any ideas what could cause or fix this?? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

DDSR240 · 01-18-2009, 05:34 PM

Well my car was breaking up on the dyno when I went for my tune my so we tried a new walbro..no dice so instead of paying them $80.00 times? hrs i desided to bring it home and and try to figure it out well first I checked all the nessecery checks like boost leaks, installed a fp gauge that checked out, cheked the batt. that was good also, checked all grounds and the resistance was like .3 beetween the motor and chassis and all the eccs grounds checked out too exept one on pin 38 or 39 that read .5. Now what I have found out is that when the aem unit is hit or tapped my fuel pump relay clicks and if I tap the aem while the car is running it will shut offinstantly and before the motor completly dies the tach drops to 0. So then I checked to see if I still retianed power to my injectors and coils when the car dies and I do. Now all I have to do is cut the car off and crank it back up and most of the time it will run fine other times I can't rev the motor past 3000or someimes 5.5 and sometimes 7.5 and my favorite 9000 ond all I do is cut the car off and then back on for the rev limit to change. the funny thing is that I sent the ecu back to aem to get it looked at and they said it was fine this was about 4 months ago when I thought the ecu was why my car wouldn't run. If you want you can go to youtube to see a video of it running great .http://www.youtube.com/watch?v=q5NfKM_GKyY

DDSR240 · 01-18-2009, 05:35 PM

My friend said maybe Should try grounding the blk/pink stripe wire because when the fuel pump is off I get 12 volts at that pin on the ecu and when the fuel pump is running I get like .8 volts and when the car cuts off or back i get 12 volts at that pin. ohh and sometimes the fuel pump will keep priming nonstop no pauses.

DDSR240 · 01-19-2009, 11:11 AM

good morning bump

DDSR240 · 01-19-2009, 10:23 PM

good night bump

discosteak · 01-19-2009, 11:14 PM

the AEM box is obiviously bad if you tap it and the car dies

cotbu · 01-19-2009, 11:36 PM

video comments, your car hard starts, then doesn't even idle, you immediately rev the engine to redline+.Genius WTF?

You definitely have wiring issues, start there or if there is another AEM unit available start there. I would be going through the harness with a fine toothed comb, if it were me or if, you hired me!

idlafie · 01-20-2009, 01:26 AM

Quote:

Originally Posted by DDSR240

what I have found out is that when the aem unit is hit or tapped my fuel pump relay clicks and if I tap the aem while the car is running it will shut off instantly

Check the wiring harness going to / connected to the AEM unit...you could have a loose wire in the harness / loose pin in the plug leading to it. Wiggle those wires as your engine idles. If it craps out on you while you do, then it could be the harness & not the AEM unit.

Also, trace the line that runs to your fuel pump relay. Check that line out also along with the ground wires.

Sounds like an electrical problem....Electrical problems are usually a bitch to figure out....

Good luck!!

ID

DDSR240 · 01-20-2009, 08:40 AM

I found out that it only happened when I tap the box, if I hold the ecu still and jerk and pull

on the harness nothing happens. So that makes me lean more to a problem with the ecu

DDSR240 · 01-20-2009, 08:44 AM

[quote=cotbu;2579901]video comments, your car hard starts, then doesn't even idle, you immediately rev the engine to redline+.Genius WTF?

Well like I said he didnt get to finish my tune so there are a couple problems but it was only hard to start b/c my plugs were fouled. Further more I trust that motor to 10,000rpm and I have taken all the nessecery mesures to get it there.

((sr)) kelly · 01-20-2009, 08:53 AM

bump................

DDSR240 · 01-20-2009, 11:38 AM

Well I just got a 240 hARNESS OUT of the junk yard I'm going to power up the ecu with it ,then tap on the box and see if I get the same results to confirm if its the ecu or not.

DDSR240 · 01-22-2009, 06:24 PM

Well after plugging it up to my other 240 sohc and a buddy's red top sr I got simmilar results but while looking through the pinout I noticed that there is a eccs self shut-off relay at pin 4 so I was wondering if it would be safe to unpin that wire and also what is the purpose of the eccs self shut off?

DDSR240 · 01-26-2009, 03:56 PM

well as a last resort before i send my ecu back i plugged up my old stock ecu and I had no such problems like with the aem so I'm sending it back tomorrow

