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Discussion Starter · #1 ·
Id like to think i know my way around these but this has me a bit stumped, i got P0300 and p0301-p0306
spark plugs were fuel fouled so were replaced
Mechanical timing is in check
Unbolted cat and ran it, no difference
Live data shows o2 sensors reading rich short fuel trims are at 0 or negative, when warmed up its hard to get data as i have to have my foot on the gas to keep it from stalling
Valve clearance was on the tight side but i adjusted to looser side of spec (not my first valve clearance)
Fuel injectors click with a stethoscope on them and ohmed out in spec
IAC sensor was swapped with denso ones and an aftermarket one to be sure.
Compression is within spec according to service manuel
ECT coolant temp sensor was switched and are reading normally on scanner
IAT sensor was swapped and is working as it should on the scanner
Went over with my vacuum gauge and motor mounts are good
Pcv valve moves up and down freely
EGR ports are clean and EGR moved freely up and down and wasnt that dirty
MAP sensor was replaced
Fuel pressure tests require an 80$ fuel dampner, adapter plus another adapter to fit my fuel gauge, fuel filter is in tank.
I hear sparking coming from the ignition coil and/or the distributer which are not new but not old, dizzy cap has a little bit of white corrosion on the contacts
Replaced ignition coil with a shitty aftermarket one but ohmed out higher than my old one and still heard audible sparking on ignition coil, old ignition coil had white residue where it had been sparking to closest ground.
FPR was replaced and was not the issue.
any input is appreciated
 

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Kaua‘i North Shore Boi.Aloha❤️🤙💪😊
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272 Posts
Id like to think i know my way around these but this has me a bit stumped, i got P0300 and p0301-p0306
spark plugs were fuel fouled so were replaced
Mechanical timing is in check
Unbolted cat and ran it, no difference
Live data shows o2 sensors reading rich short fuel trims are at 0 or negative, when warmed up its hard to get data as i have to have my foot on the gas to keep it from stalling
Valve clearance was on the tight side but i adjusted to looser side of spec (not my first valve clearance)
Fuel injectors click with a stethoscope on them and ohmed out in spec
IAC sensor was swapped with denso ones and an aftermarket one to be sure.
Compression is within spec according to service manuel
ECT coolant temp sensor was switched and are reading normally on scanner
IAT sensor was swapped and is working as it should on the scanner
Went over with my vacuum gauge and motor mounts are good
Pcv valve moves up and down freely
EGR ports are clean and EGR moved freely up and down and wasnt that dirty
MAP sensor was replaced
Fuel pressure tests require an 80$ fuel dampner, adapter plus another adapter to fit my fuel gauge, fuel filter is in tank.
I hear sparking coming from the ignition coil and/or the distributer which are not new but not old, dizzy cap has a little bit of white corrosion on the contacts
Replaced ignition coil with a shitty aftermarket one but ohmed out higher than my old one and still heard audible sparking on ignition coil, old ignition coil had white residue where it had been sparking to closest ground.
FPR was replaced and was not the issue.
any input is appreciated
Could be leaking or clogged fuel injectors.. Just because they click, doesn't mean they're good. Try taking off the fuel rail (relieve pressure, pull fuel pump fuse, start car until it dies, then loosen the damper, put rags underneath), then use a 9v battery and jump each injector while spraying some electronic cleaner (I use it because it leaves no residue) through the bottom (seal the red straw to injector connection with something).. Look for a correct V spray pattern.. 3 of 4 of mine had a V at one time. The last one was just spitting gas. lol I was able to clean it though.. Good luck! Aloha🤙
 

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one wheel drive
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853 Posts
Quick check if injectors or fuel pressure regulator leaking.. you should be able to smell fuel in the intake manifold several minutes after shutting down.

Longer version is seeing if fuel pressure holds a while after shut down but you need that expensive adapter.
 

