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New engine with no start/hard start.

Caboose

NAXJA Forum User
Location
Colorado Springs
Well, I desperately come here seeking advice and help, as I'm sorta outa ideas and baffled. Now I will apologize for the novel I'm about to right, but I'd like to explain everything I've done and tried so far.

My girl's rig is a '92 XJ. In August of 2013 it decided to become a 5cylinder going down the interstate and shot the #6 rod out of the block. The wrist pin and piston are still intact in the cylinder with the top of the rod. The rod journal is still attached to the crank, and not seized. Spins freely. Earlier that summer she hydrolocked the engine going through a water crossing "hot rod style". I popped the plugs, drained the water, started up with no lopes or vibration indicating a bent rod or anything out the ordinary. Ran perfect, but I guess it cracked the rod or something. Regardless, threw the rod, out the block, and broke the cam shaft in the process. The engine would still start and move on it's own power into the shop and around the yard. Amazing.

Blast forward to December. I got a brand new engine from Dynamic Engines. Quality stuff, like em, like the engine. Spent the past month ordering some needed parts and getting funds together for those parts and stuff as after paying for the engine (it was her xmas present) and then still having xmas with the rest of the family, financially tapped for a bit. New motor mounts, a few new sensors and stuff that broke as it got pulled (I'm a professional!).

So this past weekend, January 19th, I finished the install of the engine and went to go start it. First crank yielded the fuel pressure regulator o-ring blowing out and shooting fuel out. I found it strange as I didn't separate the regulator from the fuel rail at any time, just the rail from the manifold to replace the injector o-rings and clean their tips. Well, replaced the fuel pressure regulator with a junk yard unit and no leaking. Crank crank crank (thats the short version of it), won't start. Fuel pressure gauge yields 40psi at the rail. Bleed off is super slow and indicates the regulator and fuel pump are functioning. Check for spark with inline tester, it's there. Pull plug and immediately can notice fuel in the cylinders. Hmmm... Check spark externally, still there. No "misting" of fuel out the spark plug hole while cranking. Pull the fuel rail and cycle the injectors to visually see them spray. All 6 are spraying in a short stream, which I find odd as I was expecting a "spritz". Figured maybe I messed them up when cleaning with a tooth brush. Go to the junk yard, get 6 injectors and install them and same test. The same stream, no atomizing or spritzing. I find this odd, but figure "guess it's normal". Still crank crank crank.

Well I start getting creative. Pull the fuel pump relay as it's obviously flooding the engine, crank crank crank till fuel clears out. once it starts to fire I install the fuel pump relay while it's cranking and hold wide open throttle and it fires up! So scared as I already spent a good amount of time cranking and flooding a brand new engine I waste no time to break in the cam for 15minutes at 2000rpm. At this point it's noticeable that the brand new exhaust manifold I installed (autozone stainless steel one) is glowing orange. Strange, but figure it's from stand still and no air flow. Engine oil pressure good, sounds great at 2000 rpm, very responsive and temp is holding a hair over operating temp and sometimes acts like it wants to get hot but letting off the gas and letting it idle brings the temp back down quickly. Satisfied with cam break in, I shut down engine. Try to restart and it cranks and cranks. Press wide open throttle and it stumbles but eventually fires up. Check timing, spark, fuel pressure and things again, all yield the same results. Change engine oil and filter to continue engine break in.

Go to restart engine, crank crank crank. Obviously rich again. Act's like it wants to fire the first few cranks but then floods out. Pulled plugs to confirm. Slap in another set of plugs thinking maybe the ones I have are too cold? Same results. Pull fuel pump relay, crank engine to clear fuel, once it starts firing I baby it along with some eather a tiny amount to get it to fire up and I plug in the fuel pump relay, idles out normal and sounds great. Go to rev engine and there's a nasty miss at 3000rpm. Sounds like a lean miss, and when ever it misses, the tach cuts out? Replace the coil and dizzy with junk yard units, same exact symptoms. Test coolant temp sensors, ohm's readings compare correctly to current coolant temps per a table I found on AllData (all my testing procedures are those found on my alldatapro account).

