zj shutting off

[Papa_Jon]

I just bought a 93zj 4.0 for $300. It starts fine but when you give it gas it stalls, but if you ease into it it does fine until you let off the gas then it dies. Any ideas on what it could be ?
Its my first jeep so im not to familiar with them.


p.s build thread to be started soon

 

[fattypackard]

possibly bad gas or vacuum leak...check your intake

 

[paradisePWoffrd]

what engine does it have?

id 2nd ^^^^^

or could be TPS... maybe stopped up cat, will throw TPS codes sometimes

 

[Papa_Jon]

4.0 motor


does any know what pins to jump to get the codes to flash ?

 

[mbalbritton]

Fuel pump going out.

Pull the fuel return line off the front of the fuel rail, run it to a bucket or gas can and fire up the Jeep. if no fuel comes out, then I'd certainly say fuel pump going out.

I had this on my '93 4.0 about a year or two ago. had the same symptoms, but yours sounds closer to it's death bed than mine was.

new pump is like $150 or in that range. Easy to swap, just a smelly job.

 

[Papa_Jon]

that what the guy i bought it from say he thought was wrong.

 

[mbalbritton]

... oh and don't go by a fuel pressure check. Mine checked out ok, but most certainly wasn't. It has to do with flow rate, not pressure.

 

[Papa_Jon]

lol well just pop my bubble i was about pump is fine

 

[Papa_Jon]

bump for help fuel pump is good

 

[paradisePWoffrd]

if you pull the O2 sensor out of the exhaust but leave it plugged in, you can tell whether the cat is stopped up... itll run really rich and exhaust will come out of the o2 bung... but if your problem fixes then you know its probly a stopped up cat

 

[Papa_Jon]

yea that what i was going to next

 

[Papa_Jon]

well it is the fuel pump just checked it again and nothing

thanks for the help

 

[wheelNC94GC]

Just curious but what are the plans for the zj? Sorry i don't have any help for ya, i'm gettin ready to start the build with my zj.

 

[Papa_Jon]

alest4.5 and swaping out the 30f and 35 rear full cage about all i got for now

 

[mbalbritton]

well it is the fuel pump just checked it again and nothing
thanks for the help

what was different that you checked this time on the fuel pump?

 

[Papa_Jon]

it had pressusre once then didnt