Pulsing Idle
07-12-13, 08:19 PM
#26
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Same pipe four times???? I've never seen a four sided pipe before. I was just going by what the vacuum hose diagram showed. I believe those pipes went to the twins when they were on the car, some sort of boost/vacuum information and the rats nest. I don't think they would run solid pipes through the intake.
And basically the video I posted is what the idle does before it reaches operating temp and when it hits operating temp is what you see in the second video.
I also just went down and sprayed the entire area around the UIM and LIM with carb cleaner and nothing happened. I imagine I fixed what ever vacuum leaks I have with the capping.
And basically the video I posted is what the idle does before it reaches operating temp and when it hits operating temp is what you see in the second video.
I also just went down and sprayed the entire area around the UIM and LIM with carb cleaner and nothing happened. I imagine I fixed what ever vacuum leaks I have with the capping.
Last edited by Whitetiger777; 07-12-13 at 08:35 PM.
07-12-13, 10:13 PM
#27
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There are four pipes that run through the LIM. You put caps on both ends of four pipes. The pipes do not see intake manifold vacuum or pressure. The four pipes are a means of controlling the stock twins and the EGR valve via the rat's nest. Since you don't have a rat's nest or twins where are you going to get the vacuum from? Take a piece of four mm hose. Put it on the top nipple either side. Plug the top nipple on the other side with your thumb. Suck on the hose creating a vacuum. Let go with the thumb. You capped both ends of four pipes and proclaimed you fixed a vacuum leak. You did not fix anything. JDM intake manifolds don't have any pipes going through them. They go around.
07-13-13, 12:36 AM
#28
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So, I managed to drive the FD for a bout an hour. A side from the idle wanting to die on me that car seemed to work okay. Then I got out of the car for 5 min, when I got back in to start it, it did that thing where it jumps up to 3k rpm, them fluctuates between 1.5k and 2k rpm. I then drove on the freeway for about 35 min and by the time I got off the freeway the idle was fine. WHAT THE HELL IS WRONG WITH MY CAR?????
07-13-13, 12:38 AM
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There are four pipes that run through the LIM. You put caps on both ends of four pipes. The pipes do not see intake manifold vacuum or pressure. The four pipes are a means of controlling the stock twins and the EGR valve via the rat's nest. Since you don't have a rat's nest or twins where are you going to get the vacuum from? Take a piece of four mm hose. Put it on the top nipple either side. Plug the top nipple on the other side with your thumb. Suck on the hose creating a vacuum. Let go with the thumb. You capped both ends of four pipes and proclaimed you fixed a vacuum leak. You did not fix anything. JDM intake manifolds don't have any pipes going through them. They go around.
07-13-13, 06:32 PM
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So the pulsing idle is back with a vengeance. Someone please help me here, I'm really starting to get pissed off at the car. I've got a TPS on the way hoping that will help. I'm wondering if I didn't clean the IAC valve enough or something. Is there a write up on the specifics of cleaning that damn thing? Or are they known to go bad????
07-14-13, 10:45 AM
#33
a block off plate kit would be a great place to start. you still have the split air pipe it looks like. the thing that the air pump fed into and it looks uncapped and open. it seems as though a vacuum leak is for sure what you are chasing after. since you are singled already, this should be trivial. take off the uim and look around. use this https://www.rx7club.com/3rd-generati...-turbo-749702/ and you will be very easily able to find the leak.
the 4 pipes that you capped off, those pipe do nothing more than pass through the lim. if you could shrink down small enough, you could walk in on one side and out the other. they are just a means of connected the vacuum lines from the twins to whatever under the intake manifold so that the hose dont need to wrap around. pretend as is they werent even there.
as stated earlier, they see no vacuum or anything. they just exist.
the 4 pipes that you capped off, those pipe do nothing more than pass through the lim. if you could shrink down small enough, you could walk in on one side and out the other. they are just a means of connected the vacuum lines from the twins to whatever under the intake manifold so that the hose dont need to wrap around. pretend as is they werent even there.
as stated earlier, they see no vacuum or anything. they just exist.
