Only starts on second try when warm

[Ep72]

So my 97 4.0 I just purchased I’m having issue that it doesn’t want to crank when it is warm it just turns over. If I turn the key all the way off and back on it fires right up this is very consistent. Starts on first try when it’s been sitting a while. Any ideas.
thanks EP

 

[KingCarGuyZ]

So my 97 4.0 I just purchased I’m having issue that it doesn’t want to crank when it is warm it just turns over. If I turn the key all the way off and back on it fires right up this is very consistent. Starts on first try when it’s been sitting a while. Any ideas.
thanks EP

just so I am understanding this? does it fail to crank when hot, or crank but not fire (start)?

Fail to crank I would say electric related (obv)

fail to start, need more troubleshooting but I have some ideas. whatever it is must be heat-related.

Lastly, I feel the need to shame you for your angry grill, perhaps the jeep is mad and thus won't start, but that's just my personal opinion.

 

[Ep72]

Lol my daughter says it looks like beach Barbie Jeep because of the color so I had to do something To look tough. Anyway it turns over just doesn’t fire up and start until second try.
EP

 

[KingCarGuyZ]

d

Lol my daughter says it looks like beach Barbie Jeep because of the color so I had to do something To look tough. Anyway it turns over just doesn’t fire up and start until second try.
EP

but, but, jeeps are happy vehichles they don't need to look tough.

does it starts the first time if your prime it (key on but not crank, wait until the fuel pump stops, then start) or prime it then go key off, back on, wait and then start.

(i'm trying to figure if it's fuel,spark, or something weird with the computer)

 

[Ep72]

Starts the first time with no issues when cold. I leave the key on then try thinking it is fuel pump doesn’t make a difference only thing is if I turn key to off then try again it will fire up

 

[KingCarGuyZ]

Starts the first time with no issues when cold. I leave the key on then try thinking it is fuel pump doesn’t make a difference only thing is if I turn key to off then try again it will fire up

interesting, I'm guessing that must be something with the computer? maybe a crank or cam sensor, do you have an OBD2 scanner? can you read/log some data of what happens on the failed start? any pending codes?

if it has fuel, and I see no reason why spark would start on the second time, unless, you have an ignition coil that is almost dead and needs time to "charge" and not a rail, what year? common rail ignition or distributor?

 

[KevinC74]

Is there any sluggish response when warm/hot?

 

[Ep72]

It’s a 97. It is not sluggish that I can tell there is no check engine light on

 

[Ep72]

Is there any sluggish response when warm/hot?

Not that I know of

 

[KingCarGuyZ]

It’s a 97. It is not sluggish that I can tell there is no check engine light on

i think pre 2000 the ignition system was a coil and distributor, try testing/replacing your coil.

 

[KingCarGuyZ]

while you're there make sure you getting +12V at the coil when hot.

 

[KevinC74]

It’s a 97. It is not sluggish that I can tell there is no check engine light on

If not sluggish or bogging when hot would definitely check your ignition coil.

 

[KingCarGuyZ]

also, it may sound stupid, but make sure your ignition wires are in good condition and are seated on the distributor, coil, and plugs well. check your points for excessive buildup. if your worried, pull a plug and make sure they look ok.


how many miles since the last ignition system service?

 

[Ep72]

I will try it tomorrow and let you know. Thanks for your help

 

[Ep72]

also, it may sound stupid, but make sure your ignition wires are in good condition and are seated on the distributor, coil, and plugs well. check your points for excessive buildup. if your worried, pull a plug and make sure they look ok.


how many miles since the last ignition system service?

I just purchased it so only can go off what was told to me I’m going to change all wires and plugs distributer rotor coil. Then I’ll know it’s all done

 

[Juggernaut]

My vote is fuel delivery. A weak pump or leaking injector will cause the symptoms you’re describing. When warm, after the no start, turning the key back off and then on reprimes and increase the pressure for it to start. Check the pressure at the fuel rail cold and then warm, and check for pressure bleeding when warm. Engines are less tolerant of lower fuel pressures when warmed.

 

[Juggernaut]

double post- my bad.

 

[Ep72]

I just purchased it so only can go off what was told to me I’m going to change all wires and plugs distributer rotor coil. Then I’ll know it’s all done

I’m sorry took me so long to post on what happen I changed the coil but yet it still does the same thing so I will finish the tune up and check the fuel pressure.

 

[Ep72]

I changed wires distributer cap coil plugs and it is still doing the same thing so... it must be fuel pump? How can I check

 

[KingCarGuyZ]

you tired the cycle the ignition check? ... if it still doesn't work when you do that, you can check your fuel rail pressure when warm (carefuling). or drop the tank and pull the pump and check it, but at that point, your 1/2 tempted to just replace it anyway cause you already have it out.