*SOLVED* Hesitation at full throttle and cold idle.

quartersquarters Council Member
in Electronics, Fueling & Air Conditioning
So my last few tanks have had terrible mpg. during the time my car is running prior to reaching operating temp there is a fuely smell and if i tap the gas it hesitates, kinda takes a big gulp of air then rev's up. i've noticed A LOT of fuel coming out of the exhaust when i do this. i changed the cap & rotor, no luck. spark plugs look good. wires, good.

NO CEL.

Comments

  • yellowmikebikeyellowmikebike Wagonist
    Plugs are good?

    Is yours RT4wd or 2wd?

    Fast Idle Valve or Electronic Idle Control Valve problem? Idle surge up and down too, or just runs/idles normal but rich?

    O2 sensor might be bad, Check Engine light on or off?
  • 89ac_EE289ac_EE2 Wagonist
    NO CEL
  • quartersquarters Council Member
    no engine light on.

    plugs & wires are good, also just changed cap & rotor.

    even if i am on the highway and i put the pedal to the floor, the car just bogs down then slowly sputters back to life.
  • ragenasianragenasian Moderator
    Could be a bad fuel injector stuck or maybe the fuel pressure regulator has failed.

    When you pull the dipstick do you smell gas?

    You could always stick a spark plug in the tail pipe and keep those tailgaters off your ass.
  • stampernstampern Senior Wagonist
    Well, i'm not sure if you have mpfi or dpfi, so I'll cover both. It sounds like you might have a bad injector or 2 kicking in extra fuel all the time. For mpfi, pull the spark plugs and check each one, if that cylinder is running rich from extra fuel the spark plug should be black. That will help you determine which injectors are bad. If you have dpfi there isn't really way to check to see which one of the two is bad. You could probably get 2 used ones for cheap and just replace them and go from there.
  • quartersquarters Council Member
    it's an MPFI swapped wagon. i pulled all the plugs and they look fine. i think my problem is the wiring harness... i need to re-do the MPFI section badly. i'll keep you posted.
  • quartersquarters Council Member
    my diagnosis was not accurate before. Here is the real problem: any time I punch it to full throttle it bogs/hesitates then then gradually starts going. cold or not, at any speed, in any gear. i dropped from 5th to 3rd to pass someone and the wagon hesitated badly... enough that i had to pull back in or risk certain doom.


    so ya, WOT causes hesitation. anyone had this before? did a search on honda-tech but no *SOLVED* ever came up. dead ends.
  • wagodizzlewagodizzle Council Member and EDM expert
    quarters wrote:
    i dropped from 5th to 3rd to pass someone and the wagon hesitated badly... enough that i had to pull back in or risk certain doom.

    mine has done this before as well... MPFI'd 2WD
    im looking for answers as well.. only thing i can think of is bad wiring somewhere.

    does you wagon expel a lot of black carbon deposits?
  • quartersquarters Council Member
    yes, lots.
  • wagodizzlewagodizzle Council Member and EDM expert
    then we definitely have the same problem. if i dont wash my car every week or so the back end would be covered in black sooth.

    let me know what happens when you re-do the wiring!!!
  • Okiewagon1Okiewagon1 Wagonist
    Check for a bad TPS as this is usually the problem. Most of the time it will not through a CEL.
  • wagodizzlewagodizzle Council Member and EDM expert
    how can you check to see if it works? just replace it?
  • vtecn8ivevtecn8ive Senior Wagonist
    91EERTWagon wrote:
    Check for a bad TPS as this is usually the problem. Most of the time it will not through a CEL.


    He speaks the truth. I need to do this on my car too.

    They have a method in the car manual how to do it, but off hand you will need to back probe the TPS connector, and possibly adjust the TPS.
  • rti intracrti intrac Senior Wagonist
    It could be the coolant temperature sensor, It could be reading cold all the time which means your ecu will richen up the mixture to try warm the motor.
    You can test the sensor off the car, get a old pot and boil some water, connect your meter on ohms across the sensor and put the sensor in the boiling water, watch the meter and the resistance should change as the sensor heats up, if htere is no resistance or it stays the same its time to replace your sensor
  • quartersquarters Council Member
    so it's been almost 2 years and i'm still having this problem. I avoided going WOT for the entire 2 years, but this summer i've got a lead foot after some brake & suspension work and want to fix it. I'm going to change the TPS this weekend and hope that does it, if not, i'll change the o2 sensor. will change to SOLVED if solved.
  • Silvertoe88RTSilvertoe88RT Wagonist
    Test the TPS no sense in replacing it if it is not the true problem. Plus if you don't buy the whole throttle body you will have to adjust it anyway to specifications. closed throttle is .45 to .5 volts wide open throttle is 4.5
    Also check the vacuum lines to the map "map makes me think of the bog issue, tps is more of a jerky feeling", test the coolant switch, test o2 sensor "one wire o2's are recommended to be replaced every 30k"
    obd0 is hard to diagnose with no code, but save money and test the things you can.
    There are good write-ups on here use the search feature and it should bring up test procedures - you are an elder you know.

    If you did the conversion just double check the connections.
  • quartersquarters Council Member
    changed the throttle body, with known working TPS. problems solved. gave the TB a nice cleaning too, mine old one was full of black goo.
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