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Car died while driving and now extremly rough idle!

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Old 09-29-23, 10:26 AM
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Car died while driving and now extremly rough idle!

While driving and after shifting to 2nd gear I heard a pop. I was going approximately 25 MPH at the time. The whole car started to shutter and then shut off as soon as i pushed in the clutch. My son claims to have seen a very light white smoke from the rear end. I coasted in to a parking lot where i popped the hood and tried to crank the engine again. The entire engine was shaking violently so i shut it off within 2-3 seconds. I gave up on messing with it at night and had it towed home.

Since then i have purchased in ignition tester to see if i was getting spark on all coils and i am. while doing this i pulled the plugs and put the old known good plugs back in. The ones i pulled were pretty black and the 2 front plugs looked kind of wet after tuning the engine over a few time to test the ignition. After swapping the plugs the car idled better but not like it should. Now i am hearing what sounds to be a large exhaust leak coming from the top of the keg possibly under the IM.

Anyone have any ideas on whats under the UIM that would sound like a big exhaust leak?

I have tried to get a local guy to do a compression test but he is to busy so im am going to order my own.
Old 09-29-23, 10:45 AM
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Check your Map sensor hose
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Old 09-29-23, 11:04 AM
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Can you post a video? Checking the map sensor hose is a good start for sure.

What are the details of your car? Ecu? Mods?
Old 09-29-23, 12:23 PM
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Non sequential converstion
3 inch axle back
3 inch mid pipe
HKS down pipe
Apexi intake
ETS front mount
Air pump removed due to being extremely noisy
Greddy bosst controller which has been turned off since i bought the car due to lack of an ecu
the car has not seen over 7 lbs since i have owned it because i don't want to push it with no tune.
Old 09-29-23, 12:26 PM
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all of those mods on a stock ecu? man........

check your map sensor hose then pull the spark plugs and listen for even pulses
Old 09-29-23, 02:33 PM
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Will give it a whirl thanks!
Old 09-30-23, 08:58 AM
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Originally Posted by Boosted843
Non sequential converstion
3 inch axle back
3 inch mid pipe
HKS down pipe
Apexi intake
ETS front mount
Air pump removed due to being extremely noisy
Greddy bosst controller which has been turned off since i bought the car due to lack of an ecu
the car has not seen over 7 lbs since i have owned it because i don't want to push it with no tune.
I think it's fairly unlikely that you've stayed under 7psi based on what you've listed as mods. Boost creep is a thing and fairly common with the stock twins. Did you port out the wastegate on the twins and add restriction to your 3" exhaust?
Old 09-30-23, 10:50 AM
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!t was converted when i bought it. The boost controller hasn't been set up since the car has been imported, so it has been running what the stock waste gate allows. It has never displayed over 7 psi with these mods the boost gauge has a peak hold and flashes the highest boost level , and again never over 7 psi.
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Old 10-04-23, 01:38 AM
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I think I might have found the problem....
Old 10-04-23, 01:40 AM
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.........how
Old 10-04-23, 02:36 AM
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Is that upper section of the Y-pipe?

Someone may have dropped that at some time and the crack finally gave out.

t looks like a "99 spec y-pipe/ cross pipe. in the earlier series six spec you have a rubber coupler between the y-pipe and the cross pipe.

I would have suggested that that coupler had blown out causing the big leak you suggested.

Replacement '99 spec y-pipes are a little harder to find. An earlier spec set up should be easier to find until you do.

If it is the lower rear section of the y-pipe it should be easy enough to find a replacement.

Old 10-04-23, 07:18 AM
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Yes it is the lower rear section which i am currently trying to find.
Old 10-04-23, 07:20 AM
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Originally Posted by FDAUTO
.........how
I'm guessing it may have been damaged when it was converted to non sequential.
Old 10-04-23, 07:58 AM
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That will not prevent the car from running. All the turbo piping can be removed and the car will start and run just fine
Old 10-04-23, 08:14 AM
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Originally Posted by Banzai-Racing
That will not prevent the car from running. All the turbo piping can be removed and the car will start and run just fine
I'd be inspecting that break for missing chunks and checking the intercooler if any were. While it would be difficult for a piece to get blown through to the intake in theory it is possible.
Old 10-04-23, 02:27 PM
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Please post more pics of the piece and also of the other sections of the Y-pipe.

They may have been modified. Any replacements might need to have the same modifications.

if you can't find the part locally throw me a DM.

I might even have a modified piece to match.
Old 10-04-23, 02:41 PM
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Check what ECU you have. Stock ECU will not like the modifications. You probably have something else.

Are you getting any check engine light readings?

Old 10-05-23, 04:08 PM
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Originally Posted by Molotovman
I'd be inspecting that break for missing chunks and checking the intercooler if any were. While it would be difficult for a piece to get blown through to the intake in theory it is possible.

The pieces go back together with no missing chunks!
Old 10-05-23, 04:12 PM
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Originally Posted by Redbul
Please post more pics of the piece and also of the other sections of the Y-pipe.

They may have been modified. Any replacements might need to have the same modifications.

if you can't find the part locally throw me a DM.

I might even have a modified piece to match.

yes they are modified. They are gutted and sealed.

As far as check engine lights, not sure its a 96 RHD so it doesn't have one on the dash. The boost controller is turned off so its not running over 7psi.
Old 10-05-23, 05:22 PM
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Compression test and go from there
Old 10-05-23, 09:24 PM
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BC

Check the ecu. It is behind the passenger side kick panel.

I suspect you have something other than stock ecu there.

In JDM there is no check engine light. rather if the ecu senses a default it will, in many cases, go into "limp mode".

"Limp Mode" makes the car run very poorly and when that happens the owners manual says "go to the dealer".

The dealer would have a devise to hook up to the diagnositic plug and read what the ecu thinks is wrong.

You can do the same test with a LED (with resistor) and a jumper wire.

My car, when I got it, had a backyard conversion to parrallel turbos and emission deletes.

But they left the stock ecu in there to try to manage things.

It was going into limp mode all over the place.

They sealed off the various holes in the y-pipe sections (likely like yours) but left an about 1/2" hole open to the air with a little screen over it.

I blocked that off and the car started to run poorly.

I have no idea what was going on.

If you have a stock ecu you may want to replace with a Power FC (for version 4 cars). There is software now that will help the Power FC adapt to various set-ups it may encounter.



(By "dealer" I mean dealer in Japan. Very few, if any, shops outside Japan would have the diagnostic tool. It seems very few shops in North America know, or care to, run the simple LED code checking.)




Last edited by Redbul; 10-05-23 at 09:38 PM.
Old 10-10-23, 04:34 PM
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Ok so I got the broken piep welded and resurfaced. Bolted everything back up and i still have the same problem/noise.
Old 10-10-23, 07:12 PM
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Is there any smoke out the back when it's idling like that?
Old 10-10-23, 08:00 PM
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Originally Posted by Jesturr
Is there any smoke out the back when it's idling like that?
yes!

I also noticed the rear turbo is tighter then the front. The front will spin freely for a second or 2 after you let go of it. The rear stops as soon as you let go.
Old 10-10-23, 08:02 PM
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Originally Posted by Jesturr
Is there any smoke out the back when it's idling like that?
if your referring to the exhaust not that I noticed. But it does smoke around the rear turbo.


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