07-14-13, 11:22 AM
#34
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Where abouts did you find your vacuum leak. I've sprayed carb cleaner all around the intake manifold and nothing happened. I actually posted a image I've been using earlier in the thread that shows the vacuum hosing for a single set up. It has been very useful in helping me understand what is going on under the UIM. I just feel like I've tried everything to find a vacuum leak and am coming up with nothing. The split pipe you mentioned is hooked up to nothing on the back either. There is no hose that goes down to a cat.
I tried cleaning out the IAC valve again last night, so we'll see how much that fixes things. The first time I cleaned it, the problem went away for a few days.
I tried cleaning out the IAC valve again last night, so we'll see how much that fixes things. The first time I cleaned it, the problem went away for a few days.
07-14-13, 02:49 PM
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Yup, cleaning the IAC didn't help after all and I have no idea where my vacuum leak could be. I've tried the spraying carb/choke cleaner all over the place.
07-14-13, 06:24 PM
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Also, I'm not saying that it's not, but if it is a vacuum leak, wouldn't the idle be doing this all the time instead of just when the car is fully warmed up?
07-14-13, 06:47 PM
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So i just got done spraying the crap out of my engine bay with carb/choke cleaner. Everywhere I could think of, under the UIM, the throttle body, behind the IM, down by where the runners go into the block, checked my hoses based on the single turbo diagram. Nothing....Idle continued to pulse. No chenges in idling even for a moment. Unless someone has another idea of where to check for vacuum leaks, I'm at a loss. I just want a good running car, this fluctuating idle is not good in heavy traffic and the back to back red lights we get here in Los Angeles. This is my only car.
Last edited by Whitetiger777; 07-14-13 at 06:50 PM.
07-14-13, 11:41 PM
#38
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So I tried to check my MAP today with a volt meter, but I couldn't get the needs into the back of the plug, I even tried sicking safety pins in there and using those to connect to the volt meter, but couldn't get a reading. I was going off of the manual page F-167 and guessing by the pictures the A terminal is the one closest to the fire wall.
07-15-13, 01:03 AM
#39
My FD had this same hunting idle, it turned out to be the gasket that sits between the intake manifold and the engine block. If I were you I would order a lower intake manifold gasket and upper intake manifold gasket, as well as throttle gaskets, then spend a weekend replacing them all from start of the throttle through to the block.
07-15-13, 01:31 AM
#41
Hard to say for sure if you have other issues going on at the same time that you don't know about, but I can confirm that mine was significantly punchier with the stock twins after replacing the LIM gasket.
07-15-13, 01:41 AM
#42
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Do you have a PFC and Datalogit? I watched the video again and it looks like your fuel cut is set too low. Also check your TPS with the Datalogit. You can see the PIM, should be between 3000 and 4000 at idle on a stock port. Hope this helps.
07-17-13, 02:39 PM
#43
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I do have a PFC, but I don't have a datalogit. I've not changed anything on the PFC since I got the car and this problem just started up about a month or 2 ago. The car also came with a street port engine, stock primary injectors and, I believe, 1300cc secondaries.
I currently have coming to me in the mail a TPS, a IAC valve, a upper intake manifold gasket, and lower intake manifold gasket and a throttle body gasket.
Hopefully at least one of these items will get my car back into daily running form.
I currently have coming to me in the mail a TPS, a IAC valve, a upper intake manifold gasket, and lower intake manifold gasket and a throttle body gasket.
Hopefully at least one of these items will get my car back into daily running form.
Last edited by Whitetiger777; 07-17-13 at 02:44 PM.
07-17-13, 02:42 PM
#44
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P.S. I ordered up all the gaskets from Atkins Rotary and they were totally cool. I told them I was on the rx7club forums and they knocked off my shipping costs.
07-19-13, 11:04 AM
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Fortunately my rats nest is gone, so it was real easy to get a 10 mm socket wrench in there to get the nuts off. I then sprayed MAF sensor in there, then I filled it with MAF sensor cleaner and worked the plunger with my finger until it started sliding smoothly.
07-20-13, 12:31 AM
#48
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Thank you! That makes sense and easy enough. I think I will be redoing the vacuum lines this weekend. I will clean everything then too. It is so weird, I drove it just now and it was perfect, amazing, an absolute dream, but last night would have no power and sputter/bog down if you pushed on the pedal more than about 30%.
Only difference is the ambient temperature outside. It's a really hot day and was cool last night.
-David
Only difference is the ambient temperature outside. It's a really hot day and was cool last night.
-David
