[s-cars] Fuel Injector Problems

calvinlc@earthlink.net calvinlc at earthlink.net
Tue Oct 18 23:38:48 EDT 2005

A quick update.  I took out the new injector and sprayed it with Gumout.
After placing it back into the fuel rail this immediately caused the car to
run worlds better as well as maintaining the fuel pressure in the rail for a
longer period of time...many minutes above 20 psi vs. a few seconds.  This
leads me to believe that the rich running condition is fouling the
injectors.  It is also doing so in very short order because after letting it
idle for maybe a total of 40 minutes the fuel pressure bleeds off noticeably
quicker...not the rate it was doing before the gumout treatment but it is
definitely quicker.

What in the heck could be causing such a rich condition?  I put the O2
sensor on the oscilliscope and it is only changing from rich to lean about
once every 4-5 seconds at idle.  The car also tries to initially bog when I
give it gas in neutral.  Does this sound like a possible O2 sensor issue?  I
mean it must be REALLY rich to be doing this.

Should I just replace the O2 sensor and find out?  Do you guys recommend the
universal splice in type or the harnessed up type that is like twice as



-----Original Message-----
From: Mark Strangways [mailto:Strangconst at rogers.com]
Sent: Tuesday, October 18, 2005 6:39 PM
To: calvinlc at earthlink.net; s-car-list at audifans.com
Subject: Re: [s-cars] Fuel Injector Problems

Can U find a spare ecu for that model ?
Maybe the ECU is locking up with impedance problems?

Do they hold pressure ok disconnected electrically ?
Maybe it's all just coincidental ?

----- Original Message -----
From: <calvinlc at earthlink.net>
To: <s-car-list at audifans.com>
Sent: Tuesday, October 18, 2005 8:28 PM
Subject: [s-cars] Fuel Injector Problems

> OK guys.  This one has got me totally puzzled.  This is on a '91 200 20
> valve but all experience here is applicable.  I have a problem earlier
> this
> summer where an injector was "hung open."  i.e. it was allowing fuel to
> seep
> through even after the ignition had been shut off.  I replaced the
> injector
> with a new one.  Now the new one is having the same problem not more than
> 40
> miles later.  All the cylinders are showing signs of running rich.  Is it
> possible that they are running so rich that the fuel injectors are getting
> clogged so badly that they are "hanging open"???  Has anybody got any
> ideas.
> BTW, through some wierd coincidences the injectors, the old bad one and
> the
> "new" bad one were in two different cylinders, 4 & 5.  I am at my wits end
> and getting tired of working on this thing.  It has been down for almost
> two
> months due to this problem!  Thanks for any help!
> --Calvin
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