mannydantyla

Sunday, yesterday, I put everything back together, making sure to reconnect all the wiring connectors including the o2 sensor, the fuel line and support bracket, all the vacuum lines, and grounding strap. Actually I replaced the grounding strap with a new one because old one was barely hanging on by a thread.

Oh, and I put new spark plug wires, distributor cap and rotor on since I was messing with the spark plug wires.



Now the scary part: it was time to fire it up. Here was my procedure:

1. double check the spark plug wires, vacuum lines, electrical connectors, fuel rail, etc.
2. fill up the radiator with coolant and check for leaks
3. change the oil
4. disconnect the ignition coil from the distro and the wires from the fuel injectors
5. crank the engine for several seconds to get oil to the new lifters (I never did see the oil pressure gauge move during this so idk)
6. reconnect the ignition coil and fuel injectors
7. turn on the engine
8. look for fluid leaks, vacuum leaks, smoke, pinging, etc.
9. burp the cooling system
10. let it idle and bring it up to operating temp, then slowly drive around the block and to the liquor store [edit: at this point I should have been breaking in the cam by revving it around 2k in park for about 20 minutes]

When I finally got to step #7 and I turned on the engine, it fired up but was idling very rough. Like, real bad, multiple things wrong. I new right away that the #5 fuel injector was not working - I had problems with it before tearing down the engine, unplugging it and plugging it back in usually fixes it, but not this time. The idle was very choppy and it was either idling rough enough to cause a motor mount or something to bang around, or it was pinging/knocking/detonating. I'm still not sure but it sounds real bad. Oil pressure was around 20 while idling.

While it was idling, it started to get a little better so I very slowly drove it around the block and it got better and better and oil pressure rose to almost 40 while cruising. I then slowly drove to the liquor store to buy an expensive bottle of scotch since I figured I deserved it. By the time I got home, it was running smooth as hell and sounding great!! I did a little dance in the driveway. I drove like a granny the whole time and never really tested the engine's power so maybe the dance was a little premature.

This morning I thought I would drive it to work and give the motor just a little more of a work out, to break in the lifters. Respect the red line of course but just give it a little more RPM and more throttle each time I drive it. That was the plan anyways

But today it run like crap, and - unlike yesterday - it did not get better. I think I need to double check the spark plug wiring, but I doubt that's it as I think it was running well yesterday. Maybe I need to reset the ECU. Maybe the fuel injector(s) are toast. Maybe the new distro cap and rotor is messing things up. Maybe I missed a connector. So many things it could be! The only CEL code is P0205: #5 fuel injector open circuit. So that's still my #1 suspect but it's so much worse than it was before!

????

outersketcher

I wish I could help you. Don't know enough yet about actually getting a running engine to purr yet to be able to offer any useful advice.

Definitely subscribed to this thread. Love that little rolling tool caddy you have there in that last photo. And I hope you find the solution to the rough running quick.

Good luck.

mannydantyla

I drove back home today on my lunch break it was still running poorly, no power under load and making a terrible banging sound, and the check engine light - which was already on - started flashing at me! I used my scan tool and was P0303: Cylinder #3 Misfire.



When I got home I let it idle and went to the exhaust pipe - no smell of gas or coolant or oil, no smoke, just hot air but in very pronounced pulses. Next I looked under the Jeep - the banging noise was the exhaust hitting my homemade TC skid plate. That's good! Easy fix. The exhaust must have shifted a tiny bit which I took the header off and welded new studs on it.

I turned it off and check the compression on cylinder #3 since that was the one with the misfire code. It was super high! So that's good.



Next, I reset the ECU by touching the positive and negative battery terminals together for a while, then turning the ignition to on, highlights on, headlights off, ignition off. In that order. When I turned it back on, it may have helped a tiny bit but there was obviously something wrong with the engine that an ecu reset isn't going to fix.

So maybe it's a vacuum leak. I mean, it sure does run like crap and thats the #1 symptom of a vacuum leak. So I try to find the leak by spraying starter fluid around the intake manifold. Nothing. I really listen hard and want it to be a vacuum leak because that would be a simple fix, and I try several times, but nadda. I also don't hear any hissing noises.

Next, I grabbed my vacuum gauge and plugged it into the intake manifold.



The gauge was low but not extremely low. That might be normal for a jeep 4.0. It was holding steady too, and would behave normally when blipping the throttle.

So that's where I'm at for now... I might just drop her off at a shop and let someone else deal with it.

Thanks! I got it from a garage sale, it used to be a podium. I took the top part off, where you would put your speaker notes, to turn it into a table/cart. I actually use it as a welding table normally.

mannydantyla

Oh yeah and I also stopped at Oreilly's on the way home and borrowed a noide light set to test the fuel injector wires. They were all flashing just fine. And I double checked the spark plug wiring order and that was correct too.

Then I checked the resistance of the fuel injectors. Each were reading about 13.9 or 14 Ohms. They're supposed to be 12 Ohms resistance. They're 4-hole injecors made for 2001 Cadillac Devilles, Bosch 0280155923. 22.7 lb/hr @ 43 psi, yet the XJ fuel fuel pressure is 49 psi. So they might have a wee bit more flow.

