Hiccup after 5k.......

[ducman82]

after i hit 5200 rpm ish, the car seems like it cuts out or hiccups till about redline at 6k. FINALLY got a data log. finding free room to get up to speed in LA is not easy. I'm thinking maybe more timing is needed? but not sure as i don't have a knock sensor wired up. i still need to get one and figure that whole adding knock sensor settings out etc.

here is the log and tune

i also have that dumb pop/bang in the exhaust on very slight toe in (low speed/load) say in a parking lot, or driving with just a tad bit of throttle down the street. even pops in 3rd gear engine braking after it drops below 2.5k rpm but other that that, runs like a champ!

[slow_hemi6]

Very hard to know what is going on without any AFR information in the log.

[ducman82]

works for me under AFR 1.

[slow_hemi6]

Checked your log in a spreadsheet. Nothing but zero's there for AFR and AFR2. There is AFR1 and 2 Target data and error data but no actual AFR data.

[ducman82]

hummm. that is odd. MS gets the signal.....

[ducman82]

Ok, re synced and changed data logging. Now seems to record Afr again. I will do another run today. Thanks guys

[ducman82]

FINALLY got out of the house to make a test run or two.. had the wife in the car so they had to be brief before i got hit. at the end of the logs you can see the hiccup in the RPM.. but nothing is jumping out at me......

[ducman82]

AH HA!!!!

Finally got a good data log of the hiccup... now not sure what I'm looking for...

i just added knock sensors as well, but that did not seem to make any diff.


you can see the dips bright as day on the top end of the RPM curve. starts at 5400.......

any insight would be WONDERFUL!

[ducman82]

so far i will be richening up the top end, and working on some of the acceleration enrichment settings.

[ducman82]

so none of that helped and nothing is showing up on the data logs.....

going to try a composite logger and sync loss next... I tried a trigger log, but for some reason it did not capture much... if anything

[lizard]

Been trying to help Ducman with this. I cannot find anything in the logs which shows it is being caused by any of the outputs.
We have pulled the ignition timing right back, no change.

At first he was running way way too lean. Now that is fixed...

I don't know that it could be a trigger hiccup as there is no signs that the injectors are drastically changing their PW, the ignition timing remains constant.

However when I was first in to MS on a car and running EDIS, there was a setting from firing on rising edge vs falling edge with EDIS-8 that caused something very similar to this with nothing showing in the logs. Is there any settings like this that anyone can recommend checking?

[ducman82]

here are two runs i did (found a spot here in LA with no cars!!!!, well for short period anyway)

one with knock, one with out knock activated.

stumble/hiccup/missfire, what ever it is is at about 5300 and up.. you can see the RPM dips when it happens.

[ChevytoyR1]

I pm u my number im free after 5pm usually if u want to bring it by. Plenty of free space in my back streets

[lizard]

Have just been talking to Ducky and have had him adjusting a number of settings to do with driving the coils.

It appears as though the coil dwell time was creating issues. We have adjusted this down, and he claims it is much better...... he needs to do some more testing. But results sound promising

[ducman82]

thanks Chev, i got the PM.

indeed the coil dwell was to high. dropped that down and that hiccup is gone.

also adjusted the crank dwell. i was having an issue of it dying a few seconds right after it started. that is also gone now.

so we found the area of trouble. ... to to finish polishing that portion of the tune