guys, i just recently converted my 99 accord from auto to manny for a turbo system that i had planned on putting on. Before i place the turbo on though, i had purchased a mild ported and polished head to help the engine breath better for the turbo. That is were i am having the problem now. I replaced everything while putting the new head on including timing belt, water pump, etc etc. I also put on a AEM fuel rail, cam gear, and FPR. Once everything was done, and test drove, we found that the car was spitting at 4grand and would really not go any higher, as if there was a 2 step there. We found that the FPR from aem was broken in that the diaphram in it was messed up and pushing fuel back through the vacumm line. We then placed the oem FPR back on the car. The car continued to break up at 4grand and not go any further. The car is on perfect timing, checked over and over. when we hook the car up to the computer, it states that it is haveing multple miss fires, nothing about the car running lean or rich. So we then checked the dizzy with a spare dizzy that i have gotten when i purhcased the extra head. Still that didnt solve the problem. the first funny thing...twice the car actually went passed 4 grand and didnt break up, but both times when i turned the car around to come back down the street, the car would not then go passed the 4 grand mark...both times the car actually went pass 4 grand, it still felt like it was holding back.
One of my freinds says that since the car has bigger ports that when opened up the car gets more air, thus needing more fuel, which it is not getting thus breaking up and being that the car is OBDII it automatically retards itself to a safe spectrum. If this is true though, how come the car will not break up or anything when not under load and is just fine when sitting in the drive way and reving????
I was just planning on placed the stock head back on becuase i have been waiting so long to place the turbo on that i feel like i should have not even have bothered with changing the head cause it has gotten me no where. Can this head problem actually be because the car is detecting larger ported and is adjusting itself and can this be solved with me taking the car to get tuned and converted to obdI...i really dont want to do that becuase i am going to have to take the car right back to get it tuned again for the turbo.
Like i said, i am really in the dark about this and as of right now i plan on just placing the stock head back on with the AEM fuel rail, cam gear, and replacing the FPR with a new one. I already have to get a new head gasket and new FPR, so im pissed and confused on what the problem could be,,,,any help and ideas would be welcomed,,,,cause i feel like just throwing gas on the entire car....sorry just venting,,,,and drinkin,,,,bad combo.....thanks peoples

 

help please..

 

help

 

what ecu are you using? I have 98 accord with a p28 and it was doing that for a little bit. I replaced my 3 wire to a 2 wire iacv and it runs fine. Weird solution, but it works.

 

im using a manual obdII accord ecu...but the car was fine with tranny conversion, ecu and everything. It started having this problem after i replaced the stock head with the p&p head....

 

any other ideas.....

 

ttt

 

i would start by going back over your wiring work. ie.. is everything connected up right and so on...
the p&p'ed head should not be the cause. obdII emissions logic in the computer should and will compensate for additional air up to 30% more. after 30%, it will throw a check engine light because the stock ecu's parameters only go that high.

if it isnt the wiring, try using higher octane gas.... with the new head, the characteristics of your comubstion chamber probably have changed, and the knock sensor might just be going nuts....

if you have access to a snap-on brick scanner (mt 2500) throw that on, and go drive (preferrablely take someone with you... dont want to cause an acident cuz you were looking at the scanner and not the road), and watch the data stream... specifically the short and long term fuel trims
the short term will tell you how much fuel (+ or-) the computer is allowing, and the long term will tell you a futuristic number or how much its going to need down the road a little bit. also look to see if you knock is doing anything.

 

Try changing the ecu, My buddy has a 94 civic and when he put his v-tec head on he was having the same problems until he replaced the stock ecu with a p-28

 

i rechecked the wiring, but nothing showed up and the only thing that was touched during the install of the head was the vtec solenoid plug, and that is hooked up correctly and in the right place. We tried to even unplug it to see it that was the case, but the car actually didnt even make it up to 4 grand then.
I really dont have access to a MT2500, so i cant do that.
I ordered a rebuild kit for the aem fuel pressure reg, and also a fuel pressure gauge to see if that i can maybe aid the issue by allowing more fuel in, if it in fact has anythng to do with the air to fuel ratio. I am also looking for a p28 ecu since i am going to make the car obdI anyhow for the turbo. Philly dyno works stated to me that they think the car's problem can most likely be cleared with tuning and better mapping?!?!....i figure since i am going to go obdI anyhow, that i should start looking for a p28 now. I was thinking about just going with a conversion harness and chipped ecu from Phearable.net . I can get the tuned ecu and harness for 255.00.........what do you think??......

well hammer, im going to go take her out of the garge and try some 94 octane and see if i can pick up some octane booster,,wish this luck..

