Engine pinging

[RonD]

No on the crank sensor, does it feel tight, no wiggle room, and does the tone wheel's teeth look undamaged

From description of no pinging at lower RPM with SPOUT unplugged I would think PCM first and EDIS-6 second

 

[JessC]

Would you suggest buying a remanufactured PCM from an auto parts store or having mine rebuilt or searching wrecking yards

 

[RonD]

Wrecking yard for either

EDIS rarely fail, PCM more often but still rare for the number of them used

Rebuilt just means new capacitors and cleaning and you can do that
Your PCM may have a software/firmware glitch which another one won't have used or rebuilt

 

[Shran]

Following this thread... my new '94 is pinging under load as well and haven't nailed down the cause yet.

FYI - the capacitors in your PCM usually blow out the top of the can, but sometimes the bottom blows out too. I have replaced hundreds if not thousands of caps in various electronics and they can go either way. When the tops go, they will usually pooch out or split open - when the bottoms go, there is a little plastic disc that will get pushed out. You may or may not see electrolyte goo around the cap too.

Not sure what to think about your coolant leak. Upper rad hose is my guess. I've gotten bad new hoses before where the little reinforcement strings inside the rubber break through on the inside of the hose, then coolant flows out of the little cavity where the string resides and past the hose clamp. Sometimes double hose clamps will help too.

 

[JessC]

Coolant leak was solved with a new upper radiator hose and heater hose. Replaced the PCM and it is still pinging but as soon as you unplug the SPOUT and take it for a drive there is absolutely no pinging.

 

[JessC]

I have now replaced the computer, EDIS-6 and TPS. Nothing has made the pinging go away other then unplugging the SPOUT. Any ideas on what to do next?

 

[RonD]

Do you know the model number of the spark plugs you are running?

And spark plug wire's resistance, expected is 3,000-7,000 ohms per foot, test a few
Its a carbon core suppressor type with 5,000 ohm/ft average

New version wires can be 500-700 ohms/ft which could cause issues

 

[JessC]

We have ran NGK iridiums for a while when we first rebuilt the engine then we saw on some forums that the truck might not like those so we went to what the manuel says to run which is the Motorcraft AWSF-42C. Then we just have the muralist spark plug wires

 

[JessC]

That's supposed to say duralast spark plug wires, dumb auto correct

 

[JessC]

Could I just run the truck with the SPOUT connector unplugged since that's the thing that makes this horrible noise go away lol

 

[Shran]

You can, it will always run at base timing though. No advance.

having a similar issue with mine, @gaz mentioned that it could be a compression ratio issue caused by your head/piston combo… do you know what casting number heads you have, were they resurfaced, what pistons are you using?

 

[JessC]

The whole top end of the motor has been rebuild heads and lower Intake were sent to a machine shop. Pistons are the original to the notor when motor was open the cyclinders still had the cross hatching so assumed the piston rings were fine and no need to open the bottom end of the motor.

 

[JessC]

At this point might as well pull the motor and go through the whole thing

 

[Bgunner]

Did you ever put a timing light on it? Removing the spout connector setting it to base timing and the noise goes away says it's a timing issue.

Weather or not you can change timing doesn't mean that it is not off causing your pinging. Timing lights can still be purchased I picked one up for $99 at O'Reilly's about 3 years back and it was not the cheapest they had. If I am not mistaken with the spout unplugged the timing should be at 10° (BDTC) before top dead center. If it is under or over this the timing is off. If the timing is off the ECM is setting the timing advance to far or to retarded causing the ping.

 

[gaz]

@JessC ,
I agree, verify THE BASE timing.