Misfires or fuel pressure?
Quick run down, i was driving my iO 4G94 MPI just fine when all of a sudden the power started to cut feeling kind of like a misfire, i managed to get it home as power continued to be lost on the way home, i had replaced the in tank fuel pump to an AEM pump and all was fine for about 4 months, increased power etc, after i got home, i tried to diagnose the issue but up until now i havent figured out what it can possible be, i changed spark plugs, i changed the fuel pump to a Denso pump, removed and cleaned the throttle body but the symptoms remain the same, i have coke to the conclusion it is probably fuel pressure but i dont know where to begin with that, reason i am saying fuel pressure because if i try to rev the engine sudden it would sound like it is choking but if i gradually increase the throttle ot well rev smooth or sometimes it will stutter but if i remove the air filter and spray short bursts of carburetor spray in the intake the engine will smooth out and rev fine for a few seconds, so my question what do i need to track down for my fuel problem, the pump is sending lots of pressure with the ignition on, the vehicle will also hard start and after alot of tries it will eventually start but it seems as if pressure drops off once its started, somebody help me please
Check your earth's too i had
Check your earth's too i had a missfire i couldnt diagnose, new plugs leads coils filters it was still there, i added a couple of new earth leads to the chasis and engine and she is now sorted. I think after years of driving offroad and beach's the connections wern't up to scratch. i also cleaned up the existing earth wires i could get to.
p.s there is an earth lead on the back of the throttle body that goes to the firewall that was the worst coroded one and think it caused most of the issues for me. The main earth to the block is under the inlet manifold behind the altenator.
So after months of running
So after months of running behind everything you can think about with problem, it has finally been resolved the problem was with the fuel pressure regulator, i changed the fuel pressure regulator about 3 times to different ones from other engines and still was the same results changed my fuel pump more than twice even purchased a AEM fuel pump and same problem, bought new MAF sensor, checked back all wiring, valves clearances, new coils, plugs, cleaned egr valve,cleaned and even replaced fuel injectors changed fuel pump assembly but nothing seemed to fix the problem, finally decided to purchase an aftermarket fuel pressure regulator and just like that issue was gone and the vehicle is back to normal
Syndicate
misfire
Is it only missing when the engine is loaded ? As an example, when driving up hill, does it lack power then ok on the flat.
Then you may have a faulty coil/spark plug lead.
Happy io
My io is now SOLD Thankshttp://pajerio.com/forum/claudes-io-2002-zr-built-thread-onlyhappy-io