Honda Prelude Forum
 
Go Back   Honda Prelude Forum > Tech-Talk > 4th Gen Honda Prelude

Thread Title
ECU not getting power

 
Reply
 
LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old 06-19-2008, 05:37 AM
importsnrice's Avatar
Silver Member
 
Join Date: Apr 2008
Location: Hoffman Estates IL
Posts: 282
iTrader: (1)
importsnrice is on a distinguished road
Send a message via AIM to importsnrice
ECU not getting power

Hey, after thinking my VAFC stopped working, turns out my ECU isn't getting power. Finally got my new multimeter today and checked voltage to the power wires and nothing. What do you guys think is wrong?

BTW, this all happened right after I installed my VAFC. It worked for about a day and then no power. The VAFC does still worke when I tested it out on the battery
__________________


1993 Honda Prelude VTEC
-ITS FAST! :p

1 MONTH UNTIL D-Day

RIP Danny (Prid388)

-Atif Hussain
Reply With Quote
  #2 (permalink)  
Old 06-19-2008, 07:20 AM
Mdtdnb's Avatar
Platinum Member
 
Join Date: Jul 2007
Location: Colorado Springs! MAD COLD!
Posts: 1,459
iTrader: (2)
Mdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond repute
Send a message via AIM to Mdtdnb Send a message via Yahoo to Mdtdnb
Check the ECU fuse first, if it's good, check the grounds...I'm not that familiar with VAFC and how it works in with the ECU...but how many power wires for the ECU are testing bad? Any other electrical problems start at the same time?
__________________

sig # 2 by OceanBorn


Member #28 of the BB Squad

Quote:
Originally Posted by jimmyznutz View Post
You can NEVER have too many tools.
Quote:
Originally Posted by Brash22 View Post
Custom plates are gay.
Quote:
Originally Posted by Lazer View Post
I try not to hang around people that seem like that, because lets face it you can tell by Oreilys flame decals on their cars from a mile away
Reply With Quote
  #3 (permalink)  
Old 06-19-2008, 07:31 AM
importsnrice's Avatar
Silver Member
 
Join Date: Apr 2008
Location: Hoffman Estates IL
Posts: 282
iTrader: (1)
importsnrice is on a distinguished road
Send a message via AIM to importsnrice
http://www.apexi-usa.com/pdfWiring/14.pdf *WH-1*

I tested voltage across the power and ground and nothing.

Fuse is good and what grounds should I check?
__________________


1993 Honda Prelude VTEC
-ITS FAST! :p

1 MONTH UNTIL D-Day

RIP Danny (Prid388)

-Atif Hussain
Reply With Quote
  #4 (permalink)  
Old 06-19-2008, 08:04 AM
Mdtdnb's Avatar
Platinum Member
 
Join Date: Jul 2007
Location: Colorado Springs! MAD COLD!
Posts: 1,459
iTrader: (2)
Mdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond repute
Send a message via AIM to Mdtdnb Send a message via Yahoo to Mdtdnb
There should be 2 power wires. one that is constant 12V and the other is switched, or 12V with ignition turned on.

For your ground, you may need to make sure the ecu is actually touching the frame of the car because (i could be wrong here) I think part of the ground for that unit is the mounting bolts themselves. Let me find the 4th gen service manual and look at the schematics. more to come.
__________________

sig # 2 by OceanBorn


Member #28 of the BB Squad

Quote:
Originally Posted by jimmyznutz View Post
You can NEVER have too many tools.
Quote:
Originally Posted by Brash22 View Post
Custom plates are gay.
Quote:
Originally Posted by Lazer View Post
I try not to hang around people that seem like that, because lets face it you can tell by Oreilys flame decals on their cars from a mile away
Reply With Quote
  #5 (permalink)  
Old 06-19-2008, 03:57 PM
importsnrice's Avatar
Silver Member
 
Join Date: Apr 2008
Location: Hoffman Estates IL
Posts: 282
iTrader: (1)
importsnrice is on a distinguished road
Send a message via AIM to importsnrice
O, I'll try that too. I'll check the grounds and ground the ECU. I only know of one power wire. Whats the other one?
__________________


1993 Honda Prelude VTEC
-ITS FAST! :p

1 MONTH UNTIL D-Day

RIP Danny (Prid388)

-Atif Hussain
Reply With Quote
  #6 (permalink)  
Old 06-19-2008, 04:50 PM
Prelude13's Avatar
Hi.
 
Join Date: May 2006
Location: awd land :D
Posts: 6,583
iTrader: (2)
Prelude13 Prelude13 Prelude13 Prelude13 Prelude13 Prelude13 Prelude13 Prelude13 Prelude13 Prelude13 Prelude13
VAFC if not wired correctly will cause your car to wreak havoc! especially your ECU...re-check all of the wiring done because VAFC is wired directly to the ECU...



