MSefi.com read only forum (Jan.15,2018)

Only issue with the new tune is after the Cruiser has been warmed up and has sat for awhile and re-started. WUE is on and it starts right up and idles but as you increase the throttle in idle or try to drive it chokes like it might be really lean and continues the cycle until WUE drops off. Thought it may have been that the last WUE bin was above 100 but didn't solve the issue. rpm jumps up to around 3500 from ~1800 in datalog and then drops momentarily to zero. It will continue to idle but repeats if revved up? It also does it when the IAC pulls the idle up when started? It goes away when WUE drops off. I have tried many msq's including mine and DIYautotunes's with no change?? Will be better prepared when the LC-1 comes back from Innovate but am thinking there may be more than a lean condition causing it.

Thanks, Mark

Chevy 350 TBI,MS2,2.88

You'll need to get that RPM spike fixed first. What sort of RPM input are you using?

R pin from an 8 pin HEI to tach on the relay. 5 vref is through the Fidle relay cause it didn't like being attached straight to vref. ground from 8-pin goes into the soldered lug on the manifold along with the ms2, and LC-1. This is the one I recently bought from DIY for Bryan. This is a relatively new issue. Thinking of other things that I have done that might affect this??

Ok. Inside the unit, how is it jumpered?

IGN-JS10, TACHSELECT - XG1, OPTOIN - 5 VREF in proto area.

As soon as WUE drops off it runs great with no spikes?

Thanks, Mark

That's really weird - could you post a complete data log and MSQ?

Here is the log and msq that show the spike. I have later tunes but had overwritten the spike logs. I had intended on making a new log but the weather is prevailing. let me know what you see.

Thanks, Mark

Try decreasing the afterstart next pulse tolerance from 70 to 25.

Thanks Matt, weather permitting I'll try it tonight - Mark

Tried setting afterstart next pulse down to 25 with no appreciable results. Did set the req fuel a bit higher and further tuned the injector controls(pwm). Running better and better but still has the rpm spike during WUE. verified that it does it when cold also and stops right when WUE turns off.

Odd thing- couldnt turn any of the pulse width settings down far enough to affect idle or rev? 10% and .4...

bumped the req fuel up because the pulsewidth at idle was around 1.3. also was able to change from 4 squirts to 2 after adjusting pulsewidth. I had read a post(Matt) that said if you couldn't swap between squirt settings that the PWM was not correct. Ended up at .7 for open time and threshold and 15 % on duty cycle, a bit of a guess.

attached are current msq, current msl is too big. Can I cut it down. It's the same deal as the attached msl in the previous post.

BTW- the TPS hasn't been working. not sure if it is relevant or timely with the spike issue, had the spike issue before this. It was working but fairly noisy, took it off and plugged it back in to test and mt wasn't reading it(-1 in calibration). tested continuity through to db-27 and was good. ms runs fine on stim. added a different pot to the tps weather-pack and it worked also. tested TPS and it seemed ok, tried two different ones with same result.

Any more thoughts on the spike?

Thanks, Mark

Since the last post I have reviewed many settings including the IAC and WUE settings and no longer have the spike issue? It's a good thing but not sure what it was? I will report the cause if I come across the culprit.

Still haven't figured out the TPS?

Thanks for the help, Mark

I'd check the TPS with a volt meter. What is it reading at WOT and at closed throttle?

Voltage at relay board is 0 V closed and 4.94V open. TPS is lying on engine. I had checked and found continuity up to the ms2 before. Is there a component in the board that I should be looking at? It originally worked ok if not a bit noisy. Took it off and reconnected it to test by operating by hand and it hasn't worked since. I was testing looking for a reason for the cause of false accel enrichments. Swapped out another that tested good with same results. MS2 calibrates at -, idle and WOT.

Thanks, Mark

Looks like the TPS itself is OK; does the TPS reading work correctly on a Stimulator?

Yes it does work with the stim.

Ok, I would check the wiring harness for continuity. Maybe a bad connection at the relay board?