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Strange bogging under light throttle and won't start hot

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Old 01-12-16, 08:20 PM
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Pulled the belt and the noise was the same.

Pulled the afm and took another look at the turbo.
Found some shiny oily goo in the bottom of the intake side and a fair bit of play as well. This noise just started getting really bad, and it looks like the blades might be contacting the housing when it spins up...

Here's a few pics; what do you think?

https://drive.google.com/file/d/0By2...ew?usp=sharing
https://drive.google.com/file/d/0By2...ew?usp=sharing

Last edited by 0pistons; 01-12-16 at 08:51 PM. Reason: trying to make pics display here without links. i failed.
Old 01-12-16, 08:37 PM
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pics no work
Old 01-12-16, 08:54 PM
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Originally Posted by RotaryEvolution
pics no work


was trying to get it to display in the thread with img tags to make it easier for everyone, but I couldnt figure out how to get the .jpg extention to display on google drive. Changed it to a url tag, it should work now.

And RotaryRevolution thank you so much for taking your time to help me through this. People like you are what make this community great.
Old 01-12-16, 09:47 PM
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turbo is toast, lemme know if you want this one.

i try, these cars can be a pain in the *** and expensive hobbies.

Last edited by RotaryEvolution; 01-12-16 at 09:50 PM.
Old 01-13-16, 06:18 AM
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Originally Posted by RotaryEvolution
turbo is toast, lemme know if you want this one.

i try, these cars can be a pain in the *** and expensive hobbies.
Want which one????

Edit: Just saw you had sent me a PM

I noticed N370 on the housing, meaning that is an s5 turbo.
Should I replace it with the correct turbo, or is there an advantage to using the s5 turbo on an s4 EMS?

Last edited by 0pistons; 01-13-16 at 07:37 AM.
Old 01-13-16, 08:20 AM
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the s5 turbo is a little better than the s4, the manifold to turbo bolt pattern is also different
Old 01-13-16, 08:25 AM
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ok, so if I go with an s4 turbo it needs to include the manifold as well, or could I use an s4 hotside with an s5 compressor?
Old 01-13-16, 08:33 AM
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other way around, you could retain your s5 hotside and bolt the s4 center and compressor to it however most S4 have a dual shield under the turbine that sets the turbo about 1mm further out. this probably doesn't cause any major issues but something i notice.
Old 01-13-16, 08:59 AM
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Originally Posted by RotaryEvolution
other way around, you could retain your s5 hotside and bolt the s4 center and compressor to it however most S4 have a dual shield under the turbine that sets the turbo about 1mm further out. this probably doesn't cause any major issues but something i notice.
my bad, that's what I meant.
Old 01-15-16, 10:04 AM
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Picked up a spare turbo and dropped it off to be rebuilt this morning. They just called me to tell me the hotside casting is cracked and they can't save it, but they will rebuild the cold side for me. They also told me it looks like the intake side has been upgraded; something about bigger bearings. They told me nothing came up for the model number stamped onto the casting that matched what's inside? They are doing some research for me and trying to get me replacement bearings. Going to have to pull my other turbo and hope that between the two I have now, I end up with one functioning turbo.


Hopefully by Tuesday night I will have everything I need and be reassembling.
Old 01-15-16, 05:01 PM
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nothing is stamped inside the HT18s, so i have no clue what you may have gotten. the hotsides always crack, doesn't generally mean they aren't usable.
Old 01-15-16, 05:18 PM
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Tell them it needs a one-piece carbon seal, t3 rebuild kit.
Also, some of the rotating assembly parts don't come with the standard kit so they won't replace everything.
Have them check the compressor dimensions. Stock is about 43.7 inducer/63mm exducer.
Old 01-16-16, 06:25 AM
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Originally Posted by RotaryEvolution
nothing is stamped inside the HT18s, so i have no clue what you may have gotten. the hotsides always crack, doesn't generally mean they aren't usable.
pulled the turbo off of the car and will have it dropped off on Monday. Found the lovely surprise of no gasket between the turbo and the manifold and a bunch of black RTV instead. I got a good gasket with the spare turbo I picked up as well as a spare manifold, so at least I can fix that. But it sure does make me wonder what else I'm going to find on this car...

I will have them use whatever hotside is in the best shape out of the two turbos that they have. The steering column in the RHD cars sure is a huge pain in the *** when removing the turbo, haha

Last edited by 0pistons; 01-16-16 at 06:27 AM.
Old 01-16-16, 06:28 AM
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Originally Posted by RXSpeed16
Tell them it needs a one-piece carbon seal, t3 rebuild kit.
Also, some of the rotating assembly parts don't come with the standard kit so they won't replace everything.
Have them check the compressor dimensions. Stock is about 43.7 inducer/63mm exducer.
Thank you so much for that info, I will be sure to pass it on Monday morning.
Old 01-16-16, 08:03 AM
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yeah, the hitachi uses alot of the same blueprints as Garrett did.
Old 01-19-16, 06:17 AM
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Rebuilder has both turbos, expecting a call today. Hopefully it's finished soon. I passed on all of the information in the thread. They had already figured all of it out, which gives me some faith in these guys (Derek's Diesel in Barrie). I'll post an update when I get everything put back together.
Old 01-20-16, 01:24 PM
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Well, rebuilder has informed me that both compressor wheels are damaged; the one on the car was out of spec, and the one on the junkyard turbo was too corroded to use, which I was worried about......rebuild kit doesn't include it.....so need a new one....

