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They are a pain when they have a problem, but most cars are way worse than these to fix. I used to think the same thing until I realized how many cars were waaaay worse, then I realized how simple and easy these cars really are.
man this cars giving a hard time.my 07 scion never give me this trouble. I will do a smoke test to see if i. Can fine this leak.
man this cars giving a hard time.my 07 scion never give me this trouble. I will do a smoke test to see if i. Can fine this leak.
I'd start by installing a washer on the PCV valve. You know you have a leak there since it has no sealing washer so why look for another problem when you know of one that may be the whole problem? Also, since the PCV valve is pretty low on the engine block, water might get in if it doesn't have a seal. That's not going to fix the IAT sensor code but it's still a problem that needs to be fixed.
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Re: Idle air control valve
I don't own a 7th gen but my mom does (2004 VP). It only has 85k miles on and she purchased it at 50k miles about seven years ago. It hasn't had any issues with the IACV. I'm telling you that because you may need another PCM (ecu). If it is indeed a PCM issue you may need to have a Honda dealership reprogram a new or used one. Others here may chime in to tell you what's involved if the PCM is the issue.
Most of my experience is with 5th and 6th gens and if the ECU is swapped it doesn't require reprogramming. Please understand that I am not telling you the PCM is definitely the issue, it's just a possibility.I have no idea what the cost would be to replace one in a 7th gen.
Did you or anyone else smoke test the engine for vacuum leaks?
Also, try to find in the service manual or other reliable source on how to measure voltage on the IACV and IAT harness plugs. Maybe there is a short or improper voltage?
Did you try unplugging the IACV while idling to see if there is a change in idle?
I'd start by installing a washer on the PCV valve. You know you have a leak there since it has no sealing washer so why look for another problem when you know of one that may be the whole problem? Also, since the PCV valve is pretty low on the engine block, water might get in if it doesn't have a seal. That's not going to fix the IAT sensor code but it's still a problem that needs to be fixed.
i just installed a wash on it and the problem is still there.
I don't own a 7th gen but my mom does (2004 VP). It only has 85k miles on and she purchased it at 50k miles about seven years ago. It hasn't had any issues with the IACV. I'm telling you that because you may need another PCM (ecu). If it is indeed a PCM issue you may need to have a Honda dealership reprogram a new or used one. Others here may chime in to tell you what's involved if the PCM is the issue.
Most of my experience is with 5th and 6th gens and if the ECU is swapped it doesn't require reprogramming. Please understand that I am not telling you the PCM is definitely the issue, it's just a possibility.I have no idea what the cost would be to replace one in a 7th gen.
Did you or anyone else smoke test the engine for vacuum leaks?
Also, try to find in the service manual or other reliable source on how to measure voltage on the IACV and IAT harness plugs. Maybe there is a short or improper voltage?
Did you try unplugging the IACV while idling to see if there is a change in idle?
ok. I did a smoke test myself but it was with a sigar in my mouth and blow the smoke in a hose connected to the brake booster hose but i didn't find nothing. I will make me a smoke machine and do another test soon and post if i find anything. I unplugged the idle air Control valve while the engine idling and it made a big difference. I saw a video with an old civic si that was having trouble with idling and he chaneged everything he know that could cause the issue but nothing changes until he replace the ECU.
ok. I did a smoke test myself but it was with a sigar in my mouth and blow the smoke in a hose connected to the brake booster hose but i didn't find nothing. I will make me a smoke machine and do another test soon and post if i find anything. I unplugged the idle air Control valve while the engine idling and it made a big difference. I saw a video with an old civic si that was having trouble with idling and he chaneged everything he know that could cause the issue but nothing changes until he replace the ECU.
i have a ECU with key and key cylinder at home i bought on ebay last year so if i do a smoke test and get nothing from it i will try put in the ECU and let you guys know if anything changes or not.
yup it did came back. I will do a smoke test some time this week or next week.i will get some parts to make the smoke machine then i will do it and let you guys know.
