I have a 91 civic dx with d16z6 motor.
car breaks up under any boost level ive had 2 different great tuners look at it and its going on a few years now and im frusterated. Around 6k any amount of boost breaks up ive tried everything i think its wiring on inside of car but not sure. Last motor did this same issue as well since then everything i mean everything new except for inside wiring. Seems like ignition is breaking up
75.5mm bore aries 10.5:1 pistons.
Crower rods
Css block
Car coverted to obd1 twice thinking first time wires went bad now have monotec harness. New 3 weeks
6k ferrea valves
Crower cam 63444zt
Comp springs and retainers.
vms cam gear
vms race dizy
Arp studs
je pro seal 76mm head gasket
Sk2 intake 66mm throttle body
Golden eagle fuel rail 8an braided lines
Rc1000cc injectors
Neptune rtp v2
1320 top mount
Gen 2 precision 5558 .63 trim
46mm precision wate gate
Sk2 throttle position sensor
hondata 4bar
Aem 340 fuel pump with wiring
260 gt plus 104 gas
ngk8s gapped both .015 and .018
New ngk blue wires
New msd ss coil
aem wide band wired to a26 a25 a11
Any other info need will supply. It is not the tune 100% i have had 2 of the best tuners look at it must me electrical i just dont know where to start. Sounds like ignition breaking up please i hope some one has run into this as im out of options. Seems like detonation. Blew a cometic gasket with only 8 miles on car tring to figure this out fix a test

 

Have your injectors flow tested.

 

I put in 750s and still did same exact thing. Tried 3 dizys same issue. New hondata 4 bar same thing
Was reading lean but blowing black smoke from hood exit. I replaced 255 walbro with aem 340 with harness. Same issue

 

need to verify fuel pressure
check or replace fuel filter
borrow or swap ecu’s

 

Tried new mono tec harness dpfi to mpfi. I thought that did the trick but no went to dyno mon and boost was running away hitting boost cut. Got back home fixed the wastegate now it regulates 7psi and noticed on the test hit that it was still detonating

 

i tried hondata v3 and same issue. Fuel filter is inline screen style. Fuel pressure is 45 idle and goes up with boost. I have all aem gauges. Oil pressure. Wide band boost batt and fuel pressure. By the way thank you for getting back to me

 

‘what fuel are you running and what plugs?

 

260 gt plus 104. Ngk racing 8s gapped to .018 and tried .015. Tried .020. Multiple sets tried

 

i think it may come down to wiring on inside harness. Had this issue with old motor and now this one. Since then everything new all sensors everything even turbo. What i can say is it changes from a fast detonation to a slower detonation when i dissconnected the msd box. But still did it. Tuner said leaning out and also smokes black out of the hood exit pipe when it detonates. I want to lean to a wiring issue for ignition

 

You do not need the MSD box... removing it reduces the number of critical devices that must work together to make the engine run right. I have seen VMS cam gears cause ALL KINDS of problems with proper engine function... you might consider swapping that for a stock cam gear and see if you can rev clean.

 

I did try to use oem cam gear didnt seem to solve the issue but as you mentioned the oe gear did seem to time the motor better. I was thinking about putting it back on i am expected to mave a little over 500whp and wasnt sure how oe gear would hold up. Any thoughts on that. Would aem gear be better. Or still oe

 

The black smoke is a sure sign you're losing spark. I had a dizzy fail on me long ago and this very thing happened when it crapped out. Good pull, putter putter, black smoke, dead.. Replaced distributor and never looked back. I like VMS products but some things are just pass-worthy. Get a good OE distributor, get rid of the MSD stuff, open that plug gap back to .028 and call it a day. ****, man, I even swapped out to some Amazon 80 dollar dizzy that STILL serves me well almost 3 years later. Lol! As for cam gear, I am using the AEM TruTime and have zero complaints.
You've got a hell of a build listed here and no reason at all still for anything ignitionwise be other than stock. Coil on plug potentially for a little assurance but, meh, still not "necessary".

 

‘what is 260 gt? I’m running e85 and swapped to a ngk 2669 plug and have had zero issues. You might need to find what’s right for yours. Have you checked all the engine and body grounds as well?

