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Old 03-19-2015, 11:37 PM   #1
supraheelfan
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Default To tune or Not to tune?

I have an 87 mk3 with a 7mgte; mods: Apexi Power Intake, custom 2.5 exhaust, upgraded ct26 to 57mm trim turbo, and just installed a Driftmotion intercooler.
okay now that that's out the way, my car will not run at all since the intercooler install, and I'm trying to figure out if it's the ecu not being able to compute the new telemetry like the increased airflow and stuff; which makes the car crap on it's self when it's turned on. It idles low and hesitates badly but only after the intercooler install. I just need to know if I should go Fuel controller to fix problem, piggy back it or what. Cause I can't afford a full stand alone for another year or so. So what will help the car run better with the increased airflow and power? I'm thinking it's not getting enough fuel and I do not know what to do. Any advice would be appreciated, thanks.
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Old 03-20-2015, 04:05 AM   #2
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My first thoughts on this is that there is an intercooler coupler not completely connected or something else causing a massive vacuum leak, and that's why you're idling poorly.

Double check everything you removed and worked around for your intercooler install and make sure everything is nice and tight, and if its able to idle listen for hissing or intake noise along the intercooler piping. Also, if you unplugged it, make sure your AFM is still plugged in as that can also cause the symptoms you're having.

For what its worth, I have a 3" turbo back exhaust, Driftmotion 57 trim ct26, upgraded intercooler and hard pipes, and an off brand cone filter (similar mods to what you have). Other than occasionally hitting fuel cut on cold days, I have no problems with my car running or idling. I have no tuning devices, and am running on stock fuel components.
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1989 7MGTE R154 Targa Top White Package w/Blue Interior
Driftmotion 57trim CT26, Upgraded Intercooler, 2.25" Hard Pipes, 3" Turbo Back Exhaust with Test Pipe, HKS VPC w/GM 3 bar MAP sensor, APEXi S-AFC, Walbro 255lph fuel pump, ProSport EVO Series Boost / Fuel Pressure / AFR gauges, Lotek a Pillar Gauge Pod, HKS Type 0 Turbo Timer, Eibach Lowering Springs, Tokico Illumina II TEMS struts, custom powder coated Motegi Racing TrakLite wheels
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Old 03-20-2015, 06:42 AM   #3
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Yea, That's exactly what i was thinking at the time and double checked everything and made sure nothing was lose or not connected, intercooler piping and vacuum hoses. But you don't think lack of fuel could possibly be causing these types of problems?
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Old 03-20-2015, 01:15 PM   #4
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I really don't, at low rpm and idle all the mods still don't really amount to anything more than stock, and its definitely within the capabilities of the stock fuel system. Until you build boost, you're still under vacuum, meaning there is no additional air being forced into the engine. After I did all my mods, I was at -16inHg at warm idle. After trying like hell to fix a misfire at idle, I eventually found vacuum leaks I could not detect (mostly in intercooler couplers, one big one was a split in my accordion hose where it slips over the turbo), and my warm idle vacuum is now at -20inHg. So I have more vacuum now then I did with my old setup, which means the engine is drawing in more metered air then before. I eventually found out that the random misfire I had at idle was actually a bad AFM. It turns out when the compressor wheel on my old turbo grenaded, a large chunk of it hit the stalk inside the AFM and must have done just enough damage for it to occasionally get poor readings and screw up my air/fuel mix.

