MudPuppy76

Comboverfish wrote:

> MudPuppy76 <"<moc.rr.pacyn"@"pupralop"> wrote:
>
>>93 grand cherokee 4.0 (buying for my wife) has a
>>hard time starting after it's sat for a while,
>>overnight not so bad, but a couple days and she
>>cranks for a while. i want to say fuel pump check
>>valve is draining back. sound about right? if this
>>is it, i might build a timer circuit to bump the
>>pressure before cranking.
>
>
> Put a gauge on it and monitor bleeddown pressure overnight. If it is
> your pump checkball, then I would think you would want to replace the
> pump - esp. if it is a high mileage unit, rather than insert a homemade
> timer into the FP circuit. The pump should run Key On anyway. Its the
> operation of the injectors during cranking that bleed the fuel line of
> air when you have a fuel drainback problem, not fuel pressure alone.
>
> And incase this is just coincidence that the engine only has trouble on
> extended sits --- the 4.0 of that era had problems with its crank
> sensor. Not sure if it was still a problem part by 1993 though. Their
> output level would weaken at cranking speeds and cause either a no
> start or a long crank. Just something to think about,
>
> Toyota MDT in MO
>
will check the fuel pressure when i get back to
the shop on monday. maybe put a scope on the crank
sensor just to see.

--
Ben Jerew AKA PolarPuppy
ASE Certified Master Technician
New Country Lexus of Latham, NY, USA
Amateur Off-Roader 93 YJ 4.0l 3spd

MudPuppy76

Comboverfish wrote:

> MudPuppy76 <"<moc.rr.pacyn"@"pupralop"> wrote:
>
>>93 grand cherokee 4.0 (buying for my wife) has a
>>hard time starting after it's sat for a while,
>>overnight not so bad, but a couple days and she
>>cranks for a while. i want to say fuel pump check
>>valve is draining back. sound about right? if this
>>is it, i might build a timer circuit to bump the
>>pressure before cranking.
>
>
> Put a gauge on it and monitor bleeddown pressure overnight. If it is
> your pump checkball, then I would think you would want to replace the
> pump - esp. if it is a high mileage unit, rather than insert a homemade
> timer into the FP circuit. The pump should run Key On anyway. Its the
> operation of the injectors during cranking that bleed the fuel line of
> air when you have a fuel drainback problem, not fuel pressure alone.
>
> And incase this is just coincidence that the engine only has trouble on
> extended sits --- the 4.0 of that era had problems with its crank
> sensor. Not sure if it was still a problem part by 1993 though. Their
> output level would weaken at cranking speeds and cause either a no
> start or a long crank. Just something to think about,
>
> Toyota MDT in MO
>
will check the fuel pressure when i get back to
the shop on monday. maybe put a scope on the crank
sensor just to see.

--
Ben Jerew AKA PolarPuppy
ASE Certified Master Technician
New Country Lexus of Latham, NY, USA
Amateur Off-Roader 93 YJ 4.0l 3spd

MudPuppy76

Comboverfish wrote:

> MudPuppy76 <"<moc.rr.pacyn"@"pupralop"> wrote:
>
>>93 grand cherokee 4.0 (buying for my wife) has a
>>hard time starting after it's sat for a while,
>>overnight not so bad, but a couple days and she
>>cranks for a while. i want to say fuel pump check
>>valve is draining back. sound about right? if this
>>is it, i might build a timer circuit to bump the
>>pressure before cranking.
>
>
> Put a gauge on it and monitor bleeddown pressure overnight. If it is
> your pump checkball, then I would think you would want to replace the
> pump - esp. if it is a high mileage unit, rather than insert a homemade
> timer into the FP circuit. The pump should run Key On anyway. Its the
> operation of the injectors during cranking that bleed the fuel line of
> air when you have a fuel drainback problem, not fuel pressure alone.
>
> And incase this is just coincidence that the engine only has trouble on
> extended sits --- the 4.0 of that era had problems with its crank
> sensor. Not sure if it was still a problem part by 1993 though. Their
> output level would weaken at cranking speeds and cause either a no
> start or a long crank. Just something to think about,
>
> Toyota MDT in MO
>
will check the fuel pressure when i get back to
the shop on monday. maybe put a scope on the crank
sensor just to see.

