rough idle when cold hard start
02-17-2009, 02:11 PM
#1
rough idle when cold hard start
Hey guys, trying to get the VE road worthy again,after many many years of being a really big yard ornament, need some suggestions on where to look to try and figure out why the car has a rough idle and hard to start. Ive been searching for a few days now, I have tried/replaced just about everything that has been mentioned by everyone so far for a fix,though the problem is still there.
Problem (this is sporadic):When turning the car over it takes a few tries with turning the key off and on for it to start,when it does finally start the car idles like the timing is very retarded,if I try to give it some gas the rpm's will go up but not real smooth,almost like its running on 3 injectors.I can practically hear the pistons firing out of the intake filter,after the car is running and "if it doesn't die out" as the car warms up, the noise from the intake goes away and the engine idles smooth like normal,when I give it gas the engine revs nice and smooth up and down,idles right at 750. I have zero codes in the ecu
After the car is some what warmed up, it drives smooth,gear changes are nice and smooth and accelerates like normal. WOT the car hauls A**.
I say sporadic because it seems that it does it after the car has sat overnight.
"example"
Yesterday morning get up about 8am go out to the car does what I mentioned, Didn't really feel like messing with it so I let it sit all day til about 10pm that night tried it again,same results.this morning I get up try it again and vroom car starts right up no bogging,rough idle, nothing?
Things Ive tried/changed:
Replaced the 3 rear coil packs (JY specials). front 3 are brand new This seemed to help my bucking problem.but that another problem.
coolant temp sensor
fuel filter
spark plugs
oil change
cleaned the iacv "wasnt really dirty"
Problem (this is sporadic):When turning the car over it takes a few tries with turning the key off and on for it to start,when it does finally start the car idles like the timing is very retarded,if I try to give it some gas the rpm's will go up but not real smooth,almost like its running on 3 injectors.I can practically hear the pistons firing out of the intake filter,after the car is running and "if it doesn't die out" as the car warms up, the noise from the intake goes away and the engine idles smooth like normal,when I give it gas the engine revs nice and smooth up and down,idles right at 750. I have zero codes in the ecu
After the car is some what warmed up, it drives smooth,gear changes are nice and smooth and accelerates like normal. WOT the car hauls A**.
I say sporadic because it seems that it does it after the car has sat overnight.
"example"
Yesterday morning get up about 8am go out to the car does what I mentioned, Didn't really feel like messing with it so I let it sit all day til about 10pm that night tried it again,same results.this morning I get up try it again and vroom car starts right up no bogging,rough idle, nothing?
Things Ive tried/changed:
Replaced the 3 rear coil packs (JY specials). front 3 are brand new This seemed to help my bucking problem.but that another problem.
coolant temp sensor
fuel filter
spark plugs
oil change
cleaned the iacv "wasnt really dirty"
02-17-2009, 09:19 PM
#4
I'm going to put my lunch money on it being dirty injectors. After the car sits that long, the fuel that was in the lines has varnished and the injectors are gummed up.
Run a can of BG44K through the car with some 93 octane and see how that does.
Run a can of BG44K through the car with some 93 octane and see how that does.
02-18-2009, 12:47 AM
#5
Senior Member
Join Date: Apr 2008
Location: Surrey, B.C
Posts: 1,355
did u check ur EGR if it is working properly? and take off the harness on left side of the engine beside VTCs for hidden injectors and see if it makes any difference or not and do that with other 3 injectors too...and then report bak...plus check the diaphragm in the EGR and see if u can push it up....wen u push with ur fingers engine should stall like its jus gonna shutt down...if it doesn't do anything u got a BAD EGR...but before take the vacuum hose off from EGR tho..
Last edited by burhan92SE; 02-18-2009 at 02:53 AM.
02-18-2009, 06:49 AM
#6
Senior Member
Join Date: Feb 2008
Posts: 488
im thinking the same thing, seems like when the injectors start to fail, problems like this come and go until they fail completely
maybe even check the tps harness for corrosion. it wont make the car run like its only on 3 injectors, but it will make it harder to start if the wires or sensor itself is bad. It could be possible you have a couple of different problems on hand. Being a lawn decoration for a few years i wouldnt be suprised
Last edited by maximaman1313; 02-18-2009 at 06:52 AM.
02-18-2009, 07:02 AM
#7
Senior Member
Join Date: Feb 2008
Posts: 488
another thing. being that it sat for so long, I would reccomend using some seafoam. Use some bg44k like matt suggested with 93 octane.
You can also put about half a can into the oil, and then suck the other half through the brake booster. Directions are on the can, and I believe there is a sticky somewhere in maintence on how to use seafoam.
What I like to do is put about half a can into the oil. Ill drive the car with it in there for a few hundred miles. Then when that comes, Ill drive the car for maybe 20 minutes, get it hot. Park it in driveway still running, and begin sucking the seafoam in through the brake booster hose, when im out of seafoam, shut the car off and let the seafoam do its work for 15minutes. Then i'll start it up and let it idle for 10-15minutes, you can rev it but not much, just a slight blip on the throttle. It should be pooring out blue smoke and all the carbon its burning out of your motor. Then go take it for a spirited drive. You'll smoke out your neighborhood, but this is normal. more smoke, usually the more crap its cleaning up. After driving around, ill change the oil.
might not help the actual problem, but it will help remove deposits inside the motor and in the intake, possibly making it run smoother etc..
I still am thinking your injectors are on their way out tho
You can also put about half a can into the oil, and then suck the other half through the brake booster. Directions are on the can, and I believe there is a sticky somewhere in maintence on how to use seafoam.
