Check ebay.  I saw many 37820-P0A-A51, is that the auto version?

Hope it helps.

dan

:  Howard Goldstein wrote:
: > Tons of them right in town here but they're all automatics :(
:
:  the auto will work on the stick, but not the other way around.  i'd be
:  inclined to buy one and use it for testing because:
:
:  1. you still need the diagnosis.
:  2. most junkyards offer guarantees, so you can take it back if you get
:  codes.
:
:  the point being that it will allow you to diagnose the problem.  and for
:  $35 [what it costs for a junkyard ecu around here], that's cheap enough
:  to experiment.

I need some of your junkyards around here.  Maybe with the a/t version
so common I'll be able to find it at that price instead of the 4x that
price they're shown at on car-part.  I can live with it throwing codes
if it works until I get the one for the standard and as you and tegger
point out, it'll nail the diag for sure

the auto will work on the stick, but not the other way around.  i'd be
inclined to buy one and use it for testing because:

1. you still need the diagnosis.
2. most junkyards offer guarantees, so you can take it back if you get
codes.

the point being that it will allow you to diagnose the problem.  and for
$35 [what it costs for a junkyard ecu around here], that's cheap enough
to experiment.

:  hgoldste@mpcs.com (Howard Goldstein) wrote in
:  news:1203800764.93878@news.queue.to:
: > Then I tossed the ECM in the fridge for a half hour, put it in the
: > car, and it's perfect.  If it starts acting up in a few hours it
: > sounds like it's time for a new ECM, would you think that's a good
: > bet?
:
:
:
:
:  From what you've observed here, I think you've sort of won the "reverse
:  lottery" and your ECM is actually bad.
:

The problem sort of reminds me of power on reset circuitry problems in
other embedded systems, and some of the cheezy ones rely on caps
charging, and there's all this talk about leaky electrolytic caps.  If
only I had a schematic I'd take a surgical strike at at the rest
components on the ECM.  Instead I guess I'll buy a lottery ticket this
week too to go along with the crapped ECM.

:
:
:  
: > :
: > :  You can call you local dealer (or go there) with your VIN. They
: > :  will be able to tell you what ECM part numbers your car came with.
: >
: > I got it off the ECM, and it matches the part number from the site in
: > California that digests VINs.
:
:
:
:  What site is that?
:

http://www.slhonda.com/partsservice/orderparts.jsp

I can't believe I found it in the browser history

:
:
: >  My next problem is how to locate ecm
: > part # 37820-P0A-A01 and not spending a fortune.
:
:
:
:  As jim beam says, you should be able to find a suitable used ECM quite
:  inexpensively from any U-pull wreckers which stocks older cars.

Thank you jim beam, and tegger. that's the good path to follow.
car-part finds quite a few of these.  The pricing is way different
between down here in Fla and up north, I can get two of them and have
$25 left over afer shipping for the same cost as one is  posted at online
in Tampa.  I'll mail order one if I can't get a better price

:
:  I have a few wreckers in my area of that type. Accords are exceedingly
:  plentiful in those yards.
:
:

Tons of them right in town here but they're all automatics :(

From what you've observed here, I think you've sort of won the "reverse
lottery" and your ECM is actually bad.

What site is that?

As jim beam says, you should be able to find a suitable used ECM quite
inexpensively from any U-pull wreckers which stocks older cars.

I have a few wreckers in my area of that type. Accords are exceedingly
plentiful in those yards.

:  hgoldste@mpcs.com (Howard Goldstein) wrote in
:  news:1202736722.94552@news.queue.to:
:
: > On Mon, 11 Feb 2008 02:21:26 +0000 (UTC), Tegger <tegger@tegger.c0m>
: > wrote:
:
: > :
: > :
: > :
: > :  I'm suspecting a bad ECM just now, but that's *extremely* rare in
: > :  the absence of moisture.
: >
: > I don't want to throw parts at it especially in that you and another
: > person have noted that this sort of failure is so rare.
:
:
:
:  It's /exceedingly/ rare.
:
:  If you have no moisture damage, replacing the ECM is a shot-in-the-dark
:  type of repair, the sort you do only if you can get a part really cheap.
:
:
:
: >
: > :
: > :  Have you checked the ignition switch wiring to make sure you've got
: > :  consistent power when and where you need it? Pull the steering
: > :  column shroud and check the switch under there.
: >
: > The only place I've checked it is at the main relay.  It's now too
: > cold to *)(&$%*(&$% reproduce the problem.
:
:
:
:  Interesting that it happens only in warmer weather...
:

Weird, isn't it?  But not if the car has been run for a half hour or
more, then it's fine.  