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Re: Idle air control valve
Originally Posted by Tracecross30
i have a ECU with key and key cylinder at home i bought on ebay last year so if i do a smoke test and get nothing from it i will try put in the ECU and let you guys know if anything changes or not.
did you try idle with iacv unplugged?
check harness voltage and continuity?
yup it did came back. I will do a smoke test some time this week or next week.i will get some parts to make the smoke machine then i will do it and let you guys know.
Are you having an issue with the way it idles or runs? Also, you don't need a smoke machine to do a smoke test, you can do it with a cigar, you just blow the smoke into one of the vacuum lines. Plug off the throttle body somehow first because on these cars the IAC valve is fully open with the engine off, so if you don't plug the throttle body off you won't be able to build any pressure in the manifold, all the smoke will escape through the throttle body.
Are you having an issue with the way it idles or runs? Also, you don't need a smoke machine to do a smoke test, you can do it with a cigar, you just blow the smoke into one of the vacuum lines. Plug off the throttle body somehow first because on these cars the IAC valve is fully open with the engine off, so if you don't plug the throttle body off you won't be able to build any pressure in the manifold, all the smoke will escape through the throttle body. https://www.youtube.com/watch?v=zMok2y05jNE
i tried this before with the throttle bod on the manifold but i didn't see any smoke escaping anywhere. And yes, I'm having idling issues. It surge a little when i stop at the light or if i stop in general. The idle would not go to narmol like it should. If i could post makeva video and post it here so you would see what I'm talking about. I'm having this issue from last year and it not getting anywhere.
i tried this before with the throttle bod on the manifold but i didn't see any smoke escaping anywhere. And yes, I'm having idling issues. It surge a little when i stop at the light or if i stop in general. The idle would not go to narmol like it should. If i could post makeva video and post it here so you would see what I'm talking about. I'm having this issue from last year and it not getting anywhere.
Something I forgot to mention is that the brake booster could also cause a vacuum leak that won't be detected by brake clean or a smoke machine, plugging off the vacuum line to the brake booster and seeing if it idles correctly is worth a try. I presume you tried spraying brake clean where the manifold bolts to the head and around the fuel injectors too?
When did this idle issue start? Did the car have this issue when you bought it or did it start having the issue while you owned it?
Something I forgot to mention is that the brake booster could also cause a vacuum leak that won't be detected by brake clean or a smoke machine, plugging off the vacuum line to the brake booster and seeing if it idles correctly is worth a try. I presume you tried spraying brake clean where the manifold bolts to the head and around the fuel injectors too?
When did this idle issue start? Did the car have this issue when you bought it or did it start having the issue while you owned it?
yes, i sprayed brake clean around the areas you just mentioned. I started having the issue since i owned the car.i will try unplugging the brake booster hose and see if it makes any different.
yes, i sprayed brake clean around the areas you just mentioned. I started having the issue since i owned the car.i will try unplugging the brake booster hose and see if it makes any different.
so today i swapped out the ECU thats in my car this one i bought on Ebay last year but it didn't seem to work. It was only turn over but wont start. It read the key and everything but just wont start. Then when i carefully look at the numbers on
Both ECU,the top numbers are the same on both of them but the bottom set of numbers are different. Also after i put back my ECU just now noticed after i got off work and start the car the light in the dash are not as bright as they should. The light is not bright at all but If you look to the left side at the pic you can see that theres a big difference. Before i move forward with this car I'm goi
ng backwards instead.
so today i swapped out the ECU thats in my car this one i bought on Ebay last year but it didn't seem to work. It was only turn over but wont start. It read the key and everything but just wont start. Then when i carefully look at the numbers on
Both ECU,the top numbers are the same on both of them but the bottom set of numbers are different. Also after i put back my ECU just now noticed after i got off work and start the car the light in the dash are not as bright as they should. The light is not bright at all but If you look to the left side at the pic you can see that theres a big difference. Before i move forward with this car I'm goi
ng backwards instead.
