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Jim T
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Join Date: Jul 2014
Posts: 1

No Spark on '95 Jeep 4.0

07/25/2014 1:19 PM

Jeep ran fine 7-24, this morning it would not start. No spark, checked one plug, checked coil wire still no spark. Checked Dis.& fuses under hood all good. Changed coil due to cracks in case. No help. (can't afford computer tester, $295.00)
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redfred
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#1

Re: no spark on 95 jeep 4.0

07/25/2014 1:27 PM

I can see your problem from here. You can see the problem from here.

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Crabtree
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#2
In reply to #1

Re: no spark on 95 jeep 4.0

07/25/2014 1:46 PM

Hahahahaha!

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RAMConsult
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#3

Re: no spark on 95 jeep 4.0

07/25/2014 4:40 PM

There's other "stuff" that goes into making that ignition system work. Look here or other forums:

http://troubleshootmyvehicle.com/jeep/4.0L/how-to-test-a-no-start-condition-1

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redfred
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#5
In reply to #4

Re: no spark on 95 jeep 4.0

07/25/2014 4:59 PM

Will this be the new Cavalier?

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lyn
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#6
In reply to #5

Re: no spark on 95 jeep 4.0

07/25/2014 5:03 PM

Maybe the start of the "bad ignition switch" forum.

So far there have been over 28 million vehicles recalled for bad ignition switches.

Who knows how many more are still out there?
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cuba_pete
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#7

Re: no spark on 95 jeep 4.0

07/25/2014 8:15 PM

What year 4.0? Check ballast resistor?
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lyn
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#8
In reply to #7

Re: no spark on 95 jeep 4.0

07/25/2014 10:07 PM

Is that a trick question?
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cuba_pete
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#13
In reply to #8

Re: no spark on 95 jeep 4.0

07/26/2014 11:41 AM

Nope...I've owned several, so covering the easy stuff.

Says a '95, but I wonder about the year of the engine.
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JWthetech
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#14
In reply to #13

Re: no spark on 95 jeep 4.0

07/26/2014 12:35 PM

States 4.0 so at least it's the right size. Ya I just sold 1, and am buying another, Significant Other has one. Great for 3rd world countrys. Easy to fix, lots of suppliers.
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HiTekRedNek
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#9

Re: no spark on 95 jeep 4.0

07/25/2014 11:00 PM

Many cause for this,including fuel cut-off pump,which activates if vehicle is turned over,as in an accident.

Sometimes they go bad anyway,accident or not.

A start relay that applies power to the ECC,

a security system failure,key recognition failure.

As you can see, it can get pretty deep.

Check all the forums listed elsewhere.

You are not alone...someone else has or has had that same problem.

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ormondotvos
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#10

Re: no spark on 95 jeep 4.0

07/25/2014 11:42 PM

Are any DC 12v pulses coming to the coil? You can test for that with a 12v tail light. Steal the one from the license plate light. Polarity doesn't matter. A small light will light in series with the coil. Current should be about 4 amps with a 3 ohm coil at 12v. For full current, just stick a 10 amp ammeter in the circuit.

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Ed Watts
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#11

Re: no spark on 95 jeep 4.0

07/26/2014 2:12 AM

Check -- or replace -- the crankshaft position sensor, which is mounted on the top of the bellhousing next to the engine block.

Very common problem with 4.0's.
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JWthetech
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#12

Re: no spark on 95 jeep 4.0

07/26/2014 3:24 AM

OBDI, code reader is not needed. Turn the key on/off 5 times. The check engine light will flash in a sequence. Copy this sequence and go JeepForum.com. Go to the YJ forum and do a search, you will find the codes.

Oh if you get an OBDII vehicle readers can be had for under 20 bucks
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Yahlasit
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#16
In reply to #12

Re: no spark on 95 jeep 4.0

07/26/2014 4:53 PM

Good answer pal, does it work with all makes?

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JWthetech
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#17
In reply to #16

Re: no spark on 95 jeep 4.0

07/26/2014 5:14 PM

To my knowledge, that is true for most OBD1 vehicles. When they went to OBD2 you needed the readers. A scanner is better, but OBD2 has many vehicle specific codes, they are no longer standard. There are forums for most makes of vehicles. Even Cavaliers and the upscale Citation. Wait until OBD3 becomes a nightmare.

Wonder what happened to the O.P.?
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Yahlasit
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#15

Re: No Spark on '95 Jeep 4.0

07/26/2014 4:46 PM

Is it a Wrigley or a Liberace ?; Anyways, I have a CJ5 '76 with electronic ignition module, and it when it's time to replace it (I have owned it for 16 years) it will give the same symptoms that you describe, if yours has one too, instead of a drivetrain control module or computer, go ahead and buy one.

I have checked the distributor pick-up coil signal with a scope, and compared a new module to a bad one, and I've only found a slight difference of less than 1 volt between them (bad one always reads lower).

By the way, If you do such a test, don't expect to see square pulses from the pick-up coil, It will look more like frequency bursts followed by null traces (alternated).

Regards

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JWthetech
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#18
In reply to #15

Re: No Spark on '95 Jeep 4.0

07/26/2014 5:23 PM

Nice car, what other mods have you done? Mine are about as stock as you can get them. The significant other has a Pavement Princess. Our club has a rally tomorrow we for a neighboring town. Spent the day polishing
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Users who posted comments:

Crabtree (1); cuba_pete (2); Ed Watts (1); HiTekRedNek (1); JWthetech (4); lyn (3); ormondotvos (1); RAMConsult (1); redfred (2); Yahlasit (2)

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