01-18-2009, 05:34 PM	#1
DDSR240 Zilvia Member Join Date: Dec 2006 Location: South Carolina Age: 34 Posts: 259 Trader Rating: (0) Feedback Score: 0 reviews	any ideas what could cause or fix this?? Well my car was breaking up on the dyno when I went for my tune my so we tried a new walbro..no dice so instead of paying them $80.00 times? hrs i desided to bring it home and and try to figure it out well first I checked all the nessecery checks like boost leaks, installed a fp gauge that checked out, cheked the batt. that was good also, checked all grounds and the resistance was like .3 beetween the motor and chassis and all the eccs grounds checked out too exept one on pin 38 or 39 that read .5. Now what I have found out is that when the aem unit is hit or tapped my fuel pump relay clicks and if I tap the aem while the car is running it will shut offinstantly and before the motor completly dies the tach drops to 0. So then I checked to see if I still retianed power to my injectors and coils when the car dies and I do. Now all I have to do is cut the car off and crank it back up and most of the time it will run fine other times I can't rev the motor past 3000or someimes 5.5 and sometimes 7.5 and my favorite 9000 ond all I do is cut the car off and then back on for the rev limit to change. the funny thing is that I sent the ecu back to aem to get it looked at and they said it was fine this was about 4 months ago when I thought the ecu was why my car wouldn't run. If you want you can go to youtube to see a video of it running great .http://www.youtube.com/watch?v=q5NfKM_GKyY __________________

01-18-2009, 05:35 PM	#2
DDSR240 Zilvia Member Join Date: Dec 2006 Location: South Carolina Age: 34 Posts: 259 Trader Rating: (0) Feedback Score: 0 reviews	My friend said maybe Should try grounding the blk/pink stripe wire because when the fuel pump is off I get 12 volts at that pin on the ecu and when the fuel pump is running I get like .8 volts and when the car cuts off or back i get 12 volts at that pin. ohh and sometimes the fuel pump will keep priming nonstop no pauses. __________________

01-19-2009, 11:11 AM	#3
DDSR240 Zilvia Member Join Date: Dec 2006 Location: South Carolina Age: 34 Posts: 259 Trader Rating: (0) Feedback Score: 0 reviews	good morning bump __________________

01-19-2009, 10:23 PM	#4
DDSR240 Zilvia Member Join Date: Dec 2006 Location: South Carolina Age: 34 Posts: 259 Trader Rating: (0) Feedback Score: 0 reviews	good night bump __________________

01-19-2009, 11:36 PM	#6
cotbu Post Whore! Join Date: Sep 2005 Location: SWFL Age: 47 Posts: 3,318 Trader Rating: (3) Feedback Score: 3 reviews	video comments, your car hard starts, then doesn't even idle, you immediately rev the engine to redline+.Genius WTF? You definitely have wiring issues, start there or if there is another AEM unit available start there. I would be going through the harness with a fine toothed comb, if it were me or if, you hired me! __________________ LoverTechnologies "Half Broken Things!"

01-19-2009, 11:14 PM	#5
discosteak Leaky Injector Join Date: Aug 2007 Location: Maryland Age: 35 Posts: 109 Trader Rating: (0) Feedback Score: 0 reviews	the AEM box is obiviously bad if you tap it and the car dies

01-20-2009, 08:40 AM	#8
DDSR240 Zilvia Member Join Date: Dec 2006 Location: South Carolina Age: 34 Posts: 259 Trader Rating: (0) Feedback Score: 0 reviews	I found out that it only happened when I tap the box, if I hold the ecu still and jerk and pull on the harness nothing happens. So that makes me lean more to a problem with the ecu __________________

01-20-2009, 08:44 AM	#9
DDSR240 Zilvia Member Join Date: Dec 2006 Location: South Carolina Age: 34 Posts: 259 Trader Rating: (0) Feedback Score: 0 reviews	[quote=cotbu;2579901]video comments, your car hard starts, then doesn't even idle, you immediately rev the engine to redline+.Genius WTF? Well like I said he didnt get to finish my tune so there are a couple problems but it was only hard to start b/c my plugs were fouled. Further more I trust that motor to 10,000rpm and I have taken all the nessecery mesures to get it there. __________________

01-20-2009, 08:53 AM	#10
((sr)) kelly BANNED Join Date: Jun 2007 Location: Zebulon... NC Posts: 1,035 Trader Rating: (6) Feedback Score: 6 reviews	bump................

01-20-2009, 11:38 AM	#11
DDSR240 Zilvia Member Join Date: Dec 2006 Location: South Carolina Age: 34 Posts: 259 Trader Rating: (0) Feedback Score: 0 reviews	Well I just got a 240 hARNESS OUT of the junk yard I'm going to power up the ecu with it ,then tap on the box and see if I get the same results to confirm if its the ecu or not. __________________

01-22-2009, 06:24 PM	#12
DDSR240 Zilvia Member Join Date: Dec 2006 Location: South Carolina Age: 34 Posts: 259 Trader Rating: (0) Feedback Score: 0 reviews	Well after plugging it up to my other 240 sohc and a buddy's red top sr I got simmilar results but while looking through the pinout I noticed that there is a eccs self shut-off relay at pin 4 so I was wondering if it would be safe to unpin that wire and also what is the purpose of the eccs self shut off? __________________

01-26-2009, 03:56 PM	#13
DDSR240 Zilvia Member Join Date: Dec 2006 Location: South Carolina Age: 34 Posts: 259 Trader Rating: (0) Feedback Score: 0 reviews	well as a last resort before i send my ecu back i plugged up my old stock ecu and I had no such problems like with the aem so I'm sending it back tomorrow __________________

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