try messing with the ignition settings myself i guess

Any clue why values like engine speed, load, and injector pulse would freeze up during cranking? Is that a symptom of the ecu being shot?