What I like to do is put about half a can into the oil. Ill drive the car with it in there for a few hundred miles. Then when that comes, Ill drive the car for maybe 20 minutes, get it hot. Park it in driveway still running, and begin sucking the seafoam in through the brake booster hose, when im out of seafoam, shut the car off and let the seafoam do its work for 15minutes. Then i'll start it up and let it idle for 10-15minutes, you can rev it but not much, just a slight blip on the throttle. It should be pooring out blue smoke and all the carbon its burning out of your motor. Then go take it for a spirited drive. You'll smoke out your neighborhood, but this is normal. more smoke, usually the more crap its cleaning up. After driving around, ill change the oil.
might not help the actual problem, but it will help remove deposits inside the motor and in the intake, possibly making it run smoother etc..
I still am thinking your injectors are on their way out tho
02-18-2009, 08:33 AM
#8
I wouldn't recommend any of that stuff until the engine is running on all 6 cyls.
cleaning the manifold and such will stress an already stressed system and may keep it from running at all for a while.
you should, however, change the oil ASAP if you haven't. That old oil has broken down and all of its anti-corrosion properties and such are gone.
cleaning the manifold and such will stress an already stressed system and may keep it from running at all for a while.
you should, however, change the oil ASAP if you haven't. That old oil has broken down and all of its anti-corrosion properties and such are gone.
02-18-2009, 08:49 AM
#9
Senior Member
Join Date: Jan 2007
Location: NJ
Posts: 475
i would recommend a good high mileage oil as to they have some of the best additives. i would run that for a couple hundred miles then do another oil and filter change.
:edit: fixed
:edit: fixed
Last edited by 300zmax; 02-18-2009 at 02:10 PM.
02-18-2009, 01:49 PM
#10
ok thanks guys I will try those things in the next couple of days.
"Matt93SE" where can I get the BG44k at? I was gonna grab some seafoam on the way home today. the oil was changed this saturday along with the other thigns i mentioned above.
"Matt93SE" where can I get the BG44k at? I was gonna grab some seafoam on the way home today. the oil was changed this saturday along with the other thigns i mentioned above.
02-18-2009, 05:26 PM
#11
I picked it up at the local CarQuest, but other auto parts stores have it.
It's quite a bit more expensive than the regular injector cleaners, but it's worth it.
Because of the price, they keep it behind the counter- go up to a "computer user" (note I didn't say parts salesman......) and ask them for it. I think autozone and Napa both carry it...
It's quite a bit more expensive than the regular injector cleaners, but it's worth it.
Because of the price, they keep it behind the counter- go up to a "computer user" (note I didn't say parts salesman......) and ask them for it. I think autozone and Napa both carry it...
02-19-2009, 11:00 AM
#12
Junior Member
Join Date: Oct 2002
Posts: 87
After reading the thread title and your original post, I thought it sounded like injector problems as well.
However, I am a bit in disbelief that our maxima injectors commonly actually fail internally, or commonly become "clogged". Our cars have a pretty decent fuel filter after all. I have experienced on two OEM sets (from 3rd gen maximas) displaying high ohm readings, that the problem was not internal failure of the injector at all, but was just surface corrosion developing on the copper conductors. This layer of copper corrosion will not conduct electricity... at all. And must be removed to restore low-ohm readings and proper injector function. This corrosion can be repaired completely by scraping the corrosion off without even removing the injectors from the engine. (However to access some of them, removing upper intake manifold/plenum is required. Some can be reached (on VG motor at least) without removal of upper intake/plenum).
Fortunately, the repair is much cheaper than buying new injectors ($$$$$). And, buying cleaning fluids to put in your gas tank, or even having a mechanic to a special injector flush/cleaning would not get you anywhere if your problem is really corroded injector electrical connectors. So, I would check the ohm readings of yours first, at least the easily accessible ones. Just remove the electrical connector, and use an ohm-meter on the two copper terminals sticking out of the injector.
I cleaned the corrosion off a few of mine (the easily accessible ones in the front
) and have 2-3 left that still need cleaning, and the symptoms are exactly like you describe - intermittent miss, usually only occurring at idle and after a cold start. If the engine misses when you are actually driving under load it is not good for it at all and kills your fuel economy.
However, I am a bit in disbelief that our maxima injectors commonly actually fail internally, or commonly become "clogged". Our cars have a pretty decent fuel filter after all. I have experienced on two OEM sets (from 3rd gen maximas) displaying high ohm readings, that the problem was not internal failure of the injector at all, but was just surface corrosion developing on the copper conductors. This layer of copper corrosion will not conduct electricity... at all. And must be removed to restore low-ohm readings and proper injector function. This corrosion can be repaired completely by scraping the corrosion off without even removing the injectors from the engine. (However to access some of them, removing upper intake manifold/plenum is required. Some can be reached (on VG motor at least) without removal of upper intake/plenum).
Fortunately, the repair is much cheaper than buying new injectors ($$$$$). And, buying cleaning fluids to put in your gas tank, or even having a mechanic to a special injector flush/cleaning would not get you anywhere if your problem is really corroded injector electrical connectors. So, I would check the ohm readings of yours first, at least the easily accessible ones. Just remove the electrical connector, and use an ohm-meter on the two copper terminals sticking out of the injector.
I cleaned the corrosion off a few of mine (the easily accessible ones in the front
) and have 2-3 left that still need cleaning, and the symptoms are exactly like you describe - intermittent miss, usually only occurring at idle and after a cold start. If the engine misses when you are actually driving under load it is not good for it at all and kills your fuel economy.
04-07-2009, 12:25 PM
#16
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Join Date: Feb 2008
Posts: 488
04-07-2009, 01:52 PM
#17
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