Posting this for a friend's car I tune. I rarely post here asking for help but I was out of time and this has me stumped. So any help is much appreciated

Give the run down on some of the setup first

* VP C16
* Benson 84mm B18c1 block
* T1 Cam Trigger Kit
* AEM EMS 30-1040
* Injector Dynamics 2000cc injectors @ 43.5 base
* OEM Honda distributor
* OEM Honda spark plug wires
* Skunk2 Pro 1 cams
* Skunk2 Pro valve springs
* Skunk2 titanium retainers
* Manley valves
* OEM valve guide seals
* OEM guides
* OEM valve keepers

A little history on the head/motor. When installing the Skunk2 Pro 1 cams. There was retainer to valve guide seal clearance issues. The retainer hit pretty bad. I'd guess for about 30 degrees of crank rotation or so. Intake side retainers have about a 0.035" of interference with the valve guide seal. Exhaust side is fine. He had the choice of new custom retainers, have the existing ones milled for clearance, mill the valve guide down some or modify the install height some or switch to ITR cams. He had a machine shop mill the retainers. I can't remember how much right now but I am trying to find out

Fast forward. Everything is good. Start motor. Break in on the dyno. Makes 540whp @ 23lbs. Anything above 23lbs fuel pressure dropped. So we called it a day. Rewired the Walbro pumps with 10 gauge wire. Went to track. Ran 11.2 @ 140 with no launch. Just 2nd, 3rd and 4th gear

Fast forward. Sump tank. Install two Bosch 044 pumps. Goto dyno. First pull car misfires bad. Second pull car misfires bad. So put new NGK iridium 9's in. Car misfires but not as bad. Gap the plugs down to .018. Misfires. Run the car at 11.5:1. Misfires. Run the car at 10.8:1. Misfires. Run the car at 12.2:1. Misfires but not as bad. Change the rotor to brand new OEM Honda. Misfires. Change the coil to brand new OEM Honda. Misfires. Double check timing. Good. Double check air gap between Hall sensor and cam gear. It's at .050. Bring it down to .040. Misfires but a little better. Bring it down to .025. Misfires the same. Try NGK BKR7E plugs. Misfires. During this time I am going talking to Tony Palo and Ed at AEM to make sure I am not missing something. Logs look fine. Calibration/Tune looks fine. Try another distributor with another ICM. Misfires. Try adding grounds to motor. Misfires. Reflash firmware. Misfire. Rebuild an entirely new calibration. Misfire. Pull 3* of timing. Misfire. Pull another 3*. Misfire. Put back in 6*. Misfire. Put another 3* in. Misfire. Try another set of spark plug wires. Misfire. All the time watching fuel pressure. It's good. Try the gap at .023 and .025. Misfire. Repin the ecu to use coil output #2 instead of coil output #1. Misfire. We've done everything outside of trying another ecu (it was too late) and try another set of injectors. Some of this is obviously out of order and we probably tried more than I posted but it was a long day/night

Could this possibly be related to the cams, retainers, etc causing a valve float misfire or similar? Car was fine last month at the track. Only change was the Bosch 044 fuel pumps. And like I said. You can watch the air:fuel. It's relatively steady at/around 10.8:1, 11.5:1 and 12.2:1. I verified the air:fuel with an FJO with NTK sensor and AEM with brand new Bosch sensor. They were within .2 of each other

You can find the internal logs if you're interested below ... No loss of stat sync and/or cam/crank signals

http://www.inductionperformance.com/...7-Internal.stf

http://www.inductionperformance.com/...7-Internal.stf

http://www.inductionperformance.com/...8-Internal.stf

http://www.inductionperformance.com/...4-Internal.stf

I'm waiting for Proven Power of Tampa (dyno we use) to e-mail me the run files

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<Edit March 31 2010 10:28AM>



</Edit March 31 2010 10:28AM>

 

i have seen this happen before with the first gen AEM boxes (believe 30-1000). change box, loaded same map and it was good.

im guessing your coil dwell in the wizzard hasnt changed? or its for stock honda or CDI?

whats the BAtt voltage doing when it misses?

whats the fuel press doing? does the tank have a proper vent?

I had a car recently that would do the same thing, finally logged coolent temp "fast" and found it was sporadically losing signal anwhere in boost, causing it to cut in and out. All because of a pushed pin.
Im guessing you have logged all that could be comping the tables?

