crank but no spark no start

I've researched 3 forums now and wasted $100 I think it's time to bug you guys

driving it and it died out of no where. tried to start up again. weak start and died after 5 seconds. now it only cranks
1993 jeep xj 4.0 Aw4

I have power to the fuel pump
does not start with starting fluid
replaced cap and wired
tried bypassing ballast resistor. got that mixed up now I'm not sure which wire plugs to which side of the resistor
replaced crank position sensor
there IS fuel pressure buildup
fuel pump DOES NOT energize when key is turned to accessory
all fuses have power and are good
distributor works. and the engine is throwing a code but I can't read it

camshaft position sensor? bad wiring? computer is fried?
I just don't know what else to look for. I'm about to have it towed to a shop tomorrow I quit

I just had a similar issue on my 99. Do your gauges come alive with the key? (fuel, battery, pressure etc?)

Things that I checked based on reading for hours and hours:
#21 Fuse under hood (will be different for the 94, but check your 15 and 20amp fuses), and check your 15amp and 20amp fuses inside.
I did continuity checks on all fuses, and others have found fuses that look ok but failed the continuity checks.
CPS, I know you replaced it but others have had bad aftermarket CPS's right out of the box!
I read that a bad cam position sensor will have the same effect as the crank position sensor.
You said you have power to the pump, did you hotwire it? You also said you have fuel pressure, how did you check it?

when the experts wake up I'm sure they will be better able to help. Good luck.

To check the code on a 93, turn the key on off three times, leave it on the fourth time. The check engine light will flash a code. Pay close attention as there are pauses.

Minor point but there is no reason that the fuel pump should energize when turning the key to accessory since you are not attempting to start the motor. Does pump energize when key is turned to start?

It does not matter which wire goes where on the ballast resistor--there is no + or -.

Why can't you read the code?

Since you have fuel pressure and it won't start with starting fluid, likely problem is spark.

the key trick didn't work only one I found only was on off on off on
the fuel pump always energizes every time when I turn the key to accesory in every jeep I've had
I have fuel pressure because gas squirted out of that valve on the fuel rail

I do have 1 blown fuse. its a yellow 30 I think I don't remember what it powers. but we swapped it for the interior lighting fuse and still no good
I really should've posted earlier yesterday. I think I'm just going to have it towed to a shop it's my DD and I need it

I wouldn't doubt that it's a cam sensor. I just can't afford to throw more parts at this thing. I wish I was at home today to try to read that code

Did you bring it to the shop? Since you already replaced the CPS, maybe you can test the cam sensor before you buy the part. Also, when you turn the key does your fuel, electric, and oil pressure gauge move?

all gauges work. jeep was towed this morning. I am anticipating the solution to this mystery
I had 3 experienced hands look at it before towing it. we're all stumped

This EXACT thing happened to me about a month ago. Jeep ran fine, then while driving back to camp died on the road. No warning, no signs that something was wrong...it just quit. Tried to start the first couple times then just cranked and cranked.

Tested fuel pressure (seat of the pants method....crack the schreader valve, look for strong flow) and only got a weak squirt. Decided the fuel pump was bad and the fuel filter was literally falling apart from rust. Replaced both. Strong fuel flow, no start. grrr...

Went back to the basics - Fuel, air, compression, timing, ignition. Getting plenty of fuel. Air cleaner removed, no change. Pulled a plug and cranked it over. Got a big spray of gas. Compression is good (didn't think it was comression anyway, since the motor was working fine). Checked spark at the coil. There, but kinda weak. Still, we saw spark. Rotor turned while cranking. Timing was most likely good. No bad mechanical interference noises while cranking. Went back to spark. Checked from the distributor - very, very weak. We also checked the CPS. Best test: Check for spark. Then unplug the CPS. No spark. Plug it back in, spark came back. CPS was good.

Did the 2 and a half hour round trip to the parts store for a new coil, plugged it in and it fired right up. My guess is the fuel pump was failing, allowing the engine to fire with the weaker spark until the coil just finally gave it up. New pump and filter gave MUCH stronger fuel flow, and the weak spark couldn't fire. New coil solved that. It's been running great ever since.

turns out it's a bit more complicated than that. had it towed in on tuesday and they checked it out
they said I had fluid backed up into the wiring harness? they cleaned and inspected it for 3 hours and finally bought parts and billed me
not only was this a fire hazzard but it caused ALL my sensors to short out and throw codes left and right
so I'm in it for $600 so far. I'm having them do a full inspection of the jeep just to be safe.
I could've thrown parts at it all day and never found that

CAJJ93XJ said:

turns out it's a bit more complicated than that. had it towed in on tuesday and they checked it out
they said I had fluid backed up into the wiring harness? they cleaned and inspected it for 3 hours and finally bought parts and billed me
not only was this a fire hazzard but it caused ALL my sensors to short out and throw codes left and right
so I'm in it for $600 so far. I'm having them do a full inspection of the jeep just to be safe.
I could've thrown parts at it all day and never found that

Click to expand...

Well I hope it works out for you, but that sounds like a snow job rip off to me.