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Spray some brake cleaner around the intake manifold and listen to see if the idle speed increases.
 
ChasingSand said:
Spray some brake cleaner around the intake manifold and listen to see if the idle speed increases.
Click to expand...
Yep, I did that. I couldn't pick up any changes in the idle when I sprayed all around there. Maybe I just missed the leak location. I went ahead pulled the intake off to have a look and the gaskets seem to show some fluid on them from when I was spraying, but it could be my imagination.

The torque spec for the intake is 16lbs. Which I followed along with the tightening sequence. I'm afraid to crank the bolts too tight and break one.
All new gaskets from doing the intake rotation.

Is it weird that it's surging though if it's an air leak? Seems like it would just be a constant high idle not surging higher to lower to higher.
 

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It is very common for the IAC to get shit in it and get stuck open. Cleaning it sometimes works. They are available in the aftermarket.
 
Well I am not having much luck with this surging idle issue.

I replaced the IAC, no change.
I replaced the MAP sensor and connector just because the the wires were hot glued into it (previous owner), no change.
I pulled the plenum and intake off again to see if anything looked suspicious. I pulled the (new) fuel injectors and put them back in making sure all the grommets were fully seated. Reassembled per torque and sequence specs, no change.
I hooked up the coolant lines to the IAC just so I could rule that out, no change.
Sprayed all around with carb cleaner and could not get it to react and point me to a vacuum leak.
At some point during all this I noticed a misfire, found an ignition coil that seemed bad (no change to how it ran when I disconnected the wires), so I replaced it with a new ignition coil. Smoothed it out but still surging between 1k and 2k.

When I first start it up, if I don't hit the throttle it will idle smooth, but at about 1500 rpm. I let it run like that for a good 5 minutes to get it up to temperate, and during that time I was bleeding the coolant. I am confident there is little to no air in the coolant system (which per some YouTube videos can cause this issue).
After I blip the throttle to 3-4k it starts the surging again.

I'm running out of mechanical ability on this one. What else can I check?

I have a new throttle position sensor I can install. I just haven't done that yet because I need to cut slots in the original rivets, but might as well do that.

The main thing that I have changed when I swapped from the donor to my buggy is flipping the intake, so I can't help but think it's related to that.
Oh yeah, I also added JB weld to the upper intake plenum to seal that portion of the EGR track. Previously I had only sealed the hole at the bottom part of the intake (per post #508).

Sorry this is so long. Just trying to give as much info as possible in hopes of a suggestion.
Do I need to do a "re-learn" of the IAC? I came across a couple Youtube videos regarding that.
 
More info: I can start it, put my gloved hand over the throttle body and it immediately dies, so no vacuum leak.
 
MPC said:
More info: I can start it, put my gloved hand over the throttle body and it immediately dies, so no vacuum leak.
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I had a similar problem recently. I won't go into details because it will just confuse things, but we switched to dbw throttle body and fixed a lot of issues. I think my stock throttle body was just worn out. This was after replacing the iac, checking for leaks, etc.
 
Any possibility it could be too low fuel pressure?
 
Thank you for the suggestions. I'm curious why the drive by wire throttle body worked better.

I have an inline fuel pressure gauge. It's reading 80 psi. I'm using the same fuel pump that was in my buggy that worked fine for the 2.2 Ecotec I removed, but that is something that is different in this setup from how I bought the engine. Could the fuel pressure be overwhelming the fuel injectors, causing them to shut off, turn on, shut, turn on? Fuel is returning to the tank via the return line, but maybe not enough??

I thought I was on to something when I remembered that the engine as I got it had a wire coming from the harness that went to the fans (relay input). I wired my fans separately because I prefer to control the fans by a dash switch. So I thought maybe the engine doesn't know when it's warmed up and it's time to drop the idle, creating a high idle condition that it is then trying to fix (cuts fuel) then it goes back to high (adds fuel, etc. SO... I wired my fan relay input to that wire from the ECU/harness. The temp got up to 208 and the fans never came on, so I shut it down.

Then I tried adding the switch back in and I manually turned the fans on, sending 12v to the wire from the harness, no change. Still surges.
The saga continues. I'll tinker some more after the engine & I both cool down, haha.
 
Pulled this from Odyclub:

update:
I cleaned AIC valve again, it was drenched in carb cleaner. cleaned and tapped with hammer. after it was dry, I sprayed some wd-40 and I saw an improvement - the internal "throttle" inside AIC was now closing completely. Cleaned and lubed it again. Installed all parts and the car's idle recovered to normal - 1100 on cold engine, and about 750-800 on warm.
 
MPC said:
Thank you for the suggestions. I'm curious why the drive by wire throttle body worked better.

I have an inline fuel pressure gauge. It's reading 80 psi. I'm using the same fuel pump that was in my buggy that worked fine for the 2.2 Ecotec I removed, but that is something that is different in this setup from how I bought the engine. Could the fuel pressure be overwhelming the fuel injectors, causing them to shut off, turn on, shut, turn on? Fuel is returning to the tank via the return line, but maybe not enough??