 

We've had one knowledgeable person suggest bringing the air gap lower than .025. His would only pull cleanly at .004

 

We ran into this problem with Tampa Mike and a buddies car while we were there, found it to be the plug wires. He was using the OEM wires and no matter what Mike did it would break up higher in the RPM range we put some NGK wires on and misfire was gone. Throw a set of the NGK blues on there and you should be good.


Keep us posted

 

The few hundred AEM's I have tuned I have seen some weird things as well. Usually ground related. Like in the post. I reflashed the firmware and built a new calibration. Same issue. I'm confident it's not the AEM EMS itself as this box has been solid

All coil dwell settings are correct. Verified twice by myself and Ed at AEM

Battery volts have not changed from the track. A little low but same as track. 13.0v going down to 12.8v at lowest

All the internal logs show ALL sensors are working great

 

you said you added grounds to the engine, did you place them at the head, specifically, near the dizzy and or cam gear side to proper ground?

 

Battery, intake manifold, distributor

 

did ya try the plug wires?

 

One set of brand new OEM Honda wires and another set of used OEM Honda wires

 

Updated original post with dyno sheet. The dyno shop only had time to send/upload run files 37 - 41

 

When i was down in Mobile with Tampa Mike i think we found the limit on the OEM wired and that was right about 450-500hp.

Also where in the RPM range are you gettin the misfire?

 

Car previously went 140 with OEM Honda wires. Definately isn't the wires. Mike knows OEM wires are good for more than that. The wires you were using might have been old, had breaks and were arching. If you have AEMLog take a look at the log files and you will see where the issues begin

 

hmm not to sure then, probly was because they were old. all i know what we did was swap new ones on misfire cleaned up, then came back he swapped a new distributor on and no more after that. Distributor was new when the car went to the dyno too.

I do not have AEMLog to look at the files unfortunatly.

 

Everything minus the Hall sensor has been changed on this car. If I can't get any ideas from this post the next time out I am going to bring the air gap down little by little to see if that eliminates the issues. Right now it's at .025

 

hmm odd indeed.. Good luck sir, hope you can get it all figured out

 

oem "unmodified" (no "tuck", reloom, etc?) engine harness?

 

No wire tuck, reloom, etc. When the motor went in the engine harness was in great condition. Definately not your typical off the street Honda harness. Last I checked it still was. Next time I am with the car I will try to go over what I can. And I will ask the owner too as well

 

injector??

 

i had this problem with 1320whitecrx's car (oz)..
turbo k20 in a crx. he had brought it to someone in orlando and they were having these same issues.. messed with it for hours and nothing

he brought the car down here and i made a few pulls. checked the plugs and 1 was a little lighter than the rest. i cleaned the injectors out with brake cleaner and pressurized air. throw them back in and first pull it went from 330hp to 420hp. graph was super clean after cleaning the injectors.. i'll post the graph's in a minute



here u go..both pulls were on 11psi. only change was cleaning the injectors. car ended up making 615hp on a stock k20 without a hickup

 

I was kinda thinking the same thing with the injectors... How thoroughly were those new fuel lines cleaned after they were cut and assembled before they were installed back on the car??? Possible maybe a miniscule piece of that line maybe left over from when it was cut, and clogged up an injector???

 

i'm bot an expert ... but i think if u run 10 mm magnecor cables EMI suppressed u can clean out any doubt on spark cables. Are u sure ur coil is giving u out enough mA for making out a good spark to burn out all the fuel from 2000cc inj?
Isn't ur injector opening time too much for ur timing?
Personally i will try to replace all ground with cables almost the double size than stock to lower the cable impedance.
Why dont u use a fuel additives to clean out fuel system?
Are u sure ur magnetic pick up giving u aways a good signal?
Good luck

 

I brought this up last night. We have a set of ID 1000cc but ran out of time

Thanks. The graphs look similar in ways. We're going to take the injectors out and have them tested

The coil is definately working and working correctly. All the grounds are actually double the size of stock. I'm big on grounds. The cam/crank signals look great. I'm not loosing a signal. Going to try closing the air gap some more and get the injectors checked out

 

Hey whats up ,we had a similar issue with my car and i run a .015 on my trigger kit , i went through similar issues and ended up being the hall sensor from the t1 trigger kit ,datalog the stats synch on the hall sensor and see if its loosing signal at high rpm that was my issue
.

 

same thing i do ,,,works good ....thats prob it,,especially after you sumped the tank...all kinds a **** in their im sure

 

Are those internal or pc logs? Does the car have an EGT? What fuel filters and where is the fuel pressure gauge?