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Date:         Tue, 17 Jul 2007 19:43:21 -0700
Reply-To:     David Kao <dtkao0205@YAHOO.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Kao <dtkao0205@YAHOO.COM>
Subject:      Re: ECU and starting question
Comments: To: Joseph Fortino <fortino1@EARTHLINK.NET>
In-Reply-To:  <28374191.1184716557943.JavaMail.root@elwamui-hybrid.atl.sa.earthlink.net>
Content-Type: text/plain; charset=iso-8859-1

That's entirely possible. Normally the ECU is quite reliable. It uses an old Intel Z80 cpu inside (there may be different versions with different CPUS) and an EPROM with a small memory size. There are a few power transistors inside that may be more prone to break down. It is a 30 year old technology but quite durable.

I had 2 or 3 ECU boards that I acquired for research purposes. The hardware is very basic and simple. The trick is in the program. I used to write assembly code for Z80. If I have the source code I can still do it. It is plain simple and reliable.

Today's modern ECUs with OBD2 is a different beast. It's better to leave it alone. The ECU is designed to prvent any attempt of tempering. Imagine if it can be easily tempered there would be no need of smog check, which tracks error code if any exists. Just reset it and go ahead to get the smog check done. It does not work like that. If you reset the error code the smog check system will know it has been reset. The emission check will be rejected instantly.

Sorry if this bores you out. This is really NVC, just like some Subi talks. If you have newer cars and have trouble with OBD2 we can talk about it.

David

--- Joseph Fortino <fortino1@EARTHLINK.NET> wrote:

> I found that my bad ECU awhile back was flooding the plugs with gas.. causing starting issues.. > > Joe 85gl > > -----Original Message----- > >From: most david <dmost@YAHOO.COM> > >Sent: Jul 17, 2007 5:48 PM > >To: vanagon@GERRY.VANAGON.COM > >Subject: Re: ECU and starting question > > > >I'll check, but I think that the pulley is in good shape (i.e., no wobble). > > > >Is the problem with your '87 intermittenet, or does the fuel pump simply never get power? > > > >----- Original Message ---- > >From: Anthony Kimmons <akimmons@GMAIL.COM> > >To: vanagon@GERRY.VANAGON.COM > >Sent: Tuesday, July 17, 2007 3:39:48 PM > >Subject: Re: ECU and starting question > > > > > >Having a similar issue with my 87. No power to fuel pump, but wires > >are good and there is power at the relay. Today, while waiting for new > >relays to ship though, I noticed that my alternator pulley was > >wobbling badly. Pulled it apart and noticed that the wobbling had > >completely messed up one of the contacts on the regulator. Ordered a > >new alternator today. Wondering if this could be the cause of the fuel > >pump not getting the power it needs (?). Any thoughts on this? > > > > > >On 7/17/07, most david <dmost@yahoo.com> wrote: > >> Hi David. Thanks so much for checking out the wiring diagrams. I've swapped the fuel pump > relay with a known working relay, and this didn't fix the problem. I'd like to check the > wiring, and, though I have a Bentley, I'm still learning (or trying to remember) how to read the > diagrams. > >> > >> Can anyone confirm if the 2.1 wiring ('87) is the same as the 1.9 description below (for my > purposes)? > >> > >> Meanwhile, if the engine always starts and runs well once the fuel pump gets initial power > upon turning the key, is it still possible that loose wires at the coil or the ignition module > could be causing the problem. > >> > >> Thanks again for the much needed help. > >> > >> David > >> > >> > >> ----- Original Message ---- > >> From: David Kao <dtkao0205@yahoo.com> > >> To: most david <dmost@YAHOO.COM>; vanagon@GERRY.VANAGON.COM > >> Sent: Tuesday, July 17, 2007 3:08:20 PM > >> Subject: Re: ECU and starting question > >> > >> > >> David, I am not trying to race to answer your question. But I can't help it. > >> > >> I just looked at my Bentley manual at the electrical diagram. There are > >> two wires and one relay you want to check. > >> > >> The relay is naturally the fuel pump relay. Why two wires? one is supplying > >> power to the relay and the other supplies power to the switch controlled > >> by the relay. This switch if activated will power the pump. So if the pump > >> doesn't pump, either the relay is not getting the power or the switch controlled > >> by the relay is not getting power. These two wires are not connected together. > >> Each has its own connection to somewhere else. > >> > >> The wire that feeds power to the switch in the relay is directly connected to > >> the battery. It is always hot as long as the battery is connected. This is > >> shown on the diagram. This makes sense as you don't want fuel to be cut off > >> anytime you are driving. > >> > >> The wire that feeds power to the relay (which activates or deactivates the switch) > >> is coming from the pin #4 of the transistor ignition control module. This pin > >> also has a wire that connects itself to the ignition coil's terminal #15. On the > >> diagram the wire that feeds the switch in the relay comes from this #15 terminal > >> (instead of #4 on the ignition module). But they should be connected together > >> on the #15 terminal of the coil. The coil's #1 terminal also has another wire that > >> goes to the #1 pin of the ignition module. > >> > >> It looks like you may have a loose connection on the #15 terminal of the coil, > >> or you have a loose connection on pin #4 on the ignition module. It's not ECU. > >> But there are wires connecting the ECU and the ignition module. Still it's not > >> likely to be an ECU problem. > >> > >> If you have a Bentley manual this is on the diagram. Well, I am talking about > >> wasserboxer 1.9 engine. If you have a 2.1 it may be or many not be the same. > >> If you have a subi... Oops, forget it. Don't mean to go there. Pardon me. No humor > >> intended. Ask Benny if it is a subi. > >> > >> Hope this helps. > >> > >> David > >> > >> > >> --- most david <dmost@YAHOO.COM> wrote: > >> > >> > I still haven't figured out why the fuel pump gets power intermittently when turning the > >> > ignition key. For those of you that didn't read my posts from the last couple of weeks, > I've > >> > checked the relays, replaced the ignition switch, and tested for power at the fuel pump. > When > >> > the fuel pump gets power, the engine starts every time and runs well. > >> > > >> > A local mechanic is convinced that the ECU is causing the problem based on my > characterization > >> > of the problem. I asked a second mechanic about this, and he didn't think that this was > likely. > >> > I then told the second mechanic that I'm able to start the engine by pushing the van and > >> > popping the clutch (on those rare occassions when turning the key on and off a number a of > times > >> > doesn't result in my hearing the fuel pump come on). Upon hearing this, the second > mechanic > >> > said that he's certain that the ECU isn't causing my problem. > >> > > >> > So, if I can start the engine by popping the clutch, does this definitely mean that the ECU > is > >> > not the source of my intermittent power at the fuel pump upon turning the key to the second > (not > >> > start) position? > >> > > >> > Thanks for the help, > >> > David > >> > > >> > > >> > > >> > ____________________________________________________________________________________ > >> > Building a website is a piece of cake. Yahoo! Small Business gives you all the tools to get > >> > online. > >> > http://smallbusiness.yahoo.com/webhosting > >> > > >> > >> > >> > >> ____________________________________________________________________________________ > >> Be a better Heartthrob. Get better relationship answers from someone who knows. 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