I thought I was on to something when I remembered that the engine as I got it had a wire coming from the harness that went to the fans (relay input). I wired my fans separately because I prefer to control the fans by a dash switch. So I thought maybe the engine doesn't know when it's warmed up and it's time to drop the idle, creating a high idle condition that it is then trying to fix (cuts fuel) then it goes back to high (adds fuel, etc. SO... I wired my fan relay input to that wire from the ECU/harness. The temp got up to 208 and the fans never came on, so I shut it down.

Then I tried adding the switch back in and I manually turned the fans on, sending 12v to the wire from the harness, no change. Still surges.
The saga continues. I'll tinker some more after the engine & I both cool down, haha.
Click to expand...
If I remember correctly the fan trigger on the harness on mine is a ground switched wire.
 
ChasingSand said:
Pulled this from Odyclub:

update:
I cleaned AIC valve again, it was drenched in carb cleaner. cleaned and tapped with hammer. after it was dry, I sprayed some wd-40 and I saw an improvement - the internal "throttle" inside AIC was now closing completely. Cleaned and lubed it again. Installed all parts and the car's idle recovered to normal - 1100 on cold engine, and about 750-800 on warm.
Click to expand...
Thank you for looking into that. I have replaced the original IAC with a new one, but I will do a good cleaning of the throttle body and IAC passage and see what happens.

Fuel pressure regulator costs about $140, so not replacing that unless needed. I found no gas in the vacuum line that's connected to the fuel pressure regulator, so I'm assuming it's working.
The other various sensors are cheap and if they weren't needed I'm happy to have them as trail spares anyway.
 
EastMT said:
If I remember correctly the fan trigger on the harness on mine is a ground switched wire.
Click to expand...
OK, I will look into that. Thank you. The fan definitely should have turned on by 208 degrees. The wire coming from the harness was red, so was assuming it was either wanting or sending positive voltage. Wait... that was the color of the wire spliced in by previous owner. On closer look it is a green wire headed into the harness. Anyway, something to investigate.
 
MPC said:
Thank you for looking into that. I have replaced the original IAC with a new one, but I will do a good cleaning of the throttle body and IAC passage and see what happens.

Fuel pressure regulator costs about $140, so not replacing that unless needed. I found no gas in the vacuum line that's connected to the fuel pressure regulator, so I'm assuming it's working.
The other various sensors are cheap and if they weren't needed I'm happy to have them as trail spares anyway.
Click to expand...
OEM fuel pressure is around 64
Lbs. I only run about 40ish at idle and I am running larger injectors.
 
MPC said:
OK, I will look into that. Thank you. The fan definitely should have turned on by 208 degrees. The wire coming from the harness was red, so was assuming it was either wanting or sending positive voltage. Wait... that was the color of the wire spliced in by previous owner. On closer look it is a green wire headed into the harness. Anyway, something to investigate.
Click to expand...
In case you ever want one, Mishimoto makes a lower temperature water sensor.
 
ChasingSand said:
OEM fuel pressure is around 64
Lbs. I only run about 40ish at idle and I am running larger injectors.
Click to expand...
The fuel pump I'm using is a Walbro GSL392, 255LPH.
Worked fine on my Ecotec, but yeah, my 80 psi reading is a lot higher than your 40. Is there a recommended/ideal fuel pump for the Honda V6?
 
Maybe too high a fuel pressure is causing you an issue. I would reduce that to the 55 as it is recommended.
Also, I think my fans came on at 210 and when they did, they would pull temp down right away.
 
EastMT was correct about the fan signal. I hooked up a test light to the battery positive terminal and the fan wire. Sure enough the light came on at about 204 degrees when the temperature sensor sent the ground signal. So then I rewired the fan relay to have the ground connected to that wire and started it up again. I have been letting it just idle on it's own without touching the pedal until it gets up to temperature - it is idling at around 1500, no surge. Fans pop on at about 204 degrees. So then I blip the throttle to 3k and the surge starts again. Good to get the fan start up worked out though. I will look for a new sensor that has the fan come on at a little earlier.

The fuel pressure regulator looks like a stock part to me, but it has been relocated from the fuel rail to a block on a bracket (previous owner). The blue fitting is the fuel in line and I don't know what the plastic part is beyond that. The fuel return line seemed small to me, so when I plumbed it back to my tank, I increased the sized of the tube I added. That is something different on the engine from when I bought.... I don't know if that makes a difference on how the fuel pressure regulator performs ??

The other thing that is different that you guys have been pointing me to is the fuel pressure. I'd like to switch fuel pump out for one that does not push as much pressure. Can someone recommend one? J35A4, NA. Thank you all.

Fuel Pressure Regulator.jpg
 
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