...my SAFC was kaput and almost blew up my motor :(
__________________
'14 Impreza
'04 TSX sold
'90 Si sold


Everyone! Resource guides are here:
5th gen.
4th gen.
3rd gen.
2nd gen.
Reply With Quote
  #7 (permalink)  
Old 06-19-2008, 11:13 PM
importsnrice's Avatar
Silver Member
 
Join Date: Apr 2008
Location: Hoffman Estates IL
Posts: 282
iTrader: (1)
importsnrice is on a distinguished road
Send a message via AIM to importsnrice
Well there is no power so it won't do anything. Did you setup your safc before turning your car on??
__________________


1993 Honda Prelude VTEC
-ITS FAST! :p

1 MONTH UNTIL D-Day

RIP Danny (Prid388)

-Atif Hussain
Reply With Quote
  #8 (permalink)  
Old 06-24-2008, 07:19 AM
importsnrice's Avatar
Silver Member
 
Join Date: Apr 2008
Location: Hoffman Estates IL
Posts: 282
iTrader: (1)
importsnrice is on a distinguished road
Send a message via AIM to importsnrice
Checked fuse, ground, wiring, everything and now I'm stumped. This happened after I tried to plug in the VAFC while the car was running. Any ideas? And would a fried ECU still have power coming in from the wires or no?
__________________


1993 Honda Prelude VTEC
-ITS FAST! :p

1 MONTH UNTIL D-Day

RIP Danny (Prid388)

-Atif Hussain
Reply With Quote
  #9 (permalink)  
Old 06-24-2008, 02:39 PM
Mdtdnb's Avatar
Platinum Member
 
Join Date: Jul 2007
Location: Colorado Springs! MAD COLD!
Posts: 1,459
iTrader: (2)
Mdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond repute
Send a message via AIM to Mdtdnb Send a message via Yahoo to Mdtdnb
if the ecu is fried then it wont matter if you have power/ground or not. have you tested the power wires with the ecu completely removed? if you can get power flow with the ecu out, then at least you have isolated the problem a little more. as far as the ecu itself and whether it is fried or not, you will have to do some testing there too. myabe swap it temporarily with another one to see if that one works. how easy is it to remove the VAFC and try to power it up without that mod?
__________________

sig # 2 by OceanBorn


Member #28 of the BB Squad

Quote:
Originally Posted by jimmyznutz View Post
You can NEVER have too many tools.
Quote:
Originally Posted by Brash22 View Post
Custom plates are gay.
Quote:
Originally Posted by Lazer View Post
I try not to hang around people that seem like that, because lets face it you can tell by Oreilys flame decals on their cars from a mile away
Reply With Quote
  #10 (permalink)  
Old 06-24-2008, 11:00 PM
T.E.L.'s Avatar
Six Figs Club
 
Join Date: Apr 2006
Location: On My Pocket PC
Posts: 5,038
iTrader: (0)
T.E.L. has a reputation beyond reputeT.E.L. has a reputation beyond reputeT.E.L. has a reputation beyond reputeT.E.L. has a reputation beyond reputeT.E.L. has a reputation beyond reputeT.E.L. has a reputation beyond reputeT.E.L. has a reputation beyond reputeT.E.L. has a reputation beyond reputeT.E.L. has a reputation beyond reputeT.E.L. has a reputation beyond reputeT.E.L. has a reputation beyond repute
Send a message via AIM to T.E.L. Send a message via MSN to T.E.L.
Quote:
Originally Posted by importsnrice View Post
Well there is no power so it won't do anything. Did you setup your safc before turning your car on??

how did you wiring yours? with the power on?
__________________

Reply With Quote
  #11 (permalink)  
Old 06-25-2008, 05:43 AM
importsnrice's Avatar
Silver Member
 
Join Date: Apr 2008
Location: Hoffman Estates IL
Posts: 282
iTrader: (1)
importsnrice is on a distinguished road
Send a message via AIM to importsnrice
Battery was unplugged. Car wasn't starting when VAFC was plugged in. So I started the car with it unplugged and then plugged it in and BAM! No more power to the ECU or VAFC.
__________________


1993 Honda Prelude VTEC
-ITS FAST! :p

1 MONTH UNTIL D-Day

RIP Danny (Prid388)

-Atif Hussain
Reply With Quote
  #12 (permalink)  
Old 07-02-2008, 08:32 AM
importsnrice's Avatar
Silver Member
 
Join Date: Apr 2008
Location: Hoffman Estates IL
Posts: 282
iTrader: (1)
importsnrice is on a distinguished road
Send a message via AIM to importsnrice
So I took power from my battery and attached it to the VAFC to see my volt readings for pressure and throttle. They come out to be nothing which makes me believe that the cause has something to do with my harness. What do you guys think it can be?
__________________


1993 Honda Prelude VTEC
-ITS FAST! :p

1 MONTH UNTIL D-Day

RIP Danny (Prid388)

