Dirty Injectors

Here's one. I just bought this '91 to replace my totaled '95 last
month. The car had 88k on it and I set about righting what was wrong
with it. In addition to changing the plugs, plugs wires, fuel filter,
cleaning the air filter, cleaning the throttle, I put a a bottle of STP
injector cleaner because the engine hesistated a bit about 2 to 3k RPM.
After this she purred nicely and life was good for the next 2000
miles.

Last night, on the way home from work, she was running quite rough at
2k RPM through 17 miles of mixed driving. I checked all the fore
mentioned items, and they looked good. I put in another bottle of
injector cleaner. This morning on the way to work she started out
rough but got progressively better until about half way when everything
straightended out and she was smooth as ever.

On my old car I'd pour in a bottle of cleaner a couple of times a year.
I once had the injectors cleaned by the dealer (the service rep.s
idea). Is the STP enough to clean the injectors? Do I need to have
the injectors pulled and steam cleaned? Should I start buying better
gas? Or is something else going on completely unrelated to the fuel
injectors.

Jeff Remson
'91 Mariner (Betty) Blue

On Wed, 17 Aug 2005 21:10:12 GMT, wrote in
oups.com:

> On my old car I'd pour in a bottle of cleaner a couple of times a year.
> I once had the injectors cleaned by the dealer (the service rep.s
> idea). Is the STP enough to clean the injectors? Do I need to have
> the injectors pulled and steam cleaned? Should I start buying better
> gas? Or is something else going on completely unrelated to the fuel
> injectors.

Maybe the previous owners had a buildup of crap in the
gas tank and you're using gas that is helping to disolve
it. I was once warned about using gas with alcohol in it
because the alcohol would disolve things gas alone would
not. I don't know how much truth there was in it.

I had a motorcycle that fouled the carbs or plugs because
there was some serious corrosion in the gas tank.

Maybe a tank inspection is in order.

This one was above the crankshaft nose VIN, right?

Leon

wrote:

>Here's one. I just bought this '91 to replace my totaled '95 last
>month. The car had 88k on it and I set about righting what was wrong
>with it. In addition to changing the plugs, plugs wires, fuel filter,
>cleaning the air filter, cleaning the throttle, I put a a bottle of STP
>injector cleaner because the engine hesistated a bit about 2 to 3k RPM.
> After this she purred nicely and life was good for the next 2000
>miles.
>
>Last night, on the way home from work, she was running quite rough at
>2k RPM through 17 miles of mixed driving. I checked all the fore
>mentioned items, and they looked good. I put in another bottle of
>injector cleaner. This morning on the way to work she started out
>rough but got progressively better until about half way when everything
>straightended out and she was smooth as ever.
>
>On my old car I'd pour in a bottle of cleaner a couple of times a year.
> I once had the injectors cleaned by the dealer (the service rep.s
>idea). Is the STP enough to clean the injectors? Do I need to have
>the injectors pulled and steam cleaned? Should I start buying better
>gas? Or is something else going on completely unrelated to the fuel
>injectors.
>
>Jeff Remson
>'91 Mariner (Betty) Blue

--
Leon van Dommelen Bozo, the White 96 Sebring Miata .)
http://www.dommelen.net/miata
EXIT THE INTERSTATES (Jamie Jensen)

On 17 Aug 2005 14:10:12 -0700, wrote:

>Here's one. I just bought this '91 to replace my totaled '95 last
>month. The car had 88k on it and I set about righting what was wrong
>with it. In addition to changing the plugs, plugs wires, fuel filter,
>cleaning the air filter, cleaning the throttle, I put a a bottle of STP
>injector cleaner because the engine hesistated a bit about 2 to 3k RPM.
> After this she purred nicely and life was good for the next 2000
>miles.
>
>Last night, on the way home from work, she was running quite rough at
>2k RPM through 17 miles of mixed driving. I checked all the fore
>mentioned items, and they looked good. I put in another bottle of
>injector cleaner. This morning on the way to work she started out
>rough but got progressively better until about half way when everything
>straightended out and she was smooth as ever.
>
>On my old car I'd pour in a bottle of cleaner a couple of times a year.
> I once had the injectors cleaned by the dealer (the service rep.s
>idea). Is the STP enough to clean the injectors? Do I need to have
>the injectors pulled and steam cleaned? Should I start buying better
>gas? Or is something else going on completely unrelated to the fuel
>injectors.
>
>Jeff Remson
>'91 Mariner (Betty) Blue


Techron - the stuff in the bottle, is recommended by the mechanics I
deal with. Its supposed to clean up the injectors and help clean up
the crud in the intake manifold and the valves (remember, you are
receirculating exhaust gas and sucking crankcase fumes throught he
intake manifold and after a few thousan miles, and it gets nasty in
there.)