Anyway it's a little warmer today and while it was failing I traced
the troubleshooting flowchart all the way through until I wound up at
"replace with known good ECM".

Then I tossed the ECM in the fridge for a half hour, put it in the
car, and it's perfect.  If it starts acting up in a few hours it
sounds like it's time for a new ECM, would you think that's a good
bet?

:    
: >
: > :
: > :  Can you locate a replacement ECM at the wreckers?
: > :
: >
: > Not yet locally.  Online, a couple, yes.  Do you recommend that I pull
: > the ECM to get the part number off the label or should anything pulled
: > from a 94 Accord EX 5speed with the same engine do the trick?
: >
: >
:
:
:  I know ECM's from automatics and manuals are different. An automatic one
:  will work in a manual (albeit with weird errors), but not vice versa.
:  Beyond that I don't know what differences there are.
:
:  You can call you local dealer (or go there) with your VIN. They will be
:  able to tell you what ECM part numbers your car came with.

I got it off the ECM, and it matches the part number from the site in
California that digests VINs.  My next problem is how to locate ecm
part # 37820-P0A-A01 and not spending a fortune.

It's /exceedingly/ rare.

If you have no moisture damage, replacing the ECM is a shot-in-the-dark
type of repair, the sort you do only if you can get a part really cheap.

Interesting that it happens only in warmer weather...

 

I know ECM's from automatics and manuals are different. An automatic one
will work in a manual (albeit with weird errors), but not vice versa.
Beyond that I don't know what differences there are.

You can call you local dealer (or go there) with your VIN. They will be
able to tell you what ECM part numbers your car came with.

:  hgoldste@mpcs.com (Howard Goldstein) wrote in
:  news:1202690026.50199@news.queue.to:
:
: > On Sun, 10 Feb 2008 23:26:26 +0000 (UTC), Tegger <tegger@tegger.c0m>
: > wrote:
: > :  hgoldste@mpcs.com (Howard Goldstein) wrote in
: > :  news:1202670746.29089@news.queue.to:
: > :
: > : > On Sun, 10 Feb 2008 18:12:18 +0000 (UTC), Tegger
: > : > <tegger@tegger.c0m> wrote:
: > :
: > : > :
: > : > :  All I can suggest right now is to monitor the two-second
: > : > :  continuity at the Main Relay plug using an analog VOM. You
: > : > :  should also get continuity at that terminal when you crank the
: > : > :  starter.
: > : >
: > : > see above for # of pins
: > :
: > :
: > :
: > :
: > :  It looks like I'm going to have to update my diagrams.
: > :
: > :  Although all the Honda manual /diagrams/ are the same, the pin
: > :  assignments shown on the Accord ones are slightly different from
: > :  the Civic ones.
: > :
: > :  What I refer to as Terminal 8 is actually Terminal ONE on your car.
: > :
: > :  (And seven pins is all you'll ever find connected on any Main
: > :  Relay.)
: > :
: >
: > Ahhh ok.  This is one I actually checked back at the ECM too.  I
: > didn't want to check resistance there because there's 12v from the
: > battery coming through the other side of that relay.  I did maybe the
: > next best thing:  I measured 12v at my terminal one on the relay all
: > the way back to the ECM A7.  When it's doing it there's battery
: > voltage at A7 and the relay.  When it works I see it's getting pulled
: > to ground.
:
:
:
:  I'm a bit surprised you didn't use the diagrams from the site you
:  referenced before. It tells you pretty much what to expect when. (See
:  the Fuel/Emissions PDF>)

I have the first printing of the service manual.  That's where I came
up with measuring at the ECM.  Someone on a web forum pointed me to
the site with the pdfs over the weekend, makes it handy to talk about
online that's for sure.

