Thread: Having trouble tuning fuel trims cant be controlled by maf table

Hey guys having trouble getting the tune spot on and was just looking for some insight. Currently I can't really tune via the maf because its weird I could be at 2500hz one time and be -5 ltft and another time I could be at 2500hz and he at +5. So I noticed this problem mostly after switching to 60# injectors and so I'm thinking would the injector table being off cause this to happen. Cause my current maf table is only about 5% different from stock but yet in running 60# injectors on e54 and a bunch of other mods. So I'm thinking I over adjusted the fuel injector table which is now making it impossible to fine tune the fueling through the maf. Is this possible, thanks for your input guys

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I would check and make sure you have the correct injector flow rate. the IFR is a one time adjustment, set and forget. Like we said before, having a vacuum leak will skew all sorts of things. did you take the maf screen out of your throttle body? that will cause maf tuning issues too. another thing that can cause your maf to go rich then lean or vice versa is by making too many adjustments to fast, not an issue with the HP Tuner.

for E85 all I did was change the cylinder gain from 1.00 to 1.3. for E54 I would try 1.15

Well what I think the problem is when I first tuned for my injectors rather then just changing ifr to reflect 60# injectors I did that but then added like 20% to the ifr table instead of the maf table to compensate for the e54. I'm asking if that's probably the reason why I'm getting wack readings because I basically f*cked up tuning the ifr table and then used the maf table to fix my mistake unknowingly.

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not sure about that. does dhp have a cylinder gain table? maybe you should load a maf table from the last time it was good, then load the correct IFR and then adjust the cylinder gain to 1.15 or whatever.

Originally Posted by Scottydoggs

you still got a breather on the valve cover? if so check back after you put a cap on.

I put the cap back on when I was trying to diagnose the other issue and it changed absolutely nothing I didn't even need to retune it at all. Like I said earlier this problem started a few months ago when I was trying to tune for the new injectors. Idk why everyone hates on the valve cover breather the car runs completely the same at most I might have lost .5hg of vacuum which makes 0 difference.

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Originally Posted by Scottydoggs

it does make a difference. your not supposed to run one unless your a turbo set up.

Ya but what's the alternative? Have oil shooting out my dipstick onto my headers or spending hundreds of dollars on a lim that has that stupid hole machined in it?

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Ugh Scotty why you always trying to make me do things the right way instead of the easy way 😢

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Originally Posted by Scottydoggs

or if your ic has the pcv hole that dont match the hole in the lim, you can just drill a hole in the lim where its needed. iirc that info is within that link i posted.

Its the newest zzp one so I'm pretty sure it does have the hole but it wasn't as simple as just drilling a hole in the lim. You had to make a little recessed valley that went to a hole which is why I didn't do it because I didn't think I would be able to get the exact measurements correct just by looked at pictures. I know you can also put a nipple in the original oil cap or in the valve cover itself and run a vacuum line to it, but I forgot exactly where the vac line needs to come from. I believe it needs to be after the maf but before the butterfly.

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Originally Posted by Swiggles

I know you don't want to hear but do the VE tune then retune the maf. I did the VE tune and it made it so much easier. Right now I still have to fine tune it as I'm running a bit rich at times. I'll have 0.0 at idle then at the next stop light it'll drop to -9 and then come back up to -3. I have to fine tune the VE because it's the same place on the maf all 3 times.

Ya I haven't done a ve tune yet so maybe I should mess with that

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