88 5.0 failed emmisions.

Hey all! You probably have been seeing all my recent posts about the use 88
5.0 with t-tops that I just bought. I took it today to get the emmisions
tested and failed (Tennessee).
HC: 1446 (max allowable 220)
CO: 2.35 (max allowable 1.20)

I emailed the guy I bought it from and asked him if he had done any mods or
disconnected anything that might cause me to be dumping so much gas. I'm
getting about 30-40miles for half a tank. He said he "put a 160 degree
t-stat in it for more power. That keeps it in openloop at idle which is a
very rich condition. Try putting in a 180 or 190."

Would just the thermostat cause it to dump hat much fuel and get readings
that bad? What is the stock thermostat rated for and I'll pick one of those
up at autozone? I have been driving it out in the hot sun with the AC on
and I haven't notice it running any hotter than my other mustang.

If the t-stat woldnt cause this much of a bad reading then I can take it to
the local BP shop and for $70 they said they can debug the vehicle and tell
me exactly whats wrong that is causing me to fail.

Thanks!
--Cameron

Cameron wrote:
> Hey all! You probably have been seeing all my recent posts about the use 88
> 5.0 with t-tops that I just bought. I took it today to get the emmisions
> tested and failed (Tennessee).
> HC: 1446 (max allowable 220)
> CO: 2.35 (max allowable 1.20)
>
> I emailed the guy I bought it from and asked him if he had done any mods or
> disconnected anything that might cause me to be dumping so much gas. I'm
> getting about 30-40miles for half a tank. He said he "put a 160 degree
> t-stat in it for more power. That keeps it in openloop at idle which is a
> very rich condition. Try putting in a 180 or 190."
>
> Would just the thermostat cause it to dump hat much fuel and get readings
> that bad? What is the stock thermostat rated for and I'll pick one of those
> up at autozone? I have been driving it out in the hot sun with the AC on
> and I haven't notice it running any hotter than my other mustang.
>
> If the t-stat woldnt cause this much of a bad reading then I can take it to
> the local BP shop and for $70 they said they can debug the vehicle and tell
> me exactly whats wrong that is causing me to fail.

The computer will cause the engine to run rich until the normal engine
operating temperature is reached which is approximately 190 degrees.
Running rich will definitely affect the emissions readings. Also,
running the engine cooler causes more wear on metal parts and bearing
surfaces. You should change back to the OEM thermostat for this reason
alone. It could very well solve your emissions problems too. Until the
thermostat is replaced I wouldn't even bother with running the codes.
If it still fails the test then run the codes.

Thanks for that info. I will 100% be slapping a new $5 thermostat from
autozone in there today. I was just wondering if that alone could cause
such a drastic bad reading?

Is there any way a regular guy like me could tell if it's helping alot, once
I put the stat in, before I take it back to the emissions place?

I figure I will dump some fuel injector cleaner in there while I'm at it and
maybe change all the spark plugs. Then I'll fill the tank back up and
cruise around for a bit. If I drive 20 miles and dont use much gas then I
can assume it's better and I'll try the emissions test again tomorrow.

> The computer will cause the engine to run rich until the normal engine
> operating temperature is reached which is approximately 190 degrees.
> Running rich will definitely affect the emissions readings. Also, running
> the engine cooler causes more wear on metal parts and bearing surfaces.
> You should change back to the OEM thermostat for this reason alone. It
> could very well solve your emissions problems too. Until the thermostat
> is replaced I wouldn't even bother with running the codes. If it still
> fails the test then run the codes.

Cameron wrote:
> Thanks for that info. I will 100% be slapping a new $5 thermostat from
> autozone in there today. I was just wondering if that alone could cause
> such a drastic bad reading?
>
> Is there any way a regular guy like me could tell if it's helping alot, once
> I put the stat in, before I take it back to the emissions place?

If a car is running rich you will see black smoke coming out of the tail
pipes and/or have a faint oder of gasoline. Other than this you will
need the emissions test to be sure.

> I figure I will dump some fuel injector cleaner in there while I'm at it and
> maybe change all the spark plugs. Then I'll fill the tank back up and
> cruise around for a bit. If I drive 20 miles and dont use much gas then I
> can assume it's better and I'll try the emissions test again tomorrow.

An improvement in gas mileage could be another indicator. As for fuel
injector cleaner, I suggest getting a can of BG fuel injector cleaner.
It is a little pricey at $20/can but it works much better than the cheap
brands sold at auto parts stores.