I'd feel better running down the troubleshooting charts if I had one
of those breakout boxes for easier access, and if it could be
reproduced more easily.  Luck of the draw and a cold front moved
through so it's in the 50-60s and the problem only happens when it's
in the 70s or 80s and the car is cold (as in not driven for 3 hours or
so)

:
:  You can compare these:
:  http://www.tegger.com/hondafaq/mainrelayoperation/index.html
:  against the DPFs on the site you mentioned.
:
:
: <snip>
:
:
: >
: > Yes, ECM looks great.  I pulled the bracket off and everything to get
: > at the connectors (I'm not blessed with the breakout box doohickey).
: > She's sparkling crystal clean.  No never any leaks (one owner car and
: > you're talking to him)
:
:
:
:  I'm suspecting a bad ECM just now, but that's *extremely* rare in the
:  absence of moisture.

I don't want to throw parts at it especially in that you and another
person have noted that this sort of failure is so rare.

:
:  Have you checked the ignition switch wiring to make sure you've got
:  consistent power when and where you need it? Pull the steering column
:  shroud and check the switch under there.

The only place I've checked it is at the main relay.  It's now too
cold to *)(&$%*(&$% reproduce the problem.  

:
:  Can you locate a replacement ECM at the wreckers?
:

Not yet locally.  Online, a couple, yes.  Do you recommend that I pull
the ECM to get the part number off the label or should anything pulled
from a 94 Accord EX 5speed with the same engine do the trick?

I'm a bit surprised you didn't use the diagrams from the site you
referenced before. It tells you pretty much what to expect when. (See
the Fuel/Emissions PDF>)

You can compare these:
http://www.tegger.com/hondafaq/mainrelayoperation/index.html
against the DPFs on the site you mentioned.

<snip>

I'm suspecting a bad ECM just now, but that's *extremely* rare in the
absence of moisture.

Have you checked the ignition switch wiring to make sure you've got
consistent power when and where you need it? Pull the steering column
shroud and check the switch under there.

Can you locate a replacement ECM at the wreckers?

:  hgoldste@mpcs.com (Howard Goldstein) wrote in
:  news:1202670746.29089@news.queue.to:
:
: > On Sun, 10 Feb 2008 18:12:18 +0000 (UTC), Tegger <tegger@tegger.c0m>
: > wrote:
:
: > :
: > :  All I can suggest right now is to monitor the two-second continuity
: > :  at the Main Relay plug using an analog VOM. You should also get
: > :  continuity at that terminal when you crank the starter.
: >
: > see above for # of pins
:
:
:
:
:  It looks like I'm going to have to update my diagrams.
:
:  Although all the Honda manual /diagrams/ are the same, the pin
:  assignments shown on the Accord ones are slightly different from the
:  Civic ones.
:
:  What I refer to as Terminal 8 is actually Terminal ONE on your car.
:
:  (And seven pins is all you'll ever find connected on any Main Relay.)
:

Ahhh ok.  This is one I actually checked back at the ECM too.  I
didn't want to check resistance there because there's 12v from the
battery coming through the other side of that relay.  I did maybe the
next best thing:  I measured 12v at my terminal one on the relay all
the way back to the ECM A7.  When it's doing it there's battery
voltage at A7 and the relay.  When it works I see it's getting pulled
to ground.

:
:
: >
: >
: > :
: > :  You may also want to chek all the voltage feeds from the ignition
: > :  switch to make sure the ignition switch is actually carrying steady
: > :  current at all its usual "key-on" live locations.
: >
: > I'll do that right now
: >
: > :
: > :  Does the Check Engine light illuminate during the first two-seconds
: > :  of key- on, then go off again right away?
: >
: > It comes on right away, and it goes off two seconds after the fuel
: > pump starts when the pump starts.
:
:
:
:  That's totally screwy.