They have been unable to find the part number of the compressor wheel and their suppliers say they dont have enough info about that turbo to figure out what they need. Mazda was no help.

Doed ANYONE know what the part number for the compressor wheel is???

Thanks.
Old 01-25-16, 02:40 PM
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Well, all back together and still having big problems.

Rebuilt turbo and fuel injectors installed.

Fired it up and it will only run on one rotor.
Have good spark on all 4 plugs.
Have good even compresstion on both rotors.

If I can get is started, it runs on one rotor, then floods. By the looks of the plugs, the front rotor is the one firing....

please help!

Edit: I also have the correct N318 pressure sensor installed.

Last edited by 0pistons; 01-25-16 at 02:43 PM.
Old 01-25-16, 05:43 PM
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Double check the connectors on your injectors.
Old 01-25-16, 05:54 PM
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I took them out and plugged them back in one by one, so they couldn't be mixed up.

The plugs only really reach one injector properly without stretching, so I'm 99.9% sure they are correct....I'll pull the manifold and triple check, but I'm not holdong my breath.
Old 01-25-16, 05:58 PM
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Did you have a single dead rotor prior to disassembly?
Old 01-25-16, 06:01 PM
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Nope, ran ok except for whining coming from the turbo, which has been replaced with a freshly rebuilt one to the tune of $700.

I'm looking at it now with the ic and uim off, and it doesn't seem possible that I have them plugged in wrong. The wires at the front go to the front rotor, back to the back rotor, longer wires are secondaries, shorter wires are primaries....

I get three strong, even pulses with front or rear plugs removed.
Old 01-25-16, 06:45 PM
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One of the "rebuilt" injectors must have been bad; put old injectors back into the primaries and it's running on both rotors now, I'll ket it warm up and maybe go for a drive and post back with any continuing issues....thanks for the fuel injector suggestion, definitely on the right track and led me to the problem.

EDIT: shut it off, tried to start it back up and it promptly flooded.....I'm running out of ideas here.....what else could make it flood?

Last edited by 0pistons; 01-25-16 at 06:53 PM.
Old 01-25-16, 08:53 PM
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Just drove it a good 40km under 3500rpm and it drove alright, but smelled too rich to me. It did rev nice and smooth and was ok ok the highway for a good 15 minutes.

When I got home, I let it idle for 10 minutes and then shut it off.
It would not start again, flooded as usual.

I noticed that the ac fan kept running for a good 25-30 minutes after I took out the keys, and only stopped when I disconnected the battery.

I also see 2 sensors at the back of the thermostat housing. One looks like a green fuel injector clip, and the other looks like an old thermo sensor that both wires are broken off of. It looks just like the one on the bottom of the radiator. There are no spare plugs or anything that looks like it would go there on the wiring harness. I do, however, have 3 loose wires in my fuel injector harness that are in sort of the right area. The FSM doesn't say anything about that sensor.

Could the fact that the ac fan keeps running after I turn off the car be related to my flooding issue? Does anyone know what that sensor might be?

I'm at a loss here. Took today off to get this turbo back together and get plates so I can drive it, but ran out of time again and am working 12+ hours a day for the next 10 days. My safety runs out in 21 more days, so I need to figure this out ASAP.

PLEASE help!!! Thanks for any suggestions.
Old 01-26-16, 10:43 AM
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Originally Posted by 0pistons
Just drove it a good 40km under 3500rpm and it drove alright, but smelled too rich to me. It did rev nice and smooth and was ok ok the highway for a good 15 minutes.

When I got home, I let it idle for 10 minutes and then shut it off.
It would not start again, flooded as usual.

I noticed that the ac fan kept running for a good 25-30 minutes after I took out the keys, and only stopped when I disconnected the battery.

I also see 2 sensors at the back of the thermostat housing. One looks like a green fuel injector clip, and the other looks like an old thermo sensor that both wires are broken off of. It looks just like the one on the bottom of the radiator. There are no spare plugs or anything that looks like it would go there on the wiring harness. I do, however, have 3 loose wires in my fuel injector harness that are in sort of the right area. The FSM doesn't say anything about that sensor.

Could the fact that the ac fan keeps running after I turn off the car be related to my flooding issue? Does anyone know what that sensor might be?

I'm at a loss here. Took today off to get this turbo back together and get plates so I can drive it, but ran out of time again and am working 12+ hours a day for the next 10 days. My safety runs out in 21 more days, so I need to figure this out ASAP.

PLEASE help!!! Thanks for any suggestions.
Some ideas to stew on:
-Repair every electrical ground you can get your hands on. Dash, ECU, Engine harness.
-The boost gauge pegging means it is sending the same signal to the stock ecu and is triggering the over-boost fuel cut. This is the fall-on-face, backfire behavior. Possibly the wrong boost sensor.
-The fan running without the key and the boost gauge pegging indicates bad wiring and/or mismatched components.
-The thermosensor on the water pump housing affects the mixture, but shouldn't prevent it from running. Rich hot starts are an issue with the stock ecu.
-The N340 ecu is somewhat unknown, kind of like the N374 japan turbo ecu. On the N374, the USDM mileage switch signal matches up to the jdm speed limiter and cuts fuel to the rear rotor. Look into the other suggestions before tackling this one. https://www.rx7club.com/2nd-generati...rsion-1056618/


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