AEM guys...a little help!

[kjlindgr]

I'm trying to do some pre-checks on the newly installed AEM before I actually fire the car up. So far, I've got injectors working as validated by a node light. Moving onto spark, I seem to have nothing.

I hooked the igniter up and just the coil harness. No actual coils are hooked up at the moment. I tried it with coils and I'm not getting spark to the plugs so I just removed them for sake of making life simpler.

The image below is of the parameter list while I'm cranking the engine. One can see that the cam is sync'd correctly, but the 3 coils are marked as being "OFF". In the options, I have them checked as "Active" so I know it's not something dumb like that.

Any thoughts or things to try? Any other values look out of wack?

[Sky80]

Well first off, what RB are you running? Im assuming you converted from maf to map, and iat? Are you touching the throttle(.42%)? Have you messed with the advanced ignition options?

[eh?]

Have you tried reloading the .cal?Try the aem forums.. you may or may not get an answer.

[kjlindgr]

It's a RB26 with a 5-bar MAP. Not sure what the IAT is since I didn't include that in the list for some dumb reason. Kinda important when running a MAP setup.

Throttle is closed. AEM says that under 1% is closed so it's within spec.

[underground]

Battery only shows 8.77 volts, that may be the reason it's not cranking.

[kjlindgr]

I was thinking that too but it shows a full 12.5V when not cranking but jumps down once you kick the starter on. It's a brand spankin' new Optima yellow so I can't believe it's bad. I could get it load tested though.

I guess I could also try to jump it from my truck to see if that makes any difference.

[kjlindgr]

Try the aem forums.. you may or may not get an answer.

Exactly why I tried here first. Some of you guys have them installed and have experience. Plus, the AEM forums don't have as much traffic so getting an answer is usually way slow.

[Eikon]

If you are getting enough power to the starter to rotate the engine.. you must have enough power to get a signal from the coil packs right to the plugs? Or do the coils require a certain load to fire properly?

[kjlindgr]

I would sure think so. The battery has enough power to spin the engine to 160 RPM cranking so I can't imagine that it'd not fire the coils. I don't physically have the coils hooked up but I should still get the signal from the EMS to the igniter.

[zdrifter]

Well there must be some reason its showing low voltage from the battery. I would start off by doing a starter draw test. Make sure its not dropping below 9.7v while cranking. It may be firing the coils but at a very low voltage which causes the mixture in the cylinder not to combust correctly. Start off with that test and go from there. ahhh diagnostics is so much fun!!!

[Eikon]

I don't mean to speak for Karl, but...

the testing was done with the coils off the engine.. he wasn't at all trying to fire the engine.. just doing diagnostics with the new AEM unit.

I'm wondering if there is a bad ground somewhere? Could that be dropping the voltage lower than normal and causing an issue?

Are the harnesses the same between Rb20 and RB26?I could bring my car over and we could try to use my wiring as an example or even to swap over where possible...

[kjlindgr]

Yes, the coils were off of the car so no physical spark was happening. I did have a timing light hooked on the timing loop of the coil harness to see if anything was being triggered by the igniter. This is how I found that no signal was even coming to the igniter. Based on this, I see that the parameter values of the coils are "OFF" even while cranking.

[eh?]

-14.4psig is way too much vacuum for cranking and even for idle too. Are your sensors hooked right? did you select them right from the wizards?

[kjlindgr]

-14.4psig is way too much vacuum for cranking and even for idle too. Are your sensors hooked right? did you select them right from the wizards?

Yes, I very much agree. I have to check to see why my sensor isn't giving a better reading.

I did find out why my coil values show "OFF" all the time. I called AEM and talked to their very helpful staff there and they said that every once in a while you might catch them flickering to "ON" but most of the time, they'll show off. The reason for this is that the coils fire so fast that it can't refresh the screen fast enough. I've seen them flicker a few times but I thought I was just seeing things. It's nice to know I'm not 100% retarded.

[FAST-DATSUN]

you need a min of 9.6 volts when cranking the engine to make ING systen work..

[Sky80]

You said that you hooked the timing loop to the gun, are sure that this works? like have you tried it on another RB? i know i have tried my friends timing light and it does not work on the loop, we had to hook it onto cyl. 1 wiring to get it to work... just throwing stuff out at you

[Sky80]

oh also when i bought my yellow top and tried to fire up my RB the first time it wouldnt, i had to just do it with my girls RSX, after that though its been fine...

[kjlindgr]

Thanks for the suggestions guys. I think I'm making a little progress towards getting this pig up and running.

I've got the battery on the charger as per Mack's suggestion. I haven't run the battery in a car yet since it's brand new but I'm assuming it's a little low on power.

The timing light works...or at least last time I used it, it did. I can try again though because I believe I did loan it out to someone so you never know how things come back from your friends using them. Anyway, I will test that out too.

I think I have my MAP wiring straightened away too. It's reading 1.78V which should be atmospheric pressure. I'm assuming that the AEM software records "MAP as load" PSI values without regard to atmospheric pressure...meaning, that even with the car not running, it will show some pressure reading (won't show 0 PSI with the engine off). Right? If someone can confirm this, I'd appreciate it.

Thanks again everyone!

[eh?]

I think I have my MAP wiring straightened away too. It's reading 1.78V which should be atmospheric pressure. I'm assuming that the AEM software records "MAP as load" PSI values without regard to atmospheric pressure...meaning, that even with the car not running, it will show some pressure reading (won't show 0 PSI with the engine off). Right? If someone can confirm this, I'd appreciate it.

Thanks again everyone!

The aem reads the sensor as psig, meaning key on the gauge will read 0. I don't don't believe you can choose between psig and psia (under Configure:units)I have the 5bar sensor and mine reads about 0 key on and ~ -9psig at idle.

