ctxj93

I threw some jumper cables on it to try to rule out a weak battery this morning. It cranked like hell but wouldn't start. It's a balmy 9 degrees here today. Following some suspicions I've had recently, I poked around with the meter on the distributor connector until my hands stopped working. I'm not seeing any voltage at the blue and grey/tr wires. It's supposed to have 5v AC correct? I know I've read that they will start with no sync signal, but usually not well. Kind of seems like my situation here.

Does my starter sound slow/weak in this video ?

I had Oliver's driveline in NC make my double cardon rear shaft. Came with all of the options Tom Woods charges extra for and was much cheaper. Mine was built with 3" tube, greasable spicer u joints and extended splines for $338. They were great to deal with.

I'm wondering if one of my trusty old mustang injectors is leaking down into a cylinder overnight. I have a set of 746s on the way. The fuel pump came from my parts MJ which always started quickly. I also replaced the in tank rubber hose when I swapped it in. I guess I just don't understand how if my issue is losing prime, why doesnt it make difference cycling the key a few times? Same start time regardless of key cycles. Wouldn't that make up for ant prime lost over night?

Tried it again today with just a single key on, and crank and the start time was the same, 7-8 seconds

Yes 2 10 second cycles as suggested and it started as shown in my video. 8 second crank time. Tomorrow I will try with just 1 key cycle and see if that makes any difference.

Before cycling. After sitting overnight I checked to see what kind of residual pressure was in the rail, and just got a few dribbles. Like a puddle no bigger than a penny on the intake.

https://youtu.be/HBdwS-HrPNA So after 24ish hours I had just a little dribble of fuel come out of the shrader valve. As suggested this was 10 seconds key on, off, 10 seconds on, Start. Any thoughts? And before anyone comments, yes I wish I had a few more missile switches. (Not my doing)

I sort of figured that was the case. And cruiser, I agree. Totally possible my injectors are leaking down. It's been sitting about 24 hours now. When I go try it in a bit, I'll see if there's any residual pressure at the shrader valve before cycling the key

I will give it a try. When I did my fuel pressure testing I walked away for a few hours and had minimal pressure drop. In the process of trying to figure out the no start problem, I swapped the pump from my old reliable (fast starting) comanche as well. I can hear the pump prime when I turn the key, is that not enough to fully pressurize the rail? Typically if I try multiple key cycles, I won't hear the pump run on the second turn, like the system has reached it's desired pressure.

I must've been lucky with my last 2 renixes, they always fired right up quickly. I've never actually measured the crank time, I'll see if I can get a real number on it. Starter seems to crank over at a normal rate. Maybe I'll take a video of the next cold start and you guys can let me know what you think. Thanks again for the help!

I have one on order! I should add that it doesnt stumble to life like it used to. Once it finally starts, it revs up and settles down like normal. I also found the evap line from the tank was hooked directly to a fitting on the intake manifold. The PO removed the charcoal canister, but I replaced it and fixed the hose routing. I'm sure getting a direct suckle on fuel vapors was doing wonders for the air/fuel mix.

Unfortunately, I'm still battling this issue. I found my intermittent no start condition was caused by a loose pin in the fuel pump connector, but I still have a long crank on cold starts. At this point I have indexed the distributor again, replaced the map sensor line, tested the MAT and coolant temp sensors, and tested vacuum and compression. I've also adjusted the throttle stop and reset the TPS. Compression is 130-140 on all cylinders and holds 18 inches of vacuum at idle. Plugs are a little sooty, but not horrible. I'm still not sure if the IAC is working as intended. I have cleaned all my grounds and added an additional ground from the neg battery terminal to the body while I waited for my JeepCables order to show up. They will be installed this weekend. After reading through the fuel injection manual again, I came across this page (attached). Is it possible that the ecu isnt receiving a sync signal, and after enough crank time just picks an injector as described? It says it will probably start but not well. Could something be hooked up wrong it's and causing the ecu to not receive a signal? Would it still run if that were the case? A cold start these days usually takes 2- 5 second crank cycles. It would probably start on the first crank if I continued to hold the key for another 5 seconds. Once the jeep has run for even a minute, it starts perfectly every time for the rest of the day. However, if I try to start it cold again a day or so later, I'm right back to square 1. I'm trying to get my hands on a snap on brick to see if I can glean any info from what the sensors are reading while its running, but I feel like I'm running out of leads to chase here!

