Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec Need an educated guess

Well, I guess its time to ask this question:

Does the fact that I turn down the MAF voltage at low throttle (with the S-AFC due to 24# injectors) have any correlation on my timing? I try to set the AFC to give me near 0% long term fuel trim at RPMs below 4000.

I actually read on Focaljet (not usually the best source for tech, but there is some good info from time to time) that with lower MAF readings the calculated load by the PCM will be lower.

The pinging I'm getting now is much different than when I had the coil ungrounded. :rolleyes: It's light, I can only hear it at tip in (20 - 25% throttle) - not at WOT. I don't actually feel any timing pull, and it could be there at WOT but I wouldn't hear it over my exhast anyway if it was there. It is worse with the AC on. I can only tell that its there below IMRC open. Going from 93 to 94 octane made a significant dent, but there is still a little there. Running 97 octane last weekend got rid of it (duh).

So, if the calculated load is less, does that give me more timing? I'm pretty sure the SVT PCM has a little more timing than the SE map. Don't have cool intake air (yet). I certainly have enough fuel. It's wierd - get 10 3L owners in a room and you'll get 10 different answers on whether they ping or not. David Z was adamant that he didn't have any. Brad doesn't have any. I have some, and our Cougar friend above me has some.

Max power is around an A/F ratio of 12.5:1...not stoch...what are you running?

Actually, I think Jjennings is running David Z's old 3L now, so even two people with the same 3L get different answers as to whether they ping or not.

Bob

Richer than that at WOT, I suspect. But my pinging comes on just as the car goes into open loop enrichment (acceleration ~ 25% throttle or so). O2 sensors read in the .89 range - probably in the ballpark of 13:1 or so. Trying to get the AFC tuned for bigger injectors is a little tricky for less than WOT conditions. Give it too little negative correction and I throw rich codes and foul plugs at tip in. Too much negative correction and I get leaner than I'd like at tip in.

It's not the best tool, but it's what I have to work with for now.

Brad,
Lets add the elect water pump and a SVT or B&M oil cooler to the list of stuff on my engine.

This is really wierd that two people say two different things about the same engine!

Terry any harm in using the elect pump and running the engine slightly cooler then normal, say 185 degrees versus the 190-205 range? Thanks!

I didn't get any ping, only once or twice did I actually get ping for no reason, so I blamed it on bad gas.

Plus, don't forget that SVT ECUs are known for running on the rich side. Plus I had 19# injectors and Jimmy has 17#.

Running the engine at 180 deg should not be be a problem for you 3.0 fellas. I certainly have no problems with it at all in my car.

I have 24lb injectors in the engine now, plus I have a 100k ohm resistor on the IAT. I have done some testing, if I don not have the IAT mod installed, I get no pinging, but I do loose a lot of performance (it actually makes a huge difference on my car for some reason, maybe because it advances the timing so much!). Once I put the IAT back in, I get a lot of pinging, so I just have to use high octane fuel, or octane boost!!

Jjennings,
have you tried a smaller resistor for the IAT mod? If the 100K ohm advances the timing enough to cause major pinging, why not try a 20k ohm, then a 40K ohm etc., so that you get max performance on 91 octane with no pinging for everyday use? Then drop in the 100k Ohm resistor and octane boost for track use.

Any dyno numbers you can show us?

Bob

A IAT MOD TO BUMP TIMING JJENNINGS!?!?!?!?!?

JJENNINGS, you just explained your ping issue. That's not the way to correct timing on a motor with so many mods. Quit it, now, or you'll be singing the Buckshot blues. If you hear pinging, damage is being done.

PA, sounds like you're back to being the only one with a real ping issue... Just wondering, does it do it at all when the engine is still cool?