 

Sunnoco 260 gt plus is 104 octane. I have checked all grounds every where even grounds that have nothing to do with issue at hand. I have a brand new car quest dizy in the box that i tried and still had the same issue i can always go back and get a warranty one and try it again. As you mention that its spark related i have my buddy from work letting me borrow a continuity tester im going to go threw all wires for dizy to make sure wires are good atleast i did like the aem gear i still might hop on getting one

 

oh so also i replaced the batt to chassis to trans ground wire and added 3 more grounds to the engine from chassis. I read in a previous forum it cound be bad ground how ever it didnt seem to help

 

This is the most updated pic with added grounds.

 

Is there any way you can post your calibration file and a datalog showing the issue? I'm running Hondata but I think I could find a way to look at your file.

You said you're running NGK8's - what is the exact part number of the plug you are running? This is important.

I agree that it would be a good idea to have your injectors flow tested. Swapping in a different set is not a bad idea, but having yours flow tested...at least you'll know. What kind of filter are you running?

I agree that temporarily at least, you should remove the MSD.

The ground strap going from the chassis to the edge of the valve cover by the timing belt is not needed since the valve cover is isolated.

You keep mentioning wiring inside the car - has any of it been worked on or modified previously? The CKP, CYP, and TDC sensor signal wires are highly susceptible to interference, which is why they are shielded. If new unshielded wiring has been run for these sensors or if the shielding is no longer grounded on one end, this could be causing your problem.

On another note I think you'd be fine running the stock cam gear. I'm at 400 whp and running the stock cam gear.

 

‘sweet looking buil man! Have you tried swapping to E85 (if you have it available). It’s a higher octane fuel and anti-knock fuel

 

Not easily available. But my last motor did same issue before low oil pressure killed er. That was with 93 and i was only expected to get 250-300 whp. I just got a hold of a ohm meter today and tonight ill do some resistance testing from ecu going to dizy wires. Maybe I have a bad wire on the inside some where. The issue is driving me up the wall. Ive tried to dyno it 3 times thinking i fixed it and nope so im 800 in the hole from that plus a head gasket and engine bay harness. To try and fix the issue. Engine bay harness did help it pushed the detonation higher up on rpm scale

 

NGK 4554 (R5671A-8) Racing Spark Plug, . Fuel filter is straight flow screen style i swaped injectors with a set of 750s. Same issue. I also tried hondata s300. Yes wires 15 years ago have been touched to do dpfi to mpfi. Figured that went bad over the years and went monotech dpfi to mpfi. Seemed to help alot but not fully fix issue. Then coverted to obd1 vtec

 

all this seems to have started when i put last motor in after i hit 252 on dyno and a month later snapped a stock rod full y8 motor. Well motor before the last i blew up. That last motor before this one now had low oil pressure and wore out cams and bearings
i figure the carnage from exploded aluminum messed up the engine harness so i replaced it

 

NGK 4554's are non-resistor plugs. You need to use a resistor type spark plug with Honda engines. https://www.hondata.com/tech-non-resistor-spark-plugs

What do you mean straight flow screen style fuel filter? What micron? Is it the small disc-type filter or a larger pleated filter? The smaller cheap ones can choke out the fuel system up top.

I agree with turboLScrx - your build looks awesome! We've got to get this running right.

 

Ok ill try resistor type plug. Not just a disc. Has almost like a pleated look to it. This is the one i have
yes i see you point on spark plugs. Oe is resistor type.
What would you recommend as a part number for 8 heat range.

 

NGK 2668 is the BKR8EIX, which is the iridium plug in the 8 heat range.
NGK 6587 is the BKR8E, which is a copper electrode / nickel tip plug in the 8 heat range.

I'm running the NGK 4644 (BKR7E) in mine - no issues with spark at all and I'm at 400 whp / 29 psi and revving to 8,500 rpm.

Hope it's as simple a fix as changing plugs!

 

I think i had the ones u use now already in it but for the hell of it ill try them thanks for info. Ill keep you posted