1990 V8 Fuel Injection issue
03-15-2008, 07:55 PM
#11
Guest
Posts: n/a
Re: 1990 V8 Fuel Injection issue
Good to hear that you got it sorted.
Tony
Bill Mote wrote:
> Finally got around to installing the new regulator. Fuel economy @ 70 mph
> is now around 24 mpg. You are correct, most of the issue was the O2 sensor.
> Changing out the regulator helped to the tune of about 2 mpg.
> Thanks for all of your help and suggestions.
> Bill
> "TonyJ" <"tonyjnospam at nospam visi.com"> wrote in message
> news:13stv7kcltollac@corp.supernews.com...
>
>> Good to hear its improving. The regulator might be an issue too but the O2
>> was probably most of the problem.
>>
>> Let us know the result.
>>
>> Bill Mote wrote:
>>
>>> Installed new O2 sensor and the situation improved. Checked the fuel
>>> pressure and found at all times the pressure was greater than the
>>> specification. Have new regulator on order.
>>>
>>> "Bill Mote" <bandjrest@worldnet.att.net> wrote in message
>>> news:X3Ixj.678618$kj1.85387@bgtnsc04-news.ops.worldnet.att.net...
>>>
>>>
>>>> Ordered the O2 sensor today, should be in tomorrow. Thanks for the help.
>>>> will keep you posted
>>>> "TonyJ" <"tonyjnospam at nospam visi.com"> wrote in message
>>>> news:13se3bn4kejehe5@corp.supernews.com...
>>>>
>>>>
>>>>> I talked with a friend who has a lot of recent experience with these
>>>>> and his thoughts are (in this order of importance):
>>>>>
>>>>> - O2 sensor is covered with carbon due to running rich. The only reason
>>>>> that the O2 would throw an error code is if its internal heating
>>>>> element is bad.
>>>>>
>>>>> - Normal tune-up issues - Caps, rotors, wires and plugs
>>>>>
>>>>> - Log the fuel pressure over a low and high mileage cycle to find if
>>>>> the fuel pressure regulator is on the way out.
>>>>>
>>>>> Me. I bet on the O2 sensor.
>>>>>
>>>>> Let us know what you find.
>>>>>
>>>>> Bill Mote wrote:
>>>>>
>>>>>
>>>>>> The return and supply line are in good condition with no signs of
>>>>>> rust. The V8 has full electronic injection - Motronic. I will look for
>>>>>> the multifunction plug and check for corrosion. Engine temp both oil
>>>>>> and water are right on normal. Other than the injection system running
>>>>>> full rich, all seems normal.
>>>>>> "TonyJ" <"tonyjnospam at nospam visi.com"> wrote in message
>>>>>> news:13sckfj12123515@corp.supernews.com...
>>>>>>
>>>>>>
>>>>>>
>>>>>>> The T44 series had a problem with leaks in the steel gas lines that
>>>>>>> run under the car on the passenger side. The problem is that the
>>>>>>> plastic clips that hold it to the underside of the car hold moisture
>>>>>>> and cause rust.
>>>>>>>
>>>>>>> If you smell fuel when walking by the right side of the car in a
>>>>>>> closed area with no wind, that may be something to check.
>>>>>>>
>>>>>>> Does the V8 have CIS or fully electronic injection. I am more
>>>>>>> familiar with the CIS from the I5s.
>>>>>>>
>>>>>>> I seem to remember that the V8 has an electronic multi-function plug
>>>>>>> somewhere on the top of the engine, possibly in the front. When these
>>>>>>> get wet or corroded they cause a number of problems.
>>>>>>>
>>>>>>> Is the engine temperature running at the normal level?
>>>>>>>
>>>>>>> Bill Mote wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> I run Techron about every 10th tank or so. I should add that this
>>>>>>>> issue occurred very suddenly, and is also intermittent. I can be
>>>>>>>> driving at 70 mph show 12 - 14 mpg on the level and then suddenly
>>>>>>>> the mileage jumps up to 21 -22 mpg. Overall average for the past
>>>>>>>> 200 miles has been in the 11 - 12 mpg range, prior to that it was
>>>>>>>> always in the 21 - 24 mpg avg. for freeway speeds.
>>>>>>>> "TonyJ" <tonyj@visi.com> wrote in message
>>>>>>>> news:13sbul2liecaqbd@corp.supernews.com...
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>> Bill Mote wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> The fuel economy on my car has gone approximately in half. Went
>>>>>>>>>> from around 22 mpg at 70 mph to around 10 to 11. I replaced the
>>>>>>>>>> temp sensor, checked the mass air flow sensor, checked the idle
>>>>>>>>>> speed motor? and have cleaned the throttle body. Also replaced the
>>>>>>>>>> air filter all to no avail. No codes in computer.
>>>>>>>>>> What am I missing??
>>>>>>>>>>
>>>>>>>>>> Many thanks
>>>>>>>>>> Bill
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>> Winter fuel blends.
