Renix Pinging

[Saudade]

One way to test the knock sensor is to run and warm up the engine. Put a timing light on it and note the engine timing. Then take a hammer and rapidly tap on the engine block near the knock sensor. You should see the timing retard and the engine lose rpms. Of course, someone will need to tap while you time or vice versa.

If it's truly detonation, you need to address this before you blow/burn something. If it's something else "rattling", like the injectors, then you may be able to simply ignore it.

 

[stangrcr1]

You are right, I am not so sure it is pinging, as it could just be noisy injectors, even though they are new Ford Orange tops.
The knock sensor I broke had the electrical connection at the end, and the new one is a side connection, stud screwed into block and nut holds the sensor on. Could the change be a problem?

 

[Ecomike]

You are right, I am not so sure it is pinging, as it could just be noisy injectors, even though they are new Ford Orange tops.
The knock sensor I broke had the electrical connection at the end, and the new one is a side connection, stud screwed into block and nut holds the sensor on. Could the change be a problem?

Don't know for sure, but if the connector is the same it should be OK. If it requires a different connector than you need to find a matting connector and do some electric wiring work to get it connected. The knock sensors are all pretty similar in that they use a mechanical pulse (engine knock) to move a piezoelectric crystal that is mechanically constrained, which then generates a low voltage pulse due to the mechanical pulse, that the ECU reads. Just need to get them wired into the 2 wire harness connection and mechanically fixed / attached to the engine block.

 

[Saudade]

I don't think so either. That's the new style as long as it's the right part number.

 

[5-90]

You are right, I am not so sure it is pinging, as it could just be noisy injectors, even though they are new Ford Orange tops.
The knock sensor I broke had the electrical connection at the end, and the new one is a side connection, stud screwed into block and nut holds the sensor on. Could the change be a problem?

I've seen what you're talking about (GPSorenson and Standard Motor Parts are doing the same thing,) and it should not pose a problem. All a knock sensor needs is a solid mechanical connection to the engine block - anything else isn't a problem, as long as you've got a good electrical connection and it's shielded from crosstalk (if you pull back the convolute tubing slightly, you should see a copper foil covering the wires - that's the shielding.)

 

[stangrcr1]

Injectors plugged into the jeep harness and the same with the knock sensor.

Tapping the block with a hammer did make the knock sensor jump to 6 as read by my MT2500, but no noticeable change in timing. Maybe I was not quick enough to catch it.

 

[Ecomike]

Injectors plugged into the jeep harness and the same with the knock sensor.

Tapping the block with a hammer did make the knock sensor jump to 6 as read by my MT2500, but no noticeable change in timing. Maybe I was not quick enough to catch it.

It may not change the timing at idle. It may only retard timing when the engine is under a load.

The control program parrameters are somewhat of a mystery.

My FSM, 88, says that at 2500 rpm the knock sensor should show at least 10 units and less 100 units for a working knock sensor, using the DRB-II tester. No idea what a unit is. It also says a knock sensor should retard timing on at least one cylinder, maybe more, for up to 15 seconds, if it senses a knock.

 

[stangrcr1]

I have no idea on the units either, but according to my scanner, I usually only see 1 or 2 on it revving the engine, and zero at idle. I will have to try it at 2500 rpm now. Maybe I overtorqued the sensor putting it on?

 

[stangrcr1]

Okay, I decided to test all the sensors just to be sure and I think I may have found the problem. My coolant temp sensor has infinite resistance. Now to find the receipt and get a new one. I already replaced it once, apparently with a defective one.

The FSM say the coolant sensor can effect the spark advance, so it may be the cause of my issues. I will pick it up tomorrow and change the thermostat since I have to drain the system anyway. Will post results.

The knock sensor was reading in the low teens at 2500rpm, so it may be ok.

 

[cherokee chuck]

I mentioned this on another thread ,but I have seen a couple of renix motors where the hold down tab on the distributor had been cut off and a ford type distributor hold down used so you could adjust the timing at the distributor. Maybe this was done to cure pinging? just a thought.

 

[Ecomike]

Okay, I decided to test all the sensors just to be sure and I think I may have found the problem. My coolant temp sensor has infinite resistance. Now to find the receipt and get a new one. I already replaced it once, apparently with a defective one.

The FSM say the coolant sensor can effect the spark advance, so it may be the cause of my issues. I will pick it up tomorrow and change the thermostat since I have to drain the system anyway. Will post results.

The knock sensor was reading in the low teens at 2500rpm, so it may be ok.

:clap:
You did install the new one, and did not reinstall the bad one right? Not that I would ever do that, LOL.

Sometimes it pays to test parts you just installed! Sounds like you found the problem too! Good luck.

 

[stangrcr1]

No, it was the new one. And the new new Coolant Temp Sensor didn't make a difference. The old new one has a bad wire connection at the connector. Any time I wiggled it with the ohmmeter on, it would show it. So I fixed the connection and will keep it as a spare.
Anyway, since nothing yet has helped.....
I stuck the scanner back on it, and it again showed everything working, running in closed loop as much as possible, and 14 degrees of advance at idle and 30 degrees at 2500 rpm. Same timing numbers I got with my digital timing light. Seems to be what it wants to run.
Knock sensor showed mid 20s while at 2500 rpm, so its good. Strange how it is higher this time.
My thoughts about changing the "timing" by moving the distributor, it seems to me that no matter where the distributor cap is, it is going to fire the plug according to the Crank Position Sensor. Moving the distributor would only change the relationship between the sync signal generator and the cam which controls injector timing, not ignition timing.
One thing I have noticed on my scanner is the fuel bias signal is running lower than the 128 middle ground while in closed loop. It averages 90-110 at idle with the orange top injectors. When I had a set of Accel 24lb injectors in it, it would go to zero and then open loop and rich enough to cause black smoke out the exhaust. The Accel injectors had leaky pintles causing the overrich condition, but are the orange tops injecting more fuel than what is required?
I am seriously thinking of yanking the motor and going through it just to make sure it is not a mechanical issue. Piston slap? Loose wristpin? I know all the rockers are tight, but what about the springs, etc.

 

[stangrcr1]

Here is some picks and a writeup on another site:http://nwforddiesel.com/cgi-bin/yabb2/YaBB.pl?num=1198594075/0

 

[Ecomike]

Indexing, or moving the dizzy affects the proximity of the rotor tip to the cap tip when the ECU fires the spark. Being 1 tooth off still fires at the coorect time (ECU adjusts the timing correctly) but the rotor tip may cross fire to the wrong cap tip and plug at times because it is out of position.

Sounds like you may have something else going on inside, or you have miss interpreted the sound.

Mine sounded like a really bad rod knock at first, but freequent multiple oil changes, MMO and Lucas oil additives over 30,000 miles have quited it down to where it sounds like a well oil sewing machine. These 4.0s make some scarry wierd noises, but seem to keep running inspite of the noise.

I don't what to tell you at this point. Have you used a stethescope to follow the noise yet? Or does it only do it under load on the road?

Could something in the drive train be binding and pulling excessive HP?

 

[stangrcr1]

The "pinging" is under load. Fairly quiet when running/revving in the driveway.

A stethoscope makes it sound like a cross between a blender and marbles bouncing around in a tin can. Hard to tell whats what.

Its getting parked for a bit until I can get to it.