Check engine light is not on, and never came on at any time. I check codes, 12 battery disco, 21 o2 sensor voltage high, 55 end of diag codes. Tonight I replaced the o2 sensor. Crank sensor is new. TPS is new. IAC is new and throttle body/iac port spotlessly cleaned. Swapped battery for the optima out of my rock crawler and check grounds, power, fuses and relays in engine bay. Checked connectors for water (pressure washed the hell out of the engine bay) and corrosion, abnormals, etc. Didn't find anything. Gauges read properly. All vacuum lines properly hooked up. Map sensor was swapped with known good. Fuel pressure still indicates a 40psi at rail consistently while cranking and the short times I had it running it sat at 40psi (although my gauge is a hf gauge so might be a little inaccurate). Compression test was low before the initial start and cam break in. Now it's about normal, still a hair low but I think that there's still more running needed to break in the rings properly. I can coax it along to start with eather then plug the fuel pump relay in. It's 100% flooding out at start up. And when running, to me it sounds like a lean miss at 3000rpm and higher. The code 21 for the o2 sensor is still present after clearing codes numerous times.

The starter is starting to sound like crap from so much cranking and getting a little hot at times. But I got to thinking that it's always sounded a little slow, even with a brand new battery and cleaned grounds/ batt terminals/starter terminals. This was the same starter that started the previous engine faithfully every time first time. Now I'm wondering if it's cranking too slow for it to get a good start? Maybe not enough intake air draw to "suck" the fuel into the cylinders as a vapor? Trans functioned properly when the vehicle ran and it pulled into and out of the garage with ease. No test drive has been accomplished on this, only about 45minutes or so of total engine running as it's hard to get the thing to start up with the eather coax then plug the fuel pump relay in and wide open throttle while you're by yourself doing it (hot wiring starter solenoid so I can be in engine bay during cranks). When it does run, it sounds great at idle. Super smooth, good response. But this no start thing is driving me nuts as all of the electrical sensors/components functioned before pulling them off and installing on the new engine. Now I'm another few hundred and with no closer to solving this issue. Next idea is to get a new starter, as I would like to do so anyhow. I'm a pretty inclined mechanic, and realize there's not too much to these 4.0's and I've never had this problem or really any problem with a 4.0 that wasn't a blatantly obvious fix with common trouble shooting, so this thing has me stumped and confused. As my jeep memory has faded out quite a bit since I converted to suzuki's for my personal rock crawler, the yeep has always been faithful and a great rig for my lady to wheel with me. And I'm really wanting to get this thing running again to get her back on the trails with me (that, and I've got lockers and other parts I need to get installed on my samurai and this pink yeep is hogging up the shop lol).

So I reach to you guy for assistance and guidance, pleeeease. Before I go crazy. :( Or just start wheeling without her, which will probably turn into the death of me I've been told :nono:

Ask away on any further questions of stuff maybe I didn't cover and I will post an explanation as quickly possible. Thank you very much in advance for any input :cheers:

Jay
 
It would be much easier to help you out if you condensed the narrative to just the facts and tried to organize it some.

First, forget full throttle and trying to start. If the IAC is working properly you shouldn't need any throttle. If the IAC isn't working properly an inch of throttle is more than enough.

Fifteen second rule, if you crank it any longer than 15 seconds, the starter is going to overheat and the likelihood of it ever starting is reduced due to unburnt fuel soaking everything. And you'll likely pollute your new oil with fuel eventually.

New motor problems are usually the distributor not set up to TDC 1. And/or this throws off your firing order a cylinder and the cam position sensor is out of time. Cruiser54 did a nice writeup on finding TDC 1.

You forgot the ground from the rear of the block to the firewall or maybe another ground.

A connector got covered in oil and a necessary sensor signal isn't making it to the PCM and/or a necessary signal or spark is shorting through coolant to ground.

Open up an old plug to .060 and check the spark through the plug. A good quick test is to hook up a timing light to each individual spark plug wire and check the light pulse against a dark background, you can see weak spark, misses and misfires this way.

Double check your intake and make sure you didn't suck a piece of paper or something else in there.

Flooding, if it is fact flooding and you aren't flooding it trying to crank it over with bad (weak) spark or a plugged intake, it is usually a sensor issue, most often the MAP. Though I guess you could have an O2 sensor issue, if it is at operating temperature. Make sure the O2 sensor wire isn't cooking on the exhaust in the front, hard to see, a quick look isn't enough.

Lastly if at TDC one, good spark and fuel and it still doesn't start. You need to check your initial setup. The header glowing doesn't sound like too much fuel, it sounds like too little fuel and/or firing order and spark timing.

If all else fails do a compression test. This will show you if your valves are timed to your ignition or not. At TDC 1, the cylinder one valves should be as high as they will go at the rockers. If the cylinder one rockers are uneven height at TDC 1, your cam is timed wrong. Not advisable to run it this way, the exhaust valves may eventually burn up.
 
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