-Atif Hussain
Reply With Quote
  #13 (permalink)  
Old 07-03-2008, 12:05 AM
mizlude's Avatar
Grand Member
 
Join Date: Sep 2006
Posts: 3,045
iTrader: (1)
mizlude has a reputation beyond reputemizlude has a reputation beyond reputemizlude has a reputation beyond reputemizlude has a reputation beyond reputemizlude has a reputation beyond reputemizlude has a reputation beyond reputemizlude has a reputation beyond reputemizlude has a reputation beyond reputemizlude has a reputation beyond reputemizlude has a reputation beyond reputemizlude has a reputation beyond repute
Send a message via AIM to mizlude Send a message via Yahoo to mizlude
the car starts with out it hooked up?????then its the vafc for sure
__________________
mike the miz



Club Ultimate Sleeper

Quote:
Originally Posted by Pooponurhead View Post
Thanks for lookin' out man.
Still love ya mike...no homo

Quote:
Originally Posted by ogsmakdade View Post
that wasn't an earthquake, that was tedd's mom throwing a fit because she was out of twinkies.
Reply With Quote
  #14 (permalink)  
Old 07-03-2008, 02:17 AM
Mdtdnb's Avatar
Platinum Member
 
Join Date: Jul 2007
Location: Colorado Springs! MAD COLD!
Posts: 1,459
iTrader: (2)
Mdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond repute
Send a message via AIM to Mdtdnb Send a message via Yahoo to Mdtdnb
if its the harness, you should be able to physically see a problem. otherwise i'm with Miz, sounds like the vafc is bad. if the car starts when the vafc is removed, then the ecu is fine (if no codes are thrown).
__________________

sig # 2 by OceanBorn


Member #28 of the BB Squad

Quote:
Originally Posted by jimmyznutz View Post
You can NEVER have too many tools.
Quote:
Originally Posted by Brash22 View Post
Custom plates are gay.
Quote:
Originally Posted by Lazer View Post
I try not to hang around people that seem like that, because lets face it you can tell by Oreilys flame decals on their cars from a mile away
Reply With Quote
  #15 (permalink)  
Old 07-03-2008, 02:20 AM
importsnrice's Avatar
Silver Member
 
Join Date: Apr 2008
Location: Hoffman Estates IL
Posts: 282
iTrader: (1)
importsnrice is on a distinguished road
Send a message via AIM to importsnrice
No it doesn't start at all. I think I fried my main. I'll check it out
__________________


1993 Honda Prelude VTEC
-ITS FAST! :p

1 MONTH UNTIL D-Day

RIP Danny (Prid388)

-Atif Hussain
Reply With Quote
  #16 (permalink)  
Old 07-16-2008, 07:33 AM
importsnrice's Avatar
Silver Member
 
Join Date: Apr 2008
Location: Hoffman Estates IL
Posts: 282
iTrader: (1)
importsnrice is on a distinguished road
Send a message via AIM to importsnrice
Also checked main relay. It clicks but there is still no power to the ECU wires. The ECU looks fine and I'm stumped . BTW, the main relay only clicks once.

Would the ECU harness still get power if the ECU was fried/unplugged?

What else can I check besides main relay and fuses that the ECu is getting power?
__________________


1993 Honda Prelude VTEC
-ITS FAST! :p

1 MONTH UNTIL D-Day

RIP Danny (Prid388)

-Atif Hussain
Reply With Quote
  #17 (permalink)  
Old 07-16-2008, 10:35 AM
Mdtdnb's Avatar
Platinum Member
 
Join Date: Jul 2007
Location: Colorado Springs! MAD COLD!
Posts: 1,459
iTrader: (2)
Mdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond reputeMdtdnb has a reputation beyond repute
Send a message via AIM to Mdtdnb Send a message via Yahoo to Mdtdnb
Does your radio and clock keep their memory? They are on the same circuit as the ECU's constant power. If they work, your ECU is getting primary power. it may be the switched power that isn't getting to the ECU or a bad ground. It sounds like a situation where you need to get a volt meter and the schematic and just start testing different parts to the circuit to start isolating the problem. Strange problems with electrical systems are a bad ground 99% of the time.
__________________

sig # 2 by OceanBorn


Member #28 of the BB Squad

Quote:
Originally Posted by jimmyznutz View Post
You can NEVER have too many tools.
Quote:
Originally Posted by Brash22 View Post
Custom plates are gay.
Quote:
Originally Posted by Lazer View Post
I try not to hang around people that seem like that, because lets face it you can tell by Oreilys flame decals on their cars from a mile away
Reply With Quote
Reply

Tags
ecu


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -4. The time now is 08:31 PM.



Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
LinkBacks Enabled by vBSEO 3.6.0 PL2 © 2011, Crawlability, Inc.
vB.Sponsors


Copyright © 2006-2009 PreludeZone.com All Rights Reserved.