alright i have a 90 interga with a b17 gsr swap in it the problem im having is after crossing into vtec and then stopping at a light the idle drops below 500 like its goin to die the idles up and then its fine…i swapped my pr3 ecu out and ran a pr4 ecu to see if its just a vtec system issue but nothing…now if i drive the car and let it idle after a stop it does the same thing only this time i get a code 43 for fuel supply…gonna check fuel pressure and injectors shortly…also i have an exhaust leak at the 4-2 connector which im fixing today is it possible that the exhaust leak can cause this concern…let me know wat u think thanx for your help
I had an DC5 that would do this after everytime that I disconnected the battery, and put it back on. Use the ecu for the vtec so that it sends proper fuel. Changing this stuff out so often isn’t good, and it’ll run like that until your computer readjusts itself and re learns everything. my DC5 use to do this for a few days after I would re connect the battery.
If not look for air leaks,
what mods do you have other than the swap?
Whens the last time you changed the fuel filter?
If you’re getting a CEL for fuel system, then thats naturally where your problem lies.
Do what you said, check fuel pressure and filter and go from there.
When fuel pumps get old they will tend to crap-out at high revs. My brother’s fuel gauge was ‘fluttering’ past 7k rpm. When we asked the tuner he said more than likely a worn pump… indeed it is a 12+yr old oem pump.
Given the age of our cars, it would not be a stretch to find out that your oem fuel pump cant deliver the pressure that the vtec system is needing. Tripping your CEL, engaging limp-mode, etc.
My car is doing this too every time i smash out and when i drop it to N it idle really low.like the above statement. I’m going
to change the old fuel pump and the old fuel filter and maybe the injectors but anybody know if the fuel injector cleaner work?
update!!!
after doing a fuel pressure test the pressure is fine according to alldata and the problem is fixed i had a major exhaust leak at the exhaust header and b pipe…this did a lot the car idles at 750 like its supposed to and i have more power at the vtec cross
also for the above replies i have intake,exhaust,msd setup and intake manifold and type r throttle body…and when i did the swap i changed the fuel filter and fuel pump because on my ls motor fuel pressure was dropping you know how these 19yr old fuel pumps are…and if anyone is having the same problem if fuel pressure is within spec look at exhaust leaks if its close enough to the o2 sensor it will through code 43 due to the o2 sensor getting a false reading also adjust the valves if they are too tight it will cause a slight studder on the motorsometimes but u will feel it…thanx for the help everyone
I know this thread is pretty old but I was hoping that you guys might still be checking it out this thread. Any ways I did an ls vtec and just did a street tune on it. It’s about 90% tuned and I’m waiting to get it dyno tuned. I have a uni o2 sensor and I was told they suck and to get a factory one. Any ways I haven’t done that yet but I am getting the code for fuel system and and I have installed a new fuel pump a few weeks ago as well as a new fuel filter. Does anyone know what might be my problem. I was thinking maybe my fuel filter is clogged. The reason I think that is because the car sat for a year with some gas in it. However I have put about 5 tanks of gas in the car with the new motor injectors, fuel pump and filter. I am wondering if it’s my o2 sensor that is no good. I don’t notice any lost in power at any rpm’s. There is one thing though is that the car idles funny till it is totally warmed up. It will go to about 600 rpm then jump up to it’s normal and it will stay there. Sometimes it will stay there then slowly work it’s way down to the 600’s then jump back up to 800 and run normally. When the CEL comes on it when I’m in low rpms driving. Let me know if any one has an idea of what it could be. Thanks