AEM Infinity 506 in a 3000GT

[mjannusch]

AEM says the idle circuits on the Infinity are fine and everything tests out good. So perhaps I made a mistake on the harness and have the idle steppers connected incorrectly. Guess I have to get the meter out and figure out which sets of pins are which poles of the idle steppers. Sounds like fun...

[mjannusch]

Ugh, yup - worked my way through the electrical diagrams in the service manual and the AEM documentation and I transposed two pins when I set up my adapter harness. Easy enough to fix by just swapping two pins in the molex connector on the AEM side.

I also wasn't getting the A/C command signal, so need to figure out what's happening there also.

[aaronatstate]

At least it was an easy fix!

[mjannusch]

Yeah, looks like AEM has the AC control pins reversed in their Series1/2 chart. I traced it all out in the 3000GT service manual and it looks like I just need to connect a different 3S-side pin to the Infinity input and the AC should be fixed. With luck, those are the last two fixes and I can start tuning it on the road. In my somewhat minimal testing/logging it looked like everything else was working properly.

[DCIV]

You call that minimal? I wouldn’t have gotten past a bunch of wires laid out.


Coop

[mjannusch]

Got the IAC terminals swapped. Double-checked my AC wiring and it *seems* correct. I may have missed some software controls for it when I went through the setup wizard. I'll plug it all back in tomorrow and try again.

[mjannusch]

After my wife left for Austin, TX today (yeah, traveling on Mother's Day - go figure), I spent some time out in the garage. Got the idle situation squared away and now it is idling great at 800 rpm. Needed one of my new "black" IACs instead of an original tan. Thought I had the one that was in there before, but it might've gotten mixed up - so I just plugged in a black one and the Infinity drove it fine so went with that. Could go lower on RPM, but I have cams in the car and it gets a little on the lopey side under 800, and until I get the fuel dialed in, I'll just leave it there.

I also figured out how the software maps switch inputs (which are now called "digital" inputs), and correctly set it to read the AC request from the climate control and trigger the output for the AC clutch relay, so now my AC works again, which is nice. I do still have to figure out how to get it to bump up the idle when the AC is on - not sure how to do that.

I still have to put the front bumper back on, but was hoping one of the two front-mount oil coolers that people owe me would show up. So far, no dice. I'll probably put it all back together this week (if I have time) and then do the FMOC over next winter and just enjoy the car for the summer. I'm sure it will work better with the FMOC so it isn't blocking flow of the side-mount intercooler, but it'll be okay for this year - and I'll be running E85 mostly anyways, so the intake temps aren't as big of a deal.

The only sensor that I'm not sure about yet is the ethanol sensor, and only because there's no ethanol in the tank. I'll have to pick some up and mix it in and see if the ethanol content display goes up.

I would've liked to have it at the UMG, but that's not going to happen. I don't have tuning time on it, and not sure if it is reliable yet - so I'll be driving the Stingray to UMG instead.

[DCIV]

So are you far enough along to say that this version of aem is worth it over the cheaper ones?


Coop

[mjannusch]

Mmmm, tough to say at this point. Considering that I've hardly got any time into tuning it and setting it up, the car runs and is probably able to be driven right now as it sits. I like being able to use AEMnet from the X-Series widebands so that there's no A/D conversion taking place - the controller sends the precise reading in digital format to the Infinity, so there's no guessing if the voltage offsets are correct or any of that foolishness that was there with Series 1 and to a lesser extent Series 2.

The processor is obviously quite a bit faster, as everything happens very fast and you get insane logging resolution. The way it does Flex Fuel is an improvement over Series 2. The software feels pretty solid. So far I'm happy with it, but the proof will be when I start driving the car and tuning it to see how well it runs. It seems like tuning using the new strategies is a lot easier than it was on the old EMS.

[DCIV]

Not that I would ever go this route, just not good enough at trouble shooting, wiring, all that, but I am curious to see how much more you do or don’t like it.


Coop

[mjannusch]

The biggest change is that instead of just a bunch of tables with pulsewidths and correction factors in them, Infinity runs a computational model of your engine and inputs the sensor readings and the information from the tables, and then runs an algorithm against it to determine your fuel and spark. So if you have a fuel pressure sensor and your fuel pump is a little short and you run low on fuel pressure up top it will recalculate the injector pulsewidth with that in mind and correct for it. If there's enough injector and flow volume - the engine will still run fine. Little things like that, which should make the tune be a lot more stable and repeatable versus the older technology.

