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Backfire then No start!

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Old Dec 24, 2008, 07:30 PM
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Backfire then No start!

Cliff notes: (Car has hard time starting in cold, backfired now no fuel prime or spark. AEM?)

I live in alaska. I bought an evo VIII about 2 weeks ago. It had hard problems starting in the cold, and even when turned off for 5 minutes. Temperature reaches 0 to -20 at times.

The car has been mildly modded, with an hks turbo kit, hks twin ignition system, and an AEM EMS.

One day I tryed starting the car. And it just kept cranking. I hooked jumper cables to it and begain trying to start the car with 10 sec intervals, for roughly 5 minutes. Then the car backfired about as loud as a gunshot.

The fuel pump does not prime and there is no spark. Checked all the fuses, replaced the sparkplugs, the fuse pump relays and looked for loose/disconnected wires.

The AEM EMS had a red/white wire comming from the ecu harness disconnected, it looked like the crimp came apart. After debating if i should rehook the wire, I did. Nothing changed.

Im really worried because I am mildly mechanicly inclined, but electrical is my weakness. Im pretty sure its nothing to do with the plugs, wires, or coils, but something deeper like maby the AEM.
Old Dec 25, 2008, 06:56 AM
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Look at the pinout and find out what the wire is for. If that doesn't show anything useful post a cam/crank log
Old Dec 25, 2008, 07:43 AM
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Check that your intercooler hose has not popped off...But look carefully because sometimes its slip off but not completely and you might miss it.

What you described is what exactly happened to me in the past where I couldn't start the car after cranking and cranking and then all of a sudden I hear a loud backfire....!
Old Dec 25, 2008, 08:42 PM
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Originally Posted by alpha
Look at the pinout and find out what the wire is for. If that doesn't show anything useful post a cam/crank log
The red/white wire was for injector #2.

I think its an ECU related problem. After the backfire the fuel pump doesnt prime AND there is no spark. 12v is going to the coils, but I think the AEM is not giving the coils signal.

I need to buy a cable adapter to hook it up to my AEM tomorrow so Ill let you know what i find out.
Old Dec 26, 2008, 05:04 PM
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After hooking up the AEM to my computer, the computer tells me, ECU offline. I tryed a number of different ways to get the AEM to read, but I think Its just faulty. I tryed calling AEM tech suport but they must be off for the holidays.

Ill probably be sending my AEM EMS in so they can have a look at it.
Old Dec 26, 2008, 05:11 PM
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Have you tried bypassing the HKS DLII twin ignition?
Old Dec 26, 2008, 09:10 PM
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Yes I have actually. I switched the connections back to stock but nothing changed.

After reseaching, I believe it has to be the computer. I don't know what else would cause the fuel pump not to prime AND have no spark other then the AEM EMS not giving signal.
Old Dec 27, 2008, 02:26 PM
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How are you trying to hook up to the ECU? Sometimes the usb to serial adaptors can be problematic. Also the specified port for the laptop setting can cause issues. Also, the key must be in the on postion first, then you can access the ECU.

Just trying to throw out some basics....probs I have had.
Old Dec 29, 2008, 08:05 AM
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Also the aem wont give spark or fuel if by some how your crank sensor went bad.

I would definietly look around the forums to find out what usb adapters work with the aem or get a laptop with a serial port already. If your laptop has a pcmia slot you can buy one of these cards http://www.newegg.com/Product/Produc...82E16839328015 it worked perfect for me.

--Josh
Old Dec 29, 2008, 08:45 PM
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Post a cam/crank log so we can help you more
Old Dec 30, 2008, 12:20 AM
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I did some researching and found out my orginal owners post. Very interesting because its [B]exatly what is going on with me[B]

