7mGTE GT4088 swap, runs, but weird issue? TONs of info, and I've searched.

nsngarage

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Jan 24, 2009
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Yes, I've searched a TON.

Ok, bit of background here...

I have a 89 NA Supra, that we put the turbo motor in.. Motor was from an 89 with the gray plug ecu, the ecu and the wiring harness also.. Now.. With the wiring harness.. the BODY plugs under the glove box were different, I had to repin those wires.. but I used diagrams and have had no "body" related issues.

The first motor I put in, had bad machine work done to it.. So it smoked like crazy with a brand new CT26 turbo on it.. Took it apart, had a cracked head.. Put a new head on it, still smoked, rings were terrible.

This time, I had a motor sitting for my 88 Targa car.. So I got tired of waiting and I threw it into the car.. Complete with a GT4088 turbo and 4" stainless exhaust all the way back and an HKS knockoff external wastegate. (FunkeyMunkeys) old setup.

Engine was freshly rebuilt with brand new rods/oem pistons/bearings.
Stock head
ARP head studs
ARP rod bolts
ARP flywheel bolts
Titan Motorsports 1.2mm MHG

The car runs fine, and seems to be normal except it has VERY little low end power.. and the turbo doesn't run above 0psi until 4k rpm.

Now, (I expect to hear some, "DUMBASS" here..) I am running stock 440cc injectors because I was wanting to break the motor in before the 750's came..

I've done a compression test and had no issues.. result were:

#1 - 165
#2 - 180
#3 - 165
#4 - 180
#5 - 170
#6 - 180

Timing was checked, rechecked, and rechecked again, because that's what it kinda feels like to me..

I drove the car a ton when it was NA, seemed to have more low end power.. but have never driven the Gte stock, So I may just be expecting crazy power even without boost.. But it seems weird to me..

MBC is all the way down, assuming the wastegate spring would let the turbo build the 8 or 10psi.. But I'm also not driving the car past say 4200 rpms...(break in)

I have an LC-1 wideband in the car with an XD-16 gauge to monitor the A/F and also have the LMA-3 on the way so I can datalog and at least tune for now with an SAFC Neo (flashed to the right firmware for karman to work right..)

The A/F when im WOT is between 10.8 and 13.0 roughly (No actual datalogging yet)
A/F at idle is normally higher than the 14.7 ideal.. Around 16-19, when it hits 19+ it'll bog and run weird, but go back to 16.5ish (Scary).

I have an Aeromotive AFPR kit installed and I have the base pressure set at 40 with the vac off.

My main question is.. should the car feel kinda sluggish? Not sure if it's just the big turbo not spooling at all under 4200 rpms, or if it's a fuel problem.. (20 year old injectors?)

If you have to call me a moron to fix it, that's fine.. just trying to drive my car again lol..

Thanks a ton

Also, redid the entire injector wiring harness from the ECU to the injectors, then to the resistor.. Just to make sure it wasn't a 20 year old brittle wiring issue.. 750cc injectors will be here and installed Tuesday also..


2011-05-09_08-42-56_717.jpgtoyota_supra_46.jpg2011-05-12_00-49-45_112.jpg2011-05-13_22-32-03_127.jpg2011-05-09_08-42-47_115.jpg
 

nsngarage

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Forgot to mention, car has the R154 transmission and the NA rearend, 4.30 open differential... I've read that the 4.3 rearend isn't very good for spooling a bigger turbo..
 

nsngarage

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Yeah I'm going to do a boost leak test tomorrow, I'm leaning along the lines of an intake leak myself now too.. sometimes the idle kinda surges up and down, maybe like 650 rpms to roughly 850 or so..

I don't think it's a wastegate problem, only because the power even from 1-4k rpm isn't there, it's not a "no boost" problem, it's an all out lack of power everywhere problem..

I'll post my findings tomorrow!

Thanks for the help
 

nsngarage

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Boost leak test shows a leak on both sides of the intercooler, the t-bolt clamps bottomed out before they were totally tightened all the way up... Although, upon fixing that issue, I start the car up and now there's a miss... lol.. Good game.
 

nsngarage

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Well.. again I can unplug the #1 injector and nothing changes.. it's pulsing though I can see it though the wire tester.. Seems as though I have a bad injector now.. Still can't tell if the boost leak fixed that first problem since it now has a miss.. 750s won't be here till thursday now.. great.
 

nsngarage

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EGR to intake manifold was leaking.. Fixed that, still have the same problem, boost leak tested the IC/Piping system by itself, no leaks at all..

What's the issue.. still won't pull codes.. feels to me like a timing issue..

Can knock sensors be bad and retarding the timing WITHOUT showing a code? I

Im lost, ready to put the car on craigslist lol...
 

nsngarage

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What im saying though is... it would have more power even without boost it should move.. it feels slower than my na did..

Sent from my DROID2 using Tapatalk
 

nsngarage

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checked the wastegate, took it off checked the spring.. opens and closes, lip on the 1/4" spacer is into the wastegate, gasket is between it and the manifold... car will rev to 5k at idle and not go above -3psi on the boost gauge. I'm clueless
 

nsngarage

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set @ 10btdc, checked a thousand times...

Jumped the diag box and put the light on #1, it blinks right at 10 every time.. I've removed and reinstalled it like twenty times too..

Even with 440cc injectors the turbo at 6psi or whatever the lowest is, would still build above 0 right or wrong? I'm so frustrated with this car..
 
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IJ.

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nsngarage;1716644 said:
set @ 10btdc, checked a thousand times I think..

Jumped the diag box and put the light on #1, it blinks right at 10 everytime.. I've remove and reinstalled it like twenty times too..

Even with 440cc injectors the turbo at 6psi or whatever the lowest is, would still build above 0 right or wrong? I'm so frustrated with this car..

Cam Timing NOT Ignition timing....:nono:
 

nsngarage

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I've taken the timing belt off and spun the crank around 180, redone it, undone it, taken the cam gears off to see if maybe the gear was one pin off.. they were fine.

Checked the cams to the NA cams that were taken from my car when the NA motor was in it.. I've checked everything multiple times, unless I've skipped something stupid I'm not sure.
 

Nick M

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If you don't load the engine, you will not come out of vacuum. You are close to the numbers (vacuum) of a naturally aspirated engine. Either you have an intake leak still, or you aren't building a load for one reason or another.