Fuel Pump Relay question

[Huw Powell]

>>Don't assume anything.  There must be fifty ways to get an engine to
>>backfire.
> 
> Really?  I thought pretty much the only two reasons for a backfire
> were poor timing (ECU stopping and starting spark randomly falls under
> this) and too rich of a mixture.

Well, without getting into a debate over this, aren't there fifty ways 
that timing can be off, or the mixture too rich?

>>I would say, test items to see what to replace, rather than randomly
>>trying to "think" of what it might be.  
> 
> I don't think in this case it's gonna be that simple.  The car runs
> 99% of the time, so whatever is causing the problem is WORKING (and
> going to test as so) 99% of the time also.  That's the biggest problem
> with this type of problem.

Agreed - that's why I suggested things like a test light to tell what's 
up at the fuel pump power wire.  Because it's such an intermittent 
problem, it's going to be slow going diagnosing it.

>>By the way, methodically cleaning up all the electrical connections
>> under your hood might accidentally fix the problem.
> 
> What should I try cleaning up other than the battery terminals (no
> corrosion on them at all), the battery ground wire (and all wires
> associated with it on the side of the battery tray...), and the ECU
> wires (they've been done in the last year), etc?  Am I forgetting
> something?

All of them.  So what if you clean the washer pump or radiator fan 
contacts, they'll probably like it anyway.  But there are all the sender 
connectors, coil connections, etc.

Good luck!

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/