The previous owner cut the locating tab off the distributor to make it adjustable. I messed with this adjustment a little bit and decided I should eliminate this variable. I swapped in a distributor off my other truck and followed the instructions for indexing. I checked the timing with a light and it was within spec. I swapped in a new IAC, although I'm not sure was really the correct one for the truck even though it was listed as such. It doesn't seem to make a difference in idle plugged in vs unplugged. I also checked the short section of rubber fuel line on the fuel pump to make sure it wasn't deteriorated. It looked fine. The truck starts pretty much everytime but I'm still not happy with the crank time and stumbling to life. When I was checking relays last month, it seemed like if I unplugged a relay and plugged it back in I would get a few good starts and then it would revert back to stumble city. Pretty frustrating! My MAP line seems to be fine, it also came off a running truck but I will fix it as you described and report back.

I've owned this MJ for a little over a year. I noticed the extended crank right off the bat before purchasing the truck. It currently has the dizzy off my old comanche, a brand new cap, rotor and wires. Everything is dry under the hood, i didnt notice any tracking inside the cap, and weather doesnt seem to make a difference, it has this problem year round. Pic attached purely because I'm super excited to drive this thing (if I can ever get it running right)

Yep Renix intake gasket and all sensors. It's weird sometimes I get 3 or 4 normal sounding 4.0L starts, and then it's back to the lumpy starts without the normal rev up over 1k

19lb mustang injectors, also came off a running MJ. I checked around with carb clean pretty thoroughly, I've had vaccum leaks at the manifold on another jeep and it resulted in a noticeably high idle and whistling sound from that area of the motor. I'm using the renix intake and exhaust manifolds on the HO block. This truck has been hard to start ever since I've owned it. I figured it was due to the butchered sensor set up that it had when I first got it, but even now with all the right parts it's still giving me problems!

I cleaned the Throttle body really well, and the whole intake and all sensors came off of my other MJ which ran and started perfectly. I will check the butterfly adjustment just to be sure. Thanks! This comanche I'm working on now had an HO swapped in, and the PO tried to just wire the new style sensors to the renix harness. It did not go well. I reverted everything back to renix.

Ok, just ran out and checked it in the dark, D2-5 has 11v with key on, key off it starts dropping down over a few seconds eventually getting to <0.2v

Yes sir, fuel pressure drops to 31 at idle. Thank you for the B+ diag info, I'll have to test it tomorrow.

Hi Everyone, I'm having problems with cold starts on my 88 MJ. So far I've: -Tested and refreshed the grounds -Adjusted TPS to spec -Swapped in a known good IAC, - Checked the cps when cranking (I have .498V AC) - Made sure the Coolant temp and intake air temp sensors are working as they should. - Checked fuel pressure- I have 39 psi that holds steady -Checked timing and made sure distributor was installed correctly -Checked for o2 sensor heater voltage -swapped relays around -EGR is blocked off -Checked for vaccuum leaks -swapped known good Coil and ICM -swapped known good ECU When the truck does start, usually after several extended cranks, it doesn't start like any other renix I've owned. Instead of revving up to somewhere over 1k and coming back down to ~750, it sort of stumbles to life and comes up to the 750 mark. All of this only happens if the truck has been sitting for a while. Once I've had it running, it still stumbles to life, but it will always start. Once it's running, it idles nice and smooth and revs through the rpms with no backfires or hiccups. I'm wondering if this could have something to do with the B+ latch relay? Maybe the IAC isn't returning to the correct position on shutdown? I also noticed that on the green to 3 red wire fusible link coming off of the starter solenoid, one of the red wires just deads ends. There also is an additional red wire running from the ring connector at the solenoid that runs all the way across the back of the motor and through the firewall on the driver's side. Is it possible the previous owner hacked some additional wiring in here that bypasses the B+ latch relay? Any help would be appreciated. I've done my best to research people having similar issues, but haven't found any solution yet. I'm starting to lose my mind.

Today I pulled my barn off my comanche.

XJ

Great thanks a lot! I'll have to grab one of those external torx sockets too then.

Thanks! Yeah the 89 is the goofy accordion looking one. So I'll have the pilot bushing for a 74 cj, Clutch, master cylinder and throwout for a 98 and a flywheel for an 89.