[malibuguy79]

96 Tercel, UA4C, audi COPs, external 60-2, DIYAT hall effect sensor, stock VR cam sensor, running full sequential.

Car runs pretty flawless everywhere else, but nearly everytime at 5200rpm it hiccups or misfires regardless of load. Maybe 65% of the time it pops up after 4k. If I try to drive thru the area it will pop and bang out the exhaust. It gets more severe with higher gears.

Ive tried different plug gaps all the way down to .020 (currently back at .025), different dwell & dwell tables. Different filter settings, different sensor gap. About the only noticeable thing when I richened the higher boost area a little (from low 11s to upper 10s) it seemed to "soften" it a little. Of course to make things more confusing, every once in a while I will run like champ clean and smooth, usually once a drive. When the issue happens there is no sync loss.

About the only thing I have not tried was different ground locations. I use the stock ground point on the intake manifold like OEM did, for everything.

Here is my tune, for some reason it says my datalogs have the wrong extention so it wont let me attach it

[LPG2CV]

put the tune and logs in a zip

[malibuguy79]

put the tune and logs in a zip

lets see if I did this right

[jonbill]

That works - but for even more marks, you can put them both in the same zip file
Can you point to where in the log file the problem occurs? is it happening at 9.195?
have you tried a bit more dwell?

[malibuguy79]

That works - but for even more marks, you can put them both in the same zip file
Can you point to where in the log file the problem occurs? is it happening at 9.195?
have you tried a bit more dwell?

Oh i didnt know I could put 2 in 1. I am very tech ignorant unfortunately. Cool to know.

Its towards the beginning when going WOT but it does it even at part throttle at those RPMs. I have tried just a little more dwell like 2.5 that was also when I had the plugs gapped down to .020". I was afraid to try more dwell. Most people state these coils like 1.8-2.0.

[LPG2CV]

My preference for setting dwell

With the plugs gapped correctly, and in good condition. With the engine warmed up.

In the voltage correction table, in the third column from the left, I set 100%, and whatever voltage the engine idles at. This is my reference for voltage correction. In the fifth column, I set 85%, and what ever maximum voltage was when the rpm increases. The sixth column is used as a safety value, should the alternater overcharge.

The values for column four can be obtained later by smoothing the values in the cells.
Columns one and two, I used to supply more dwell under electrical load. But first, you need to set the dwell value in Dwell Settings.

At idle, in Dwell Settings, reduce the running dwell until it starts to miss. Then increase the dwell until it doesn't miss. Your looking for the point where it is just on the cusp. Then add 0.02 ms. This should give you the minimum dwell it needs to idle.

For column two, at idle, turn on the lights, and perhaps the heater blower, This will have the effect of lowering the voltage available at the coil, enter the voltage in column two, and then, increase the % until the engine does not misfire.

Repeat for column one, and add any extra load you can find. AC for example. let the cooling fan kick in and adjust again.

When driving the car, I found I had a miss fire further up the engine rpm. I resolved this by slightly increasing the voltage correction % around 14v ie max voltage from alternator, as it was reducing dwell by to much. Then re smoothed the cells between idle voltage and max running voltage.

Hope this makes sense, as still on my first morning coffee.

[malibuguy79]

My preference for setting dwell

With the plugs gapped correctly, and in good condition. With the engine warmed up.

In the voltage correction table, in the third column from the left, I set 100%, and whatever voltage the engine idles at. This is my reference for voltage correction. In the fifth column, I set 85%, and what ever maximum voltage was when the rpm increases. The sixth column is used as a safety value, should the alternater overcharge.

The values for column four can be obtained later by smoothing the values in the cells.
Columns one and two, I used to supply more dwell under electrical load. But first, you need to set the dwell value in Dwell Settings.

At idle, in Dwell Settings, reduce the running dwell until it starts to miss. Then increase the dwell until it doesn't miss. Your looking for the point where it is just on the cusp. Then add 0.02 ms. This should give you the minimum dwell it needs to idle.

For column two, at idle, turn on the lights, and perhaps the heater blower, This will have the effect of lowering the voltage available at the coil, enter the voltage in column two, and then, increase the % until the engine does not misfire.

Repeat for column one, and add any extra load you can find. AC for example. let the cooling fan kick in and adjust again.

When driving the car, I found I had a miss fire further up the engine rpm. I resolved this by slightly increasing the voltage correction % around 14v ie max voltage from alternator, as it was reducing dwell by to much. Then re smoothed the cells between idle voltage and max running voltage.

Hope this makes sense, as still on my first morning coffee.

I will give it a go. This car I pretty much run with everything on. Its my autoX car, i always have the headlights on, the fan and pump for the a2w charge cooler run all the time and I run the cooling fan a little sooner. The alternator does a good job at maintaining voltage regardless of load.

[LPG2CV]

I did say I was still on my first coffee
I didnt really intend this as a solution, but a way of ensuring enough dwell.

I intended to add, ensure the sensor grounds go back to Speedy, rather than the block, where you can. You do appear to have an electrical issue.

[malibuguy79]

I did say I was still on my first coffee
I didnt really intend this as a solution, but a way of ensuring enough dwell.

I intended to add, ensure the sensor grounds go back to Speedy, rather than the block, where you can. You do appear to have an electrical issue.

I have never ran sensor grounds to Speedy. Always mimicked OEM. I built another car thats very similar with absolutely no issues but it uses 100% original crank trigger.

My issues started when I changed motors and was forced to run an external crank trigger. This car has never run 100% perfect yet.

I went out today and played with dwell. I also switched to slightly smaller injectors just because. (597 down to 440).

Absolutely no difference with increasing dwell. It will not hiccup free revving, only with some sort of load...in vacuum, light boost, full boost it hiccups. So freaking strange and frustrating.

[malibuguy79]

This morning I moved just the ground for the crank sensor to the other side of the intake manifold and initially the car was better the hiccups were easy half as intense but in the same kind of pattern.

So this afternoon I separated grounds today the best I could.

Crank ground had its own bolt. Sensors, injectors and ecu on another then coils on their own bolt. Now its all still on the intake manifold.

There was a definite change in the characteristics or patterns of the hiccups but the severity was nearly the same as before.

So I pulled the entire harness back out. I am going to move the grounds around. Give the coils a nice short run to the head. Might separate the injectors too. Just seems odd that I have to do this when it ran perfect last year and on the older hacked harness.

The only thing left would be to question the NGK coils...which I really doubt developed faults in about 2-3000miles of overall use in less than a year.

The car runs flawless everywhere else...up to 4k. No sync losses anytime while running.