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Discussion Starter #1
94 Cougar, 4.6, showing 61k miles on it (I suspect it to be at least double that as the odo was broke when I got it). Recently changed intake gasket. Has Motorcraft platinum plugs with around 10k on them. My issue is that it starts pinging and surging @ WOT after around 3000 RPM. I changed the fuel filter and made sure I had no vacuum leaks. It doesn't do this when the ECT is below 150 degrees. I datalogged it this evening and by what I can tell the O2 sensors almost drop out completely after 3k RPM. Fuel pressure is around 32 idling and at 40 with vac hose removed from PFR. I am not sure if it's the fuel pump that can't keep up or the MAF (which I cleaned). Here is the datalog graph showing when I roll into the throttle at around 95-98 seconds and letting off at 115 seconds. Any help is appreciated
Joe

 

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WOT Junkie and avid corn burner
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The O2's drop out because it goes into open loop. That's normal. Data log the MAF, calculated load, and spark.
 

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The fuel pressure "looks" fine, but that does not necessarily imply that fuel delivery is within spec when under load.

Why would the MAF not keep up? If it is indeed working and you haven't done massive amounts of modifications, no reason the maf shouldn't be able to keep up.

If it is not misfiring when "cold", then it is likely a fuel delivery issue since the base lambda enrichment for cooler temperatures gets everything very rich indeed.

There's still a lot of variables un-accounted for here....

My vote is vacuum leak. The cold running lambda enrichment can easily mask vacuum leaks because it accidentally takes care of them. But once there is no enrichment at full operating temp, there is no learning @ WOT hence pinging and what not start to rear their ugly heads.

Let's see the actual LTFT AND STFT's when cruising in closed loop at normal coolant temps of ~200F.
 

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Discussion Starter #4 (Edited)
I found the culprit....apparently when I was driving back from Houston 2 weeks ago, I ran over a 2x4 in the road and it jacked the right front suspension up. It also kinked the fuel line where it transitions from the braided flex to aluminum tubing. Went to pull a part, got a unmolested line and all is good again. I appreciate the help with this.
Joe
 

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Discussion Starter #5
Here is the chart on that....other than the odd spikes (I think that is LiveLink missing/misinterpreting something) they almost if not mirror each other. The coolant temp starts out at around 184 and goes up to 194 (that's as high as it would get).

 

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just as I suspected, your fuel delivery under load was not adequate as you found with the kinked fuel line. The LTFT/STFT might not have shown any deviation due to the pcm being in open loop when you went WOT when the surging happened. Glad you figured it out.
 

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Discussion Starter #7
Still pings, although not nearly as bad as before....gonna run a can of seafoam through the intake when I get back from Houston in 2 weeks and see if that helps.
 

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if you can replicate the pinging and pinpoint the RPM range (as close as possible), datalog the MAF counts, injector pulsewidths, RPM, engine load, spark advance, IAT, ECT, STFTs, relative TP and send me the log and I can analyze it.
 

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Discussion Starter #9
Still pings, although not nearly as bad as before....gonna run a can of seafoam through the intake when I get back from Houston in 2 weeks and see if that helps.
OK I am an idiot....when I was doing all this troubleshooting on the pinging, I had a 1/4 tank of gas and like a [email protected]@ I put an entire bottle of techron in. After about 50-100 miles on the first full tank of fuel the pinging stopped. The car runs like a new one. Imagine that! :facepalm:
 
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