There are also a lot of programmable safeguards that you can set up, which is nice. Series2 had some of that, but they are more extensive and programmable on Infinity.

So far I like it, but since I'm kind of on my own on a lot of this it is tricky and taking more time than I would've liked. Most of that time is just due to me not having a lot of time to dedicate towards working on the car right now. The actual work put in isn't that bad, and if the next person skips over the mistakes I made and has a guide to help them then it won't be a big deal other than making the harness.

[mjannusch]

I got the front-mount oil cooler all installed, and removed the old side-mount one. I now have all the correct "true" 1999 front end pieces on the car, including the driving lights, intercooler ducting, radiator shroud, underside lip, etc. It turned out really nice. I fired it up, and drove around for a little while, working it through the revs a bit and logging. The Infinity determines the error between what it computes to be the correct amount of fuel for given conditions, and then looks at the actual sensor data and calculates a "New VE" value. I used MegaLogViewer to plot out NewVE as a histogram plot over a copy of my Infinity VE map table, and moved the values from that over into Infinity.

After doing some gentle driving and watching the A/F ratios, I made a pull in 3rd gear with just straight wastegate pressure with ended up right around 8-9 psi of boost (though my Kinugawa gates are supposed to be 1 bar springs). The VE error on the pull for the majority of cells was right around 2%, which I would consider exceptionally good for the 20 minutes or so it took me to tune it to that level. I'm attaching the VDyno plot for good measure. Overall a pretty stable plot with A/F between 11.8:1 and 12.2:1. My target I think was 12.0:1 for this boost level. Boost looks steady, and slightly climbing >5500 rpm. Torque looks good at a peak of 329 ft/lbs, and horsepower at 352 peak. As far as spool, it was essentially at its boost target around 3000 rpm - the ramp should be quicker when I turn on boost control and it isn't feeding pressure the gate until it needs to.

Then when I got back to the house, I tried to open the hood and the hood latch won't release. FUCK. Not sure how I'm going to approach that yet. I suspect I'll have to cut a couple pieces out of the radiator shroud to let me access the bolts holding the latch to the support. That isn't going to be fun.

[DCIV]

I would take the drivers wheel off and the. The fender plastic and see if you can tell if the cable broke somewhere or if you could get another approach than cutting.


Coop

[mjannusch]

I had my son pull on the latch lever while I pushed down on the hood, and I could hear that the cable was trying to actuate the release - so the cable isn't broken. I think I just have to figure out where I need to cut the plastic shroud to get access to the latch bolts. Not much room in there, but I think* I might be able to get my Dremel in there to cut it.

[DCIV]

Sounds like the release spring is broke. I took mine off as it needed so much pressure I didn’t like it with my fiberglass hood. Now I have to pull the latch several times or have someone pull it while I pull up on the hood a little.

I eventually used a women’s hair tie (because a rubber and broke after one heat cycle) and it’s worked for about a year. Lol. But if the cable is working, then it’s the spring, and you can pull up whole the release is pulled it should let go.


Coop

[stealthee]

I would actually try to maybe release the hood cable from the release latch itself and pull extra hard with a pair of vice grips or something first.

[mjannusch]

Tried the plier-pull method, no dice. I'm thinking maybe there's something wedged in there wrong that is not letting the latch move. It was difficult to put the little plastic pins in the flaps for the radiator shroud that come up on the sides of the latch assembly, so I'm thinking I didn't get that fit in there correctly.

[mjannusch]

Okay, I got the hood open. That REALLY sucked. I had to cut out the portions of the radiator shroud, which I now realize I installed incorrectly and that's why the latch wouldn't open. The shroud goes under and behind the latch under the latch cable, instead of in front with the plastic tab going over the latch cable. Whoops.

For future reference to anyone unfortunate enough to make the same mistake - the easiest way to cut access holes through the plastic is with a very hot soldering iron. Get at the three 10mm bolts that bolt the latch to the support frame and the center brace, and use a gearwrench or similar to get the bolts out.

Looks like I broke the little plastic ferrule on the end of the cable trying to get it open, so I need a new cable or I might try to get creative with glue or the 3D printer. I'm guessing that cable isn't easy to replace.

[stealthee]

Matt, I got an extra cable still chilling on the Stealth chassis if you are in need.

[mjannusch]

I ordered one up, but if they end up hard to get I will let you know. Thanks!