so i picked up this eg sedan with a full type r swap, that ran flawless at some point, since ive had it it will run fine when cold of course no vtec but it will rev out to 9 k fine, as it warms up it runs progressively shittier. if you five it full throtle it cuts in and out and runs horrible. if given about half throttle it wl rev out and crack but still cuts out. replaced the dizzy, all sensors on head accept map, and vtec. bottom en full rebuild. changed ecu threw injector code, changed those and stlll threw code. switched back ecus and same problem as original. idk what to do anymore

 

Your revving the motor to 9k rpm when its not even warm yet?

This is exactly why it runs like ****.... Pull the motor out, sell it to someone else.

 

I simply said it will rev that high fine when cold, i didnt say i start it up and bounce re limiter. im not an idiot, nor do i need one to answer my post.

 

Just keep spending money and replacing parts

 

Spend money in the right area and bring it to a shop!

 

Thats what ive been doing, but im running out of money and hoping someone can pin point an area for me lol

 

map sensor?

 

The only other map i had was a sohc eg one off the fire wall which has a vacume line where mine does not, i tried it anyway and it seemed to run worse then when the one on the tb is hooked up.

 

how is the idle when your car is warm?? Does it fluctuate??? check for map sensor!

 

Idles fine, the prblem doesnt really start till you give it gas, its almost like a fuel cut, like one second its gettng gas then not then getting it again fast, so it cuts out but comes back with in seconds. im gonna try and get a video or audio clip up today.

 

Have you replaced the fuel filter? Sounds like what my car did a few months ago. Replaced the filter and it didn't happen again.

 

Most people dont stop and think about this but here was your first red flag. Car runs good until it warms up. Your car runs in open loop until it gets a readable signal from the o2 sensor or reaches operating temps. In this time period it dumps in more fuel then what is needed to help keep the motor running until everything gets going and to compensate for the cold denser air. People like to say "wouldnt that throw a code?" no not always or even alot of the time. The more wrong signals the ecu gets from the failing o2 sensor the worse its predicted AFR curve becomes. I had the exact same problem with my lsv until i replaced the o2 and now it runs perfect. There are several ways to test your o2 sensor if you have a digital multimeter and it will save you alot of money and time if this is your problem because you can know 100% before you buy a new one.

 

I havent replaced the fuel filter, but i have a multimeter, what should i be looking for on the o2 sensor? thanks for all the input so far

 

So we just tried an o2 disabled ecu and its still running the same. idk what else to try this is getting old, i dont want to get rid of it, but im at the point where i just want a running motor.

 

Ok I'm going to go out on a limb here.

What if it's the fuel filter or weak fuel-pump, and the reason it gets worse is that the vacuum in the gas-tank is lower when the car is 1st started. I believe the system maintains a slight vacuum. If this working theory is correct, you could test it by "warming up the car", then shut off, pull gas-cap and reinstall, then start engine and see if for the next few minutes it runs better, then gets worse again.

If that's the case, then I'd say either fuel-filter, or fuel pump is weak. Or your gas-cap isn't limiting the vacuum in the tank (the way I think it's supposed to in modern cars).

Steve

 

Ok. Tried different maps, changed every sensor on the block and head, ecu is O2 disabled so that doesnt affect it. with one ecu it will throw a code 14 i believe, fuel injector code. changed injectors with known good ones, spliced new grounds into the pigtails, no change. It has started running slightly better since the change of all sensors. And it seems most the problem is coming only when vtec engages. cracks in and out like a fuel cut or like it would be low on oil. gonna change the plugs out again tonight and only thing left is a harness. which brings up a question, are obd2a or obd2b harness 2 piece with the same amount of connectors on each shock tower? Is it possible that this is a obd2 harness plugged into a obd1 car and causing all of these issues? so dioxine: i dont think its the o2 or related to o2. thanks for the input tho. blac00si: Engine has been completely swapped into a del sol shell and ran the same. so nothing shell related ie, fuel pump,filter, interior harness, etc. Dawgc2: will try a new map tonight. one actually for the car. And for anyone else i dont want comments on my sweet typing skills or incorrect pronunciation. i dont really care

 

TTT

 

Huh?

 

Ok. Tried different maps, changed every sensor on the block and head, ecu is O2 disabled so that doesnt affect it. with one ecu it will throw a code 14 i believe, fuel injector code. changed injectors with known good ones, spliced new grounds into the pigtails, no change. It has started running slightly better since the change of all sensors. And it seems most the problem is coming only when vtec engages. cracks in and out like a fuel cut or like it would be low on oil. gonna change the plugs out again tonight and only thing left is a harness. which brings up a question, are obd2a or obd2b harness 2 piece with the same amount of connectors on each shock tower? Is it possible that this is a obd2 harness plugged into a obd1 car and causing all of these issues? so dioxine: i dont think its the o2 or related to o2. thanks for the input tho. blac00si: Engine has been completely swapped into a del sol shell and ran the same. so nothing shell related ie, fuel pump,filter, interior harness, etc. Dawgc2: will try a new map tonight. one actually for the car. And for anyone else i dont want comments on my sweet typing skills or incorrect pronunciation. i dont really care

 

take it to a shop and have then do a diagnostic.. that should of been the obvious thing to do at 1st after you tried switching out all sensors.. waste of time and $$$

 

so pretty much it boils down to everything has been replaced except for map, the harness and the head itself.. like i said bottom end has been rebuilt yes changed fuel filter i even took the motor out and put it in a diff shell still no change.. replaced injectors fuel filter plugs wires dizzy ecu and all sensors except for map (i did but dont kno if the other one i used is good either) i kno i'm repeating some stuff hang in there i'm frustrated.. before the car ran decent at one point (still slow for a type r but no fuel cut vtec cracked and it revved to 9k) then started the fuel cut thing.. i'm lost

 

i talked to a guy in town that works at a diagnostic shop i'ma take it in asap

 

and i just swapped all the sensors this past weekend so takin it to a shop is the next thing i'm doin

 

Good luck hopefully its a cheap fix. If its a major problem in vtec it could be something to do with vtec solenoid. Could be causing your oil pressure to drop dramaticly. Or maybe a fuel pressure regualator. I would keep it out of vtec until you get it in the shop.