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Old 01-14-2014, 08:43 PM   #1
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Default miata wants to die at idle

I have been working on this problem for two weeks.

01 miata custom T-25 kit
550cc injectors

It kinda rough on start up then idles fine until I go drive it and temps start to climb.
Then when I come to stop or push in clutch it wants to die. Also hesitates if right when hit gas. And when I fully boost car blows little bit of oil smoke. And my wideband is showing max lean when I punch gas.


Here's a list of what I've already tried

Replaced:

Plug wires
Crank position sensor
Can position sensor
PCV Valve
Spark plugs

I cleaned the MAF sensor
Pulled turbo and intercooler, no oil
Checked all vaccum hoses
Coolant is clear
Oil isn't foamy or muddy
Haven't checked compression yet.
plugs look a little lean but all look the same

Before I tear into engine. I bought gasket set and ARP head studs. A while back so no biggie if I have to do head gasket.

When I took intake manifold off to install turbo feed line I reused the intake manifold gasket.

Think that's causing a vaccum leak now?
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Old 01-14-2014, 08:51 PM   #2
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Pulled fuel line and primed pump. Fuel pump is working fine.
Only thing I can think of besides manifold gasket would be plugged fuel filter?
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Old 01-15-2014, 12:04 AM   #3
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Quote:
Originally Posted by kman456 View Post
I have been working on this problem for two weeks.

01 miata custom T-25 kit
550cc injectors

It kinda rough on start up then idles fine until I go drive it and temps start to climb.
Then when I come to stop or push in clutch it wants to die. Also hesitates if right when hit gas. And when I fully boost car blows little bit of oil smoke. And my wideband is showing max lean when I punch gas.


Here's a list of what I've already tried

Replaced:

Plug wires
Crank position sensor
Can position sensor
PCV Valve
Spark plugs

I cleaned the MAF sensor
Pulled turbo and intercooler, no oil
Checked all vaccum hoses
Coolant is clear
Oil isn't foamy or muddy
Haven't checked compression yet.
plugs look a little lean but all look the same

Before I tear into engine. I bought gasket set and ARP head studs. A while back so no biggie if I have to do head gasket.

When I took intake manifold off to install turbo feed line I reused the intake manifold gasket.

Think that's causing a vaccum leak now?
ahhhh.....
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Old 01-15-2014, 12:04 PM   #4
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If you haven't already, turn the idle adjustment screw on the top left side of the throttle body counter clockwise. It'll raise your idle and should help mask the issue. Also check really good for boost leaks between the MAF and engine.
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Old 01-15-2014, 12:09 PM   #5
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Quote:
Originally Posted by pdexta View Post
If you haven't already, turn the idle adjustment screw on the top left side of the throttle body counter clockwise. It'll raise your idle and should help mask the issue. Also check really good for boost leaks between the MAF and engine.
WHY in the world would you EVER want to mask an issue versus fixing it?
And I'm not even responding to OP since he is beyond help, but why would you give terrible advice to someone who is already a moron?
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Old 01-15-2014, 12:16 PM   #6
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OP, you didn't bother to post what you are using for fuel management... or if you retained your iacv.
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Old 01-15-2014, 01:00 PM   #7
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AEM FIC
IACV retained.

It started doing it out of blue one day.
18 psi. Your right I don't want to mask problem. I know i shouldnt have ran car lean to get symptoms through rpm band. But had no choice.

Im pretty sure its not my tuning haven't touched it in a month and was perfectly rich before problem started.

I also cleaned egr valve really well

I re sealed all my piping couplers when I had intercooler out.
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Old 01-15-2014, 01:02 PM   #8
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I also tried bumping up fuel 20% to compensate for extra leaness but did not work.

It will idle a/f at 13.5-14.7:1 then dive bomb lean without warning
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Old 01-15-2014, 01:05 PM   #9
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Running a MAF and an EGR. I dont know **** about AEM but what I do know is I wouldnt want to be running a MAF and EGR if I didnt have too
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Old 01-15-2014, 01:07 PM   #10
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Quote:
Originally Posted by 18psi View Post
WHY in the world would you EVER want to mask an issue versus fixing it?
And I'm not even responding to OP since he is beyond help, but why would you give terrible advice to someone who is already a moron?
Did you have better advise that didn't involve the word "megasquirt"?

If he adjusts the idle screw, the car won't die at idle. I don't see that being terrible advise given what he appears to be working with. If there's a better way, I'm not aware of it and I haven't seen any other relevant suggestions.
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Old 01-15-2014, 01:08 PM   #11
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Egr tube is capped off . But I noticed
idle gets better when I push plunger of egr down to open it
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Old 01-15-2014, 01:10 PM   #12
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Intermittent air leak on engine side of throttle body. OP, tell us about what you've done with EGR.

Edit: damn, late to the EGR Party
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Old 01-15-2014, 01:13 PM   #13
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Quote:
Originally Posted by pdexta View Post
Did you have better advise that didn't involve the word "megasquirt"?

If he adjusts the idle screw, the car won't die at idle. I don't see that being terrible advise given what he appears to be working with. If there's a better way, I'm not aware of it and I haven't seen any other relevant suggestions.
The car is idling on the stock ecu, and using the stock tb and iacv. So if all of a sudden it starts running and idling like crap, there is a problem and it needs to be fixed. I'd do a boost leak test since its simple and easy to do. Then possibly look at the iacv to see if its still good. Keep diagnosing if those are not it. But no matter what, I would not mask the problem by opening the idle screw and bumping up the inlet air at idle.
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Old 01-15-2014, 01:14 PM   #14
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Exhaust manifold has no egr outlet.

cut and welded shut egr tube on back of block

Egr connector is unplugged.
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Old 01-15-2014, 01:15 PM   #15
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check if your iacv is functioning properly. if you open the egr to let in air and it runs better, your idle valve might not be opening
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Old 01-15-2014, 01:17 PM   #16
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When I rev engine at idle it misses a little until I hit 3k rpm then symptoms go away but shows --- on my uego
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Old 01-15-2014, 01:20 PM   #17
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perhaps one of your crappy ev1 injectors failed
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Old 01-15-2014, 01:22 PM   #18
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sounds like vacuum to me also be sure to check the torque on your manifold flange bolts. mine got loose (even with locking harware) and I had misses at 3k as well.
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Old 01-15-2014, 01:22 PM   #19
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Would excessive blow by cause this cause engine is pulling too much air out of crank case..?
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Old 01-15-2014, 01:23 PM   #20
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is your turbo full of oil? is your manifold full of oil?
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