Man I'm losing my mind over this

:
:
:
: > The delay between the check engine
: > light coming on and the fuel pump start is anywhere from a fraction of
: > a second to 4-5 minutes.  Right now it's back to a fraction of a
: > second.  About an hour ago it was 5 seconds before the fuel pump ran.
:
:
:
: >
: > :  Any codes stored in the ECU? Have you checked?
: >
: > No codes.  Yes I did check (with the jumper in, MIL stays solid on
: > after the fuel pump 2 second cycle runs)
:
:
:
:  Two questions:
:  1) Have you pulled the carpet back to see if the ECM cover has any sort
:  of corrosion on it?
:  2) Do you have any unexplained water leaks onto the front passenger
:  carpet?

Yes, ECM looks great.  I pulled the bracket off and everything to get
at the connectors (I'm not blessed with the breakout box doohickey).
She's sparkling crystal clean.  No never any leaks (one owner car and
you're talking to him)

It looks like I'm going to have to update my diagrams.

Although all the Honda manual /diagrams/ are the same, the pin
assignments shown on the Accord ones are slightly different from the
Civic ones.

What I refer to as Terminal 8 is actually Terminal ONE on your car.

(And seven pins is all you'll ever find connected on any Main Relay.)

That's totally screwy.

Two questions:
1) Have you pulled the carpet back to see if the ECM cover has any sort
of corrosion on it?
2) Do you have any unexplained water leaks onto the front passenger
carpet?

:  hgoldste@mpcs.com (Howard Goldstein) wrote in
:  news:1202662858.33747@news.queue.to:
:
: > On Sun, 10 Feb 2008 10:44:59 +0000 (UTC), Tegger <tegger@tegger.c0m>
: > wrote:
:
: > :
: > :
: > :  Disconnect the Main Relay's plug from the Main Relay. Connect a
: > :  multimeter (set to Ohms) between the plug's Terminal 8 and a body
: > :  ground.
: > :
: > :  Turn the key to "II". At thre same time as you turn the key, watch
: > :  the multimeter carefully. Do you get continuity for two seconds?
: >
: > I will check this when I can reproduce it hopefully later today,
: > ambient is still a little too cool to reproduce long enough to test;
: > there's discernable (maybe a 1/4 second?) delay between going to II
: > and the fuel pump starting, and my DVM doesn't react that quickly.
: > Normally IIRC there's no delay at all.
:
:
:
:  Use an analog VOM. It's a lot easier to see a needle move than a display
:  flicker.

I wish I still had one :(  I'll have to pick a cheap one up
somewhere.  BTW it's a 7 pin plug on the main relay :(

:
:
:    
: >
: > :
: > :  Have you checked the ECU ground at the thermostat housing? Have you
: > :  checked the engine grounds at the transmission housing and from
: > :  valve cover to shock tower?
: >
: > Your memory is good: I tried to find a ground point near both radiator
: > hoses and for the life of me could not,
:
:
:
:  My memory ain't that good.
:
:  The ECU ground is often under/at the thermostat housing. Looks like in your
:  case G101 is actually at the firewall.
:

(it's close to it - the intake manifold is about 6" ahead of the
firewall and there's a nice bolt with a pair of wires going to it)

:
:
:
: > nor do I see one at the
: > transmission housing (standard transmission) Is it an undocumented
: > ground?
:
:
:
:  It's one of the battery cables, shown on pg 23-14 of the manual.
:

OK that one's solid

:
:
:    The electrical system .pdf at this page
: > http://www.dhost.info/accordinfo/ with the grounds at .pdf page 15
: > looks like it's right out of my service manual.  I have G101 very
: > tight after crimping down harder on the two leads attached to it (G101
: > being on the intake manifold; p51 of the .pdf)  
: >
: > I've re-secured all of the documented grounds in the engine
: > compartment and the one back by the fuel pump connector.  I haven't
: > checked grounds under the center console which has been off a couple
: > of times for radio installs.  I ohmed the two grounds at the ECM A23
: > and A24 connector to the vehicle body at the passenger kick
: > panel.
: >
: > It seems like the only thing I haven't checked are the connections
: > through the injector resistors and IAC (p. 14 in the fuelemiss.pdf at
: > that link, p. 12 in the Honda service manual)
: >
: > The valve cover<>shock tower<>body ground is good.
: >
: >
:
:
:  All I can suggest right now is to monitor the two-second continuity at the
:  Main Relay plug using an analog VOM. You should also get continuity at that
:  terminal when you crank the starter.

see above for # of pins

:
:  You may also want to chek all the voltage feeds from the ignition switch to
:  make sure the ignition switch is actually carrying steady current at all
:  its usual "key-on" live locations.

