Re: Help '91 yj wont start
 

I would pull a plug to check it for gas.

That points you to no fuel or no/bad timed spark.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

mike wrote:
>
> Hi, my yj hasnt started in about 4 months now and it is really ticking
> me off; luckily my trusty xj has been hauling me around but anyway if
> you think you have an idea let me know, here's the symptoms
>
> '91 yj
> 2.5 4-banger
> tps
> 112k
>
> After an oil change I parked it in the garage as it was starting to
> get a bit cold to drive it everyday.
>
> a week later i hopped in on a warmer day and cranked it over, it
> wouldnt start, it was cranking, so it wasnt the starter or battery.
>
> I figured ok, its prob the fuel filter.. so $10 and a face full of
> fuel later that was changed, the old one didnt really look clogged and
> guess what it still didnt start.
>
> If i turn on the ignition i can hear something that sounds like the
> fuel pump turning on, so maybe the pump is ok.
>
> I hooked up a timimg light to each plug wire and the light goes on and
> off as it should so I figure im getting spark.
>
> I pulled the air intake off the throttle body, am I supposed to see
> fuel coming through there when it cranks?
>
> I tried putting a teaspoon of fuel into the air intake to see if it
> fired, no luck; what is the proper way to see if fuel is actually
> getting to the throttle body or the cylinder.
>
> I am out of ideas, the only thing I can think of is maybe its out of
> time. I didnt see any markings on the front of the motor to check
> this. (maybe its under the dirt, I havent got really in there yet)
> but thats my last hope.
>
> if it is in time then do i check compression? before it wouldnt start
> anymore it wasnt any more sluggish than a 2.5 normally is. there is
> no obvious sounds of broken valves or anything like that as it turns
> over.
>
> could it be bad fuel?
>
> i've called Dad and he's even stumped on this one! Thanks for any help
> in advance!
>
> Happy Jeepin'
> -Mike

Re: Help '91 yj wont start
 

I would pull a plug to check it for gas.

That points you to no fuel or no/bad timed spark.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

mike wrote:
>
> Hi, my yj hasnt started in about 4 months now and it is really ticking
> me off; luckily my trusty xj has been hauling me around but anyway if
> you think you have an idea let me know, here's the symptoms
>
> '91 yj
> 2.5 4-banger
> tps
> 112k
>
> After an oil change I parked it in the garage as it was starting to
> get a bit cold to drive it everyday.
>
> a week later i hopped in on a warmer day and cranked it over, it
> wouldnt start, it was cranking, so it wasnt the starter or battery.
>
> I figured ok, its prob the fuel filter.. so $10 and a face full of
> fuel later that was changed, the old one didnt really look clogged and
> guess what it still didnt start.
>
> If i turn on the ignition i can hear something that sounds like the
> fuel pump turning on, so maybe the pump is ok.
>
> I hooked up a timimg light to each plug wire and the light goes on and
> off as it should so I figure im getting spark.
>
> I pulled the air intake off the throttle body, am I supposed to see
> fuel coming through there when it cranks?
>
> I tried putting a teaspoon of fuel into the air intake to see if it
> fired, no luck; what is the proper way to see if fuel is actually
> getting to the throttle body or the cylinder.
>
> I am out of ideas, the only thing I can think of is maybe its out of
> time. I didnt see any markings on the front of the motor to check
> this. (maybe its under the dirt, I havent got really in there yet)
> but thats my last hope.
>
> if it is in time then do i check compression? before it wouldnt start
> anymore it wasnt any more sluggish than a 2.5 normally is. there is
> no obvious sounds of broken valves or anything like that as it turns
> over.
>
> could it be bad fuel?
>
> i've called Dad and he's even stumped on this one! Thanks for any help
> in advance!
>
> Happy Jeepin'
> -Mike

Re: Help '91 yj wont start
 

I would pull a plug to check it for gas.

That points you to no fuel or no/bad timed spark.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

