Engine pinging

[JessC]

Hello I have a 92 ford ranger 4.0 with a pinging issue at part throttle doesn't do it at idle or when you floor it. Also has a slight miss at idle.And keep finding oil in the intake. Also having a coolant leak that I can not identify. All gaskets have been changed twice now and completely top end rebuild. Truck runs beautifully other then that no smoke and has all the power in the world.

 

[RonD]

Welcome to TRS


I assume the pinging is only after engine warms up?

I would run some 91 or 93 octane fuel to see if the pinging is octane related
Just to take it off the table

1992 4.0l could have an EGR valve/system if it was a Calif. vehicle
Does yours?

Octane/heat pinging can be fuel mix related, if you don't know the age of the O2 sensors, change them
O2s are the ONLY sensors that wear out on schedule, 12 years or 100k miles and they are untrustworthy after that and set no codes until total failure


Oil in the intake is from PCV system, clean or replace the PCV Valve, clean its hose and also the breather hose from air tube to oil fill pipe
The oil Vapor inside the engine, crankcase and valve covers, comes from Blow-By
Blow-by is exhaust gases that blows by the piston and rings each time a cylinder fires, only thing in an engine hot enough to vaporize oil, and it does vaporize some of the oil coating cylinder walls and piston/rings
All piston engines have blow-by, period, but there is more as an engine ages
Cheaper oils will produce more oil vapor as well

Most of the oil vapor should condense in the crankcase, but some will go up into the valve cover areas via the drain holes, along with the blow-by gases, and be pulled into the PCV valve and then into the intake
PCV system is there to re-burn the blow-by exhaust gases in the engine
So its an emissions system
The Breather hose is there to pull in fresh filtered air when PCV Valve is open, but if its not opening then Blow-by/oil vapor can exit out the breather and be pulled into the intake via the throttle plate, so check if throttle plate/body also has an oil coating

 

[JessC]

Pinging happens when cold and hot truck does not have EGR. I've run 93 with octane booster and still pings. O2 sensor has been replaced 3 times and pcv has been replaced.

 

[RonD]

Reads like spark timing issue, especially if it can happen before full warm up, so rules out carbon build up and self-ignition from octane/compression

Maybe time for another EDIS-6 ignition module and then next an ECM/PCM(engine computer)

EDIS-6 is a long shot, outside of being damaged in a front end collision they never break
EDID-6 uses crank sensor for startup and RPM spark advance

But its missing Load Spark advance, "Vacuum advance" on older systems
So the Computer uses a SPOUT connection to relay Load advance to the EDIS-6
Computer uses the MAF sensor, throttle position, RPM, and speed to calculate engine load, this is just part of calculating the correct air/fuel mix
It then sends that to EDIS-6 to adjust the spark timing on the SPOUT wire

If you have, or can get, an old time Timing Light might be worth while to see what spark timing is doing
As RPMs go up spark advance goes up of course, but as Load goes up spark advance gets less because the Richer Fuel mix ignites faster

 

[JessC]

Before changing the EDIS-6 and ECM would you happen to know the procedure on how to check the timing.

 

[Josh B]

If you check local pawnshops and such you might run across one, yard and estate sales etc, maybe ask some friends if have one laying around
Most of the later ones had a clip on wire you just released onto the #1 plug wire and one to hot and one to ground, then you start it and point the light at the flywheel timing marks, rotate the distributor till you get the advance you need

 

[RonD]

As said you need a timing light
4.0l OHV only has 0deg and 10deg BTDC mark on crank pulley
Warm idle should be about 20degBTDC with SPOUT connected
But it doesn't read like base timing is the problem
Reads like a Load timing issue

Just thinking, could be TPS(throttle sensor), its a 5volt sensor like all the sensors
3 wires
5v
return
ground
in that order
Key on engine off
Ground volt meter
Get sewing pin or a "needle probe"
Pierce the center wire and test voltage
Throttle closed it should read 0.69 to 0.99volt, just under 1v
Slowly open throttle and watch voltage
Should start going up with no jumps or drops
When at wide open(WOT) it should be 4.5v-4.6v
Move it back and forth a few times looking for dead spots or shorts(higher volts)

 

[JessC]

This truck doesn't have a distributor it's got a coil pack and all.im finding is that you can't adjust timing on this truck

 

[Josh B]

Sorry Jess, I didn't read back well enough

 

[RonD]

Correct, can't adjust it but can see if its a problem

 

[JessC]

Ok I got the pinging to go away but only by unplugging the SPOUT connector and leaving it disconnected and driving it. So does that mean I need a new EDIS-6.

 

[RonD]

That's a hard call

Because the EDIS-6 is one thing that Ford made that hardly ever fails on its own, I would tend towards computer issue

I would first pull out the computer and open it up
Have a look at the circuit board and parts
There are 3 blue capacitors that leak/fail after 20+ years, but they mainly deal with the fuel system not SPOUT, but they leak so that could cause a SPOUT circuit issue
Under a $5 fix to replace these 3 caps and clean up circuit board

Computer circuit board seen here: http://www.auto-diagnostics.info/ford_eec_iv

3 blue caps are at different locations by year

Also unplugging the 60 pin connector and plugging it back in cleans all the terminals, so even doing that might get SPOUT working properly, if it was a sensor or computer connection issue

 

[JessC]

I opened the computer there is nothing visually that looks like failed or leaking some connectors are a little bent and there is a little bit of dirt. Are you talking about the 3 blue rectangle plugs? Also this truck has been offroading in rivers before could submerging the EDIS-6 cause it to short out or is it waterproofed.

 

[RonD]

Yes, water intrusion into connectors and/or EDIS-6 module could effect it

Caps look good in the PCM, flat tops no leaks
And board looks clean

 

[JessC]

I have opened the flap on the EDIS-6 and it looks completely new inside. Could it also be the crankshaft position sensor? Or what else would you suggest I look for?