Which sensor do you have?

[kjlindgr]

I've got the AEM 5-bar MAP sensor. I'll check things over again soon and see what's going on. Thanks for the info though. It'll help me get things straightened out.

As far as pins mapped to the sensor, I've also got the AEM Tru Boost controller. I'm utilizing the 5V output from that. Then I'm using a chassis ground for the ground and the signal pin going to the EMS at pin 35. Could it be this combination of pins that's causing me some grief?

[anyotherone]

Try switching the ground for the map sensor to pin 30 on the AEM box, it is a dedicated sensor ground.

I'm using a 3bar GM map sensor, but it didn't read correctly using a chassis ground.

I'm using the 5V on the AEM or pin 48 too, you might try that as well.

[kjlindgr]

Awesome! I will certainly do that and let everyone know. Thanks guys.

[kjlindgr]

After an almost 3 year build, it finally runs under it's own power. Thanks for the help guys!

I still have a lot of tweaking to do as well as some shakedown items to take care of but it runs and idles for the most part. First impression was amazing. The car sounds wicked and I'm horned to get some loose ends wrapped up so I can get it on the street.

Some engine specs for those who care:

• Nissan BCNR33 RB26DETT block• CP Piston 86.5mm oversized pistons• Crower H-beam connecting rods• Connecting rods, pistons, and wrist pins balanced within 1 gram• Crankshaft balanced front to back• Crankshaft journals micro-polished• NISMO main bearings• NISMO connecting rod bearings• Power Enterprises 1.8mm head gasket• Tomei ProCam 280 11.5mm intake camshaft• Tomei ProCam 280 11.5mm exhasut camshaft• Tomei exhaust manifold gasket• Tomei lifters• Tomei titanium valve springs (9500 RPM rated)• Tomei titanium retainers• ARP 190,000 PSI head studs• STR timing pulleys• Greddy timing belt• Nissan GTR N1 water pump• ATI +1000hp rated crank damper• ATI water pump pulley• Greddy power steering pulley• Greddy alternator pulley• Full port matched and polished head• 3 angle valve job• Weaver 4-stage dry sump oil pump• Custom dry sump oil pan

[Booztd 3]

After an almost 3 year build, it finally runs under it's own power. Thanks for the help guys!

I still have a lot of tweaking to do as well as some shakedown items to take care of but it runs and idles for the most part. First impression was amazing. The car sounds wicked and I'm horned to get some loose ends wrapped up so I can get it on the street.

Some engine specs for those who care:

• Nissan BCNR33 RB26DETT block• CP Piston 86.5mm oversized pistons• Crower H-beam connecting rods• Connecting rods, pistons, and wrist pins balanced within 1 gram• Crankshaft balanced front to back• Crankshaft journals micro-polished• NISMO main bearings• NISMO connecting rod bearings• Power Enterprises 1.8mm head gasket• Tomei ProCam 280 11.5mm intake camshaft• Tomei ProCam 280 11.5mm exhasut camshaft• Tomei exhaust manifold gasket• Tomei lifters• Tomei titanium valve springs (9500 RPM rated)• Tomei titanium retainers• ARP 190,000 PSI head studs• STR timing pulleys• Greddy timing belt• Nissan GTR N1 water pump• ATI +1000hp rated crank damper• ATI water pump pulley• Greddy power steering pulley• Greddy alternator pulley• Full port matched and polished head• 3 angle valve job• Weaver 4-stage dry sump oil pump• Custom dry sump oil pan

Nice man, good luck........turbo/manifold setup?

I was also going to say for the MAP sensor, you can blow air into it and watch the voltage rise (on the aem software), you'll know its working correctly then

[kjlindgr]

Nice man, good luck........turbo/manifold setup?

The turbo is a T6 flanged GT4202 on a custom made tubular stainless manifold much like your uber nice Full Race jobbie. I had to custom make one because of the chassis...plus, I have all the tools to do it so I might as well. Turbonetics NewGen 50mm wastegate as well.

[Booztd 3]

The turbo is a T6 flanged GT4202 on a custom made tubular stainless manifold much like your uber nice Full Race jobbie. I had to custom make one because of the chassis...plus, I have all the tools to do it so I might as well. Turbonetics NewGen 50mm wastegate as well.

Nice, T6 eh? Thats ginourmous. I am seeing good boost by like 5k rpm, however I dont have any dyno's yet.....Any reason why you decided to go T6 over a 'twin-scroll' setup?

[kjlindgr]

Nice, T6 eh? Thats ginourmous. I am seeing good boost by like 5k rpm, however I dont have any dyno's yet.....Any reason why you decided to go T6 over a 'twin-scroll' setup?

It's a drag car so I don't care about turbo lag. I need high RPM power only. Nitrous and 2-steps take care of any lag issues.

[Booztd 3]

It's a drag car so I don't care about turbo lag. I need high RPM power only. Nitrous and 2-steps take care of any lag issues.

Gotcha, mine is setup the same way, I will also be experimenting with nitrous once i get some good dyno numbers and the engine built. Its just a matter of time until I'm ready to pull it out to do the work.

[kjlindgr]

Your car is sick. I can't wait till you are pounding out some huge numbers with that thing!

Are there still Nissan meets in Chitown? It would be cool to see your car sometime.

[Booztd 3]

Your car is sick. I can't wait till you are pounding out some huge numbers with that thing!

Are there still Nissan meets in Chitown? It would be cool to see your car sometime.

Thanks and ditto!

I heard the windy city Z club still does some stuff, but I havent been following much Z32 stuff around lately, i've had my head up all the GTR guys' asses lately, LOL