There is no need to alter the stock spark tables at all for 87 octane. To do it right,the changes are all in the fuel mixture,and in allowing fuel enrichment when under load.
JL

 

I bought the truck used at about 80k miles well after warranty. It pinged when I bought it.

The previous owner told me it had some pinging when I bought it.

The tune the shop did was based on their experience.

If I had the ability to tune it myself, I would have worked only on the fuel enrichment. For best performance under load, I would enrich the fuel/air mix with a progressively increasing richness from light load up to max load being optimally rich for performance. If I could do this, I expect that I would have issues with unburned fuel fouling the exhaust system components.

 

Not to mention, the catalytic converter running much hotter.

 

The OEM strategy pours fuel at the converters at approx a 10:1 air fuel ratio to cool them off after running stoich for long times under load. The hottest combustion temperatures you see are at the stoich ratio for your fuel(14.64:1 for pump gas).
JL

 

Fouling isn't a problem unless you're planning on running an absurdly rich fuel ratio. Modulars make the best power at 12.7-13:1 air fuel. For trucks under a load towing,etc..I like to see approx 12.5:1 for those applications.
JL

 

Dumping too much HC's into the cat will get make the cat hotter... hence the injector shut-off strategy when too many misfires occur. (which, coincidentally, doesn't happen as fast - or at all - with the OBD-I Superduty).

 

JL, If 12.5:1 is ideal in your opinion, how does the average guy with a knocking problem determine what ratio hes running at, and how does he change it?
Also, in a situation where the truck hasn't always had a pinging problem, what changed to cause it to start?
Is taking it in for an expensive diagnoses and fuel/air tune the answer to there problem? If so taking it to whom, I wouldn't let the average Ford service Dept. do this work on mine.

 

I agree and disagree....
Dumping unburned HC's into the cat will make it hotter, but combustion gas from a richer than stoich ratio will be cooler and will have a cooling effect on the cat. That's what Ford does in the catalyst overtemp strategy-richen the mixture to cool the catalysts.
JL

 

It's not as simple as just changing the ratio to 12.5:1 all the time. You need to run stoich at cruising,or you'll suffer pretty badly on fuel mileage. The OEM tune on the V10 Superduties does not allow any enrichment for power,and this makes the engine very knock sensitive. If you want to cure this,you can use any reputable tuning facility that knows what they're doing to make a program for your truck. I've seen and heard good things about a couple of vendors here,you'll just have to do your homework and speak to them to decide what you want/need.
JL

 

I figured instead of starting a new thread I would bump an old thread about pinging.

I bought my truck used with about 29k miles on it. It's an '01 CC 4WD. I noticed shortly after I got it, the truck would ping lightly when lugging on slight hills. Running 89 oct did away with most of the pinging.

I've had the truck almost 2 years now and have about 42k on it now. During the course of the 2 years I've owned it, I've tried a new fuel filter and I've cleaned the MAF. I think that's all I've done.

I've noticed lately the pinging is getting worse.

The truck is still covered under the Ford extended warranty I bought. I have the base care warranty. I realize this plan is unlikely to cover any of the components that might be causing the ping.

Here's the problem. I don't want to throw a lot of money at this right now, but I would really like to fix the pinging. Do you think I should start with my dealer and see what they think? I'm afraid they are going to throw a lot of BS stuff at me that is going to cost a lot of money and not solve the problem. I can replace parts, if I know what to replace.

I suppose it's also possible that someone put an aftermarket tune on it before I bought it. Is there any way to check that other than taking it to the dealer?

Thanks in advance for any advice.

 

If I were you I would find someone who is very experienced with diagnosing and tuning Ford trucks, not just a parts replacer (like most dealers).

 

I have a 2000 F250 SD 4x4 automatic and have had the pinging/knocking under acceleration ever since I bought the truck. Recently I had a check engine light with a code P0174 - Lean left bank. I would clear the code and after running the engine for a few minutes the code would come back. One day I heard a hissing/whistling noise from the engine and discovered that the Positive Crankcase Ventilation (PCV) hose, that connects to the intake manifold underneath the throttle body, was cracked. I taped the crack closed, cleared the code and the code didn't come back. My tape-up job didn't last very long so I replaced the hose with a fuel rated 3/4 rubber hose and hose clamped the other end that connects to the hose for the PCV. The other day when I accelerated up a few mountain roads, I didn't hear the pinging/knocking. I'm thinking that the PCV hose line to the intake manifold was sucking in additional air that would cause the fuel system to run lean. Anway... it seems to be working for me. In all my discussions with Ford tech, they never brought up this possibility.

 

I really want to bring this up again. Someone on here asked it but no awnsers.

Can you unplug the knock sensor and mount a new one somewhere else.

If so where is the disconnect plug located. I will try it if I can find the plug.

2003 F250 5.4l 4WD

 

No,it won't work properly. The knock sensor placement is critical for proper function. The PCM knows how vibrations that the sensor sees as knock travel through the block from each cylinder. Moving the sensor changes the resonance from spark knock for each cylinder,and the PCM will not be able to match that resonance to the correct cylinder.
JL

 

I have a 1998 class c motorhome with a v10. This summer performance went down and spark knock went up (colorado and california). Check engine light came on when I stopped for gas and then reentered the freeway. Diag. codes say banks running lean. I was able to reduce knock with premium gas and then eliminate knocks by cleaning MAF.

On way home from california it was running so well I took a chance with 87 octane. Check engine light came on right away and diag code says misfire cylinder 6 and same bank running lean.

I am guessing I am need to use high octane for ever more.