 

good luck man.... post your results, im interested

 

well hammer the higher octane didnt work...or kinda worked?!!?.......once i put the higher octane in the car, 93, the car pulled the same stunt, not going 4 on the first launch. Once on the road and placed in first gear, this launch actually went passed 4500 grand and went all the way to redline but with out any vtec what so ever and seemed to act just like the car did before i placed a 5spd ecu and had it recoded by the dealership after the tranny conversion.
Anyhow, after that second launch, and once in second, the car then went back to normal and didnt go passed 4 grand while driving. Also now though, which is different then from the beginnning of all this, the car will not even rev passed 4 grand while just sitting there!!!!...so after the car basically went back to what i like to car "limp mode" i pulled it back in the house and turned her off.
Well this is the funny part. Later before i headed to the gym, i decided to try once more just to see what happens. I turned her on and let her warm up...then proceeded to start the first pull/launch, and she again went pass 4 grand all the way to redline...but again without the Vtec!!?!?!???!!!......so i stop turn around, and then start second pull/launch. And again, the car goes all the way to redline but without VTEC!?!!?.....i couldnt try anymore since i had to head to the gym and my ride was leaving....but now its like the car is in this "limp mode" with no vtec, but how could the vtec all of a sudden leave after it was working on the very first pull with the new head, breakin up, but still workin. Now though its like the car either will not go past 4 grand, or it will and run like a very very fat pig. My Mechanic is saying that he thinks we need to pull the valve cover and check for the vtec levers to make sure that the are actually working and not stuck or broke and not engaging vtec. Im going to wake up extra early and try a couple of pulls again on the car to see its behaviors....

 

could it be possible, and maybe im just spitballing here.... are you absolutly sure that you have a vtec ecu in your car.... try swaping in a known good f23 ecu, and drive it again. if the problem clears up, its the computer.

 

it has to be a vtec ecu in the car because before the head swap, the vtec was working fine after we took the car and ecu to the dealership to have it recoded for the keys. Afterthat though, the vtec worked fine and had no problems so i doubt all of a sudden the vtec programming in the ecu stopped working.
Yesterday though i was able to buy a conversion obdII to obdI harness and picked up a TWO p28 ecus. One was virgin, and the other was chipped. figured that i would use the two for comparison. Anyhow... when i hooked up the chipped ecu, the car started, but ran with a huge, constant idle lump from 1500 grand to 2 grand. I still took it for a drive to see if it cleared the main issue. The car basically ran like poop. I took out the chipped ecu, and then tried to the stock thinking that the map curve was too extreme. We the stock ecu still had the lump, and actually made the car run worse. I figured this much since the map curves were for a 1.6 as apposed to a 2.3.
So the parameters of the stock ecu was not to blame, nor pretty much the amount of fuel since the chipped ecu probably had a higher fuel curve. so i am figuring that the problem for all this is the head, and there has to be someting mechanincally wrong with the vtec levers. ????!?!?........i think i am just going to place the stokc head back on with the aem stuff bolted to it. Last though, when the fuel pressure regulator rebuild kit and fuel pressure gauge come in, i am going to install them and see if any of that helps.. if not, i think i will just put the stock head back on....................

 

UPdate***.....has anyone ever heard of there balanceshaft coming loose and leaking oil from it!?!??!......well my freakin car is ...

we were trying to trouble shoopt the problem with the car not as of lately and we cam across the leak....who the hell has this every happened to?!!?!.....im so pissd rgiht now.....

 

Interesting developments. I thought when VTEC fails to engage, it throws a CEL code?

 

Try having a look through on this thread. It's pretty good and gives you a checklist of things to rule out as possible causes:

https://honda-tech.com/zerothread?id=830163

 

Sounds like its in limp mode. Try checking the ICM in the distributor. Is it throwing any CEL's? Put the F23 ECU back in it.

Guarantee you it is not the new head or anything fuel related. I did a head swap over 2yrs ago and never had a problem with it.

 

thanks for the info man..just seen it, and will be checkin it now....

 

well we tried the dizzy that came with new head, and the same problem occured...the only cel that was being thrown that is any different than the orginal heater(O2 sensor) cel, is that once the car would operate, then the cel light would blink and the reader basically read a code for "multiple miss fires." that was the only different With cel lights before and after the new head was placed on.
When i put the car back to obdII, with the f23 ecu, the car just basically does the same thing, but only now the car runs smooth and does not have a lumpy idle like it did with the conversion harness with the chipped p28 ecu.

 

Pull the ICM from the dizzy and test it with a multimeter. This sorta sounds like the exact problem I had last year. Do a search you should be able to find the thread.