S14 SR Is Breaking Up - Vid Inside

[SequenceGarage]

Hey guys, first of all to start i've spent hours on the car myself and have taken it to several professionals and no one could fix the car without spending an entire day on it. I have come to the point where its time to rip apart the dash and take the harness out and go over it wire by wire. This will be a pita but clearly it is the only way to solve this problem (and potentially cause new problems)

The Problem: ever since I installed the SR the car would break up under heavy load. What is heavy load? Well it was not ever one specific thing, sometimes under low boost the car would break up, sometimes I could run 1bar and not have an issue.

What is breaking up? It seems liek the ECU is resetting, spark is definatly pulled and injectors I belive are also pulled. Sometimes (however not always) the check engine light will flicker on and the tach would drop to zero. Imagine pulling power to the ecu and then putting power back to it, it is almost like that. The ECU is storing no codes however, so it makes me think hte ECU isn't seeing it as a problem - i.e. not a faulty sensor, rather the entire ecu is resetting. The car will pop and then accelerate again, usually followed by another pop within the second unless the the throttle is closed.

Specs:

Early S14 VVT SR20DET
Wiring done by an outside job (paid good money for)
Tested different ECU
Tested adding power
Tested adding grounds
Tested grounding engine to chassis better
Tested groudning battery to chassis better
Before and after S-AFC II same problem
Have checked groudns on engine
Have checked main chassis ground by ecu
Have checked eccs relay

So my question is what CAN cause the ecu to reset - in other words what would have to short or fail entirely to cause the above symptoms? I want to know what to keep an eye out for when I open up the harness.

More info that may: help A techtom daughter board was installed for eprom tuning, when the laptop was connected to the ecu for live updates the car would constantly break up with the check engine light flickering and the car popping all the time. Even at idle it did it. Sometimes it would be ok for a minute or so at idle, and then it would start to die again, we could not find any pattern.

This suggests to me that it is most definatly an engine control issue.

Here is a video of the car on a test drive after I just installeda n HKS GT-RS, RPS 6puck clutch and ATS 2way carbon LSD, teh car feels GREAT. It spools to about 5psi just in neutral which is insane, and hte power is so smooth and great, the only problem is the car breaks up at the preset boost (0.8bar i belive is what it comes with) all the time, I couldnt enjoy the car above 4500rpm once unless i was under low load (like spinning the tires in 1st)

http://www.sequence-garage.com/SandraRip.mov (quicktime about 14mb)

If you guys could throw out a couple ideas that would be great! May as well try everythign while I have her apart.

Lastly, I am getting an EMS as soona s they release a 95-96 Japanese S14 SR application, is there any chacne of this problem reoccuring with the EMS?

I hate stupid problems like this, I paid to have my harness done so that i would for sure NOT have stupid gremlins like this, however that doesn't mean it isn't something I'm doing wrong. Thanks again guys sorry for the super rediculous long post.

[dizoita]

What if the main ECU relay is droping power. Try a wire from battery direct to ECU power wire and the other power wires that go in to it. Or before this connect a test light to the power wire that enters the ECU and see if it turns off ever while driving.

[97SilviaRB]

Do you ever watch the Batt. Voltage on the safc to see if anything funky happens there? I will say that my car has been experiencing some strange voltage drops under load but it never breaks up like that..

[Dousan_PG]

how is the MAFS?
i had problme under heavy load where it just popped backrdired ran like shit
my MAFS was dead
replaced and runs normal

[luisgonz]

i say ground engine harness ground let me know if iam right

[NI_YON_Zenki]

You know something. I think some kats just purchase these engines to claim they have em' under the hood, and just to push the throttle in neutral when UFC is out of season, or unavailable through their cable provider. . . And exactly what EMS is not available for the s14 (early) SR application, currently throughout the US? Please advise me on this one. . .

[SequenceGarage]

The 1622 EMS is not released yet.

Thanks for the ideas so far. I've tried 2 mafs and the problem is still there, i'll check my grounds again and i'll keep an eye on battery voltage thats a good suggestion thanks dude!

[s14 blacktop]

this might sound crazy but what is your spark plug gap set to?
I gapped my plugs down to .025 and my car started having these exact same issues you are having, later on today im gonna take them up to .030(factory specs)....

[drew935]

I had a similiar problem but it was in my civic si. I would drive about 35-40 in 3 or 4th gear and the ecu would cut for a split second then come back. It always around that speed and I found that it wasn't just my car as it was the same for my friend with the same year civic too. The power cut wasn't long enough though the make anything flicker or make the tach drop. It definitely was the ecu though. It was resolved by changing the map sensor. then I added an eprom or chip to it and everything all good in that dept.

Not sure if this helps you though...test with another ecu...

[s14 blacktop]

well it turned out it wasnt the spark plugs but a couple of cracks in my rubber intake (behind the maf). fixed it problem went away..

[ultraDorksGarage]

are u sure ecu is dropping out?

if car just misses/backfires under load + boost, but ecu is still working, i believe speedo will still be working.(tach might drop because motor rpm is actually dropping like a rock) i had several problems that made similar problems.

maf wiring was bad..caused leaned out condition occasionally, misfireing bla blah.

maf went bad, anything above .7bar boost left me backfiring.

and on initial shakedown of car...car would miss so bad motor would stall under load+boost. this was combination of a small boost leak + too retarded timing,(used a timing light that was stuck on 5 degress retarded). stupid light><.

only way i really noticed that my ignition timing was crappy was lack of below 3k power and excess heat buildup. oh, and occasional backfire on deceleration