Previous post

I've got a 2005 Evo VIII. I bought the car in California and drove it back up here to Alaska. I got busy one night and left it outside in -30 degree weather for about 4 hours. I did a quick attempt to start it, hoping the engine was still a little warm, and quickly stoped trying because it just seemed too cold. I pushed the car into my garage and let it warm back up. I went to start it after it warmed up for a few hours and got nothing, I pulled the plugs to see if I was getting spark and there was nothing. I had a guy test the Crank position sensor and the cam sensor, both were fine. We then tested the injectors and were recieving no injector pulse which led us to the ecu and not to my ignition. We then tried hooking a laptop up to the ems and it said that the ems was offline, even though it was connected properly. My car has the Aem Ems on it so I called them and decided to send it in to AEM yesterday, Feb 19th. What could be the problem with it? The cold must have did something to my poor ems. Also, can they retrieve all the tuning off of the ems or will I have to start from scratch? There is no tuners up here in Fairbanks, AK so is it only a professionals job or can someone like myself figure it out? I hear they have "base maps" for cars. My car isn't stock, I have a long list of mods to it so maybe there is still some map to go off of? Should I try to contact tuning technologies in Calf. where it was tuned? I know little about the system so any info will help. Thanks, I appreciate it.

If needed here is a list of modifications to my evo:
HKS GT30307s turbo set up @ a conservative 22psi making 417awhp and 333tq
Fynetune custom shortram intake
HKS 280 cams
HKS Adj cam gears
ARP headstuds
HKS 3’indown pipe,testpipe, HKS 20th ann hi-power exaust
-Exedy Twin Carbon clutch
HKS SSQV V2 w/hardpipe BOV
samco radiator hosing
AEM wideband
AEM standalone tuned
HKS DLI-II
HKS EVC limited edit boost controller
Defi boost gauge
HKS T-0 turbo timer
HKS R-type intercooler
walbro 255lph fuel pump
Greddy 1020cc injectors
dynamic turbo alky setup w/ light and 150psi pump
ferrera valves and retainers/ ported & polished head, koyo radiator, torque dampiner, odsse



I bought the car knowing cold starts were a problem. I test drove it, boosted up to 15 psi before tires broke and I was sold. Car ran perfectly. it was around -4 or so when I parked it for the night outside. I tried starting it in the morning but it would crank and try, until it backfired very loud. Thats when I lost spark, and fuel pump prime.

The car is parked in my friends garage. I talked to AEM and i am sending the EMS to them tomorrow. If that was the problem before, it has to be the problem now. I wonder if the cold really effects the EMS or if its the tune. Anyways Ill keep you updated. Thanks alot for everyones feedback
Old Dec 30, 2008, 12:51 AM
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I also should add, I read that for the AEM EMS you must give the ECU time to sync before startup which is usually after the full fuel pump prime. I neglected this because I didnt know better. Would this cause the AEM to fail after so many unsynced attempts?

I hope I make sense. Im learning more and more about this computer every day.
Old Dec 30, 2008, 09:08 AM
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Originally Posted by Ekoy
I also should add, I read that for the AEM EMS you must give the ECU time to sync before startup which is usually after the full fuel pump prime. I neglected this because I didnt know better. Would this cause the AEM to fail after so many unsynced attempts?

I hope I make sense. Im learning more and more about this computer every day.
That wont hurt the aem one bit. It'll just take more cranks before starting. It wont sync till you start cranking the motor cause it has to sync the cam and crank sensors before it will fire.
Old Dec 30, 2008, 11:00 AM
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I'll try to help but there is alot going on.
What is the temperature that you are try to start the car at? If you are below 0 F It's going to be very hard get the car to start. It's just too cold.

Some Facts
-fuel pump doesn't prime after the main relay is on. It only primes the first time you turn the key or if you turn the key off. Wait 30 or so seconds and turn it on again.
-If the car is on speed density pop off IC piping will not effect start.
-you need to get in contact with the ECU. Remove and reinstall software. What cable adapter are you using. Are you trying to connect with the car in the on position.?
Old Jan 3, 2009, 07:39 PM
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In alaska its -30 now, The car is parked in my friends garage. We sent the EMS to AEM to see if its damaged. We tryed connecting it with a serial to usb adapter, a long list of jumbo started scrolling down, while it said ECU offline. After about 30 seconds it gave the laptop the blue screen and crashed.

Im just waiting on AEM to give me a call. Hopefully monday they will contact me and tell me whats up.


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