1996 Honda Accord fuel injectors

I hope brake cleaner didn't damage anything. I would have recommended carb cleaner. As far as a lean mixture, if the fuel pressure is within the manufacturer's specs, check for engine vacuum leaks unless you have a check engine light on that indicates an issue with the O2 sensors.

I have a check engine light it says BANK 1 TOO LEAN the car is a 4 cylinder. Does brake cleaner damages injectors?

I checked the fuel pressure it s in spec and the regulator is good the pressure goes up when i unhook the vacuum line goes to the fuel regulator

there is no vacuum leaks neither

I have to be honest, I question if brake cleaner was a good choice. Did you replace o-rings?

After thought...

Did you replace the injectors with the exact same type of injector? Same part number? Could they be a lower CFM and creating a lean mixture? Did this problem just start with the replacement injectors?

i think brake cleaner is safe because it does not hurt rubber brake components
I took the used injectors from a 97 Honda accord.
the computer is adding 25% gas . long fuel trim is 25% and short term is about 10%

yes the problem start after i replaced the injectors

I looked at part numbers between a 97 and 96. They were the same. Since the problem started since you replaced them, I really feel the issue is either a vacuum leak that you are missing or the injectors are different. Is there any way you could check the part numbers and compare?

yes on the injectors there is a number is 4008 and match with the old one so the part is the same

That's good. Did you replace the o-rings on the injectors when you replaced them? Also, when you checked for vacuum leaks, how did you go about it?

the injector at the rail end has a o ring. however at the intake manifold end the injector has not a o ring. there is a ring seal goes in the hole of the intake manifold where the injector goes. i did not replace the o rings or the ring seal i checked for vacuum leak using car cleaner i sprayed on the intake no vacuum leak.
today i tried again to clean the injector i used fuel injector cleaner the chevron brand it was not a success it went worse the computer is adding now 45% short fuel trim and the engine is misfiring rough idle.

Did you remove the injectors again? You know, this almost sounds like a coolant temp sensor issue, but since it started when you replaced the injectors, that leads me away from that possibility. The computer is trying to keep up with the lean mixture... thus the readings you are getting. Is the car blowing any black smoke? I know you hate hearing me say it, but I still think there is a leak. Something is allowing added air into the engine. Unless an O2 sensor is bad, but that leads me back to the idea that is just started this.

Okay, I have avoided asking but feel I have to. Why did you replace the injectors?: What was the car doing?

the car does not blow black smoke when I start the engine it sounds like popping sound and some times it catch and run good for a second or so.
i removed the injectors for the first time to just cleaning them i used carb cleaner after that the injectors stopped spraying fuel. I hooked up to the injectors a syringe at one end and at the other end i hooked up the carb cleaner can there are a lot of video on youtube just enter
"how to clean fuel injectors at home" when i hook up a scanner to the car you will see long fuel trim is at 45%

They all stopped working? Are you getting power to them?

yes they have power to them. they spay gasoline but i think its not enough. they are from the junk yard

It's odd that all wouldn't spray enough. However, with used parts, one can never tell.

by the way thank you for answering my questions and helping me.
when the injectors are off the engine with what chemical we can clean them . I hear paint thinner works is it true?

I wouldn't use that. Go to the parts store and get a quality injector cleaner. That way we know it's safe.

i heard that the cleaners in cans are the best like OTC cleaner?

I agree.

ok i put 4 new injectors. i reset the ECM i drove the car few miles. at idle the short fuel trim is around 4% when i rise the RPM 2500 the short fuel trim goes negative 12%. the long fuel trim is at negative 1.56% . like i said i did not drive the car a lot. is these numbers good?

Yes... How is it running now?

its running good no missing anymore.
ok i want to understand fuel trim today at idle the long fuel trim was at 7.8% and short fuel trim was switching between 3,4,5%.should short fuel trim switch between negative and positive numbers?my car was switching between only positive numbers

The trims are determined by several things... ambient temp, coolant temp, sensor readings, driving conditions, accessories being used. So, it still sounds normal to me.

i m curious what is the value of long term fuel trim at idle for a brand new car.

what parameters the target fuel map has. i know it has load and rpm does it has more than that.?

Long term fuel trims should be close to zero, positive or negative single digits under normal conditions. Short term will change more quickly. They should be aprox between -5% and +5%. As you are aware, fuel trims are basically the amount of time the computer allows the injector to be open to compensate for different driving conditions. STFT therefore change often. LTFT is an average of the STFT. You mentioned that your STFT were changing only in the positive numbers. That is fine. Usually, they don't go above 8 or 9%.

i ve seen the STFT of my car goes above 10 at idle for few second

If it's only for a couple seconds, don't worry. It's fine. When you were getting 45%, that was a concern. The computer was allowing the injector to be open for too long to compensate for the lean fuel mixture.

do you know any book , eBook. resources about fuel trim , advanced fuel trim . i want to read about it

Sorry, I don't. You should be able to find info on the Internet.

can you watch this video on YouTube and tell me what can causes the stumbling

if you type on YouTube search

(91 Accord Cold Start Stumbling)

it should be the first video

Thank you

Is this the one you mean?

http://www.youtube.com/watch?v=QvaIItCLSBo

If so, if it only happens on a cold engine, it could be a few things. You could have a bad coolant temp sensor, a bad IF switch (which is the same as a IAC), weak ignition...

Keep in mind, you are dealing with two different animals with a 91 and a 96.

my 96 accord does not long crank anymore since i replaced the fuel injectors however it intermittent stumbles not always. sometimes it cranks two cycles and stumbles and fires up. sometimes it cranks one cycle stumbles and fires up . sometimes it does not stumbles at all it fires right up

Does it happen regardless if the engine is cold or warm? Have you checked compression? Have you confirmed that the fuel pressure regulator is doing its job?

usually it stumbles after it sits for few hours .and i can hear the compression of the engine but just one compression after that it stumbles.i checked the fuel pressure regulator it good. i did not compression test