I'll do that right now

:
:  Does the Check Engine light illuminate during the first two-seconds of key-
:  on, then go off again right away?

It comes on right away, and it goes off two seconds after the fuel
pump starts when the pump starts.  The delay between the check engine
light coming on and the fuel pump start is anywhere from a fraction of
a second to 4-5 minutes.  Right now it's back to a fraction of a
second.  About an hour ago it was 5 seconds before the fuel pump ran.

:  Any codes stored in the ECU? Have you checked?

No codes.  Yes I did check (with the jumper in, MIL stays solid on
after the fuel pump 2 second cycle runs)

Use an analog VOM. It's a lot easier to see a needle move than a display
flicker.

 

My memory ain't that good.

The ECU ground is often under/at the thermostat housing. Looks like in your
case G101 is actually at the firewall.

It's one of the battery cables, shown on pg 23-14 of the manual.

 The electrical system .pdf at this page

All I can suggest right now is to monitor the two-second continuity at the
Main Relay plug using an analog VOM. You should also get continuity at that
terminal when you crank the starter.

You may also want to chek all the voltage feeds from the ignition switch to
make sure the ignition switch is actually carrying steady current at all
its usual "key-on" live locations.

Does the Check Engine light illuminate during the first two-seconds of key-
on, then go off again right away?

Any codes stored in the ECU? Have you checked?

:  hgoldste@mpcs.com (Howard Goldstein) wrote in
:  news:1202582202.68680@news.queue.to:
:
: > On Sat, 09 Feb 2008 11:29:54 -0700, motsco_ <motsco_@interbaun.com>
: > wrote:
: > :  Howard Goldstein wrote:
: > : > Anyone ever repair a funky ECM by opening it up and cleaning up
: > : > any bad solder joints?  Will the ECM avoid sending fuel if it sees
: > : > something "wrong" at its sensors although there aren't any codes
: > : > stored?  Should I toss the ECM at this point?
: > : >
: > : > Long nauseating details and plea follow:
: > : >
: > :
: > :  --------------------
: > :
: > :  If you sit there with key in position II and nothing happens (no
: > :  fuel pump), smack the dash on the left side. If the fuel pump goes
: > :  GzzzzzzCLICK, the car will now start. They NEVER fail while the
: > :  engine is running because the vibration makes the bad solder
: > :  connection work enough.
: > :  Resolder or replace the relay.
: >
: > Hi, we chatted about this a few months ago.  Neither resolder nor
: > replace makes no difference.  Sitting there with the key on II for a
: > few minutes and it starts working.  The ECM isn't pulling the second
: > relay down :(
: >
:
:
:
:  Disconnect the Main Relay's plug from the Main Relay. Connect a multimeter
:  (set to Ohms) between the plug's Terminal 8 and a body ground.
:
:  Turn the key to "II". At thre same time as you turn the key, watch the
:  multimeter carefully. Do you get continuity for two seconds?

I will check this when I can reproduce it hopefully later today,
ambient is still a little too cool to reproduce long enough to test;
there's discernable (maybe a 1/4 second?) delay between going to II
and the fuel pump starting, and my DVM doesn't react that quickly.
Normally IIRC there's no delay at all.  

:
:  Have you checked the ECU ground at the thermostat housing? Have you checked
:  the engine grounds at the transmission housing and from valve cover to
:  shock tower?

Your memory is good: I tried to find a ground point near both radiator
hoses and for the life of me could not, nor do I see one at the
transmission housing (standard transmission) Is it an undocumented
ground?  The electrical system .pdf at this page
http://www.dhost.info/accordinfo/ with the grounds at .pdf page 15
looks like it's right out of my service manual.  I have G101 very
tight after crimping down harder on the two leads attached to it (G101
being on the intake manifold; p51 of the .pdf)  

I've re-secured all of the documented grounds in the engine
compartment and the one back by the fuel pump connector.  I haven't
checked grounds under the center console which has been off a couple
of times for radio installs.  I ohmed the two grounds at the ECM A23
and A24 connector to the vehicle body at the passenger kick
panel.