--
Ben Jerew AKA PolarPuppy
ASE Certified Master Technician
New Country Lexus of Latham, NY, USA
Amateur Off-Roader 93 YJ 4.0l 3spd

Phil Rynn

If it is the fuel pump check valve, you would probably only have problems
starting when the engine is warm. (same symptoms as a bad fuel pressure
regulator). If you put a pressure gauge on the fuel test port you should
hold pressure after shutdown. If not it is either the fuel pressure
regulator or the aformentioned check valve.
If it is the valve, I agree with above post, you should replace the pump.
I just did this on my '94, not a bad job, but the pump is expensive. I got
one for 235 from autozone.

HTH,
Phil
"MudPuppy76 <"<moc.rr.pacyn"@"pupralop">" <--SDRAWKCAB> wrote in message
news:l%BPd.6337$vK5.2939@twister.nyroc.rr.com...
> Comboverfish wrote:
>
>> MudPuppy76 <"<moc.rr.pacyn"@"pupralop"> wrote:
>>
>>>93 grand cherokee 4.0 (buying for my wife) has a
>>>hard time starting after it's sat for a while,
>>>overnight not so bad, but a couple days and she
>>>cranks for a while. i want to say fuel pump check
>>>valve is draining back. sound about right? if this
>>>is it, i might build a timer circuit to bump the
>>>pressure before cranking.
>>
>>
>> Put a gauge on it and monitor bleeddown pressure overnight. If it is
>> your pump checkball, then I would think you would want to replace the
>> pump - esp. if it is a high mileage unit, rather than insert a homemade
>> timer into the FP circuit. The pump should run Key On anyway. Its the
>> operation of the injectors during cranking that bleed the fuel line of
>> air when you have a fuel drainback problem, not fuel pressure alone.
>>
>> And incase this is just coincidence that the engine only has trouble on
>> extended sits --- the 4.0 of that era had problems with its crank
>> sensor. Not sure if it was still a problem part by 1993 though. Their
>> output level would weaken at cranking speeds and cause either a no
>> start or a long crank. Just something to think about,
>>
>> Toyota MDT in MO
>>
> will check the fuel pressure when i get back to the shop on monday. maybe
> put a scope on the crank sensor just to see.
>
> --
> Ben Jerew AKA PolarPuppy
> ASE Certified Master Technician
> New Country Lexus of Latham, NY, USA
> Amateur Off-Roader 93 YJ 4.0l 3spd

Phil Rynn

If it is the fuel pump check valve, you would probably only have problems
starting when the engine is warm. (same symptoms as a bad fuel pressure
regulator). If you put a pressure gauge on the fuel test port you should
hold pressure after shutdown. If not it is either the fuel pressure
regulator or the aformentioned check valve.
If it is the valve, I agree with above post, you should replace the pump.
I just did this on my '94, not a bad job, but the pump is expensive. I got
one for 235 from autozone.

HTH,
Phil
"MudPuppy76 <"<moc.rr.pacyn"@"pupralop">" <--SDRAWKCAB> wrote in message
news:l%BPd.6337$vK5.2939@twister.nyroc.rr.com...
> Comboverfish wrote:
>
>> MudPuppy76 <"<moc.rr.pacyn"@"pupralop"> wrote:
>>
>>>93 grand cherokee 4.0 (buying for my wife) has a
>>>hard time starting after it's sat for a while,
>>>overnight not so bad, but a couple days and she
>>>cranks for a while. i want to say fuel pump check
>>>valve is draining back. sound about right? if this
>>>is it, i might build a timer circuit to bump the
>>>pressure before cranking.
>>
>>
>> Put a gauge on it and monitor bleeddown pressure overnight. If it is
>> your pump checkball, then I would think you would want to replace the
>> pump - esp. if it is a high mileage unit, rather than insert a homemade
>> timer into the FP circuit. The pump should run Key On anyway. Its the
>> operation of the injectors during cranking that bleed the fuel line of
>> air when you have a fuel drainback problem, not fuel pressure alone.
>>
>> And incase this is just coincidence that the engine only has trouble on
>> extended sits --- the 4.0 of that era had problems with its crank
>> sensor. Not sure if it was still a problem part by 1993 though. Their
>> output level would weaken at cranking speeds and cause either a no
>> start or a long crank. Just something to think about,
>>
>> Toyota MDT in MO
>>
> will check the fuel pressure when i get back to the shop on monday. maybe
> put a scope on the crank sensor just to see.
>
> --
> Ben Jerew AKA PolarPuppy
> ASE Certified Master Technician
> New Country Lexus of Latham, NY, USA
> Amateur Off-Roader 93 YJ 4.0l 3spd

Phil Rynn

If it is the fuel pump check valve, you would probably only have problems
starting when the engine is warm. (same symptoms as a bad fuel pressure
regulator). If you put a pressure gauge on the fuel test port you should
hold pressure after shutdown. If not it is either the fuel pressure
regulator or the aformentioned check valve.
If it is the valve, I agree with above post, you should replace the pump.
I just did this on my '94, not a bad job, but the pump is expensive. I got
one for 235 from autozone.

