Well I've been making so many tuning changes in an attempt to get my ltrms under control I'm not sure if what I'm experiencing is a bad tune or sparkplug blowout. Basically around 4-5K RPM my car starts miss firing. Like it's hit it's limit. I still am able to pull, but the engine gets choppy. No knock occurs and ATAP sees things as normal(granted I'm not monitoring misses). I have an ATI Procharger, D1SC 8# tuner kit. When this started my IFR was a flat 5.40, I have since moved it back to a flat 5.51. Mostly stock MAF table extended to 12000 Hz. Moderately retarded high and low octane timing tables. Backed off as much as 12 degrees at max. I have NGK TR6s gapped at .035. What do you guys think? Should I drop the gap down to .032?

Talking to an experienced boosted Stang friend he is sure that reducing spark plug gap will solve my problem. The only thing that concerns me is this gapped worked at first, and now all the sudden it has stopped. Perhaps due to a build up of carbon. Maybe you guys have a theory.

Let me know. Thanks for your help.
Mike

 

Mine did that too. Bumped my timing back up to near stock and it ran great. Maybe try that in little steps. If you are using atap 2.0, then on the kr gauge you can set an alarm to pley if it gets over a set point, so you can know when to let off if any trouble.

 

I also had it a bit too rich.

 

i agree, you just dont have enough timing.. i wouldnt think you need to go below 17* with 8psi

 

OK, I bumped my timing up to 18* at WOT. I also bumped my IFR back to 5.51. I'm hoping this doesn't throw my ltrms back out of wack. I'm having a hell of a time tuning them and getting them straight.

Thanks for the advice guys, I'll let you know if this solves the problem.

Mike

 

Let us know how this works. I have a similar issue on my Powerdyne that I am starting to look at. Mine starts missing at about 5800, same as you with no knock.

-Geoff

 

OK, So last week I bumped my timing up to 18* at WOT and moved my IFR back to 5.51. I got a few WOT runs and that seemed to cure the problem. Today I got the Hawk againb. This time I only moved the IFR to 5.40 and bang I got spark blowout again. Why is this happening? By lowering the IFR I'm creating a richer condition in my engine. But why at WOT am I getting spark blowout? I need to find some way to lower my LTFTs. My MAF is stock so it seems stupid to mess with the MAF table.

Is the solution to gap my plugs down from .035 to .032? Is there a downside to gapping the plugs shorter?

Mike

 

New Wires.

 

I think you are fouling out the plugs.

I see no reason for you to run a .30 gap.

 

Why not try adjusting part of the flowrate table? You don't need to change all of the cells. You could just make a line with a nice little slope to it if you wanted.

 

I just bought upgraded wires not to long ago. So I doubt that is the problem.

I'll try changing just part of my IFR table and see if that cures the problem. If not I'll regap the plugs tomorrow and see if that helps. I'll post up my results.

Mike

 

OK before making any changes today i decided to look at my latest ATAP run. The good thing is my LTFTs seems to be coming down. Using the Autotap Data Analysis Spreadsheet I can see that my FTC 22 has gone down -0.3. The only FTC in the positive was cell 4 a 2.8 which is a non-load cell. Not sure how to adjust for that.

OK some wierd stuff. Even though my FTCs seem in line on the LTFT under load graph everything is stable till about 71% TPS when my LTFTs shoot up to around 6.0. I only got one WOT run in on this scan and that's the one that was spuddering. Should I go do more logging with the same settings? Should I lower my IFR table? Should I only lower part of my IFR table? Which part?

Also my timing seems screwed up. Even though my hiugh octane table(and I'm running 94 octane right now) says I should be at 18* at WOT I'm only seeing 12-14*. Why? I didn't get a trace of knock during that run, what would be pulling my timing like that?

Mike

 

You are probably too rich up top. Mine has been so rich that it wouldnt even do a burnout at the track.....I'd try just setting your timing to say 17 across the board......do some runs with atap and watch that KR. Then start leaning out the PEvsRPM up top. Watch that KR. Do you have a vacuum/boost referenced fp regulator?

 

oh...what injectors are you using?

 

Hey cable thanks for the advice. FYI I'm using 42# SVO injectors and I do have a boost referenced FPR. After this afternoon's runs I'm starting to think that or my pump is the problem.

