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Help '91 yj wont start

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

Reply to
mike
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Reply to
James Gemmill

Where are you located? Maybe one of us wouldn't mind swinging by for a look.

Jerry

Reply to
Jerry Newton

Try more than a teaspoon.... more like 1/2 cup. Why would it be out of time... you didn't do anything to it? Yes, you should see fuel spray into the intake while trying to start. If not, then either the pump or the injector is bad or the computer is not allowing them to work.

-- JimG

80' CJ-7 258 CID 35" BFG MT on 15x10 Centerlines D44 Rear, Dana 30 Front. SOA 4.56 Gears, LockRight F&R Dana 300 w/4:1 & Currie twin sticks Warn X8000i w/ dual batteries
Reply to
JimG

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:

Reply to
Mike Romain

Mike Romain did pass the time by typing:

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.

Reply to
DougW

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
Reply to
Mike Romain

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.

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

  2. 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

Reply to
mike

OK, now you have introduced a new (and significant) factor into the mess. The fact that you had bad connections on at least one fuse says that ALL the connections are suspect. I have to sing Mike Romain's favorite song here: remove and clean ALL the ground straps, especially the one between the block and the firewall (braided strap).

Out of curiosity, did this th> Hi guys,

Reply to
Will Honea

I guess I won't have to say it then.... ;-)

Mike

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

Will H>

Reply to
Mike Romain

It's funny how some of these questions evolve as the thread goes on - to hell with the dead guages, why won't it start type of thing.

Way back when, I spent all sorts of time look> I guess I won't have to say it then....

Reply to
Will Honea

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