HTH,
Phil
"MudPuppy76 <"<moc.rr.pacyn"@"pupralop">" <--SDRAWKCAB> wrote in message
news:l%BPd.6337$vK5.2939@twister.nyroc.rr.com...
> Comboverfish wrote:
>
>> MudPuppy76 <"<moc.rr.pacyn"@"pupralop"> wrote:
>>
>>>93 grand cherokee 4.0 (buying for my wife) has a
>>>hard time starting after it's sat for a while,
>>>overnight not so bad, but a couple days and she
>>>cranks for a while. i want to say fuel pump check
>>>valve is draining back. sound about right? if this
>>>is it, i might build a timer circuit to bump the
>>>pressure before cranking.
>>
>>
>> Put a gauge on it and monitor bleeddown pressure overnight. If it is
>> your pump checkball, then I would think you would want to replace the
>> pump - esp. if it is a high mileage unit, rather than insert a homemade
>> timer into the FP circuit. The pump should run Key On anyway. Its the
>> operation of the injectors during cranking that bleed the fuel line of
>> air when you have a fuel drainback problem, not fuel pressure alone.
>>
>> And incase this is just coincidence that the engine only has trouble on
>> extended sits --- the 4.0 of that era had problems with its crank
>> sensor. Not sure if it was still a problem part by 1993 though. Their
>> output level would weaken at cranking speeds and cause either a no
>> start or a long crank. Just something to think about,
>>
>> Toyota MDT in MO
>>
> will check the fuel pressure when i get back to the shop on monday. maybe
> put a scope on the crank sensor just to see.
>
> --
> Ben Jerew AKA PolarPuppy
> ASE Certified Master Technician
> New Country Lexus of Latham, NY, USA
> Amateur Off-Roader 93 YJ 4.0l 3spd

MudPuppy76

yeah, i'm gonna have to go with the fuel pump.
sadly though, i have to get a fuel pump for my 93
yj too (leaking out the top if i fill it up too
much) crap, i'm not made out of money, just carbon
and water!

Phil Rynn wrote:

> If it is the fuel pump check valve, you would probably only have problems
> starting when the engine is warm. (same symptoms as a bad fuel pressure
> regulator). If you put a pressure gauge on the fuel test port you should
> hold pressure after shutdown. If not it is either the fuel pressure
> regulator or the aformentioned check valve.
> If it is the valve, I agree with above post, you should replace the pump.
> I just did this on my '94, not a bad job, but the pump is expensive. I got
> one for 235 from autozone.

>>Comboverfish wrote:
>>
>>
>>>MudPuppy76 <"<moc.rr.pacyn"@"pupralop"> wrote:
>>>
>>>
>>>>93 grand cherokee 4.0 (buying for my wife) has a
>>>>hard time starting after it's sat for a while,
>>>>overnight not so bad, but a couple days and she
>>>>cranks for a while. i want to say fuel pump check
>>>>valve is draining back. sound about right? if this
>>>>is it, i might build a timer circuit to bump the
>>>>pressure before cranking.
>>>
>>>
>>>Put a gauge on it and monitor bleeddown pressure overnight. If it is
>>>your pump checkball, then I would think you would want to replace the
>>>pump - esp. if it is a high mileage unit, rather than insert a homemade
>>>timer into the FP circuit. The pump should run Key On anyway. Its the
>>>operation of the injectors during cranking that bleed the fuel line of
>>>air when you have a fuel drainback problem, not fuel pressure alone.
>>>
>>>And incase this is just coincidence that the engine only has trouble on
>>>extended sits --- the 4.0 of that era had problems with its crank
>>>sensor. Not sure if it was still a problem part by 1993 though. Their
>>>output level would weaken at cranking speeds and cause either a no
>>>start or a long crank. Just something to think about,
>>>
>>>Toyota MDT in MO
>>>
>>
>>will check the fuel pressure when i get back to the shop on monday. maybe
>>put a scope on the crank sensor just to see.

