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Surely you jest
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Discussion Starter · #1 ·
I'm recieving a Code (44) lean exhaust and a "hunting" idle on my 87 GN after replacing some parts and tuning. Also, my BLMs are high at 140 to 150. I get 20 lbs of boost with zero knock, though. The following replaced stock parts just prior to the tune:

TE-44
MSD 50s
Dutt. neck IC
THDP
ATR 2.5" exhaust
Lubrant 93 chip
O2 sensor

Before the parts were replaced, I had ALOT of oil being released by the turbo (oil in IC, up pipe and throttle body). I hit the throttle body with some carb cleaner, but I didn't pull the IAC and clean that space.

What are the chances of getting a bad O2 sensor off the shelf?

A fouled IAC?




[This message has been edited by *JOKER* (edited November 16, 2001).]
 

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Have you tried a different chip....??

I think Joe runs his pretty lean for better spool off idle.

It's possible to get bad sensors. Are you using Delco units?



 

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Surely you jest
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Discussion Starter · #4 ·
LOL...I'm working on it!


I don't have any other chips right now, so I'm having to work around this one. Knowing that Joe makes them a little lean helps though. He said to run 43.5 to 45.5 psi of fuel pressure and I'm only running 43. That, in addition to my BLMs topping off with 138 (4 second blast), is pointing me in the direction of a lean condition.

I ran out of time to play today, so I'll hit again tomorrow and see what she gives.

As far as the O2 sensor goes, it's brand new and the CCs were within range, so I'm saying she's good.

Will post results.
 

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Surely you jest
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453 Posts
Discussion Starter · #5 ·
Well, I went for another few runs last night before I started playing. Apparently, last nights cold air played a difference in the fuel requirements. She gave me 2 lights on the Caspers knock gauge and the BLMs went to 140. I went from 43 psi of fuel pressure to 44 and the knock went to one light...BLMs 136. The funny thing is, she gives that small knock in the very beginning. I've got a tie-down strap and the mounts are strong.

Should I go with more fuel?

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87 GN (50K miles)
-TE-44
-Dutt. necked IC
-MSD 50's
-THDP
_ATR 2.5" Exhaust
-boost/knock gauges
-Tlink
-Hotwired RA XPFP
-BGC AFPR
-Lubrant 93 chip
-Translator Plus
-LT1 MAF
-ATR Bad Boy cold air kit
-Vac brakes
 

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colder air is more dense and may require more fuel. I would try more...also be sure the tie down strap is not too tight...that can transmit vibration that triggers the sensor as well.



 

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Surely you jest
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Discussion Starter · #7 ·
Will do. I'm curious: Is a nearly-immediate, low-grade knock on a hard run from a stop symptom of an overtight strap?

I've also got an intermitent rattle (THDP vs bottom of firewall). Any cures? LeHammour?

[This message has been edited by *JOKER* (edited November 18, 2001).]
 

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Usually those kinda "knocks" are from the sensor hearing something when you step on it.

It could be the strap or it could the the dp.

You can try lowering the rear end of the pipe...loosen the bolts that hold the dp to the turbo and then see if you can reposition the pipe downward....watch out for the the rear ear of the control arm tho'....





 

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Joker my car hits as well, I've been told body mounts or motor mount drivers side. Yes I read about your mount, I'm going with the HR Parts one soon, well if I ever order the darn thing.


I already cut the heat shield don't want to trim the underpan overhang.

So check the body mounts next. Mine are shot.
 

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Surely you jest
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Discussion Starter · #10 ·
Steve, if I loosen the DP to exhaust housing bolts, how is that going ot help. Once I tighten the bolts back up, it will regain it's old position and I can't clock that portion of the turbo. It's mounted to the header. I'm missing something. Could you clarify please?

Salvage, I haven't made a detailed investigation of the situation. But it appears, from the engine bay, that the top of my DP is hitting the fire wall. Looking down, I can see a pretty clear path beneath the DP. Wouldn't replacing the mount raise my engine, thus increasing the contact between my pipe and firewall (if it is, indeed, the case)?
 

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the holes in the mounting face of the dp are slightly larger than the bolts as I recall.

this means that a slight repositioning of the dp to the turbo will be magnified at the cat end of the pipe. It may be that the pipe is already hanging at the lowest possible position...usually, I have seen the need to raise the tail end of the pipe rather than lower it...if it is as low as it will go...sounds like Hammer time! no, MC, stay back!



 
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