With the engine idling, if I pull the #3 fuel injector it does change a tiny bit but not as much as the other cylinders.

Maybe I should put the original fuel injectors back on.

If not the fuel injectors then camshaft position sensor?

mannydantyla

dzywicki

Nice work. It is always nice when you finally get everything worked out. Double and triple checking everything does wonders.

mannydantyla

One last thing to do is go on a looooong test drive and see if this really did fix the overheating issue. Supposed to be very hot on Thursday, high of 103*F, that should do the trick

Bugout4x4

How many miles were on this engine before you tore it down?

PatHenry

Whoooooooo!!!!!! Nice!!!!

mannydantyla

about 254,000

outersketcher

you might want to consider dumping a can of injector cleaner into your gas tank and going for a nice loooong drive.

Also, I noticed earlier in your posts that you were considering cleaning out that ridge of carbon at the top of the cylinders. I'm not entirely sure why.. but I've heard plenty of mechanics tell me that you don't want to do that unless you plan to hone the cylinder walls and install NEW rings on the pistons. Once guy even described that ring of carbon as a little nest that the piston rings had created for themselves. And removing it will result in a loss of power and a drop in fuel efficiency.

Can anyone back this up? or am I blowing smoke outa my ears.

Bugout4x4

Thank you. I asked because I'm not sure if anyone else noticed it or not... But either these things are incredible about wearing slow or that engine doesn't actually have that many miles on it? I will leave it up to those more experienced with these but did anyone notice that crosshatch in the cylinder walls? Looks like it isn't even broke in yet! If this is original that is absolutely incredible! lol

mannydantyla

Today I'm getting 15.69 MPG all in the city where I rarely get above 40 mph. Not too bad! Will improve as the computer relearns I think.

The fuel injectors are not dirty, they're brand new almost, the problem was that I'm using ev1 to ev6 adapters because the injectors I bought are ev6 yet the '97 XJ used EV1. And, because I'm an idiot, I put dielectric grease on the adapters because I thought that would help. I think that was my problem, right there!

I have a can of DeoxIT on the way from Amazon, which is a contact cleaner and enhancer. I already used QD electric cleaner but I guess that wasn't good enough. Here's a good article about it: http://www.intendedacceleration.com/html/tip_14.html "Sometimes a poor connection is actually caused by a well meaning person trying to help the problem by using cleaning sprays that contain silicones to make the connections water-repellent. Why is this harmful? This is because silicone when certain conditions exist, can combine with metal ions to form high resistive films such as sodium silicate."

what I did have (stock)
=======================
'96-'98
#53030778 23.2 lb/hr @ 49psi
243cc/min @ 337KPa
EV1
12 Ohm resistance


What I have now:
================
Bosch 0280155923
172.0 g/min. @ 43 psi (22.7 lb/hr)
for: 2001 cadillac, oldmobile, pontiac engines
EV6
12 Ohm resistance
* needs USCAR to EV1 adapters

I think at the 49 psi that the XJ fuel rail is pumped to, they'll spray a little faster than the stock XJ injectors. And when I look at my Long Term Fuel Trim levels, they're around -10% when idling, and get up to 0% when accelerating. I don't know what the minimum negative trim level the injectors can be, but I know that you don't want them to spray for too long (or too short?) because that can be bad on them, pulses too long can cause them to overheat or something. I just looked at the LTFT levels again today and they might be one or two percent less than before the head rebuild, and I think that's a good thing, or that it's a good sign that the engine is more efficient. If it gets too low, it will throw a CEL and I'll need to find different fuel injectors I think.

Edit: according to this fuel injector calculator - https://witchhunter.com/injectorcalc1.php - my new injectors are pumping about 24.2 lb/hr @ 49psi, which is a bit more than stock (by 1.0 lb/hr). And more and I would need to get an adjustable fuel pressure regulator or something.

5-Speed

I just skimmed through this thread so I hope I missed something... but, you put new lifters in, I know that. Did you add any zinc/break in oil to the oil? After you first fired the engine up, did you keep the RPM up around 1800-2200 for 20-30 min? Or did you just let it idle the whole time?

mannydantyla

Yes I used Shell Rotalla T6 5w-40, which has lots of ZDDP but is also synthetic and I've read that it's better to use non-synthetic for breaking in engine parts but too late now!

I let it idle for maybe 10 minutes with an occasional tap on the throttle, then I very very slowly drove it around the block. Drove like my grandma was in the passenger seat, wearing her nicest white dress and holding a pitcher tomato juice. After that drive, my fuel injector connectivity issues must have resolved themselves and the engine was doing fine when I turned it off. The next day, yesterday, it was worse than ever though, but I thought that maybe it would improve like it did on Sunday. It did not. That was a rough ride, especially trying to get up a steep hill going slooooooow.

I also smeared the bottom of the lifters with engine assembly lube, the kind that is grey and a little gritty. I think it has graphite and moly in it