>>>>>>>>>
>>>>>>>>> May have dirty injectors with poor spray pattern. Try some Techron
>>>>>>>>> injector cleaner.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>
>>>
>>>
>
>
>
Tony
Bill Mote wrote:
> Finally got around to installing the new regulator. Fuel economy @ 70 mph
> is now around 24 mpg. You are correct, most of the issue was the O2 sensor.
> Changing out the regulator helped to the tune of about 2 mpg.
> Thanks for all of your help and suggestions.
> Bill
> "TonyJ" <"tonyjnospam at nospam visi.com"> wrote in message
> news:13stv7kcltollac@corp.supernews.com...
>
>> Good to hear its improving. The regulator might be an issue too but the O2
>> was probably most of the problem.
>>
>> Let us know the result.
>>
>> Bill Mote wrote:
>>
>>> Installed new O2 sensor and the situation improved. Checked the fuel
>>> pressure and found at all times the pressure was greater than the
>>> specification. Have new regulator on order.
>>>
>>> "Bill Mote" <bandjrest@worldnet.att.net> wrote in message
>>> news:X3Ixj.678618$kj1.85387@bgtnsc04-news.ops.worldnet.att.net...
>>>
>>>
>>>> Ordered the O2 sensor today, should be in tomorrow. Thanks for the help.
>>>> will keep you posted
>>>> "TonyJ" <"tonyjnospam at nospam visi.com"> wrote in message
>>>> news:13se3bn4kejehe5@corp.supernews.com...
>>>>
>>>>
>>>>> I talked with a friend who has a lot of recent experience with these
>>>>> and his thoughts are (in this order of importance):
>>>>>
>>>>> - O2 sensor is covered with carbon due to running rich. The only reason
>>>>> that the O2 would throw an error code is if its internal heating
>>>>> element is bad.
>>>>>
>>>>> - Normal tune-up issues - Caps, rotors, wires and plugs
>>>>>
>>>>> - Log the fuel pressure over a low and high mileage cycle to find if
>>>>> the fuel pressure regulator is on the way out.
>>>>>
>>>>> Me. I bet on the O2 sensor.
>>>>>
>>>>> Let us know what you find.
>>>>>
>>>>> Bill Mote wrote:
>>>>>
>>>>>
>>>>>> The return and supply line are in good condition with no signs of
>>>>>> rust. The V8 has full electronic injection - Motronic. I will look for
>>>>>> the multifunction plug and check for corrosion. Engine temp both oil
>>>>>> and water are right on normal. Other than the injection system running
>>>>>> full rich, all seems normal.
>>>>>> "TonyJ" <"tonyjnospam at nospam visi.com"> wrote in message
>>>>>> news:13sckfj12123515@corp.supernews.com...
>>>>>>
>>>>>>
>>>>>>
>>>>>>> The T44 series had a problem with leaks in the steel gas lines that
>>>>>>> run under the car on the passenger side. The problem is that the
>>>>>>> plastic clips that hold it to the underside of the car hold moisture
>>>>>>> and cause rust.
>>>>>>>
>>>>>>> If you smell fuel when walking by the right side of the car in a
>>>>>>> closed area with no wind, that may be something to check.
>>>>>>>
>>>>>>> Does the V8 have CIS or fully electronic injection. I am more
>>>>>>> familiar with the CIS from the I5s.
>>>>>>>
>>>>>>> I seem to remember that the V8 has an electronic multi-function plug
>>>>>>> somewhere on the top of the engine, possibly in the front. When these
>>>>>>> get wet or corroded they cause a number of problems.
>>>>>>>
>>>>>>> Is the engine temperature running at the normal level?
>>>>>>>
>>>>>>> Bill Mote wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> I run Techron about every 10th tank or so. I should add that this
>>>>>>>> issue occurred very suddenly, and is also intermittent. I can be
>>>>>>>> driving at 70 mph show 12 - 14 mpg on the level and then suddenly
>>>>>>>> the mileage jumps up to 21 -22 mpg. Overall average for the past
>>>>>>>> 200 miles has been in the 11 - 12 mpg range, prior to that it was
>>>>>>>> always in the 21 - 24 mpg avg. for freeway speeds.
>>>>>>>> "TonyJ" <tonyj@visi.com> wrote in message
>>>>>>>> news:13sbul2liecaqbd@corp.supernews.com...
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>> Bill Mote wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> The fuel economy on my car has gone approximately in half. Went
>>>>>>>>>> from around 22 mpg at 70 mph to around 10 to 11. I replaced the
>>>>>>>>>> temp sensor, checked the mass air flow sensor, checked the idle
>>>>>>>>>> speed motor? and have cleaned the throttle body. Also replaced the
>>>>>>>>>> air filter all to no avail. No codes in computer.
>>>>>>>>>> What am I missing??
>>>>>>>>>>
>>>>>>>>>> Many thanks
>>>>>>>>>> Bill
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>> Winter fuel blends.
>>>>>>>>>
>>>>>>>>> May have dirty injectors with poor spray pattern. Try some Techron
>>>>>>>>> injector cleaner.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>
>>>
>>>
>
>
>
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