AEM tune issues, fuel question, and my map

[jtvr4]

Im having an issue with my AEM. The car does not start anymore. I have attached my map, could any of you 3S AEM guys please take a look at it?

Also, when I turn the car to "on" position the fuel pump comes on for a few moments. I see pressure on the gauge goto 35psi, but as soon as the pump turns off the fuel pressure goes to zero.

Any ideas?

[UPP]

So far your map looks good, nothing way out of the ordanary.

Tell a little more about the problem, when did it happen, how....

Did it die when driving, or just no start one morning?

Anything funny last time it was driving?

Ever had problems with AEM starting, or was your tune dialed in pretty well that it always started?

E85 or Gas?

Is it even trying to fire, or just plain cranking?

What have you done/checked? Spark firing? Compression?

What A/F are you running durring cruise/boost? Plugs may be fouled.

The problem with the fuel doesn't sound right either, I'd be looking at the FPR, cause with the ign off it should hold 10-15psi less than when activated. Is it keeping full pressure while cranking?

Also take a log file when you're cranking, make sure you can see the cam and crank pos.


UPP

[jtvr4]

Originally Posted by UPP

So far your map looks good, nothing way out of the ordanary.

Tell a little more about the problem, when did it happen, how....

Did it die when driving, or just no start one morning?

Anything funny last time it was driving?

Ever had problems with AEM starting, or was your tune dialed in pretty well that it always started?

E85 or Gas?

Is it even trying to fire, or just plain cranking?

What have you done/checked? Spark firing? Compression?

What A/F are you running durring cruise/boost? Plugs may be fouled.

The problem with the fuel doesn't sound right either, I'd be looking at the FPR, cause with the ign off it should hold 10-15psi less than when activated. Is it keeping full pressure while cranking?

Also take a log file when you're cranking, make sure you can see the cam and crank pos.


UPP

Ill get a log file while im cranking. The plugs are new, AFR is around 12-16 while driving. Ill have to check if it is keeping pressure while im trying to start the car. That could be the reason it is no longer starting. I have no pressure test the car yet, I can do that Thursday night, and check for spark as well. The car is trying to fire, I can hear it about to start.

The tune has never been dialed in. The car has 680cc injectors.

[pearlwhitwin]

i believe that the car should retain some fuel pressure after the pump turns on (what it is doing is priming the system) so the fact that the gauge is dropping to zero almost instantly could definitely be a problem seeing as how that makes the fuel priming that the pump is trying to do pointless. Hope this makes sense. Can someone confirm this?

[2xmks]

I had the same issue. It turned out to be the fuel relay located under the engine bay fuse box. When you first start the car the fuel pump turns on for about 2 seconds then switchs through this relay. If you relay is bad or if you hotwired this relay and the jumper came loose then your pressure drops to zero right away.

Trying jumping the relay.

Good luck

[UPP]

That does make sense with the fuel relay. Also I once had a problem with the output on AEM. It would fire the car but then a second later shut it off. The fuel pump would go through it's priming, then shut off completely. I was able to start the car (sometimes) but only for about 1-2 seconds. The main boad in the EMS was fried. You can see this durring loggin with AEM. Log the output to your fuel pump, and also open the instructions for 1311 and figure out what the "real name" of the fuel pump output is and log that too. It should be like LS1 or LS10 or something, can't remember.

AEM was acutally shutting it down, and telling me that it was shutting it down, but I couldn't figure out why. It was like it was only running the fuel pump durring cranking, and as soon as I let off, it would kill it. Something with the Switch#1 input was fried. I screwed with the settings of Switch#1 and got it to work, but ultamately had to send the EMS in for repair. So Log Switch #1 too, and see what it's doing.

The fact that it's trying to fire helps, cause you probably have compression and spark. If you're speed/density, you can disconnect the I/C piping and spray some starter fluid into the TB and see if you can get it to fire that way. I usually do that durring hard starts to help make sure I'm not washing down the cylinder walls. Also if it's a fueling problem you'll know right away, cause you (and a friend) can keep the car running with starter fluid....

Hope some of this helps...

UPP

[mehlosTT]

As UPP said.
There should be fuel pressure held during cranking. If there is a leak, you would smell the raw fuel for sure.
AEM ems does not like having any of it's assigned Low Side outputs being tagged with anything that draws 1.5 amps or more ( in case you had added some extras there to a LS.)

[jtvr4]

I have not logged the car yet, I will do that soon. However I pressure checked the system, and fixed alot of the boost leaks.

The car still does not keep fuel pressure. I can start and run the car, however when I turn the car the to the "on." The fuel pump starts and the system pressurizes, than the fuel pressure gauge goes to zero. Yet the car will start, it just takes a few seconds.

Any more idea's?

[UPP]

Well if the car starts and runs...that's good!

Just a guess, if you hold proper fuel pressure when it's running, it increases durring tip-in, than I would have to guess that the back flow on your fuel pump isn't working, but your reg is fine.

UPP