Sorry for your troubles having to deal with inoperable vehicle. You will to have diagnostic codes ran, it could be several different components. From what you said i would suspect fuel pump. I doubt that the crankshaft is broken, that is extremely rare. I am quite old and have never seen a broken crankshaft. Your vehicle will have to to repair shop.
An engine needs 3 things to run. Fuel, Air and spark. You've checked the spark so move onto the air and fuel system. I'm assuming you did a full service on the replacement engine after you fitted it? Even a dirty Air filter can cause bigger issue that you would expect.
Have you checked to see if the engine is getting Fuel? If it is just turning over and not trying it might not be getting fuel to the cylinders. When you checked the plugs for a spark were they wet and smell of fuel when you first took them out?
Have you had the vehicle scanned with an OBD2 scanner for trouble codes? These can give clues to what and where the problem might be. If you have to pay for the scan get prices at 4 or 5 different places as prices can be VERY different.
Question edited for clarity. Cranking IS turning over. You are cranking but not firing, or starting, or running.
If you haven't much pressure at the rail, your likely problem is not enough fuel pressure and the fuel pump needs replacing. One post here says you need 39 PSI and another says 49 PSI. What do you have? You need to test with a pressure gauge.
https://www.google.com/search?q=1994+jeep+grand+cherokee+laredo+4.0+fuel+pressure+specs
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From our Pro Technician.
Anonymous Mar 08, 2022
Look for broken wires inside the flex boot , black rubber boot from the body of the vehicle to divers door. That year vehicle happens a lot after you open the door a million times.
Find a good local auto-electrician.
Question edited to fix second code.
Grand Cherokee P0700 Code Definition
If you are scanning your vehicle right now, you should be looking for a second code that tells you what is actually wrong. Think about it like this.
P0700 Says- "Hey there's something wrong with this transmission.
The Next Code(s) Say- "I'm the actual problem going on with the transmission. I'm what you're looking for."
Question edited for clarity and some sentences.
Question moved to Jeep sub category.
The way to fix that is to go to a local auto-electrician and they will just replace the contacts in the junction box by crimping a new one to the wire, and locking it back into the junction box.
You might even be able to do it yourself by bending the contacts in the socket a little with a thin blade screwdriver.
Your is easy,but there are 2 types they used in this year,do you have factory alarm or aftermarket, If its factory you will need a toothpick,if its aftermarket you will need to cancel the relay.let me know what you have. If you have one of the factory alarm the activation and deactivation is the door lock and unlock,it only disables the starter, go to the starter relay take it apart, when this relay collapse it engages the starter,with a key or without a key, stick the tooth pick in there so the relay is always closed.Go to the vehicle start it up.You defeated the alarm,With this type you need to becareful you have two different types I only gave you the easy one, if this is a manual transmission and you collapse the starter relay and the key is on away the car goes without you,so care need to be taken dont just do this without some with you put someone in the car stepping on the brake wheel block e brake on you not standing in the front and vehicle not in gear.becareful
I had a problem similar to that described. I took my cherokee to my local Jeep dealer who having charged around £1000 sent me away with the a warning light still showing. Several independant units advised I should dispose of the vehicle because this intermittand issue is common. Finally I fould a Jeep dealer with a technician who actually understood the cause of the intermittant issue. He removed, cleaned and refitted all the earth (ground) conections to the chassis and the problem was cured. Time to complete 1 hour! !0K miles later all is still good. A DIY job if only I had known.
If computer sees no crank sensor signal it shuts down pulses to the injectors. But, you bring something new into the mix. Make sure fender grounding is good so the relay can operate properly and make sure power going to it is not restricted by a loose or dirty contact on the power side.
TO REPLACE A DISTRIBUTOR FIRST YOU HAVE TO GET ENGINE IN NUMBER 1 FIRING POSITION IN COMPRESSION STROKE.WITH ROTOR POINTING TO NUMBER 1 POSITION ON DISTRIBUTOR CAP BESURE TO PUT NUMBER ALL PLUGS WIRES AND NUMBER ON DISTRIBUTOR SO YOU WONT GET CONFUSE AND MARK THE DISTRIBUTOR BASE ALSO SO YOU CAN PUT IT BACK IN THE ORIGINAL POSITION.
moved you to JEEPS, from computers
just sold mine, 2002, (sad I did 2008 stinks)
first of all, in English,
no engine size told,
nor what country sold new, Jeeps are made all over the world now and for sure no the same (not engines or electrics, nor EFI)
petrol or gasoline ?? later is USA name, but translaters lose that fact.
pu j'ai de l'essence qui == gasoline or French Petrol>?>>>>>???
are you in Europe or france or in USA or canada speaking French.
all that is good and fun sure.
but cars are not the same on earth, for a fact.
I can not look under your cars hood nor read your VIN.
English answer + translated.
Generic 100%
On all our cars USA ,I spark dies , the PCM cuts fuel.
yours did not so may be just flooding fuel engine.
are all 4 spark plugs dripping raw fueL?
ever replace the spark plug or are the 20 years old?
50k miles max is the rule , 2002 engines smoke so is less.
on spark plugs life. and gapped correctly
the owners manual on the car tells now to clear flooding
(spark good)
put throttle foot to the floor, WOT.
turn key and crank and fall fuel injections are cut, and now tries to start. (5 seconds max) on starter spins.
but fails, now repeat with no foot actions.
see it start and run. now
if not engine needs service.
way 2 , new spark plugs and all 4 tested for live spark first.
we then remove the fuel pump relay or fuse
and crank engine over using test fuel in hand
see scotty do that we love him here.
https://youtu.be/064Ilsz8Fzg
Question moved from Computers to Jeep Grand Cherokee
There is so much under there, it is impossible to tell. The most likely is a connector getting warm, but it could be so many things, even the radio, or the resistor on the heater blower.
