[Diy_efi] info

Mon Oct 31 05:11:35 UTC 2005

Hi Thanks a lot for the many suggestions. I dried the board off and 
bought a can of compressed air and very gently blew under the chips. 
This is a 1991 Circuit Board and as such is all discrete and has no 
surface mount parts. The board was conformally coated and didn't seem to 
have suffered any damage anywhere, and none of the parts seemed to have 
been stressed. Sure enough it fired right off the bat . The check engine 
light is out and every thing seems ok. The little engine seems to "come 
up in the cams" with spades. ie below normal engine rpm it seems ok but 
when it gets over the rpm limit and if I have even about half throttle 
it just flat bombs. verry impressive. 90 in third gear and it is still 
pulling! I haven't had a chance to check the timing and I am going to 
hook up the injectors up to my scope and look around. Thanks a lot for 
all the suggestions.
John A. Allison

Mike wrote:

>At 05:13 AM 10/31/05, you wrote:
>  
>
>>Actually,  they call water the 'universal solvent' for a reason.  I'd start
>>there,  and if it appears there is some residue the water can't get I might
>>try more agressive solvents.
>>    
>>
>
>mmmm, not really - Water is a fairly good ionic solvent but suffers
>from the H to OH equilibria, in that its neutrality is probabilisitc,
>when it gets to actually dissolve anything and is either acidic or caustic
>as a consequence and has repercussions on that basis. Vis a vis
>using water as engine coolant where electrolytic damage is so prevalent,
>the H to OH equilibrium seems to win out regardless of what chemicals
>are added. That green inhibitor needs frequent changing, what I've
>settled on is a tannin type pill which coats the alloy with a protective
>layer and seems to work effectively for long periods. The only downside
>is a little brown sludge if instructions/amounts not precisely adhered to.
>
>Electronic components are not generally designed for immersion
>in water, sure some can tolerate water for cleaning - but for electronics
>Isopropanol is more generally accepted as the universal cleaner
>and might be interpreted as the universal solvent for pollutants
>affecting electronic repair and service. Its also ionic and boards
>shouldnt be left in it for long otherwise there electrolytic effects.
>The good thing about it is - its so volatile and drys off in a few
>mere seconds on some occasions, plenty of ventilation is essential
>as it is combustible and although it smells (ok) I wouldnt breath
>the stuff at all if I could help it.
>
>Interesting your comment re "aggressive" bringing a human emotive
>issue to one of chemical compatibility. What I mean to say is there
>are so many products and processes that have only a compatibility
>issue not one which is either passive or aggressive
>and to use those terms seems discontinuous with solvents. Sure,
>the appearance is either one is more or less aggressive than another
>but it comes down to a sheer compatibility only in the long run.
>
>Also water is (AFAIK) only ionic whereas Isopropanol is ionic and
>covalent in terms of its capacity to dissolve most pollutants which
>can affect electronics, the Isopropanol is designed around for that purpose.
>
>Rgds
>
>Mike
>
>
>
>
>
>
>  
>
>>Again,  just mho.
>>
>>Bill
>>
>>    
>>
>>>From: "Mike" <niche at iinet.net.au>
>>>
>>>At 08:31 AM 10/29/05, you wrote:
>>>      
>>>
>>>>I'd remove it from the case,  wash down the PCB and case good with clear
>>>>clean water,  then blow it with compressed air and let it dry for a few days.
>>>>Once I was sure it was complete dry I'd reassemble it and try running it.
>>>>What id there to loose?
>>>>        
>>>>
>>>Best solvent to remove other things is Isopropyl alcohol (Isopropanol),
>>>let dry normally - dont use compressed air, there is potential for localised
>>>static damage,
>>>
>>>Rgds
>>>
>>>Mike
>>>
>>>
>>>
>>>
>>>
>>>      
>>>
>>>>Just MHO :-)
>>>>
>>>>Bill
>>>>
>>>>From: "Lee M. Lemoine" <llemoine at gmail.com>
>>>>
>>>>        
>>>>
>>>>>John, if antifreeze can damage paint, think about
>>>>>what it may do
>>>>>to a PCB.
>>>>>You could spend a lot of time replacing parts, and
>>>>>still have an 
>>>>>unreliable
>>>>>ECU. Wrecking yard option sounds good. Make sure it
>>>>>comes from a
>>>>>car
>>>>>without a leaky heater core.
>>>>>
>>>>>Geoff H
>>>>>          
>>>>>
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>>>>        
>>>>
>>>Regards from
>>>
>>>
>>>Mike
>>>Perth, Western Australia
>>>VL Commodore Fuse Rail that wont warp or melt !
>>>Twin tyres for most sedans, trikes and motorcycle sidecars
>>>http://niche.iinet.net.au
>>>_______________________________________________
>>>Diy_efi mailing list
>>>Diy_efi at diy-efi.org
>>>http://lists.diy-efi.org/mailman/listinfo/diy_efi
>>>      
>>>
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>>    
>>
>
>
>Regards from
>
>
>Mike
>Perth, Western Australia
>VL Commodore Fuse Rail that wont warp or melt !
>Twin tyres for most sedans, trikes and motorcycle sidecars
>http://niche.iinet.net.au
>_______________________________________________
>Diy_efi mailing list
>Diy_efi at diy-efi.org
>http://lists.diy-efi.org/mailman/listinfo/diy_efi
>
>  
>
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