--
Ben Jerew AKA PolarPuppy
ASE Certified Master Technician
New Country Lexus of Latham, NY, USA
Amateur Off-Roader 93 YJ 4.0l 3spd

MudPuppy76

yeah, i'm gonna have to go with the fuel pump.
sadly though, i have to get a fuel pump for my 93
yj too (leaking out the top if i fill it up too
much) crap, i'm not made out of money, just carbon
and water!

Phil Rynn wrote:

> If it is the fuel pump check valve, you would probably only have problems
> starting when the engine is warm. (same symptoms as a bad fuel pressure
> regulator). If you put a pressure gauge on the fuel test port you should
> hold pressure after shutdown. If not it is either the fuel pressure
> regulator or the aformentioned check valve.
> If it is the valve, I agree with above post, you should replace the pump.
> I just did this on my '94, not a bad job, but the pump is expensive. I got
> one for 235 from autozone.

>>Comboverfish wrote:
>>
>>
>>>MudPuppy76 <"<moc.rr.pacyn"@"pupralop"> wrote:
>>>
>>>
>>>>93 grand cherokee 4.0 (buying for my wife) has a
>>>>hard time starting after it's sat for a while,
>>>>overnight not so bad, but a couple days and she
>>>>cranks for a while. i want to say fuel pump check
>>>>valve is draining back. sound about right? if this
>>>>is it, i might build a timer circuit to bump the
>>>>pressure before cranking.
>>>
>>>
>>>Put a gauge on it and monitor bleeddown pressure overnight. If it is
>>>your pump checkball, then I would think you would want to replace the
>>>pump - esp. if it is a high mileage unit, rather than insert a homemade
>>>timer into the FP circuit. The pump should run Key On anyway. Its the
>>>operation of the injectors during cranking that bleed the fuel line of
>>>air when you have a fuel drainback problem, not fuel pressure alone.
>>>
>>>And incase this is just coincidence that the engine only has trouble on
>>>extended sits --- the 4.0 of that era had problems with its crank
>>>sensor. Not sure if it was still a problem part by 1993 though. Their
>>>output level would weaken at cranking speeds and cause either a no
>>>start or a long crank. Just something to think about,
>>>
>>>Toyota MDT in MO
>>>
>>
>>will check the fuel pressure when i get back to the shop on monday. maybe
>>put a scope on the crank sensor just to see.

--
Ben Jerew AKA PolarPuppy
ASE Certified Master Technician
New Country Lexus of Latham, NY, USA
Amateur Off-Roader 93 YJ 4.0l 3spd

MudPuppy76

yeah, i'm gonna have to go with the fuel pump.
sadly though, i have to get a fuel pump for my 93
yj too (leaking out the top if i fill it up too
much) crap, i'm not made out of money, just carbon
and water!

Phil Rynn wrote:

> If it is the fuel pump check valve, you would probably only have problems
> starting when the engine is warm. (same symptoms as a bad fuel pressure
> regulator). If you put a pressure gauge on the fuel test port you should
> hold pressure after shutdown. If not it is either the fuel pressure
> regulator or the aformentioned check valve.
> If it is the valve, I agree with above post, you should replace the pump.
> I just did this on my '94, not a bad job, but the pump is expensive. I got
> one for 235 from autozone.

>>Comboverfish wrote:
>>
>>
>>>MudPuppy76 <"<moc.rr.pacyn"@"pupralop"> wrote:
>>>
>>>
>>>>93 grand cherokee 4.0 (buying for my wife) has a
>>>>hard time starting after it's sat for a while,
>>>>overnight not so bad, but a couple days and she
>>>>cranks for a while. i want to say fuel pump check
>>>>valve is draining back. sound about right? if this
>>>>is it, i might build a timer circuit to bump the
>>>>pressure before cranking.
>>>
>>>
>>>Put a gauge on it and monitor bleeddown pressure overnight. If it is
>>>your pump checkball, then I would think you would want to replace the
>>>pump - esp. if it is a high mileage unit, rather than insert a homemade
>>>timer into the FP circuit. The pump should run Key On anyway. Its the
>>>operation of the injectors during cranking that bleed the fuel line of
>>>air when you have a fuel drainback problem, not fuel pressure alone.
>>>
>>>And incase this is just coincidence that the engine only has trouble on
>>>extended sits --- the 4.0 of that era had problems with its crank
>>>sensor. Not sure if it was still a problem part by 1993 though. Their
>>>output level would weaken at cranking speeds and cause either a no
>>>start or a long crank. Just something to think about,
>>>
>>>Toyota MDT in MO
>>>
>>
>>will check the fuel pressure when i get back to the shop on monday. maybe
>>put a scope on the crank sensor just to see.

