AKghandi

So 90 xj, 4.0 242 189k yadayadayada

so, this issue I'm having is that the truck just doesn't want to start if its sat for a few hours. after key on and of a few times and cranking it a bunch it finally starts, pretty irritating. how ever if i just park, it will restart like nothing.

I replaced every sensor except the knock. that I left unhooked. the truck has some pretty bad piston slap so it was affecting the way it ran.

the CPS has been replaced probably 10 times in the 6 months. some were faulty some I thought were faulty. the current one reads .8v napa part. did the top hole redrill.

fuel pump is oly 3 months or so old, though I did remove and bypass the resistor. I can always hear the fuel pump turn on, though right before it starts it almost seems like it runs longer.

I have refreshed all the grounds and I have also cleaned quite a few more. i will be thoroughly cleaning and greasing all connections later today.


Getting pretty irritated because I want to go wheeling but I don't trust the truck right now.

I'm also about to go index the distributor and seal all that up in prep for a cowl intake.


Also I have another 90 xj, the twin to mine actually but it spins over much faster than mine, noticeably so. Is it possible that it doesn't spin fast enough to kick over?

87lowcog35s

I can't guarantee it'll fix your problem, but I'd run another ground (4g?) from the ground on the battery to the frame rail directly under it. There is even a bolt there you can ground to, but make sure you clean all the paint off the frame under the bolt head. Those "pointy" washers are your friend here. There are 4 grounds coming out of your wiring harness, grounded to the block. They are by your oil dipstick. Make sure your battery ground is on the same bolt as these small grounds. Again, bare metal contact here. Under your dash, on the driver side: remove the lower dash panel (screws in that black line that runs across the dash.) look around above the hood release cable. You should see a ground coming out of your wiring harness, bolted to a lower dash support. This ground is for your gauges, computer, and who knows what else. Make another ground, running from this bolt (you cleaned the steel, right?) to the metal structure behind the drivers side kick panel 10 or 12" away. And for the love of bacon, clean the contact spots! It also couldn't hurt to separate your engine harness from the body harness and clean it up. Re grease the connector and reassemble. It should be a 1/4" socket from under the hood, under the brake booster, then pull off. You don't unbolt the fuse block under the dash.

AKghandi

All of that has already been done including a 4 gauge from engine to battery and engine to body. I just finished cleaning and greasing all the connectors under the hood. it seems to be a bit better but I wont know until it has sat for a little while. there were a few that were pretty corroded.

I noticed the starter vent was full of mud. might have to go and get a new one I sprayed it out the best I could with electronic cleaner but who knows if it helped.

AKghandi

So i noticed something today after having to floor it get on the highway. Its breaking up in the higher rpms. Not much but its noticeable

cruiser54

Good chance your injectors are bleeding off when parked.

You should replace them with Volvo 746 injectors anyway as they're prone to leaking externally.

Contact Programbo here on CF to get a refurbished set.

I would also index the distributor just cuz.

AKghandi

I think you're right. And i fully intend to pick up a set when i can.. but ive been dumping all my money in a another car that gets better mileage. So i can afford more jeep parts lol

AKghandi

Well today its raining prett good. And it didnt want to start again and it was breaking up pretty bad on my way to work..it almost felt like the torque converter was locking and un locking.obviously it wasnt as the rpms never changed but thats what it felt like.

DFlintstone

One of my 90"s had LCD. (Long Crank Disease) I ran a couple tanks of Chevron Premium with Techron for a different reason. (mileage experiments) Waz a little shocked when my LCD cleared up! Then back on regular it came back. ( I get it , that makes no sense). Now the LCD is gone and it runs fine on regular. My guess is it was the NEW stock injectors the PO had installed. I happen to be the first guy to run 746's Btw, and agree with Cruiser. An excellent choice wherever you find them.

AKghandi

Whats odd is after it starts and i shut it down. It will restart imediatly. Faster than the other 2 renix i have messed with. Usually fires after the 3rd blip. But if it sits for a while it doesnt want to fire. I could crank all day and it wont fire but if i turn the key a few times in and off eventually it will fire.

DFlintstone

That's called "the poor mans prime". Since the pump only runs about two seconds when you turn on the ign, those loosing pressure, (often the check valve in the pump), can turn it on and off a few times to pressure up the rail before turning it to start. Idk if mine was the check valve, the injectors, or the FPR, but the Techron in the Chevron premium surprisingly fixed mine. Worth a shot in my opinion!

AKghandi

Well the pump is new only about 2k miles on it. And what is also strange is when i turn the key on the first time the pump runs the normal like 2.5 seconds. But if i turn the key off and right back on. Nothin happens.but if i turn it off and wait 2or 3 seconds and turn it back on it will run for about a half second.. sometimes it starts then. Also i noticed sometimes when i turn on the key the brake light on the left side of the dash lights up. And other times it doesnt ebrake never moves. And brakes are in working order.

AKghandi

I'm starting to wonder if it might be the fuel pump.

the hesitation while drive feels like its trying to run out of gas. the filter is as old as the pump so i dont think thats the issue.

i bought the pump from oriellys, it was the precision i believe. thinking of getting a delphi from autozone.

AKghandi

Well i just ruled out fuel as the culprit. 31psi at idle 39 with fpr unhooked. I strung the gauge outside so i could watch it while i drove and it stayed solid depending on throttle. I turned on the key and it shot right to 39psi so i dont think its a priming issue. There was some pressure left in the line.the pressure lowers a bit while cranking.
i do have a pressure leak somewhere.i shut it off and 10 mins later im only at 25psi 20 mins and now im at 10psi

Oddly my bouncy idle seems tied to my fuel pressure. When it lowers the needle dances but when the idle smooths it sits solid.. weird.


So that only leaves ignition as the issue. Though i have replaced everything already. Except the coil but i just returned it because it didnt help the issue. I have replaced the icm(twice) and cps plugs wires cap and rotor not sure what else would cause this. It was really hard to start when i went to lunch.

Guess i need to check the cps again.

And i think ill prime the ststem and pinch the fuel line to the pump and see if thats where my pressure is going

AKghandi

Ok. Just did the pressure check with the fuel line to the pump pinched. Pressure dropped at the same rate. So it is injectors. However i released all pressure from the fuel line turned the key on and it put 39psi to the gauge and fired right up. No priming needed apparently. Just wondering what else in the ignition system would cause this. Getting on my damn nerves

cruiser54

Basics here.

When did it last get plugs wires cap and rotor?

Ever cleaned the throttle body?

Intake manifold bolts snug?

How's that line from the throttle body to MAP sensor?