hard to start
06-05-2005, 09:26 AM
#2
Guest
Posts: n/a
Re: hard to start
At that age, I would suspect a dirty computer sensor connection affected
by heat.
The likely one is the CPS plug and socket sitting on top of the exhaust
manifold behind the throttle body.
The other two that contribute are the TPS and IAC on the throttle body.
I would recommend you open these plugs and sockets and clean them with a
spray contact cleaner. An electronic contact cleaner is the best, but
WD40 will work ok too. I use dielectric grease on the plug seal skirts
when I put it back on. They seem to stay cleaner longer with it on.
Then I would hear about it if I didn't mention the ground strap from the
engine head to the firewall. ;-) That gets dirty and actually crumbles
with age as well. Because it is on the head, heat affects it too.
If you haven't put a new distributor cap and rotor in recently, they
would be worth a look at or replacement. That 'usually' acts up in
humidity more than heat though....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
curbrider wrote:
>
> i have a 91 jeep cherokee 4.0 its hard to start at first when i shut it off
> it restarts just fine i let it sit about 15 min its hard to start again
by heat.
The likely one is the CPS plug and socket sitting on top of the exhaust
manifold behind the throttle body.
The other two that contribute are the TPS and IAC on the throttle body.
I would recommend you open these plugs and sockets and clean them with a
spray contact cleaner. An electronic contact cleaner is the best, but
WD40 will work ok too. I use dielectric grease on the plug seal skirts
when I put it back on. They seem to stay cleaner longer with it on.
Then I would hear about it if I didn't mention the ground strap from the
engine head to the firewall. ;-) That gets dirty and actually crumbles
with age as well. Because it is on the head, heat affects it too.
If you haven't put a new distributor cap and rotor in recently, they
would be worth a look at or replacement. That 'usually' acts up in
humidity more than heat though....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
curbrider wrote:
>
> i have a 91 jeep cherokee 4.0 its hard to start at first when i shut it off
> it restarts just fine i let it sit about 15 min its hard to start again
06-05-2005, 09:26 AM
#3
Guest
Posts: n/a
Re: hard to start
At that age, I would suspect a dirty computer sensor connection affected
by heat.
The likely one is the CPS plug and socket sitting on top of the exhaust
manifold behind the throttle body.
The other two that contribute are the TPS and IAC on the throttle body.
I would recommend you open these plugs and sockets and clean them with a
spray contact cleaner. An electronic contact cleaner is the best, but
WD40 will work ok too. I use dielectric grease on the plug seal skirts
when I put it back on. They seem to stay cleaner longer with it on.
Then I would hear about it if I didn't mention the ground strap from the
engine head to the firewall. ;-) That gets dirty and actually crumbles
with age as well. Because it is on the head, heat affects it too.
If you haven't put a new distributor cap and rotor in recently, they
would be worth a look at or replacement. That 'usually' acts up in
humidity more than heat though....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
curbrider wrote:
>
> i have a 91 jeep cherokee 4.0 its hard to start at first when i shut it off
> it restarts just fine i let it sit about 15 min its hard to start again
by heat.
The likely one is the CPS plug and socket sitting on top of the exhaust
manifold behind the throttle body.
The other two that contribute are the TPS and IAC on the throttle body.
I would recommend you open these plugs and sockets and clean them with a
spray contact cleaner. An electronic contact cleaner is the best, but
WD40 will work ok too. I use dielectric grease on the plug seal skirts
when I put it back on. They seem to stay cleaner longer with it on.
Then I would hear about it if I didn't mention the ground strap from the
engine head to the firewall. ;-) That gets dirty and actually crumbles
with age as well. Because it is on the head, heat affects it too.
If you haven't put a new distributor cap and rotor in recently, they
would be worth a look at or replacement. That 'usually' acts up in
humidity more than heat though....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
curbrider wrote:
>
> i have a 91 jeep cherokee 4.0 its hard to start at first when i shut it off
> it restarts just fine i let it sit about 15 min its hard to start again
06-05-2005, 09:26 AM
#4
Guest
Posts: n/a
Re: hard to start
At that age, I would suspect a dirty computer sensor connection affected
by heat.
The likely one is the CPS plug and socket sitting on top of the exhaust
manifold behind the throttle body.
The other two that contribute are the TPS and IAC on the throttle body.
I would recommend you open these plugs and sockets and clean them with a
spray contact cleaner. An electronic contact cleaner is the best, but
WD40 will work ok too. I use dielectric grease on the plug seal skirts
when I put it back on. They seem to stay cleaner longer with it on.