>> The computer will cause the engine to run rich until the normal engine
>> operating temperature is reached which is approximately 190 degrees.
>> Running rich will definitely affect the emissions readings. Also, running
>> the engine cooler causes more wear on metal parts and bearing surfaces.
>> You should change back to the OEM thermostat for this reason alone. It
>> could very well solve your emissions problems too. Until the thermostat
>> is replaced I wouldn't even bother with running the codes. If it still
>> fails the test then run the codes.
>
>
>

So if I run the car at idle in tmy driveway with the bunk thermostat in I
should see a little smoke and maybe smell some gas?

I havnt notice any driving around town, but then again I wasnt behind the
car looking at the exhaust.

"Michael Johnson, PE" > wrote in message
...
> Cameron wrote:
>> Thanks for that info. I will 100% be slapping a new $5 thermostat from
>> autozone in there today. I was just wondering if that alone could cause
>> such a drastic bad reading?
>>
>> Is there any way a regular guy like me could tell if it's helping alot,
>> once I put the stat in, before I take it back to the emissions place?
>
> If a car is running rich you will see black smoke coming out of the tail
> pipes and/or have a faint oder of gasoline. Other than this you will need
> the emissions test to be sure.
>
>> I figure I will dump some fuel injector cleaner in there while I'm at it
>> and maybe change all the spark plugs. Then I'll fill the tank back up
>> and cruise around for a bit. If I drive 20 miles and dont use much gas
>> then I can assume it's better and I'll try the emissions test again
>> tomorrow.
>
> An improvement in gas mileage could be another indicator. As for fuel
> injector cleaner, I suggest getting a can of BG fuel injector cleaner. It
> is a little pricey at $20/can but it works much better than the cheap
> brands sold at auto parts stores.
>
>>> The computer will cause the engine to run rich until the normal engine
>>> operating temperature is reached which is approximately 190 degrees.
>>> Running rich will definitely affect the emissions readings. Also,
>>> running the engine cooler causes more wear on metal parts and bearing
>>> surfaces. You should change back to the OEM thermostat for this reason
>>> alone. It could very well solve your emissions problems too. Until the
>>> thermostat is replaced I wouldn't even bother with running the codes. If
>>> it still fails the test then run the codes.
>>
>>

Cameron wrote:
> So if I run the car at idle in tmy driveway with the bunk thermostat in I
> should see a little smoke and maybe smell some gas?

If it is running very rich you should.

> I havnt notice any driving around town, but then again I wasnt behind the
> car looking at the exhaust.

One other thing to do is disconnect the battery for 30 minutes while
changing the thermostat. This will clear the computer buffer and allow
it to relearn your driving habits based on the new operating
temperatures. Drive it around a few days before doing the emissions test.

> "Michael Johnson, PE" > wrote in message
> ...
>> Cameron wrote:
>>> Thanks for that info. I will 100% be slapping a new $5 thermostat from
>>> autozone in there today. I was just wondering if that alone could cause
>>> such a drastic bad reading?
>>>
>>> Is there any way a regular guy like me could tell if it's helping alot,
>>> once I put the stat in, before I take it back to the emissions place?
>> If a car is running rich you will see black smoke coming out of the tail
>> pipes and/or have a faint oder of gasoline. Other than this you will need
>> the emissions test to be sure.
>>
>>> I figure I will dump some fuel injector cleaner in there while I'm at it
>>> and maybe change all the spark plugs. Then I'll fill the tank back up
>>> and cruise around for a bit. If I drive 20 miles and dont use much gas
>>> then I can assume it's better and I'll try the emissions test again
>>> tomorrow.
>> An improvement in gas mileage could be another indicator. As for fuel
>> injector cleaner, I suggest getting a can of BG fuel injector cleaner. It
>> is a little pricey at $20/can but it works much better than the cheap
>> brands sold at auto parts stores.
>>
>>>> The computer will cause the engine to run rich until the normal engine
>>>> operating temperature is reached which is approximately 190 degrees.
>>>> Running rich will definitely affect the emissions readings. Also,
>>>> running the engine cooler causes more wear on metal parts and bearing
>>>> surfaces. You should change back to the OEM thermostat for this reason
>>>> alone. It could very well solve your emissions problems too. Until the
>>>> thermostat is replaced I wouldn't even bother with running the codes. If
>>>> it still fails the test then run the codes.
>>>
>
>