The spark blowout is gone. My timing seems in line. Perhaps that first run was just a flouk. My WOT timing seems to be 16-18* right now which is fine. I haven't seen any KR on the last 5 logs which maes me very happy.

On the data analysis spreadsheet my LTFT graph is constantly changing. It's very h\ard to decipher a pattern on it. My FTC's on the other hand seem to act similarly. Cell 4 is always positive(~3-4), cell 21 is always very negative( ~(-8)-(-10) ), cell 22 is now hovering around zero( ~1 - (-1) ). All other cells, 0, 1, 8, 12, 13, 19, and 20 tend to be slightly negative( ~ 0 - (-2) ). This trend seems to stand true through all logging, with a few exceptions here and there.

The thing that I noticed on these last few runs is that I watched my FP. It isn't rising with the boost. It won't go over 62 psi and usually hits 60 and just stays there. One time I downshifted from 5th to 2nd and the FP gauge was bouncing all over the place(~50-62psi). Now I'm not sure if that wazs merely the needle getting jarred around but the violent shifts or if the FP was actually fluctuating like that. I tried a 4th gear blast from 30 and just let the boost slowly build. FP stayed steady at 60psi the whole time even with 5psi of boost.

I'm very new to all this. My initial thoughts are; The walbro is having an issue getting fuel to the rails, The boost referenced FPR isn't working properly, I have a leak somewhere.

I know I had leaks prior, cause I could smell them, but since then I haven't smelled any fuel. Could there still be a leak?

If the FPR isn't working right how would I know? If it is working right I'm certainly not seeing a 1:1 boost psi to FP psi, cause when I'm idling I'm at -12 vaccuum in the MAP, but my FP is at 52 psi on the FP gauge. My sender is mounted right onto the FPR so it should be pretty accurate. I suppose the sender also could be malfunctioning.

If the walbro is the problem, then I honestly have no idea where to start trouble shooting that. I'm open to suggestion. I will say this I am using stock wires which means stock voltage. Some people suggested running 14 gauge wires directly from the battery(or ON curcuit) to the pump to get additional voltage which would give me more FP. Somehow I doubt this is the problem, but I figured I'd throw that out there.

Or am I totally barking up the wrong tree? Thanks for reading all this crap and thanks for any suggestions you guys might have.

Mike

 

Update:

OK, I think I might have figured out what is going on and did so by total coincidence. So I'm upgrading my PCV system because it's having difficulties with the boost. While on the driver's I was getting annoyed by the wire that used to go into the AIR system but is now just dangling there since I removed it. Well I "thought" this was an electrical connection, but it turns out it was a vaccuum line connection. So I traced the line and it goes into this component clamped onto the back of the engine(I couldn't see it only feel it). Then from there to the check valve and my vaccuum line which feeds my FPR, Boost gaige and surge valve. So I'm guessing this line was open the whole time throwing all my boost referencing off. So now my vaccuum line is the only connection on the black end of the check valve. I'm praying this helps, there is a possibility that I have dissconnected something important and just screwed myself :p Let us pray I did not.

I haven't had a chance to drive it yet as it's pooring outside right now. Hopefully tomorrow I can figure out if this helped me out.

Anyone know what that module/clamp/whatever on the back of the block that the AIR vaccuum line went to was? I sure hope that wasn't the MAP sensor.

I'll keep you guys updated tomorrow

Mike

 

LOL, it sounds like you are talking about the MAP sensor, which is mounted to the back of the intake...

Scott

 

I don't remeber any vacuum lines going to the AIR system. All it is is an air pump. That thing on the back of the intake is the map sensor. That line is were david and I hooked our vacuum 'accessories' to.

Is your fp rising(smoothly) as you decrease the vacuum(rolling into it), until 0 then it stops? Maybe the line going to the fpr only sees vacuum and no boost?

 

Yeah I had a feeling that was the map.

As for the line, it's confusing cause my boost gauge, which runs off the same vaccuum line, seems to read fine. So it seems the line is seeing boost.

Mike

 

Well I hooked the MAP back up and ran my vaccuum line to that sensor where the AIR vaccuum line used to go. Now I'm seeing -20 psi of Vac instead of the 12 I saw before. FP goes down to 50 psi at idle now. But it still won't go above 60 psi when I'm getting into boost. Any ideas what this could be? This would explain why my car is going lean up top.

Mike