2.4LR E85 misfire or what?
 

Help needed guys,

Mods:
Evo8 2.4LR, 9:1 1400hd wisecos, ported head with stock size valves, Gsc S3
htz Fp black (turbine wheel swapped to 9 blade), mhi housing
Magnus V5
Buschur race ic and pipes
Buschur 3" tbe and 3" recirc elbow (and modified Buschur downpipe)
450 Walbro, hardwired with boost hobbs switch, drilled siphon
Bosch EV14 1500 injectors (probably the same basic injector as fic1650)
aem fuel rail, stock fuel lines except there is an6 size hose between the hard fuel line and aem rail.
Sparktech non cdi, Bpr7es plugs
still running maf

Switched to E85 and I am trying to get my Evo8 to dynojet 600whp (vd). I have tuned it carefully toward my goal, but yesterday I got a bad misfire or something like that. First I tuned the boost to hit about 34-35 and drop to 29- 28psi at 7krpm. Timing was 1 degree at peak, 2 at 5.5krpm, 4 at 6krpm and 6 degrees at 6.5krpm. So timing was pretty low and it hit about 550whp (11.6 afr).

I then turned the timing to 0 at 4.5krpm (to control the torque), 1 at 5krpm, 3 at 5.5krpm, 5 at 6krpm and 7 at 6.5krpm then up to 10 degrees at 8krpm. So nothing crazy on E85, I guess? On this pull at around 6krpm it sounded like a misfire and the power dropped rapidly. I just cruised home about 5 miles and it worked fine. Reading the log, I can see the timing going up as it should, but around 6krpm, the rpm numbers drop a little and the timing drops from 6 to 4 and then rises to 9 and the map shows crazy 43psi and up to 18 knocks and the afr jumped from 11.56 over 13.

So what you guys think about it, was it misfire or something else like going over the mbt (at this low of timing)?

The afr:s have been below 12, but I think at this power level I have too low fuel pressure because I have to adjust the fuel maps around 11.0 from mid to high rpm. Could a low fuel pressure cause the problem? I been thinking of to remove the intank filter and put better flowing filter between the hard line and aem fuel rail.

I hope it was just a bad plug and I am going to install a new set of bpr7es. And if the issue is with the spark, would it benefit from adjusting coil dwell time? LOL I can't do it and haven't found any definitions for rom 96940011.

I try to get the best hp around 6500rpm because of the back pressure. The emap vs boost is 1:1 around 6000rpm and about 1.5-1.55:1 at 7000-7500rpm. This was on ron98 and 11blade turbine wheel. The 9 blade didn't help (maybe just a little). It's just that stock turbine housing...

Please check the attacment, the pull starts at row 130 and the problem starts at row 179 (my throttle body sensor is only reading 98-99, it's an aftermarket one)

At that boost level I'd go with a older plug to be honest. What is your duty cycle also.

I have a set of a bpr8es too. I ran them on 98ron for a while but they weren't any better.

Injector Duty cycle is around 88-90 at 7krpm

I installed bpr8es plugs. lowered boost and made a test drive.... same thing at 27psi, misfire. I took the plugs off and made a compression test all between 165-180 (warm engine). Then I looked at the last log and noticed that it was running lean! Tought that the wally broke, but I found that the hose of the fuel pressure regulator had popped off. I had 7 to 4 knock counts on the last run (and those bad up to 18 knocks on 1st bad run) Hope I didn't blow my new head gasket. I put new bpr7es plugs in and it fired up. Now I let it cool down as do I.

.....waiting for the next test drive.

Did a 25psi test drive and it runs fine again. So the problem was lack of fuel because of the fpr hose popped off.

need a AFR gauge in the car... so you can keep an eye on that...
very important bit of info.

Thanks for your comment Hutch959. I knew someone will write about the afr gauge.

Yes, I agree. In my opinion, it's the most important gauge. I have it and the one I normally keep eye on, as much as you can on the road.

When the hose blow off first time,, it was a rapid moment. But when I replaced the plugs and made the test drive, I thought it was spark related problem and just waited if the misfire will appear again. I should have kept my eyes on the afr gauge, so I would have seen the lack of fuel creeping. Did I blame myself about this, sure.

Are you planning on going SD? I'm sure you are running that MAF to the raged edge!

Yes, I have to get a SD tune for it in the future. What is limiting the maf tune? I have removed the honey comb.

It's just a restriction at at certain power level. You will also have to do some ecu mods in the coding to get fueling right past a certain hp. For example I had to play with the maf compensation table in the higher load cells to get the fueling where I wanted it to be on my 35r. I think our maf sensor maxes out at 3200hz which is probably well into the 600hp range.