I recall someone once saying that the pinging could be cured by changing the heat range of the spark plugs, but I don't know if they said hotter or colder. Would that work?

 

too hot of a heat range plug will cause pinging
too cold will cause fouling

injector with poor spray pattern will also cause pinging from non uniform air/fuel mix with lean sections in combustion chamber

 

Turbulence in the intake ports will generally prevent the mixture from having lean pockets unless the injector was extremely bad. However, a partially plugged injector will cause the entire cylinder to run lean.

 

more so in SFI engines with the injector spray pulse at the peak of the 1 cyl intake runner velocity...not so true in MFI engines since the injector pulse usually takes place when the intake valve is closed and minimum runner air velocity
fuel droplet size and plenum runner velocity are the 2 critical factors in perfect fuel atomization mix with air.
not so much a problem in the old carb'd systems, at cruise the fuel from the jets was located right at max air flow and air flow rate was essentually the same no matter where a particular cyl was in cycle. the problem came with cold start and any WOT, both had very poor air/fuel mix because of low air velocity past jets and large amount of raw liquid gas dumped in by accelerator pump
cold start is so much better with modern FI engines. try starting a carb'd engine at -30d F.

the next step in FI air/fuel mix technology is 1 O2 sensor per cylinder...already in use in European high end cars...will be common on the road in US in 5 years as sensor prices come down
these new gen. high tech aluminum block and thin alum. head engines will not stand lean or rich fuel mixes...costly to replace a 3 hp per CI twin turbo engine with cracked heads or fuel dilution damage to cyl. walls

 

That's what I was saying before; the bank fired fuel injectors are actually a step backward in fuel control. Other than poor atomizing, the pooling of the fuel behind the intake valve causes more build up of deposits.

It's stopped raining today, so as soon as I get done with my other chores, I'll pull some plugs on the pinger. Hope I can get to it before it starts raining again.

 

Got the old plugs out and replaced. Found the pinging cylinder; its plug had a lot of tan build-up around the electrodes and between the insulator and shell. The pinging was so bad that one of its platinum points was gone.

All the other plugs had lots of reddish deposits on the ground electrode; not as bad as the pinger, but worse than the originals I removed from my other van at 105k+ miles. Since these were APP765, it means they are at least the second set. Now I'm worried about why they're in such bad condition.

 

engine is running too rich
MAF, IAT, ECT or O2 sensor
should be almost no desposits on plugs of correctly running Ford OBD1 EEC-IV engine unless lots of cold starts and short distance cold runs....
that one cyl may have a leaky injector
also check compression and leak down in that one cyl for burned or bent exhaust valve, common with bad pinging

my last set in 4L EEC-V were spotlessly clean but gap had opened up to 0.100+ at 80k miles, no tip wear

 

O2 sensor recently replaced, MAF cleaned recently. I'm not sure how to check IAT or ECT sensors, other than to measure their resistances at cold and hot engine conditions. KOEO test shows no errors, even right after smog test that indicated just barely passing HC. But that would be consistent with running too rich. I'll re-run test to see whether it's picked anything up since. However, the only way to know for sure would be to run another smog test.

I've been careful driving, backing off as soon as I hear pinging, so I hope engine isn't damaged. But I will check compression next, as soon as I get a gauge.

What's the best way to check for a leaky injector?

 

pull and have tested and cleaned with spray pattern test.
do all at same time and have the injector specialist shop balance flow test all 6 for <10% variation

 

My original motorcrafts came out 18 months ago at 236,000 kms. They were in fairly good shape. Engine is 3LVulcan -96 EEC V, I beleive. Gaps were about .125" or 1/8" in old money. The engine had a misfire during the winter of 2004/5 which cured itself but must have set a code because the MIL "blinked" a few times when the misfire was at it's worse. Luckily I did not write off the catylist. The NEXT FALL I changed all the plugs , the misfire dissappeared , MIL went off. Only to come back on about 6 months later ,when a P0340 code reared it's head. However, now the ECU reports full functionality (all engine/ emission tests passed) since I have replaced the failed CMP sensor/drive unit , which threw a code & also a freeze frame. The engine ran fine even with the failed CMP drive, but I think fuel consumption was up a tad. However it still ran smoothly & did not foul any plugs, so I assume the fuel strategy was still good enough!

It's interesting to note that with this EEC V & SEFI, temperature or any driveability problems are extremely rare. The engine runs faultlessly in temps from -30 to +30* C. The only difference is in the bank book, while I can get as much as 670 kms (H/way kms) from a tankfull in the summer temps, during the winter I'm lucky to get 450kms /tankfull.

I have to say I'm really impressed with this Ford engine, so much so I really would not know what to do when a replacment is needed (an Escape maybe, is the Duratec engine as reliable ?).

Anyhow , she's good for now & looking into the future, looks bright enough for a few years yet.

ATB Aeroman

 

My KOEO test did not show anything; nothing new or stored.

When I have time, I will have to get to the fuel injectors. This means removal of intakes again. Now I get to repair the oil and coolant leaks on this car...

 

If you have time to ship them, these guys do a nice job. I had them service the injectors on my TurboCoupe. They will even give you before and after specs.

 

Thanks VanGo. I'll have to give them a shout.

Does anyone know what the flow rating is for the injectors on a 4l v6? 30lbs/hr @ 40psi?