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Idle issues after head gasket replacement

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May be worth checking in the settings of the hand controller, under the airflow setting. I had accidently changed mine from sr20 to vq35 iirc. This made me have a similar idle to what your describing. Worth a look.
 
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If you go all the way back you should have monitor, settings, and information I think. Its in settings on mine. Ill double check and get back to you though.
 
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I checked, but I don't have anything for airflow. I can take a pic of it for you, but I won't be able to upload it until I get home.

I did go to the hobby shop and rented out a bay for an hour. I ended up unplugging a connector that was installed on the intake manifold. Unplugging it made the car idle perfectly, no surging or hunting at all. The pic below shows where it is:



I'm guessing that plug has something to do with the airflow sensor. I believe my Power FC is the D-Jetro version since I don't have a AFM/MAF connected near the intake filter. Is there a setting I can go into on my hand controller that I might be able to mess with to get the car to idle right with the sensor plugged in? As far as a airflow option, I can't find one anywhere on the hand controller.

I got to thinking, while my car was waiting for the parts for the head gasket replacement, it was sitting down in the shop for about 2 weeks with the battery disconnected. I'm guessing that may have reset the map that was on my Power FC. It's strange though, the settings all look familiar. Perhaps it only had a few things changed from the base map, or perhaps it was never mapped at all? I don't know.
 
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Got home and checked over a few things. Noticed it was still surging even with the plug undone. I undid the TPS plug and noticed that the wiring was looking brittle. Upon closer examination, the middle wire was real frayed, then it just broke off. Looks like I'll need to figure out how to repin the connector or just get a new one. It seems never ending with this car.
 
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It's gotta be the TPS or the TPS loom (I hope lol). I cut off the plug and had to repin the connector. Once done, I started up the car. At first it seems like it was running just fine. It was doing its usual cold star idling, around 1300 rpms, then it was dropping down to around 950 rpms. I gave it some throttle, stayed up. Did it a few more times, then on the 5th or 6th time the idle started to surge down to 500 then up to 1300.


Gonna stop by the hobby shop and use their meter to check the voltage tomorrow. Think I may be in the market for a new TPS and possibly the loom.
 
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Really? I guess I can give it a little more slack, but it doesn't seem that tight to me when I press on it.

As far as the TPS issue, I unplugged it this morning when I started up the car and it was still surging. It feels like I'll never get to the bottom of this issue. Everytime I do something that seems to make the issue better, the next day it doesn't help. I really wish I was back in the states and my close friend (who's been a mechanic for like 30 years) would take a look at it for me. I've got it scheduled today to be looked at, again. Hopefully I'll be able to get to the bottom of this issue.
 
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There is a increase in the clean threaded adjustment on the cable tensioner, they really don't need to be adjusted that much. There should be a easy amount of slack in the cable.

TBH, I would look at your tune as I know the Power FC is renowned for a slight hunt on idle, I think you need to get it to someone who can put it on the rollers and look at your maps.
 
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There is a increase in the clean threaded adjustment on the cable tensioner, they really don't need to be adjusted that much. There should be a easy amount of slack in the cable.

TBH, I would look at your tune as I know the Power FC is renowned for a slight hunt on idle, I think you need to get it to someone who can put it on the rollers and look at your maps.
I definitely do need to get it to a tuner. That is in the plans, but as of right now, I cannot afford the £300+ to get it mapped properly. Once I do, it will be done.

As far as the idle hunt, before getting the head gasket replaced, the car ran perfectly (besides the fact the coolant and oil mixing). It never had an issue idling. Now that I got the car back, the idle will hunt/surge every time I start it up. It eventually goes away after 15 or so minutes, but I just don't have the time to allow it to run for that long before driving. There is the possibility that the original maps were lost. When I dropped the car off to get repaired, he had the head off within the first couple of hours. Of course he had the battery disconnected. The car sat with the battery disconnected for a good 2 weeks because I was waiting on all the parts to come in from the US. But even with the maps being lost, wouldn't it only need to do the idle hunt once? I've done it a few times with no success.

Is that a Greddy copy plenum BTW?
As far as it being a Greddy copy, I'm not 100% sure. I know the intake piping has a Greddy stamp on it, but as far as it being a copy or genuine, I have no idea. I like Greddy as a brand, so it made me happy seeing I had some in the car, even if they aren't all genuine.
 
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Well, took the car to the shop and didn't find the cause to the issue. The TPS checked out just fine. Had to adjust it slightly. It looks like all that is left is to wait until I can get it to a tuner to get mapped. Not sure when that'll be. I'll also need to get an exhaust manifold. Not sure on what else to try. I'll just let it run for 15 or so minutes before I drive it.
 

Jay

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is your blow off valve (dump valve) vent to atmosphere, or recirculated? removed entirely? the sr engine is picky when it comes to bov options. my bov is vta and occasionally i have similarish problems to yours, plus stalling sometimes when revs fall after blipping accelerator. all this can be attributed to vent to atmosphere bov. my mapper told me its the price i pay for the noise. (recirc and remap coming in new year)
 
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How can I tell if my bov vents to atmosphere or is recirculated?

I was checking the PFC the other day and unplugged and checked all the wires. One wire seemed a little crimped, I think it's coming in from the MAP sensor. I reconnected it and fired up the car. I noticed that my air temp reading on the PFC hand controller was at -33C. I let the car run up and it didn't do the idle surging. I messed with the wire that was pinched a little and the air temp reading came back. I turned off the car and let it cool down. When I fired it back up, the air temp reading was spot on, but the idle surge was back, I moved the wire a little and the idle surge stopped, but the air temp reading went back to -33C. It appears my idle issues might be due to faulty wiring. I'm not sure though. I respliced the wire and now it appears my air temp sensor is working perfectly, but the idle surge is back.

Either way, if I resolve this idle surge issue or not, when I get the car remapped, I want the tuner to take a look at the wiring and make repairs if necessary. Hopefully it's not as big of a mess as I think it is.
 
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Below is a pic that I posted earlier with a plug that seemed to have helped my idle surging earlier.



The red wire on the plug is the one that was causing me issues. The plug is connected, but I've disconnected the red wire that goes to the PFC. With it unplugged, the air temp reads -33C, but my idle is steady around 1k-1050ish. When I connect the red wire again, it immediately starts surging between 500-1300. I previously thought this was a wire connecting to the MAP, but it actually connects to this plug. I'm not sure if this plug controls more then just the air temp sensor, but disconnecting the red wire seems to be keeping my car at a steady idle.
 
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New update.....

So I've reconnected the red wire and while the car was running (and doing the damn annoying surging), I went into the Power FC hand controller and in the ing/inj correction option, I increased the inj correction from 1.000 to 1.199 and now the car idles perfectly. I have to manually do the correction every time I start the car, but at least for now it seems to be temp fix. I'm guessing/hoping that a good map will fix this issue. I'm thinking about maybe getting a few upgrades for the motor before I go and get the map done. The injectors installed have a red or orange top. The previous owner said that he thinks the injectors were upgraded, but if they weren't, and they are stock, then I definintely plan on getting some upgraded ones. I also might be looking into either a new turbo, or getting mine rebuilt. I have no idea what size or brand/model the one installed is. There are no markings on it anywhere that say anything. I also need to get a new exhaust manifold (not really an upgrade). Not sure on what else I would want to get before doing the mapping. Of course getting these upgrades will delay in me getting the map done, but it doesn't make too much sense to do a map now, and then get the upgrades, and get another map done.
 
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