--
Ben Jerew AKA PolarPuppy
ASE Certified Master Technician
New Country Lexus of Latham, NY, USA
Amateur Off-Roader 93 YJ 4.0l 3spd

Lawrence Glickman

On Tue, 15 Feb 2005 01:50:19 GMT, "MudPuppy76
<\"<moc.rr.pacyn\"@\"pupralop\">" <--SDRAWKCAB> wrote:

>yeah, i'm gonna have to go with the fuel pump.
>sadly though, i have to get a fuel pump for my 93
>yj too (leaking out the top if i fill it up too
>much) crap, i'm not made out of money, just carbon
>and water!

Ditto. That is why you get the parts from somewhere and do the job
yourself.

>Phil Rynn wrote:
>
>> If it is the fuel pump check valve, you would probably only have problems
>> starting when the engine is warm. (same symptoms as a bad fuel pressure
>> regulator). If you put a pressure gauge on the fuel test port you should
>> hold pressure after shutdown. If not it is either the fuel pressure
>> regulator or the aformentioned check valve.
>> If it is the valve, I agree with above post, you should replace the pump.
>> I just did this on my '94, not a bad job, but the pump is expensive. I got
>> one for 235 from autozone.

not OEM? here is an article about autozone fuel pumps you might want
to read first, I have it archived so don't have the message number:
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ \\\\\\\\\\\\\\\\\\\\\\\
Your fuel pump is more than likely on it's way out, and it would be
wise to replace it now than to wait and be stranded (don't ask me how
I know this). I remember reading somewhere that these fuel pumps would
get contaminated with the left over solder from when the fuel tanks
were put together and get louder and fail. The same thing happened to
me, and mine went all of a sudden. How I missed that noise that
night...
Also, spend the extra money and get a >OEM< fuel pump. As a tech, I
have replaced many pumps 2 and 3 times because the aftermarket ones
failed after a couple of months. I too bought a Master fuel pump from
Autozone, and after 2 months the noise was back, so I returned it and
got a Ford one, and haven't had trouble since. Since this is a very
aggravating job and the pumps seem to always go right AFTER you fill
up, do yourself a favor and get a good one the first time.
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ \\\\\\\\\\\\\\\\\\\\\\
EDITED: >OEM< was originally "Ford" in original message.

Now do you _still_ want to go through all that HELL of replacing a
fuel pump with autozone part, only to have to do it again in 2 months?

Lg



>>>Comboverfish wrote:
>>>
>>>
>>>>MudPuppy76 <"<moc.rr.pacyn"@"pupralop"> wrote:
>>>>
>>>>
>>>>>93 grand cherokee 4.0 (buying for my wife) has a
>>>>>hard time starting after it's sat for a while,
>>>>>overnight not so bad, but a couple days and she
>>>>>cranks for a while. i want to say fuel pump check
>>>>>valve is draining back. sound about right? if this
>>>>>is it, i might build a timer circuit to bump the
>>>>>pressure before cranking.
>>>>
>>>>
>>>>Put a gauge on it and monitor bleeddown pressure overnight. If it is
>>>>your pump checkball, then I would think you would want to replace the
>>>>pump - esp. if it is a high mileage unit, rather than insert a homemade
>>>>timer into the FP circuit. The pump should run Key On anyway. Its the
>>>>operation of the injectors during cranking that bleed the fuel line of
>>>>air when you have a fuel drainback problem, not fuel pressure alone.
>>>>
>>>>And incase this is just coincidence that the engine only has trouble on
>>>>extended sits --- the 4.0 of that era had problems with its crank
>>>>sensor. Not sure if it was still a problem part by 1993 though. Their
>>>>output level would weaken at cranking speeds and cause either a no
>>>>start or a long crank. Just something to think about,
>>>>
>>>>Toyota MDT in MO
>>>>
>>>
>>>will check the fuel pressure when i get back to the shop on monday. maybe
>>>put a scope on the crank sensor just to see.