Fuel system troubleshooting recommendations?
 

About a month ago I first experienced some problem with the fuel
system on my '93 Cherokee(4.0L, 128K).

Usually when it happens I am driving down the road and the fuel seems
to just cut out for a second or two, but comes right back. On two
occasions now it has cut out and wont start for a couple minutes, then
all of a sudden it starts getting fuel again and runs fine.

I'm thinking, at the very least, I need to replace the fuel filter. I
havent yet looked in my repair manual, but did a brief search online.
Do I have to pull the whole fuel tank to get to the filter?

Anyone got any insight to what this problem might be?

TIA
Matt Mika

Re: Fuel system troubleshooting recommendations?
 

Why do you think it's a fuel related problem? Could be, but...

What came to my mind was also a faulty CPS. When it gets hot it stops
working, then cools down and works again. Could of course also be fuel
related, ignition related, computer related etc...

regards
Odd-Inge Larsen

"MattMika" <mattmika@hotmail.com> wrote in message
news:hsqv7391cmen2jl4e5kovgjbkdceji44tj@4ax.com...
> About a month ago I first experienced some problem with the fuel
> system on my '93 Cherokee(4.0L, 128K).
>
> Usually when it happens I am driving down the road and the fuel seems
> to just cut out for a second or two, but comes right back. On two
> occasions now it has cut out and wont start for a couple minutes, then
> all of a sudden it starts getting fuel again and runs fine.
>
> I'm thinking, at the very least, I need to replace the fuel filter. I
> havent yet looked in my repair manual, but did a brief search online.
> Do I have to pull the whole fuel tank to get to the filter?
>
> Anyone got any insight to what this problem might be?
>
> TIA
> Matt Mika

Re: Fuel system troubleshooting recommendations?
 

Why do you think it's a fuel related problem? Could be, but...

What came to my mind was also a faulty CPS. When it gets hot it stops
working, then cools down and works again. Could of course also be fuel
related, ignition related, computer related etc...

regards
Odd-Inge Larsen

"MattMika" <mattmika@hotmail.com> wrote in message
news:hsqv7391cmen2jl4e5kovgjbkdceji44tj@4ax.com...
> About a month ago I first experienced some problem with the fuel
> system on my '93 Cherokee(4.0L, 128K).
>
> Usually when it happens I am driving down the road and the fuel seems
> to just cut out for a second or two, but comes right back. On two
> occasions now it has cut out and wont start for a couple minutes, then
> all of a sudden it starts getting fuel again and runs fine.
>
> I'm thinking, at the very least, I need to replace the fuel filter. I
> havent yet looked in my repair manual, but did a brief search online.
> Do I have to pull the whole fuel tank to get to the filter?
>
> Anyone got any insight to what this problem might be?
>
> TIA
> Matt Mika

Re: Fuel system troubleshooting recommendations?
 

Why do you think it's a fuel related problem? Could be, but...

What came to my mind was also a faulty CPS. When it gets hot it stops
working, then cools down and works again. Could of course also be fuel
related, ignition related, computer related etc...

regards
Odd-Inge Larsen

"MattMika" <mattmika@hotmail.com> wrote in message
news:hsqv7391cmen2jl4e5kovgjbkdceji44tj@4ax.com...
> About a month ago I first experienced some problem with the fuel
> system on my '93 Cherokee(4.0L, 128K).
>
> Usually when it happens I am driving down the road and the fuel seems
> to just cut out for a second or two, but comes right back. On two
> occasions now it has cut out and wont start for a couple minutes, then
> all of a sudden it starts getting fuel again and runs fine.
>
> I'm thinking, at the very least, I need to replace the fuel filter. I
> havent yet looked in my repair manual, but did a brief search online.
> Do I have to pull the whole fuel tank to get to the filter?
>
> Anyone got any insight to what this problem might be?
>
> TIA
> Matt Mika

Re: Fuel system troubleshooting recommendations?
 

Why do you think it's a fuel related problem? Could be, but...

What came to my mind was also a faulty CPS. When it gets hot it stops
working, then cools down and works again. Could of course also be fuel
related, ignition related, computer related etc...

regards
Odd-Inge Larsen

"MattMika" <mattmika@hotmail.com> wrote in message
news:hsqv7391cmen2jl4e5kovgjbkdceji44tj@4ax.com...
> About a month ago I first experienced some problem with the fuel
> system on my '93 Cherokee(4.0L, 128K).
>
> Usually when it happens I am driving down the road and the fuel seems
> to just cut out for a second or two, but comes right back. On two
> occasions now it has cut out and wont start for a couple minutes, then
> all of a sudden it starts getting fuel again and runs fine.
>
> I'm thinking, at the very least, I need to replace the fuel filter. I
> havent yet looked in my repair manual, but did a brief search online.
> Do I have to pull the whole fuel tank to get to the filter?
>
> Anyone got any insight to what this problem might be?
>
> TIA
> Matt Mika

Re: Fuel system troubleshooting recommendations?
 

On Mon, 25 Jun 2007 19:30:46 +0200, "Odd-Inge Larsen"
<oddingelarsen@dcpost.no> wrote:

>Why do you think it's a fuel related problem? Could be, but...