Only the numbers on the top of the ECU need to match, both of those ECUs are part number 37820-PLR-L05 and therefore they are functionally identical. It will not start with a new ECU unless you have it flashed to your immobilizer by a locksmith or the dealer. ECUs very rarely fail unless something goes horribly wrong with the electrical system like the alternator falling off, but since the car had this problem since you bought it who knows what happened previously. I would disconnect and plug off the brake booster vacuum line and see if the idle issue goes away before replacing the ECU though, it's much more likely to be the problem. The brake booster can fail internally and always allow air to pass through, causing a vacuum leak.
Only the numbers on the top of the ECU need to match, both of those ECUs are part number 37820-PLR-L05 and therefore they are functionally identical. It will not start with a new ECU unless you have it flashed to your immobilizer by a locksmith or the dealer. ECUs very rarely fail unless something goes horribly wrong with the electrical system like the alternator falling off, but since the car had this problem since you bought it who knows what happened previously. I would disconnect and plug off the brake booster vacuum line and see if the idle issue goes away before replacing the ECU though, it's much more likely to be the problem. The brake booster can fail internally and always allow air to pass through, causing a vacuum leak.
to be honest, i changed the brake booster about two months ago. I took it to a shop to check it when i was having the same issue that I'm having now. The check for vacuum leak and said that they didn't find nothing. They left the hose off the booster and almost ran in someone car because i didn't have any brakes at all and so replace it because in the winter realized that when i start the car there was always i tight brake pedal so i got one from a junkyard and it was all good. But yeah,i think it was you or someone else said to remove the brake booster hose while the engine is idling to see if anything changes..
to be honest, i changed the brake booster about two months ago. I took it to a shop to check it when i was having the same issue that I'm having now. The check for vacuum leak and said that they didn't find nothing. They left the hose off the booster and almost ran in someone car because i didn't have any brakes at all and so replace it because in the winter realized that when i start the car there was always i tight brake pedal so i got one from a junkyard and it was all good. But yeah,i think it was you or someone else said to remove the brake booster hose while the engine is idling to see if anything changes..
When i first bought thus car the only issue i was having was the engine overheating on me and took it apart and have the head reconditioned,replace one bend valve and replace the valve stem seals and i replaced the rings since i was already that close but months after all that work done to it i started having these vibrations and pcv valve code p1505 and stuff. What you think about the pic i post with light in the dash that dimmed after i remove the ECU today .
to be honest, i changed the brake booster about two months ago. I took it to a shop to check it when i was having the same issue that I'm having now. The check for vacuum leak and said that they didn't find nothing. They left the hose off the booster and almost ran in someone car because i didn't have any brakes at all and so replace it because in the winter realized that when i start the car there was always i tight brake pedal so i got one from a junkyard and it was all good. But yeah,i think it was you or someone else said to remove the brake booster hose while the engine is idling to see if anything changes..
If the problem is still identical with another booster that's probably not the problem then. Also, to be clear, you cannot simply disconnect the brake booster hose, you must plug the hole in the hose as well so air can not enter the manifold, leaving the hose off will cause a massive vacuum leak.
If the problem is still identical with another booster that's probably not the problem then. Also, to be clear, you cannot simply disconnect the brake booster hose, you must plug the hole in the hose as well so air can not enter the manifold, leaving the hose off will cause a massive vacuum leak.
ok understood well. Whst you think about the light in the picture i send earlier?
When i first bought thus car the only issue i was having was the engine overheating on me and took it apart and have the head reconditioned,replace one bend valve and replace the valve stem seals and i replaced the rings since i was already that close but months after all that work done to it i started having these vibrations and pcv valve code p1505 and stuff. What you think about the pic i post with light in the dash that dimmed after i remove the ECU today .
Oh, I misunderstood you to say that it had these issues since you got it. I have no idea why the left side of the gauges dimmed, maybe a bulb burned out. Are the lights on the gauges only dim with the replacement ECU plugged in? Also, did you have that ECU programmed to your immobilizer? It won't start if you didn't.
