Pham (Pham@NoBlok.net) wrote on Saturday 24 April 2004 12:25 am:
> My '93 300TT suddenly seemed to me like it wasn't firing all cylinders
> back in 2/04: Engine felt rough and weak, with change in exhaust note
[quoted text clipped - 15 lines]
> THanks,
> Pham
Your mechanic should have replaced them all at once. The labor to get to
the injectors is a lot more than the cost of a single injector. And once
you have the access to one injector, you can easily get to them all. I
recently had Nissan replace all of them on my '90 TT, and it runs much
smoother.
Now if I can only figure out a way to stop my wastegates from sticking....

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Pham - 25 Apr 2004 08:18 GMT
> Pham (Pham@NoBlok.net) wrote on Saturday 24 April 2004 12:25 am:
>
[quoted text clipped - 25 lines]
>
> Now if I can only figure out a way to stop my wastegates from sticking....
Well Thanks so much for the education, and I Will ask that they *all* be
replaced ... BUT what/why clogs them?
If it's sludge then I'd have thought that some solvent would dissolve
the gook... or is it some mechanical (and irreversible) change... like
the injectors droop or physically narrow ? or the blockage is insoluble?
Steve T - 25 Apr 2004 20:28 GMT
> Well Thanks so much for the education, and I Will ask that they *all* be
> replaced ... BUT what/why clogs them?
From my experience they don't get "clogged", the stop working mechanically,
i.e. the pintle get's stuck in it's bore or they electrically fail. They
have a screen behind them to protect them and fuel washes over this screen
to keep it clean so basically they are self cleaning. I guess your mechanic
just calls any failed injector "clogged" to keep things simple for the
customer. Most people never give stuff like this a second thought as to why
it happened.

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Steve
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Peter Hill - 25 Apr 2004 21:04 GMT
>> Well Thanks so much for the education, and I Will ask that they *all* be
>> replaced ... BUT what/why clogs them?
[quoted text clipped - 6 lines]
>customer. Most people never give stuff like this a second thought as to why
>it happened.
It's possible if the solenoid hasn't failed electrically to get them
ultrasonically cleaned. They pump solvent though the injector, while
pulsing the solenoid and subjecting the injector to ultrasonic
vibrations. This breaks down the gum and varnish that makes the
pintle valve stick. A new filter is often fitted at the same time.
Few shops will do this as it means the car is stuck on their premises
while the injectors are sent away to be cleaned. Quicker, warranty on
new parts, don't have possibility that an injector is not recoverable
+ more profit to just fit a new injector. So you either need a loan
set (join a owners club and make some good friends?) and get them out
yourself or have to take the car to an injection specialist with the
cleaning equipment. There are on car processes using solvents but
they just run the thing and hope, they don't verify the spray pattern
or match flow rates.
http://www.babcox.com/editorial/ic/ic30336.htm
--
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Pham - 26 Apr 2004 05:12 GMT
>>>Well Thanks so much for the education, and I Will ask that they *all* be
>>>replaced ... BUT what/why clogs them?
[quoted text clipped - 24 lines]
>
> http://www.babcox.com/editorial/ic/ic30336.htm
Peter-
Cool link! Gees I wish you were around here so I could know a real
scientist was in on my car!
-P
Pham - 26 Apr 2004 05:07 GMT
>>Well Thanks so much for the education, and I Will ask that they *all* be
>>replaced ... BUT what/why clogs them?
[quoted text clipped - 6 lines]
> customer. Most people never give stuff like this a second thought as to why
> it happened.
Steve said that "Sounds like you just have bad luck? It's pretty rare
for them to die and to have 2 die that close together is weird....."
If so... if the fact that one (or even two) have "clogged" doesn't alter
odds that others will fail (any more than rolling snake eyes twice
alters the chance they'll come up on next roll) is it still the smart
move to replace them *all* instead of just the ones that are
malfunctioning?
THanks, Pham
Steve T - 26 Apr 2004 06:29 GMT
> Steve said that "Sounds like you just have bad luck? It's pretty rare
> for them to die and to have 2 die that close together is weird....."
[quoted text clipped - 4 lines]
> move to replace them *all* instead of just the ones that are
> malfunctioning?
One thing you might have going on is something wrong with the fuel. I had a
200SX years ago that was doing something like this. Had 2 stuck injectors,
replaced them and the other 2 stick before it could be delivered. I
replaced them and a week later came back with 2 of the new ones stuck. I
had replaced the filters etc so this time I drained and flushed the tank,
replaced all the injectors again and it was fixed. Never seen anything like
that again but could be what's going on with you?
But yea to be sure it's fixed, you need to replace them all AND clean the
tank etc. Also you need to know what's actually wrong with them. Are they
electrically dead (open circuit), stuck pintel or "clogged" up.

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Steve
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Gordon - 06 Jun 2004 04:35 GMT
>Pham (Pham@NoBlok.net) wrote on Saturday 24 April 2004 12:25 am:
>
[quoted text clipped - 17 lines]
>> THanks,
>> Pham
Your mechanic should have asked if you wanted all of the injectors
replaced since they are easily reached once all the intake runners are
taken off of the engine.
I just hag all my injectors changed (@152K miles). One of the
injectors failed but my mechanic asked me if I wanted all of them
changed since they were right there for them to reach and considering
the milage on my car another injector could fail again.
BTW you should also have the mechanic change the valve cover gaskets
while he has everything off the engine.
Injectors and gasket replacement cost me about $1740.
>Your mechanic should have replaced them all at once. The labor to get to
>the injectors is a lot more than the cost of a single injector. And once
[quoted text clipped - 3 lines]
>
>Now if I can only figure out a way to stop my wastegates from sticking....
> My '93 300TT suddenly seemed to me like it wasn't firing all cylinders
> back in 2/04: Engine felt rough and weak, with change in exhaust note
[quoted text clipped - 11 lines]
> When do these things need to be replaced, or should my mech have advised
> me to run some solvent in my fuel?
Sounds like you just have bad luck? It's pretty rare for them to die and to
have 2 die that close together is weird. BTW most can be changed without
removing the intake manifold if you know how to do it.. $1000 is WAY too
much for this job!

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Steve
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