1995xjcherokee4.0

So here is the story. 1995 Cherokee 4.0 inline 6. I have owned it for ballpark 2 years. It has many many man hours into it and many new parts.

The issue at hand is, i will go to crank it and the starter will spin the motor but the jeep does NOT want to "turn over" or run on its own. Excuse me if i used the wrong terms.

I have chased many issues in the past and am well knowledged on these Jeeps

I hooked a fuel pressure gauge to the rail... no fuel pressure. I put a screwdriver in a spark plug boot and held it by the block... no spark. I put a jumper wire in place of the fuel pump relay and the pump DOESNT run. But if i run power from the battery directly to the pump it will give me fuel pressure. Obviously still no start though because pretty sure theres no spark or injector pulse. Initially i thought it was a fuel issue until i did the fore-mentioned tests.

Anywho, i have access to new parts so i tried replacing a few infamous parts that are associated with no spark and no fuel such as a New ignition switch which did nothing, new ecm didnt help. new cps didnt help.

If i remove the fuel pump relay and the asd relay and hit them with a test light the position to the left has power (i THINK position 86 if i remember correctly) so the relays are getting power that would cause a no start.

All fuses under hood and by drivers feet are fine, all relays are fine.

The Jeep was cranking perfect, about 2 weeks ago i parked it to replace my radiator / water pump / thermostat. Well i got side tracked and it took me until 2 weeks after being parked to finish up. I finish up my install and go to crank it... and thats when this issue presented itself. I initially thought it was a fuel issue (xjs and fuel issues so i checked aspects of the fuel system) Its whenever the fuel system checked out and i realized i believe i have no spark, that is when i realized i was in some deeper trouble than usual.


So what else could i check? Can anyone provide some diagnosing ideas? I have a multimeter and a good amount of auto let alone Jeep knowledge.

I checked all grounds that i could think of or see. I checked for power at the side post of under hood fuse box, i checked battery voltage, i checked all my sensors, even have doubles i keep in the shop for diagnosing purposes alone.

Something else to add, when i go to do the check code sequence on my obd1, the ol turn key turn key wait... well the check engine light just stays illuminated. Doesnt blink any codes.. doesnt do the usual turn on than off when i turn the key to acc, no, i turn key to acc and it just stays illuminated. Now this could be because ive swapped an ecm or two in there to see if its an ecm issue and the jeep hasnt been cranked successfully since the ecm has been reconnected. Thats just a side note.

The issue at hand is plain and simple. The jeep cranks but will not start and run on its own. Something is not communicating to something telling the jeep to allow or activate fuel and i believe spark also. I am just not sure WHAT could do that since ive tried replacing ecm, ignition switch, relays, pcm, etc.

Mines a 95, ballist resistors stopped in 93 ish, i keep getting told to check that a lot... on less knowledged forums...

I am driving myself crazy over here, i have an event at the end of May i need this up and running by. I give it a new cooling system and this is how it repays me... Jeeps... so ungrateful

It ran and started on a dime just fine until now.

new/newer parts: alternator, battery, cps, tps, iac, map, vacuum lines various, ignition switch, remaned ecm, radiator, water pump, tstat, 02 few months ago, etc etc

Other information: 1995 cherokee 4.0 inline 6 247.000 miles automatic. oem motor and tranny. oem rebuilt t-case np231. 5.5-6" lift. Coils upfront leafs outback. shackle relocation brackets. shackes. leafs. d44 rear (yes the rear xj one), d30 hp upfront. 488 yukon front and rear I JUST DID A MONTH AGO.



update. im 110 percent positive i have NO SPARK either along with NO FUEL. retried an ecm...cps... and ingition switch from a running jeep just to make sure i didnt get faulty parts at the store.

Got a fancy spark tester and i for sure have NO SPARK. Accompanied by no fuel.

tech

Have you checked the ADS relay ( auto shut down relay ) you will not get spark or fuel pump if it does not turn on , but ECM will not turn on the relay if it does not get a crank sensor in put and cam sensor in put .

BillyBoy

Redneck way...
step one... Put on a leather or rubber glove...

Step2... Have someone try to start it while you grab various wiring harnesses or connections and wiggle them around...

step 3... When wiggling one of those around causes the Jeep to start, start looking there for a short in a wire or a connection...

side note... Start at the wiring harness that runs across the entire firewall right underneath the front of the windshield... that and the coil are the two most likely places that wiggling something will cause the Jeep to start... When it does again, find out why... It is usually either a dirty connection for a broken wire in a harness that you have to cut open and replace... you should also make sure all of your grounds are clean... Even the ones on the dipstick and the coil to the engine block... It sounds dumb but these engines are damn near bulletproof if maintained properly...

this is a cheap and easy way to figure out how to fix your Jeep... Before you bust out the multimeter and start testing plugs... This is something you can do on the side of the road or the trail...

99.9% of the problems with a no-start can be figured out in the old-fashioned way instead of resorting to multi meters and following book Trails on how to track down electrical Gremlins...

this is why real men... or women... are called jeepers...

Noah911

This is a strange one. The main thing throwing me off right now is the fact that you say when you jumper the fuel pump relay doing this does not energize and run the pump, yet when you checked the fuel pump relay for power coming from the ignition side it is there... This is a strange thing to see, and have happen like this.

Maybe it definitely sounds like separate issue happening simultaneously to cause your Jeep to have neither fuel and spark to occur? But, also at the same time, it could be one issue causing both of these problems too?

With what I know, I think I would want to try and chase down the one I was most sure of with the diagnostics.. Right now, you know the fuel pump works since you had it energize to run when supplying battery power directly to it at the pump. You also know the point to where the power is getting up to for the fuel pump from one direction too. It sounds like the fuel pump power stops somewhere in-between the fuel pump relay and at the fuel pump. I would probably want to begin with tracing the wires back from the fuel pump until I found exactly where the power stops after it leaves coming from the fuel pump relay.

I would also want to know where the fuel pump specific ground runs to on the chassis. I believe the fuel pump grounds to either behind the driver side front door panel, or else it is behind the rear panel behind where a spare tire would normally be on the drivers side in the back? I think it is the front drivers side door behind that panel almost certain of it, but not 100% I would want to trace the ground for the fuel pump from there too.

I would first go after the fuel.. maybe it will lead to the reason for having no spark too? (although, it does not sound like it will though)

Noah911

Just to be sure.. you did this?

Insert jumper wire between Pin 30 and Pin 87 into the Fuel Pump Relay socket – you should have power at the fuel pump.

dt750

could it be the neutral safety switch? but it does sound more like an issue with the asd. have you tried swapping relays?