Koin

What is your idle rpm at stop in D?

It will drop oil pressure from low idle and tick like that depending on what it is. Mine was driving fine but idling like poop with a tick like that just from the vac leak at the TB, along with oil pressure drop from the poor idle.

Hotwire

It idles down around 600rpm in drive when at operating temp.

cruiser54

What happens with the oil pressure if you bring the idle up to 750 while holding your left foot on the brake?

Hotwire

https://youtu.be/aoCR3TlIPPE

The pressure drops off at 1000 rpm, and doesn't raise again until it hits 1250 - 1500 rpm again. This is while at operating temp.

When cold its right up at 3 bar.

Weak pump? Clogged screen?

Hotwire

Today I passed the 800km Mark since the oil change and tune up. It still ticks, but the knocking is gone. Even when stopped in traffic and with the temp up near 100c. Oil pressure still indicated as nearly 0, but now it's just a lifter tick noise I'm guessing.

Tonight I installed an electric fan and a relayed harness for an aux fan switch. Tomorrow I will pick up a temp switch and put it inline to try and "automate" the electric fan. It never came with one stock... So there is NO harness for it from the factory. Even though the original slip says it came with the tow package.

I'm going to swap out the oil preasure sensor tomorrow, but only after I have verified the pressie using a mechanical oil pressure gauge. This will put my mind at ease. Or at least answer some questions.

Thanks for the help from everyone!

cruiser54

Great job of sticking with it!!!!

Hotwire

Well, The mechanical guage tells me that its low on pressure. THAT we all kinda knew, Why... that is to be seen.

As of this morning the new sensor is showing he pressure does drop, but its not as sudden as the old sensor indicated. Also, its not raising as high as the old sensor indicated either.

With the amount of sandy grime that was on the top of the head, I imagine that the oil pump is probably worn to ****. So.. I inspect that, along with the pickup and screen. But this may just be a band aid fix.. it may be too late.

Koin

Good going with the mech pressure gauge. Sounds like a pretty good assessment to me if you did have major crud in there. Hats off and good luck with cleaning it out. Hopefully that will help with the tick. Might be a good idea to pull the valve cover and check rocker torque and see if any rods are bent or lifters are squishy.

Bugout4x4

If you have the pan off do not put it back until you drop a main and rod bearing to take a look at those.

Hotwire

Im at 1200 km since the oil change. Pressure seems to keep rising, and the knocking is gone, except for on a hot start, it revs up to like 2000 rpm, rattles for a half a second then idles down.

At 2000 km I am going to drain it, have an oil sample sent out, and pull the pan, oil pump, and caps. Im also going to tear apart the pump and check for damage and clogging.. With the caps off, I will check the bearings, and condition of the crank. I will plasti-guage them too to check clearances as well.

Thanks everyone for all the help!

Bugout4x4

Sounds like you are on top of it! I think they all have that rattle for a bit when they first start. Mine is newly rebuilt tight and it still does that. I am leaning towards normal slack in the timing chain until it gets some oil on it.

cruiser54

Just run it.

97grand4.0

There was a post on another jeep forum from a guy who was told to just run it. He said it fixed itself driving to work at 75 mph. Posted pictures of the shattered piston, or should I say the cylinder and rod an wrist pin with no piston.

cruiser54

It shouldn't rev up to 2000 RPM on start-up. You have a TPS and/or TPS, MAP, IAT, CTS ground circuit issue. Do this next.

The sensor ground circuit affects the CTS, TPS, IAT, MAP, ECU and diagnostic connector grounds. It’s very important and not something to overlook in diagnosing your Renix Jeep as it is common for the harnesses to have poor crimps causing poor grounds. If any or all of the sensors do not have a good ground, the signal the ECU receives from these sensors is inaccurate.

Set your meter to measure Ohms. Be sure the ignition is in the OFF position. Using the positive (red) lead of your ohmmeter, probe the B terminal of the flat 3 wire connector of the TPS . The letters are embossed on the connector itself.

Touch the black lead of your meter to the negative battery post. Wiggle the wiring harness where it runs parallel to the valve cover and also near the MAP sensor mounted on the firewall. If you have an 87 or 88 with the C101 connector mounted on the firewall above the brake booster, wiggle it, too.

You want to see as close to 0 ohms of resistance as possible. And when wiggling the harnesses/connectors the resistance value should stay low. If there is a variance in the values when wiggling the wires, you have a poor crimp/connection in the wiring harness or a poor ground at the engine dipstick tube stud.

Refreshing of the dipstick tube connection is covered in Renix Ground Refreshing, and the sensor ground upgrade is covered in Tip #6 – Sensor Ground Upgrade.

On 87 and 88 models, you could have a poor connection at the C101 connector as well. See Tip #2 – C101 Refreshing and Tip #27 – C101 Elimination.



And, what brand of oil filter are you using?

97grand4.0

sounds like a vacuum leak and the IAC responds to it