New mods but same situation, fuel cut

[roth4fun]

I have been running the past couple years with minor bolt ons including Street Unit TMIC, Forge BPV, intake replaced to turbo inlet, and a test pipe. This has been fine running with Cobb AP set to Stage1+SF+TIH+IC 91 as the 93 octane would give me fuel cut even with 93 octane in the tank.

I recently replaced the test pipe due to a catless downpipe and upgraded the with new HPFP internals. New spark plugs while I was in there too (NGK's 1 range colder). I have been trying several Stage2 maps and currently running Stage2+SF+TIH+IC 91 and still getting frequent fuel cuts.

AP shows the fuel pressure is over 1600 all the way through RPM ranges. BAT is 110 degrees. Boost spikes to 20psi and settles at 18psi. Not showing any knock either. Yet it fuel cuts.

[ms3rick]

Worthless with out logs.. Post the map also if you want quick answers.

[roth4fun]

Originally Posted by ms3rick Worthless with out logs.. Post the map also if you want quick answers.

Fair enough, I wasn't thinking clearly. I will log some driving tomorrow and share my joy.

[MSMS3]

While awaiting the logs, I'll ask a simple question about plug gap. What is it? Check. The NGK 6510 (one step colder iridium), plugs are an excellent choice, but they do not come pre gapped. The out-of-the box gap is huge, .045" or more. Make sure you gapped them down to .028" or even .026". If the gap is too big, you will get spark plug boost induced blow out with high boost, high load situations, typically at 4,000-5,000 rpm when WOT in higher gears. It acts like fuel cut.

[Turbo_Steve]

You can mess with wgdc or raise your fuel cut by 1 psi if you go into atr. There is a fuel cut boost limit table.

[Turbo_Steve]

One more thought.

Are you logging throttle body position? If your fuel pressure stays steady but the car surges, it may be throttle close/cut. Ots maps go to throttle close first before they go to fuel cut.

[roth4fun]

Originally Posted by MSMS3 While awaiting the logs, I'll ask a simple question about plug gap. What is it? Check. The NGK 6510 (one step colder iridium), plugs are an excellent choice, but they do not come pre gapped. The out-of-the box gap is huge, .045" or more. Make sure you gapped them down to .028" or even .026". If the gap is too big, you will get spark plug boost induced blow out with high boost, high load situations, typically at 4,000-5,000 rpm when WOT in higher gears. It acts like fuel cut.

Now I feel a little embarrassed. Those are the plugs I got but I didn't regap them or measure prior to install. I thought these were pre-gapped and shouldn't be attempted for gapping. That delicate little iridium post seems likely to break if messed with.

Oddly enough my drive home from work I could not get it to cut out. Pulled hard in all gears, which was fun. Also I left my USB cable at the office. Will have to attempt again with the morning commute and upload datalogs if it occurs tomorrow.

[MSMS3]

No need to be embarrassed. It happens to many guys that make the switch. And it will eventually happen again when your plugs open up from wear. Now that you know that the plugs were not regapped, you should know that if you are running over 15psi boost you WILL experience spark blowout under high flow, high load conditions. That problem needs correcting before chasing anything else on your logs.

[kritz]

Get a custom tune,OTS is worthless!

[roth4fun]

Attached is a log from this morning. Between the times 13-14 seconds and 33-33.5 is when you can see the cut out was occurring. Throttle Pos is showing ~75 for these, Boost is dropping, Wastegate didn't change, and Fuel pressure was good. Sounds like the spark blow-out was the likely issue.


@kritz, I am confused, OTS as in off the shelf? Are you saying the Cobb AP tuned maps are worthless? I think they are a great step in the right direction even if not to the level a custom tune would be.

[Turbo_Steve]

Originally Posted by roth4fun Attached is a log from this morning. Between the times 13-14 seconds and 33-33.5 is when you can see the cut out was occurring. Throttle Pos is showing ~75 for these, Boost is dropping, Wastegate didn't change, and Fuel pressure was good. Sounds like the spark blow-out was the likely issue. @kritz, I am confused, OTS as in off the shelf? Are you saying the Cobb AP tuned maps are worthless? I think they are a great step in the right direction even if not to the level a custom tune would be.

Your data log is terrible btw. You should also be logging accelerator pedal position imo, as it makes it easier to see when you were in wide open throttle. But it looks like you were only in wot for a few seconds based on looking at maf voltage. I am guessing your car runs pretty crappy and you don't want to do a full 3k-redline pull. I am seeing your boost hit just above 20 psi at one point and your hpfp pressure stays constant as well as your throttle body position. You are not having boost or fuel cut in this log that I can see.

Try gap those plugs tighter. .028 should do the trick.

Then get us another log from 3k - redline with throttle pedal position in the log.

If you have not downloaded access tuner from cobb, make sure you do that too. Your ots map could use a little work I am sure.

[rfinkle2]

You are hitting a boost / fuel cut. If you donate to the site, post your map and tag me I'll create a drive-able map for you until you can have one of our e-tuners work with you.

[Raider]

Also, what brand of HPFP Internals are installed?

[Koke382]

I had fuel cut on my tune. Lowered the wgdc and bam! Gone (: now im getting a better tune. Yes I said it...better. ...

sent from my peepee

[rfinkle2]

Originally Posted by roth4fun Attached is a log from this morning. Between the times 13-14 seconds and 33-33.5 is when you can see the cut out was occurring. Throttle Pos is showing ~75 for these, Boost is dropping, Wastegate didn't change, and Fuel pressure was good. Sounds like the spark blow-out was the likely issue. @kritz, I am confused, OTS as in off the shelf? Are you saying the Cobb AP tuned maps are worthless? I think they are a great step in the right direction even if not to the level a custom tune would be.

Cobb has the burden of creating maps that are driveable in high and low altitude, hot and cold climates, different quality fuels, different hardware configurations, etc.

Unfortunately, some of the ots maps just don't work well with a particular situation (read: yours).

[roth4fun]

Originally Posted by rfinkle2 You are hitting a boost / fuel cut. If you donate to the site, post your map and tag me I'll create a drive-able map for you until you can have one of our e-tuners work with you.

Yeah, looks like I'm a brownie again as my last donation must have expired and reset my status.

[roth4fun]

I had to drive back home from Chicago before I could get to the tools to fix all this. So I regapped my NGK's to .028, tightened up the downpipe fittings, and did a run. I am still hitting an issue. I said fuel-cut before as that is my interpretation based on what my previous car (92 AWD Turbo Laser) used to do. You can see at 5.12 in time on this log that is where fuel is cut back and then everything kicks back in.

[skiptowncat]

:krys:



WTF!!!

[roth4fun]

Originally Posted by skiptowncat //LinkedIn_Image// WTF!!!

Interesting, but relevant how?

[skiptowncat]

Originally Posted by roth4fun Interesting, but relevant how?

Not relevant in the slightest. Glad you got your problem solved though.