Appreciate any help in advance. I recently bought a 98 4.0 aw4 231 previous mail jeep. Bought not running. New fuel pump installed 50psi with key on. Can crank jeep and keep spraying starter fluid and it’ll stay running only on starter fluid injectors don’t seem to fire and spark plugs are dry. However I also have an orange spark. I have verified both original and new coil are good. There is a little almost like a obd connector under the dash into a little black box that’s tied into several wires under the steering wheel. I have bought 3 separate crank sensors. Installed new distributor. Verified timing and tdc. When turning key to on I have momentary power to coil plug and injectors. I do not have constant 12v power at either the coil plug or injectors with key on. I do not have 12v constant power to fuse 21 (coil) or fuse 24 (o2) with key on. I have 5v power and 5v signal from cps and cms connectors. Have checked cps and cms for resistance readings as well. For asd relay I have 12v constant on pin 30 and 12v switched from 85. Pin 86 grounds for a few seconds which supplies the circuits with 12v the fuel pump also primes at this time. I have cleaned all of the grounds in the engine bay as well as new battery terminals. I have done multiple pin out tests but seem to find myself going in a circle now and unsure what is supposed to have power when and what readings. Also noticed when key is in ignition it sometimes beeps and other times doesn’t I can wiggle the ignition switch and it’ll beep or quit. Jeep cranks good and has 12v or 5v where it needs to be I’m assuming. Fuse 11 inside the kick panel fuse box also has 12v and all other fuses have been checked. Fuse 21 and 24 are the only ones that do not have constant power. Only when key is switched to on momentarily. For cel codes I haven’t really been able to follow a good trail with any of them. And they have not come back. I’ve swapped relays around. I have a 2000 xj that I’ve been sharing parts with as well to at least give me some direction. I’m thinking it is going to be a wiring problem but I’m going in circles now. Any help would be great thanks guys
98 Cherokee crank no start
- Thread starter Xjkcb
- Start date
- Location
- Minneapolis, MN
I would assume that is an aftermarket anti-theft device and needs a "key" plugged into it. I would do some research on any part number, brand name markings or serial numbers and determine how to remove it.
The spark should bright blue and snapping, an orange/yellow spark is a weak spark.
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Thank you for the response I will look into the box.
Hi from South Africa. Have read dozens of posts. Have the same no start issue on my old '98 XJ (150,000 miles)... not much to add, but this may be a new twist. Put on new tires, shocks and new fuel filter. Over the next 3 days it went from running 100%...to multiple cranks to start... to no start and no instruments. Swopped out PCM and have instruments back, but no start. No trouble codes on cheap OBD scanner. Has spark + power + signal to injectors. If I manually squirt gas into a cylinder it fires briefly. Only possible issue left to check is low fuel pressure when I get my fuel pressure tester. Otherwise I am stumped! Hope some XJ guru can solve these inexplicable XJ "no-start" mysteries!
sailorjim86
NAXJA Forum User
- Location
- NoVa
Could be a CPS (crankshaft position sensor) which is located on the driver side at the front of the transmission. Common failure. I've got a '98 and never had a problem with it but heard of a lot of others that have. If the CPS is not sending a good signal to the ECM, then it won't spark.
Thx... Sailorjim86 but it's not that... there is a good spark, and the engine fires when Engine Start sprayed into the manifold.
The only thing that doesn't seem to be working is the fuel injectors. There is 12v power and grounding signal at each injector.
I have cleaned all the grounds associated with the PCM grounding, so cannot figure why the injectors won't fire.
There is 45psi fuel pressure at the rail.
The only thing I can think of is that the ground signal to the injectors is not right (it should be 0v) I don't have a suitable multimeter to check it.
Am lost for ideas.
sailorjim86
NAXJA Forum User
- Location
- NoVa
Do you hear the fuel pump cycle on when you turn the key? When you turn the key to "run" (not all the way to start), you should hear a hum for a couple of seconds indicating the fuel pump is priming the fuel rail. If you hear the hum and it still doesn't fire, then try immediately cycling the key back to off then back to on and it might start. This can be caused by a bad check valve in the fuel pump, which allows the fuel to drain back from the rail into the tank when the engine is off (by doing this process, you are basically "double priming" the fuel rail to make up for the bad check valve). If no hum at all when you turn the key, then there's no power to the pump or the pump is bad. Before going with the pump is bad route, there's some play with relays you can try. Try swapping the A/C clutch relay with the fuel pump relay in the PDC under the hood. If it runs then,the relay is bad.