mike wrote:
>
> Hi, my yj hasnt started in about 4 months now and it is really ticking
> me off; luckily my trusty xj has been hauling me around but anyway if
> you think you have an idea let me know, here's the symptoms
>
> '91 yj
> 2.5 4-banger
> tps
> 112k
>
> After an oil change I parked it in the garage as it was starting to
> get a bit cold to drive it everyday.
>
> a week later i hopped in on a warmer day and cranked it over, it
> wouldnt start, it was cranking, so it wasnt the starter or battery.
>
> I figured ok, its prob the fuel filter.. so $10 and a face full of
> fuel later that was changed, the old one didnt really look clogged and
> guess what it still didnt start.
>
> If i turn on the ignition i can hear something that sounds like the
> fuel pump turning on, so maybe the pump is ok.
>
> I hooked up a timimg light to each plug wire and the light goes on and
> off as it should so I figure im getting spark.
>
> I pulled the air intake off the throttle body, am I supposed to see
> fuel coming through there when it cranks?
>
> I tried putting a teaspoon of fuel into the air intake to see if it
> fired, no luck; what is the proper way to see if fuel is actually
> getting to the throttle body or the cylinder.
>
> I am out of ideas, the only thing I can think of is maybe its out of
> time. I didnt see any markings on the front of the motor to check
> this. (maybe its under the dirt, I havent got really in there yet)
> but thats my last hope.
>
> if it is in time then do i check compression? before it wouldnt start
> anymore it wasnt any more sluggish than a 2.5 normally is. there is
> no obvious sounds of broken valves or anything like that as it turns
> over.
>
> could it be bad fuel?
>
> i've called Dad and he's even stumped on this one! Thanks for any help
> in advance!
>
> Happy Jeepin'
> -Mike

Re: Help '91 yj wont start
 

Mike Romain did pass the time by typing:
> I would pull a plug to check it for gas.
>
> That points you to no fuel or no/bad timed spark.
>

Or pull a sparkplug and check that it jumps a spark
about 1/2 inch to the block. A timing light trips on
current levels that will not produce a good spark.

Re: Help '91 yj wont start
 

Mike Romain did pass the time by typing:
> I would pull a plug to check it for gas.
>
> That points you to no fuel or no/bad timed spark.
>

Or pull a sparkplug and check that it jumps a spark
about 1/2 inch to the block. A timing light trips on
current levels that will not produce a good spark.

Re: Help '91 yj wont start
 

Mike Romain did pass the time by typing:
> I would pull a plug to check it for gas.
>
> That points you to no fuel or no/bad timed spark.
>

Or pull a sparkplug and check that it jumps a spark
about 1/2 inch to the block. A timing light trips on
current levels that will not produce a good spark.

Re: Help '91 yj wont start
 

DougW wrote:
>
> Mike Romain did pass the time by typing:
> > I would pull a plug to check it for gas.
> >
> > That points you to no fuel or no/bad timed spark.
> >
>
> Or pull a sparkplug and check that it jumps a spark
> about 1/2 inch to the block. A timing light trips on
> current levels that will not produce a good spark.

A timing light has suckered me the other way...

The thing didn't flick on 3 cylinders leading me to think a spark issue
when it was one of the carb barrels not giving gas to half the engine.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Re: Help '91 yj wont start
 

DougW wrote:
>
> Mike Romain did pass the time by typing:
> > I would pull a plug to check it for gas.
> >
> > That points you to no fuel or no/bad timed spark.
> >
>
> Or pull a sparkplug and check that it jumps a spark
> about 1/2 inch to the block. A timing light trips on
> current levels that will not produce a good spark.

A timing light has suckered me the other way...

The thing didn't flick on 3 cylinders leading me to think a spark issue
when it was one of the carb barrels not giving gas to half the engine.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Re: Help '91 yj wont start
 

DougW wrote:
>
> Mike Romain did pass the time by typing:
> > I would pull a plug to check it for gas.
> >
> > That points you to no fuel or no/bad timed spark.
> >
>
> Or pull a sparkplug and check that it jumps a spark
> about 1/2 inch to the block. A timing light trips on
> current levels that will not produce a good spark.

A timing light has suckered me the other way...

The thing didn't flick on 3 cylinders leading me to think a spark issue
when it was one of the carb barrels not giving gas to half the engine.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Re: Help '91 yj wont start
 

Hi guys,

Thanks for the ideas, I put a fuel pressure tester on the fuel rail's
shrader valve this evening and it was between 30-40psi when cranking -
which is within spec acording to the haynes manual.

Its sounding like less than four cylinders are firing, i'll try the
plug to block test - if it isnt enough spark im guessing to try
changing the coil

other stuff i noticed, the horn wasnt working, nor the gauges or the
dummy lights in the center of the dash, upon removing all fuses under
the dash and scraping off any corrosion and spraying the hell out of
it with electrical cleaner i got the horn working, but still none of
the gauges or dummy lights. all the fuses in the block next to the
battery are good, the 3 50amp fuses and the 20amp iod fuse were the
only ones not to have 12 volts running across them with the ignition
in the on position and the vehicle off.

my thoughts now have it down to about 3 things...

1. some crazy electrical problem that will cause much pain to find.

2. dirty/clogged injector(s) (will it run on 3 cylinders?)

3. weak coil (i'll try the post that said to see if the spark jumps
about 1/2 inch to the block - i'll get my roommate to hold it.. hehe)


side note:
i'm located in north raleigh, nc

thanks for the ideas guys - any more?

Happy Jeepin,
Mike