Then I would hear about it if I didn't mention the ground strap from the
engine head to the firewall. ;-) That gets dirty and actually crumbles
with age as well. Because it is on the head, heat affects it too.
If you haven't put a new distributor cap and rotor in recently, they
would be worth a look at or replacement. That 'usually' acts up in
humidity more than heat though....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
curbrider wrote:
>
> i have a 91 jeep cherokee 4.0 its hard to start at first when i shut it off
> it restarts just fine i let it sit about 15 min its hard to start again
by heat.
The likely one is the CPS plug and socket sitting on top of the exhaust
manifold behind the throttle body.
The other two that contribute are the TPS and IAC on the throttle body.
I would recommend you open these plugs and sockets and clean them with a
spray contact cleaner. An electronic contact cleaner is the best, but
WD40 will work ok too. I use dielectric grease on the plug seal skirts
when I put it back on. They seem to stay cleaner longer with it on.
Then I would hear about it if I didn't mention the ground strap from the
engine head to the firewall. ;-) That gets dirty and actually crumbles
with age as well. Because it is on the head, heat affects it too.
If you haven't put a new distributor cap and rotor in recently, they
would be worth a look at or replacement. That 'usually' acts up in
humidity more than heat though....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
curbrider wrote:
>
> i have a 91 jeep cherokee 4.0 its hard to start at first when i shut it off
> it restarts just fine i let it sit about 15 min its hard to start again
06-05-2005, 09:26 AM
#5
Guest
Posts: n/a
Re: hard to start
At that age, I would suspect a dirty computer sensor connection affected
by heat.
The likely one is the CPS plug and socket sitting on top of the exhaust
manifold behind the throttle body.
The other two that contribute are the TPS and IAC on the throttle body.
I would recommend you open these plugs and sockets and clean them with a
spray contact cleaner. An electronic contact cleaner is the best, but
WD40 will work ok too. I use dielectric grease on the plug seal skirts
when I put it back on. They seem to stay cleaner longer with it on.
Then I would hear about it if I didn't mention the ground strap from the
engine head to the firewall. ;-) That gets dirty and actually crumbles
with age as well. Because it is on the head, heat affects it too.
If you haven't put a new distributor cap and rotor in recently, they
would be worth a look at or replacement. That 'usually' acts up in
humidity more than heat though....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
curbrider wrote:
>
> i have a 91 jeep cherokee 4.0 its hard to start at first when i shut it off
> it restarts just fine i let it sit about 15 min its hard to start again
by heat.
The likely one is the CPS plug and socket sitting on top of the exhaust
manifold behind the throttle body.
The other two that contribute are the TPS and IAC on the throttle body.
I would recommend you open these plugs and sockets and clean them with a
spray contact cleaner. An electronic contact cleaner is the best, but
WD40 will work ok too. I use dielectric grease on the plug seal skirts
when I put it back on. They seem to stay cleaner longer with it on.
Then I would hear about it if I didn't mention the ground strap from the
engine head to the firewall. ;-) That gets dirty and actually crumbles
with age as well. Because it is on the head, heat affects it too.
If you haven't put a new distributor cap and rotor in recently, they
would be worth a look at or replacement. That 'usually' acts up in
humidity more than heat though....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
curbrider wrote:
>
> i have a 91 jeep cherokee 4.0 its hard to start at first when i shut it off
> it restarts just fine i let it sit about 15 min its hard to start again
06-05-2005, 05:30 PM
#10
Guest
Posts: n/a
Re: hard to start
curbrider proclaimed:
> i have a 91 jeep cherokee 4.0 its hard to start at first when i shut it off
> it restarts just fine i let it sit about 15 min its hard to start again
>
Describe "hard to start" a bit more completely.
If hard to start means that the engine cranks for a few seconds before
it starts....and only does this after the engine has been off for a
while, the next time you try it first turn the key to the on
position but do not try to start. You should hear the fuel pump
run for a couple seconds and then quit. If you can then turn the
key off and back on and it starts, you have a pressure leakdown.
> i have a 91 jeep cherokee 4.0 its hard to start at first when i shut it off
> it restarts just fine i let it sit about 15 min its hard to start again
>
Describe "hard to start" a bit more completely.
If hard to start means that the engine cranks for a few seconds before
it starts....and only does this after the engine has been off for a
while, the next time you try it first turn the key to the on
position but do not try to start. You should hear the fuel pump
run for a couple seconds and then quit. If you can then turn the
key off and back on and it starts, you have a pressure leakdown.