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Discussion Starter · #4 ·
Could be leaking or clogged fuel injectors.. Just because they click, doesn't mean they're good. Try taking off the fuel rail (relieve pressure, pull fuel pump fuse, start car until it dies, then loosen the damper, put rags underneath), then use a 9v battery and jump each injector while spraying some electronic cleaner (I use it because it leaves no residue) through the bottom (seal the red straw to injector connection with something).. Look for a correct V spray pattern.. 3 of 4 of mine had a V at one time. The last one was just spitting gas. lol I was able to clean it though.. Good luck! Aloha🤙
I took off the 1-3 cylinder fuel rail and primed it, waited, then tried to start with spark disabled of course and they were spraying fine (sprayed onto a bunch of rags) but didnt do 4-6 cylinder fuel injectors to check. ThIs was when i first got it ( bought it with this problem for a deal ) maybe i should pull the other rail and check. Idk im at a loss with this one, seems everything i do doesnt work.
 

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Elvira
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@Dronose

How are your brakes ? Does it tend to misfire when the brakes are applied more often than at any other time?

A possibility of a damaged brake booster diaphragm causing the extra air to get into the engine when you step on the brakes can cause misfires.

Since this happens after the car warms up (closed loop control) the reason it might run "OK" when cold is because it dumps loads of fuel when cold. Gas soaked plugs?

Just because a PCV rattles doesn't mean there can't be a HUGE leak if it is open.

Check the hoses going to the booster and possibly recheck the PCV or replace for good measure. I've had a PCV rattle but only because it was broken internally.
 

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one wheel drive
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853 Posts
@Dronose

How are your brakes ? Does it tend to misfire when the brakes are applied more often than at any other time?

A possibility of a damaged brake booster diaphragm causing the extra air to get into the engine when you step on the brakes can cause misfires.
Interesting thought. These engines dont have an air flow sensor, only a manifold pressure sensor so any extra air, like a vacuum leak, is seen the same as opening the throttle. So any air that enters the intake is still "metered" in a sense that the manifold pressure increases. The question here would be, how much extra air would cause a disagreement between MAP and throttle position input to cause a problem?? We know that lots of people who have vacuum leaks while idling get surging because the throttle is seen closed but RPM is above 1100 (when at operating temp) so it cuts fuel off, as you would get if you were coasting in gear. To test the brake booster leak theory, warm the engine up and pump the brakes while parked and see if RPM changes.
 
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Discussion Starter · #7 ·
@Dronose

How are your brakes ? Does it tend to misfire when the brakes are applied more often than at any other time?

A possibility of a damaged brake booster diaphragm causing the extra air to get into the engine when you step on the brakes can cause misfires.

Since this happens after the car warms up (closed loop control) the reason it might run "OK" when cold is because it dumps loads of fuel when cold. Gas soaked plugs?

Just because a PCV rattles doesn't mean there can't be a HUGE leak if it is open.

Check the hoses going to the booster and possibly recheck the PCV or replace for good measure. I've had a PCV rattle but only because it was broken internally.
Interesting thought. These engines dont have an air flow sensor, only a manifold pressure sensor so any extra air, like a vacuum leak, is seen the same as opening the throttle. So any air that enters the intake is still "metered" in a sense that the manifold pressure increases. The question here would be, how much extra air would cause a disagreement between MAP and throttle position input to cause a problem?? We know that lots of people who have vacuum leaks while idling get surging because the throttle is seen closed but RPM is above 1100 (when at operating temp) so it cuts fuel off, as you would get if you were coasting in gear. To test the brake booster leak theory, warm the engine up and pump the brakes while parked and see if RPM changes.
Braking wont work when its missing and idling low but pumping then makes no difference acts the same, if im driving it brakes work fine until idling gets super low when coming to a stop. When driving it rpms will cut off while driving. And ignition switch recall was done on this one already so i know it isnt that

Thanks for all the advice guys i think im gonna check my fuel rail on my 2nd bank for cylinders 4-6 for leaking fuel injectors i dont know what else to check.
 
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