st0vetop

Hello all, first problem I've come across that search didn't yield an answer.

Bought a d16y7 5spd 2dr coupe, with many many issues. Runs pretty well now with a few small exceptions, one being the idle on start up. This happens not only when engine is cold, but is more likely to occur.

So the engine on start up will idle around 2k but sometimes is around 3k. The other day i let it idle until it reached full operating temp, no change. Then drove for a few miles, after a few times turning off the ignition off and bump starting while driving the idle drops to about about 400 for a few seconds then steadies at 650+- 70.

According to Torque pro the car is also starting in closed loop when cold. I was under the impression that it should be in open loop on cold start. The car does go into open loop at WOT or deceleration as i believe it should. Don't know if this is related.

I also smell a little bit of gas, not sure if its because im running rich or because previous owner ripped out evap. Bought new canister & purge, will install soon.

here is a description of the car and what ive done to it since i bought it.

D16y7 with y8 manifold swap (1/2 done by previous owner)
4-2-1 header
5spd swap

Replaced TB with y7 to make 3 wire iacv work
blocked off cold air assist ports on IM
cleaned and tested iacv
Replaced both o2 sensors
New plugs
new wires
Replaced with y7 fuel injectors
Replaced ecu (had auto ecu)
Replaced thermostat
Drained and bled coolant
Fixed the vacuum leaks
Replaced IM Gasket
Adjusted Ignition timing
Adjusted Valve clearance
Crank position bypass trick
replaced VSS


I have data logs of various sensors if it would help. just seemed liked a lot to post. just let me know


PS: BIG thank you to everyone on the forum, i wouldn't have the car running and inspected without the help of so many people here

Former User

CEL codes?

Test the ECT sensor and the TPS.

st0vetop

i get a purge solenoid code, but as i said going to replace the evap this week.

I tested tps, never tested ect as i could see the temp raising on the scantool.
What should the voltage be? i will test tomorrow.

Ryan Lwin

Do you press the gas paddle when you start the car?

st0vetop

no i don't use the pedal to start the car, but i have tried playing with the pedal no effect on idle

Former User

What specific code? Does it return after resetting the ECU? If so, a vacuum leak could be the problem.

Did you test these sensors while the high idle problem was happening?

Is the throttle cable adjusted with some slack?

Ryan Lwin

Like Ron said, there could be a vacuum leak. You said you have Y8 mani with Y7 TB? Did you get the correct gasket for it? Y8 TB gasket and Y7 TB gasket are not the same. There will be a big leak that will make your idle either really high or bounce like crazy.

Try force closing the throttle switch with the throttle cable off. See if that slows down the idle. if not, check the vacuum leak. Take the intake out and close the TB with your hand. See if engine dies. If engine stays on, you got vacuum leak.

Y7 on the left. Y8 on the right.

Former User

This^ is a potentially important point. If a 99-00 Y8 IM was installed on a 96-98 Y7 engine, then you will have an intake air leak due to the FIA system of the Y8 IM.

st0vetop

Dont know the code can check tomorrow, but is normal because there is no purge solenoid, will be replaced this week, removed by previous owner
Evap port blocked on IM and leak tested with TB cleaner

Never tested during high idle, will try this week.

Throttle cable has plenty of slack.

st0vetop

Using correct Gasket, replaced with TB swap

engine dies when TB is blocked

st0vetop

[QUOTE=RonJ@HT;47904326]This^ is a potentially important point. If a 99-00 Y8 IM was installed on a 96-98 Y7 engine, then you will have an intake air leak due to the FIA system of the Y8 IM.
[QUOTE]



Blocked off the ports on the IM

Ryan Lwin

You keep mentioning evap purage valve but you said you have Y8 mani. Y8 mani doesn't use evap purage valve I believe. Do you have that hose capped? If that hose is open, you will have high idle too. Also check the bottom picture. (For the bottom picture. Ignore the other stuffs. Just look at the one marked in red.) That is what Ron is talking about.

Former User

This^ and also:

When the idle is high and fluctuating, remove the air intake system and then use your finger to cover the hole inside the TB leading to the IACV. Does this cause the idle to drop and steady?

st0vetop

I think maybe the purge valve isn't needed in the image because its an odb1 y8 swap. I the p2e ecu is looking for a purge valve. I have capped the appropriate ports and jb welded the for small holes inside the IM. The top hose is also capped off, even though it blocked by the gasket.

st0vetop

Will test TPS and ECT during high idle condition tomorrow, then block iacv port and check response.

Ryan Lwin

Which top hole are you talking about? The one that goes to crank box? That should not be closed by gasket since it's directly drilled into mani.

Also, what other stuffs have you done to your mani? Please describe in detail. Pictures would help a lot.

st0vetop

no, on the 99-00 IM there are four small ports unused by the 96-98 models. There is also on port on the top of the IM right where it meets the head which is blocked as it is unused by 96-00 models. It is marked in the image you posted. I have the 96-00 IM gasket, all ports match perfectly, with exception of unused air port.

Blocking These ports, replacing the TB and gaskets, are the only mods done to IM

st0vetop

Shouldn't the car be cold starting in open loop? Could this not be part of the issue?

Ryan Lwin

Do the IACV test as Ron said and provide more detail.

st0vetop

no time to work on the car until Friday unfortunately.....will post results then

st0vetop

whoops, feel like an idiot, plugged iacv port idle dropped back down
took the iacv apart and cleaned it again, problem seemingly solved

thanks!

Hrcustoms

Hey can I ask where you guys get those diagrams you showed of the intake system?

Ryan Lwin

Google and Search option.