"Michael Johnson, PE" > wrote in message
...
> Cameron wrote:
>> Hey all! You probably have been seeing all my recent posts about the use
>> 88 5.0 with t-tops that I just bought. I took it today to get the
>> emmisions tested and failed (Tennessee).
>> HC: 1446 (max allowable 220)
>> CO: 2.35 (max allowable 1.20)
>>
>> I emailed the guy I bought it from and asked him if he had done any mods
>> or disconnected anything that might cause me to be dumping so much gas.
>> I'm getting about 30-40miles for half a tank. He said he "put a 160
>> degree t-stat in it for more power. That keeps it in openloop at idle
>> which is a very rich condition. Try putting in a 180 or 190."
>>
>> Would just the thermostat cause it to dump hat much fuel and get readings
>> that bad? What is the stock thermostat rated for and I'll pick one of
>> those up at autozone? I have been driving it out in the hot sun with the
>> AC on and I haven't notice it running any hotter than my other mustang.
>>
>> If the t-stat woldnt cause this much of a bad reading then I can take it
>> to the local BP shop and for $70 they said they can debug the vehicle and
>> tell me exactly whats wrong that is causing me to fail.
>
> The computer will cause the engine to run rich until the normal engine
> operating temperature is reached which is approximately 190 degrees.
> Running rich will definitely affect the emissions readings.

160 is too low, you can do a 180, water will still get up to 210.
The thermostat just opens at 180, dosent keep the engine @180 it is just
when it opens the engine will still climb on up in temperature.



>Also, running the engine cooler causes more wear on metal parts and bearing
>surfaces.

Not that much, oil has almost the same properties over a 50 degree range.


>You should change back to the OEM thermostat for this reason alone. It
>could very well solve your emissions problems too. Until the thermostat is
>replaced I wouldn't even bother with running the codes. If it still fails
>the test then run the codes.

Zmegile wrote:
> "Michael Johnson, PE" > wrote in message
> ...
>> Cameron wrote:
>>> Hey all! You probably have been seeing all my recent posts about the use
>>> 88 5.0 with t-tops that I just bought. I took it today to get the
>>> emmisions tested and failed (Tennessee).
>>> HC: 1446 (max allowable 220)
>>> CO: 2.35 (max allowable 1.20)
>>>
>>> I emailed the guy I bought it from and asked him if he had done any mods
>>> or disconnected anything that might cause me to be dumping so much gas.
>>> I'm getting about 30-40miles for half a tank. He said he "put a 160
>>> degree t-stat in it for more power. That keeps it in openloop at idle
>>> which is a very rich condition. Try putting in a 180 or 190."
>>>
>>> Would just the thermostat cause it to dump hat much fuel and get readings
>>> that bad? What is the stock thermostat rated for and I'll pick one of
>>> those up at autozone? I have been driving it out in the hot sun with the
>>> AC on and I haven't notice it running any hotter than my other mustang.
>>>
>>> If the t-stat woldnt cause this much of a bad reading then I can take it
>>> to the local BP shop and for $70 they said they can debug the vehicle and
>>> tell me exactly whats wrong that is causing me to fail.
>> The computer will cause the engine to run rich until the normal engine
>> operating temperature is reached which is approximately 190 degrees.
>> Running rich will definitely affect the emissions readings.
>
> 160 is too low, you can do a 180, water will still get up to 210.
> The thermostat just opens at 180, dosent keep the engine @180 it is just
> when it opens the engine will still climb on up in temperature.

If the cooling system is operating properly the temperature doesn't
fluctuate much at all. It should be very near the thermostat rating
under most driving conditions.

>> Also, running the engine cooler causes more wear on metal parts and bearing
>> surfaces.
>
> Not that much, oil has almost the same properties over a 50 degree range.

It isn't the oil as much as it is the temperature of the metal.
Tolerances are set assuming the engine will operate at certain
temperatures.

>> You should change back to the OEM thermostat for this reason alone. It
>> could very well solve your emissions problems too. Until the thermostat is
>> replaced I wouldn't even bother with running the codes. If it still fails
>> the test then run the codes.
>
>

"Michael Johnson, PE" > wrote in message
...
> Zmegile wrote:
>> "Michael Johnson, PE" > wrote in message
>> ...
>>> Cameron wrote:
>>>> Hey all! You probably have been seeing all my recent posts about the
>>>> use 88 5.0 with t-tops that I just bought. I took it today to get the
>>>> emmisions tested and failed (Tennessee).
>>>> HC: 1446 (max allowable 220)
>>>> CO: 2.35 (max allowable 1.20)
>>>>
>>>> I emailed the guy I bought it from and asked him if he had done any
>>>> mods or disconnected anything that might cause me to be dumping so much
>>>> gas. I'm getting about 30-40miles for half a tank. He said he "put a
>>>> 160 degree t-stat in it for more power. That keeps it in openloop at
>>>> idle which is a very rich condition. Try putting in a 180 or 190."
>>>>
>>>> Would just the thermostat cause it to dump hat much fuel and get
>>>> readings that bad? What is the stock thermostat rated for and I'll
>>>> pick one of those up at autozone? I have been driving it out in the
>>>> hot sun with the AC on and I haven't notice it running any hotter than
>>>> my other mustang.
>>>>
>>>> If the t-stat woldnt cause this much of a bad reading then I can take
>>>> it to the local BP shop and for $70 they said they can debug the
>>>> vehicle and tell me exactly whats wrong that is causing me to fail.
>>> The computer will cause the engine to run rich until the normal engine
>>> operating temperature is reached which is approximately 190 degrees.
>>> Running rich will definitely affect the emissions readings.
>>
>> 160 is too low, you can do a 180, water will still get up to 210.
>> The thermostat just opens at 180, dosent keep the engine @180 it is just
>> when it opens the engine will still climb on up in temperature.
>
> If the cooling system is operating properly the temperature doesn't
> fluctuate much at all. It should be very near the thermostat rating under
> most driving conditions.