It seems like the only thing I haven't checked are the connections
through the injector resistors and IAC (p. 14 in the fuelemiss.pdf at
that link, p. 12 in the Honda service manual)

The valve cover<>shock tower<>body ground is good.

Disconnect the Main Relay's plug from the Main Relay. Connect a multimeter
(set to Ohms) between the plug's Terminal 8 and a body ground.

Turn the key to "II". At thre same time as you turn the key, watch the
multimeter carefully. Do you get continuity for two seconds?

Have you checked the ECU ground at the thermostat housing? Have you checked
the engine grounds at the transmission housing and from valve cover to
shock tower?

:  Howard Goldstein wrote:
: > Anyone ever repair a funky ECM by opening it up and cleaning up any
: > bad solder joints?  Will the ECM avoid sending fuel if it sees
: > something "wrong" at its sensors although there aren't any codes
: > stored?  Should I toss the ECM at this point?
: >
: > Long nauseating details and plea follow:
: >
:
:  --------------------
:
:  If you sit there with key in position II and nothing happens (no fuel
:  pump), smack the dash on the left side. If the fuel pump goes
:  GzzzzzzCLICK, the car will now start. They NEVER fail while the engine
:  is running because the vibration makes the bad solder connection work
:  enough.
:  Resolder or replace the relay.

Hi, we chatted about this a few months ago.  Neither resolder nor
replace makes no difference.  Sitting there with the key on II for a
few minutes and it starts working.  The ECM isn't pulling the second
relay down :(

--------------------

If you sit there with key in position II and nothing happens (no fuel
pump), smack the dash on the left side. If the fuel pump goes
GzzzzzzCLICK, the car will now start. They NEVER fail while the engine
is running because the vibration makes the bad solder connection work
enough.
Resolder or replace the relay.

'Curly'

Anyone ever repair a funky ECM by opening it up and cleaning up any
bad solder joints?  Will the ECM avoid sending fuel if it sees
something "wrong" at its sensors although there aren't any codes
stored?  Should I toss the ECM at this point?

Long nauseating details and plea follow:

Recap: 94 Accord with the classic main relay (PGM-FI) symptoms (no
fuel pump sound for 2 seconds as required when starting, check engine
light on, can't start) with a twist: It only fails in a cold car when
ambient is around above about 70F/27C, *and* leaving the key in the II
(IGN) position for anywhere from 1 to 4 minutes has always allowed the
second relay and then the fuel pump to kick in, CIL goes off and we're
off.  Never a problem while driving, and if the engine is warm it's
never a problem starting.  It also isn't a problem when the entire car
has cooled to the low 60s/low 20s F/C or below.  Cranking it doesn't
help.

What I've done: I've verified there's no 12v back at the fuel pump
when this happens but for good reasonI've measured battery voltage
at the relay pins 6 (good) and 1 (bad) and back at the ECM A25&B1 and
A7 (these are the connections to the relay) where it's good and bad
(both at Vbatt).  I've jumpered the service connector and the CIL
stays on all the time.  I've got good grounds at the ECM A connector
and the PGM-FI.

What seems to be busted: WTF is up with my ECM?  The skiz show the
fuel pump relay in the PGM-FI won't close unless the ECM pulls down
its A7 (which is PGM-FI pin 1).  It doesn't pull it down, not unless
the car is left in II/IGN for a couple of minutes under the conditions
above.

Some specific questions:

- What else am I missing?  

- Does the ECM look for other things, a sensor in a sane range or
something other than battery voltage coming off of PGM-FI 6, before
it'll turn on the fuel pump for the 2 seconds?

- Is it worth cracking open the ECM to reheat any obviously flakey
solder joints?  Can the ECM be cracked open easily?

- Anyone have a compatible ECM they'd loan me to do a swap check if
I've ruled out everything else?