Did you inspect the old fuel filter? You may have sediment, water, or
something else, in the tank. If you run less than a quater tank you
may be picking up wha or water at the bottom of the tank, or you may
also have had a bad load or gas.

Draw a sample of gas from the bottom of the tank and inspect it, or
have the tank scoped.

Having gone through a water and dirt in the gas tank (silt in
carburator bowls) experience, this is what I try to do:

Put in a bottle of Heet in the gas tank every six months or so to
scavenge any water.

Put a bottle of Techron once a year (usually before emissions test)

Stick to a single quality gas station whenvern possible, and get a
receipt, it helps track mileage and gives you proof in case of
trouble.

Like good wine, you want gas that has had a chance to rest and you
don't want old stuff. Water and solids are at the bottom of the
tank at the gas station. Avoid filling up from a near empty tank.
and avoid filing up when the station is receiving a delivery, pumping
the gas is stirrs up the muck in the tank

Leon van Dommelen wrote:
> This one was above the crankshaft nose VIN, right?
>
My VIN is clear, thanks. She's a December '91.

> Techron - the stuff in the bottle, is recommended by the mechanics I
> deal with. Its supposed to clean up the injectors and help clean up
> the crud in the intake manifold and the valves (remember, you are
> receirculating exhaust gas and sucking crankcase fumes throught he
> intake manifold and after a few thousan miles, and it gets nasty in
> there.)
>
> Did you inspect the old fuel filter? You may have sediment, water, or
> something else, in the tank. If you run less than a quater tank you
> may be picking up wha or water at the bottom of the tank, or you may
> also have had a bad load or gas.
>
> Draw a sample of gas from the bottom of the tank and inspect it, or
> have the tank scoped.
>
> Having gone through a water and dirt in the gas tank (silt in
> carburator bowls) experience, this is what I try to do:
>
> Put in a bottle of Heet in the gas tank every six months or so to
> scavenge any water.
>
> Put a bottle of Techron once a year (usually before emissions test)
>
> Stick to a single quality gas station whenvern possible, and get a
> receipt, it helps track mileage and gives you proof in case of
> trouble.
>
> Like good wine, you want gas that has had a chance to rest and you
> don't want old stuff. Water and solids are at the bottom of the
> tank at the gas station. Avoid filling up from a near empty tank.
> and avoid filing up when the station is receiving a delivery, pumping
> the gas is stirrs up the muck in the tank

I should have mentioned that the car wasn't driven in the winter. Quite
possible there's been some accumulation int there. I don't know what
these kind of fair weather Miata owners do with the gas when they don't
use their cars. Is suppose it just sits in there until spring. Me, I
drive as many days as I can. That means as long as there's less than 4"
of unplowed snow on the streets of southern New England, I'm miataing
....er mxfivin'...er is there a verb for what it is we do?

How about Lanny's suggestion to me about cleaning the grounds?

Leon

--
Leon van Dommelen Bozo, the White 96 Sebring Miata .)
http://www.dommelen.net/miata
EXIT THE INTERSTATES (Jamie Jensen)

wrote:

> I should have mentioned that the car wasn't driven in the winter. Quite
> possible there's been some accumulation int there. I don't know what
> these kind of fair weather Miata owners do with the gas when they don't
> use their cars. Is suppose it just sits in there until spring. Me, I
> drive as many days as I can. That means as long as there's less than 4"
> of unplowed snow on the streets of southern New England, I'm miataing
> ...er mxfivin'...er is there a verb for what it is we do?
>
You should lay up a car with either a completely full tank or a
completely empty - and I mean removed and drained - tank. The former is
more practical.

Leave 1/4 tank and you may get gum forming. Modern fuel has additives
that are supposed to prevent this, so the risk is quite small.