sr20det missing in boost

[wild streak]

I have built sr20det redtop with gt30r turbo 24lbs of boost on AEM engine management, it has been doing good for over a year but, the other day I had it on the dyno and did a test launch it boosted 1st and 2nd fine but it was spinning shifted to 3rd and it bogged down but as it came back up in rpm it had a weird misfire while in boost and now I cant figure out what it is. the car runs and drives perfect just in boost it has that slight miss and has no power it doesnt even have half the power it did before, it will still build full boost just has no power. My afr's are good I changed the fuel pump, coil packs, compression test it was perfect, checked timing, checked fuel pressure it was all good Im kinda puzzled. Wondering what else could cause this problem while in boost? Ill post the video from the test launch to show you when it started doing this and the way it sounds listen as it builds boost in third.

Fast forward it about 49 seconds to get right to the launch
sr20det Dyno Launch - YouTube (http://www.youtube.com/watch?v=LOXF0VVPLrk)

[Drift_FX]

check the gaps on your plugs/replace plugs...... also check for a boost leak....

[wild streak]

I for got to add that I boost leak tested the system up to 30lbs, I checked the plugs they werent burnt or fouled and I rechecked the gap they look good I run a very small .19 gap because stock ignition setup but has been doing good until now

[wild streak]

Any Body have any other ideas to look for????

[!Zar!]

Possibly your TPS? Is your FPR stock? Could be on its way out.

Also make sure to check your injectors.

[wild streak]

i was checking things earlier through my AEM system the tps, knock, and coolant temp sensor all seem to be fine. Im running a nismo adjustable fpr I adjusted it to 40psi at idle just to be sure, I have blitz 850cc injectors and I get a pulse signal from each and I had shop check fuel map and its getting the fuel afr in the 11's while trying to make boost.

[steve shadows]

What does your AFR graph look like at the points where it's missing?

I have seen fuel pumps crap out under intense load especially if they aren't high quality ones.

Also you can add a bit more dwell time to ignitors but it might be time to look at an upgrade here as well. Before you upgrade the ignition hardware I would make sure the coil back harness, coil packs are in great shape and of course the coil pack harness is well grounded

It's more likely a connection issue than a blow out issue if it's not a intermittent fuel cut. Spark is possible but I would hope you had NGK rang 7 or 8 in there with 0.028 gap max to begin with.

:2c:

[anthonyr sil8ty]

Do you have the aem disk in the cas? aem's disk is a 24 window disk compared to the oem 4 window disk. I had similar problems! Didn't see anything about you running a map sensor?

[wild streak]

Ill try to get a digital copy of my afr graph, Im running bkr7iex it had been doing awesome daily driving it for year and a half at 24lbs of boost 440whp on mustang dyno . Still running stock igntion setup with .019 gap on the plugs, My aem is setup with a map sensor and I have the aem disk installed. Just lost at why it done this I have launched it plenty of times, I think I may need to look more in the coil pack harness and see where that takes me. I had the tuner look at it over the weekend and he said fuel is on point he thinks there may be something up with ignition also

[cotbu]

I would get some copper plugs in there and then duplicate the missing in boost situation. iridium plugs tend to burn through anything and make the symptoms odd. If you get coppers in there you might notice more symptoms and be able to read it on the plugs.

[wild streak]

Thought I would comment back on this post tell every-one what my problem ended up being. It turned out to be one of my injectors replaced it and its doing fine now thanks for the replies everyone

[Mikester]

^^Wonder if it might be worth pulling them all & sending them off to Witch Hunter for service(?)