I thought it was fuel system related because the 'cut out' is similar
to running out of gas. It starts to sputter then gets no power at all.
Then suddenly it starts running again.

>What came to my mind was also a faulty CPS. When it gets hot it stops
>working, then cools down and works again. Could of course also be fuel
>related, ignition related, computer related etc...

Based on the seemingly high rate of failure of these devices it seems
that will be a good place to start. I see that early 90's models may
have problems with a low signal strength "due to a larger than desired
distance to the flywheel sensing ring."

http://autorepair.about.com/cs/faqs/l/bl557h.htm

I guess I'll see how well its position and move it closer if possible
or replace it and the grommet if it doesnt look like the updated type.

Thanks
Matt Mika

Re: Fuel system troubleshooting recommendations?
 

On Mon, 25 Jun 2007 19:30:46 +0200, "Odd-Inge Larsen"
<oddingelarsen@dcpost.no> wrote:

>Why do you think it's a fuel related problem? Could be, but...

I thought it was fuel system related because the 'cut out' is similar
to running out of gas. It starts to sputter then gets no power at all.
Then suddenly it starts running again.

>What came to my mind was also a faulty CPS. When it gets hot it stops
>working, then cools down and works again. Could of course also be fuel
>related, ignition related, computer related etc...

Based on the seemingly high rate of failure of these devices it seems
that will be a good place to start. I see that early 90's models may
have problems with a low signal strength "due to a larger than desired
distance to the flywheel sensing ring."

http://autorepair.about.com/cs/faqs/l/bl557h.htm

I guess I'll see how well its position and move it closer if possible
or replace it and the grommet if it doesnt look like the updated type.

Thanks
Matt Mika

Re: Fuel system troubleshooting recommendations?
 

On Mon, 25 Jun 2007 19:30:46 +0200, "Odd-Inge Larsen"
<oddingelarsen@dcpost.no> wrote:

>Why do you think it's a fuel related problem? Could be, but...

I thought it was fuel system related because the 'cut out' is similar
to running out of gas. It starts to sputter then gets no power at all.
Then suddenly it starts running again.

>What came to my mind was also a faulty CPS. When it gets hot it stops
>working, then cools down and works again. Could of course also be fuel
>related, ignition related, computer related etc...

Based on the seemingly high rate of failure of these devices it seems
that will be a good place to start. I see that early 90's models may
have problems with a low signal strength "due to a larger than desired
distance to the flywheel sensing ring."

http://autorepair.about.com/cs/faqs/l/bl557h.htm

I guess I'll see how well its position and move it closer if possible
or replace it and the grommet if it doesnt look like the updated type.

Thanks
Matt Mika

Re: Fuel system troubleshooting recommendations?
 

On Mon, 25 Jun 2007 19:30:46 +0200, "Odd-Inge Larsen"
<oddingelarsen@dcpost.no> wrote:

>Why do you think it's a fuel related problem? Could be, but...

I thought it was fuel system related because the 'cut out' is similar
to running out of gas. It starts to sputter then gets no power at all.
Then suddenly it starts running again.

>What came to my mind was also a faulty CPS. When it gets hot it stops
>working, then cools down and works again. Could of course also be fuel
>related, ignition related, computer related etc...

Based on the seemingly high rate of failure of these devices it seems
that will be a good place to start. I see that early 90's models may
have problems with a low signal strength "due to a larger than desired
distance to the flywheel sensing ring."

http://autorepair.about.com/cs/faqs/l/bl557h.htm

I guess I'll see how well its position and move it closer if possible
or replace it and the grommet if it doesnt look like the updated type.

Thanks
Matt Mika

Re: Fuel system troubleshooting recommendations?
 

MattMika wrote:
> On Mon, 25 Jun 2007 19:30:46 +0200, "Odd-Inge Larsen"
> <oddingelarsen@dcpost.no> wrote:

ref: (93 cherokee 4.0)

>> Why do you think it's a fuel related problem? Could be, but...
>
> I thought it was fuel system related because the 'cut out' is similar
> to running out of gas. It starts to sputter then gets no power at all.
> Then suddenly it starts running again.

Second CPS.

Fuel filter will show up as a power sag at full throttle (or even light ping)
Fuel cutout will give you a bit of hiccup but the engine usually keeps on
chugging along. If the fuel pump stops it generally stops, period.

>> What came to my mind was also a faulty CPS. When it gets hot it stops
>> working, then cools down and works again. Could of course also be
>> fuel related, ignition related, computer related etc...
>
> Based on the seemingly high rate of failure of these devices it seems
> that will be a good place to start. I see that early 90's models may
> have problems with a low signal strength "due to a larger than desired
> distance to the flywheel sensing ring."
>
> http://autorepair.about.com/cs/faqs/l/bl557h.htm
>
> I guess I'll see how well its position and move it closer if possible
> or replace it and the grommet if it doesnt look like the updated type.

The new ones come with a single hole, the old paper gasket type are no
longer produced.

I have a writeup on the 93ZJ on my website.
http://revbeergoggles.com/cps/
and
http://revbeergoggles.com/Fixes/diag...tml#CPSdetails


--
-- DougW -- 93 ZJ 4.0 http://revbeergoggles.com
HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors
Banks Header - and BEER, in the fridge!