I assume that since you're adding power mods, your car was running in great shape before this, correct? Also, have you checked for engine codes since the rough idle started?
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1989 7MGTE R154 Targa Top White Package w/Blue Interior
Driftmotion 57trim CT26, Upgraded Intercooler, 2.25" Hard Pipes, 3" Turbo Back Exhaust with Test Pipe, HKS VPC w/GM 3 bar MAP sensor, APEXi S-AFC, Walbro 255lph fuel pump, ProSport EVO Series Boost / Fuel Pressure / AFR gauges, Lotek a Pillar Gauge Pod, HKS Type 0 Turbo Timer, Eibach Lowering Springs, Tokico Illumina II TEMS struts, custom powder coated Motegi Racing TrakLite wheels
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Old 03-21-2015, 11:54 PM   #5
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Yes the car ran a lot better with no problems before intercooler install and now i Found out it was the AFM and I got 3 of them afm sensors laying around and it seems it just needs to be upgraded so it can handle the more airflow and performance. Even the back up sensors are having problems with the idle and increased airflow for some reason. I forgot to mention I have a MLS head gasket with ARP head bolts also so just to throw that in there i Know the engine can handle a little bit of boost and rpm's. Do you suggest a Maft pro so I can change to a GM sensor or is that not a good idea?
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Old 03-27-2015, 05:51 PM   #6
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I have another problem, every time I put the intercooler pipes on the car it looses boost and power. I pull over to check the problem but all the pipes are still attached but oil is coming out of certain pipes and I was wondering if I have to have all the right metal couplers in the right place where the pipes have beads that the metal couplings grab on to so it doesn't have any leaks? What would cause the pressure to blow oil out of the intercooler piping to make it not run right and bog out all the freaking time.
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Old 03-27-2015, 07:30 PM   #7
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Oil is coming out of the intercooler pipes at the couplers? That's a boost leak. Since oil is thicker than air, if oil is leaking air is definitely leaking. That's probably your lack of power and boost. That is also most likely your vacuum leak causing your rough idle, unless you've fixed that already.

I still don't believe your problem is a tune, your car is not significantly drawing any more air in at idle than it was before. Your problems (to me) seem more likely to be a vacuum/boost leak, which it seems you have confirmed oil seeping. To answer your question, you do not need any additional bracing to stop your pipes from leaking. I have the generic intercooler kit you see all over eBay with the 2.5" hard pipes, and I have nothing supporting them other than what they attach to. It took awhile, but after tightening them several times after running the car, I was finally able to seal the connections and no longer have vacuum/boost leaks.

The oil leaking into your pipes may likely be from a bad seal in the turbo or possibly oil from the pcv system.
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1989 7MGTE R154 Targa Top White Package w/Blue Interior
Driftmotion 57trim CT26, Upgraded Intercooler, 2.25" Hard Pipes, 3" Turbo Back Exhaust with Test Pipe, HKS VPC w/GM 3 bar MAP sensor, APEXi S-AFC, Walbro 255lph fuel pump, ProSport EVO Series Boost / Fuel Pressure / AFR gauges, Lotek a Pillar Gauge Pod, HKS Type 0 Turbo Timer, Eibach Lowering Springs, Tokico Illumina II TEMS struts, custom powder coated Motegi Racing TrakLite wheels
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Old 03-27-2015, 07:31 PM   #8
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I reread your last post, what type of intercooler pipes do you have? Are they v-band style, do they use silicone couplers, or are they something else?
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1989 7MGTE R154 Targa Top White Package w/Blue Interior
Driftmotion 57trim CT26, Upgraded Intercooler, 2.25" Hard Pipes, 3" Turbo Back Exhaust with Test Pipe, HKS VPC w/GM 3 bar MAP sensor, APEXi S-AFC, Walbro 255lph fuel pump, ProSport EVO Series Boost / Fuel Pressure / AFR gauges, Lotek a Pillar Gauge Pod, HKS Type 0 Turbo Timer, Eibach Lowering Springs, Tokico Illumina II TEMS struts, custom powder coated Motegi Racing TrakLite wheels
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Old 03-27-2015, 07:42 PM   #9
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I got silicone couplings from the Driftmotion intercooler they sell; the one with the inlet and outlet on the same side.
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Old 03-27-2015, 07:43 PM   #10
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I don't see how the turbo itself is bad but the gasket could need some attention and that might also cause this problem?
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