try measuring it, instead of guessing.

>
>>> Also, running the engine cooler causes more wear on metal parts and
>>> bearing surfaces.
>>
>> Not that much, oil has almost the same properties over a 50 degree range.
>
> It isn't the oil as much as it is the temperature of the metal. Tolerances
> are set assuming the engine will operate at certain temperatures.

When metal heats up it expands, not contract, therefore clearance will be
fine from 160 to 220 range.
How much will it expand ? less than 0.01 thousandth of an inch for steel.
People measure clearances when engine is cold.

>
>>> You should change back to the OEM thermostat for this reason alone. It
>>> could very well solve your emissions problems too. Until the thermostat
>>> is replaced I wouldn't even bother with running the codes. If it still
>>> fails the test then run the codes.
>>

Zmegile wrote:
> "Michael Johnson, PE" > wrote in message
> ...
>> Zmegile wrote:
>>> "Michael Johnson, PE" > wrote in message
>>> ...
>>>> Cameron wrote:
>>>>> Hey all! You probably have been seeing all my recent posts about the
>>>>> use 88 5.0 with t-tops that I just bought. I took it today to get the
>>>>> emmisions tested and failed (Tennessee).
>>>>> HC: 1446 (max allowable 220)
>>>>> CO: 2.35 (max allowable 1.20)
>>>>>
>>>>> I emailed the guy I bought it from and asked him if he had done any
>>>>> mods or disconnected anything that might cause me to be dumping so much
>>>>> gas. I'm getting about 30-40miles for half a tank. He said he "put a
>>>>> 160 degree t-stat in it for more power. That keeps it in openloop at
>>>>> idle which is a very rich condition. Try putting in a 180 or 190."
>>>>>
>>>>> Would just the thermostat cause it to dump hat much fuel and get
>>>>> readings that bad? What is the stock thermostat rated for and I'll
>>>>> pick one of those up at autozone? I have been driving it out in the
>>>>> hot sun with the AC on and I haven't notice it running any hotter than
>>>>> my other mustang.
>>>>>
>>>>> If the t-stat woldnt cause this much of a bad reading then I can take
>>>>> it to the local BP shop and for $70 they said they can debug the
>>>>> vehicle and tell me exactly whats wrong that is causing me to fail.
>>>> The computer will cause the engine to run rich until the normal engine
>>>> operating temperature is reached which is approximately 190 degrees.
>>>> Running rich will definitely affect the emissions readings.
>>> 160 is too low, you can do a 180, water will still get up to 210.
>>> The thermostat just opens at 180, dosent keep the engine @180 it is just
>>> when it opens the engine will still climb on up in temperature.
>> If the cooling system is operating properly the temperature doesn't
>> fluctuate much at all. It should be very near the thermostat rating under
>> most driving conditions.
>
> try measuring it, instead of guessing.

I have. A properly functioning cooling system will see little
fluctuation under most operating conditions.

>>>> Also, running the engine cooler causes more wear on metal parts and
>>>> bearing surfaces.
>>> Not that much, oil has almost the same properties over a 50 degree range.
>> It isn't the oil as much as it is the temperature of the metal. Tolerances
>> are set assuming the engine will operate at certain temperatures.
>
> When metal heats up it expands, not contract, therefore clearance will be
> fine from 160 to 220 range.
> How much will it expand ? less than 0.01 thousandth of an inch for steel.
> People measure clearances when engine is cold.

Clearances between dissimilar metals vary with temperature because they
expand at different rates. The engine was designed to operate at a
specific temperature. For an older 302 the tolerances were more
forgiving but in todays engines tolerances are tighter and operating at
the specified temperature is more critical. Also, running the engine
rich washes down the cylinder walls so there is less oil available for
lubrication. Over time, this can increase wear on the cylinder walls.

>>>> You should change back to the OEM thermostat for this reason alone. It
>>>> could very well solve your emissions problems too. Until the thermostat
>>>> is replaced I wouldn't even bother with running the codes. If it still
>>>> fails the test then run the codes.
>