High RPM Hesitation/Fuel Cut and Glowing exhaust manifold!!!!!

[pmurr181]

Okay, so i am posting a new thread with everything i know whats going on.
I have 1990 Skyline GTS-t. I have done: Cleaned MAF with MAF cleaner, Adjusted TPS to 0.48, checked the spark plugs and coil packs, changed fuel filter, oil filter, reset ECU, and diff fluid. When i got the car from Japan it came with an Very Old Apexi AFC with only one adjustment knob. After a little bit of driving i started noticing fuel cuts/ high RPM hesitations. When i push the gas half way to the floor and take RPMs all the way up to the redline i have so much hesitation/ almost like fuel cuts.....i dunno. My friend who is more experience than i am took the AFC out and bridge wires. it seemed to run fine untill then all this hesitation and fuel cuts keep happening. I then decided to put it back it so cut bridged wire and pluged it back in. It now is still doing the same thing. I also have notice at one point where i was bagging on the car at high RPMs the exhaust manifold was just about glowing RED!! Not good. I am asumming that the engine is running to lean and over heating. However the temp gauge is working at stays at consistant normal tempatures. When they installed AFC would they tune the ECU? So what i amasking is how can i get this to go away, i have done everything in the Fix your hesitation forum... i think its more to due with this AFC possibly. What should I doooo?????????

heres pics of old AFC

http://s972.photobucket.com/albums/ae202/murray4964/

Please if anyone has any idea it would help alot.

thanks

Paul

[BrianV8]

wow thats getting pretty hot, first things first get yourself a wideband see what its doing. Next make sure you have good fuel pressure

[Zacho]

Take off your kickpanel on the passenger side to see if your ECU has an a/m sticker on it.

Your stock temp gauge is not a very good indicator at all, and as to why you had a hesitation/signs of lean condition you were bagging on the car enough to make it glow red is beyond me...

Like BV8 said, check your fuel pressure. Sounds to me like you are not getting enough fuel/demands are too big. What are your current modifications/boost?

[pmurr181]

Where do i get a wideband... sorry i am noob at this. How do i see if i have good fuel pressure? Yeah i figured that the stock gauge was meaning crap when i saw red exhuast manifold. Would the AFC be making me have to much or too little fuel/air. what happens if i take it out and what is the proper way to take it out?

[BrianV8]

Wideband is and accurate air fuel gauge. It has its own O2 sensor so you need to bung your exhaust pipe to thread it in. The gauge prices range from 250-450 bucks depending on the brand and what features you want. I can get you hooked up if need be. AEM are the best bang for buck IMO

As far as fuel pressure easiest way and a good mod to make is get a aftermarket fuel pressure regulator with gauge on it. Otherwise you can get a gauge mechanics use you can hook up

[pmurr181]

Yeah man that sounds great. i would like to use one of these.

[pmurr181]

i read up on some stuff an people are saying maybe clog cat or crack in exhaust manifold and it only appears when the pipe gets heated up. oh and if i put the wideband in do i need to remove the AFC and how do i go about that?

[BrianV8]

to be honest i don't really know too much about the afc, but the wide band is it's own entity, totally separate. All you do is wire up a power, ground, and ignition for the gauge, weld in the bung for another o2 sensor and plug it in. Has nothing to do with any system on the car

[pmurr181]

Ahhh i see

[BrianV8]

if you are playing with the fuel in any way a wideband is a must!!!

[pmurr181]

im not really wanting to play with it. I am trying to figure out why its running like crap at normal engine temp and also how its running to rich/lean and how to fix it. Does anyone know how to take the AFC out? does it run on stock ECU maps/ what happens if i remove it will it change everything. and does anyone know if they tune ECU with and install of and AFC?

[BrianV8]

well again it might not be your afc, could be your fuel pressure. At least with a wideband you'll know how the engine is running and diagnos from there, even an egt gauge would help see how hot things are getting

[pmurr181]

yeah that i good idea man. How much would a wideband cost for my car? and if i get a test pipe can i put it in there? Can i remove the AFC without screwing the orignial maps up? how do i do that?

[BrianV8]

i don't know much about the AFC but if you never touched it and it never caused you a problem before it won't be your issue now. But if you have a wide band you can take advantage of the afc in the long run, if you want to add boost you can watch your air fuels with the wide band and add fuel with the afc. Learn more about the afc and use it to your advantage before you go and toss it. The guy i deal with for my supplier on wideband's is on holiday he'll be back in the office saturday. If you can hold tight i'll grab you a price on an AEM Eugo. Same one me and many others use. I'll grab a price and get back to you.

[pmurr181]

Aight man thanks alot for the information. sure sounds good no rush.