Oh, I misunderstood you to say that it had these issues since you got it. I have no idea why the left side of the gauges dimmed, maybe a bulb burned out. Are the lights on the gauges only dim with the replacement ECU plugged in? Also, did you have that ECU programmed to your immobilizer? It won't start if you didn't.
ok. I have these issues after i rebuild the engine. About a month after i bought it. It wont start so i removed the ebay Ecu and put back mine in the car.
ok. I have these issues after i rebuild the engine. About a month after i bought it. It wont start so i removed the ebay Ecu and put back mine in the car.
if i change the engine,will i need to change the ECU as well?
if i change the engine,will i need to change the ECU as well?
Not if you replace the engine with the same type that was in it, there is a code stamped into the block where the engine and transmission meet. D17A1 is non VTEC, D17A2 is VTEC, etc. If you replace it with a different type you will need to get a matching ECU. Why do you want to change the engine?
Not if you replace the engine with the same type that was in it, there is a code stamped into the block where the engine and transmission meet. D17A1 is non VTEC, D17A2 is VTEC, etc. If you replace it with a different type you will need to get a matching ECU. Why do you want to change the engine?
I'm thinking of getting rid of the engine or replace the head gasket,also if I'm going to replace the head gasket,i will double check the rings to see if any errors on how they were installed.
and yeah,i know what you saying about D17A1 and D17A2 mine is D17A2.
Last edited by Tracecross30; May 12, 2020 at 10:35 PM.
Reason: More information
I'm thinking of getting rid of the engine or replace the head gasket,also if I'm going to replace the head gasket,i will double check the rings to see if any errors on how they were installed.
and yeah,i know what you saying about D17A1 and D17A2 mine is D17A2.
Because I'm thinking if i change the engine it might solve my problem I'm having now.just my thinking.i could be wrong. But when problems occur,we think of ways to solve them.
I'm thinking of getting rid of the engine or replace the head gasket,also if I'm going to replace the head gasket,i will double check the rings to see if any errors on how they were installed.
There's no way I would consider changing the engine because of this issue unless you have a reason to, such as low compression. Did you do the engine overhaul or did someone else do it? Since this problem started right after the rebuild I am wondering if a mistake was made during reassembly such as installing the intake manifold gasket backwards or something, which causes this exact idle problem. Ask me how I know about that Also, I am wondering if wiring may have been damaged while the work was being performed, which could easily explain the IAT code. Also, there is no need to tear the engine down to check for ring issues, you can do a compression test to make sure the rings and valves are sealing correctly.
There's no way I would consider changing the engine because of this issue unless you have a reason to, such as low compression. Did you do the engine overhaul or did someone else do it? Since this problem started right after the rebuild I am wondering if a mistake was made during reassembly such as installing the intake manifold gasket backwards or something, which causes this exact idle problem. Ask me how I know about that Also, I am wondering if wiring may have been damaged while the work was being performed, which could easily explain the IAT code. Also, there is no need to tear the engine down to check for ring issues, you can do a compression test to make sure the rings and valves are sealing correctly.
i rebuild it myself. Couldn't pay for that as i just had my 07 scion wrecked so i couldn't afford some better at the moment.i did a compression test and i was getting read like between 75psi and 80 on all of them..the car starts fine but its just the rough idling, sureg idling and the IAT issues and maybe because of these issues,I'm burn more gas.cant wait to have the issues solve mon.
i rebuild it myself. Couldn't pay for that as i just had my 07 scion wrecked so i couldn't afford some better at the moment.i did a compression test and i was getting read like between 75psi and 80 on all of them..the car starts fine but its just the rough idling, sureg idling and the IAT issues and maybe because of these issues,I'm burn more gas.cant wait to have the issues solve mon.
since i have vacuum test done on it twice one by the dealer and the other by shop but none find anything so i was thinking that why do a 3rd test for vacuum leak but I'm going to do what you said do about the brake booster hose tomorrow and let you know.
Also, I am wondering if wiring may have been damaged while the work was being performed, which could easily explain the IAT code. Also, there is no need to tear the engine down to check for ring issues, you can do a compression test to make sure the rings and valves are sealing correctly. 
