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Just swapped in LT1 running like crap

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Old Oct 10, 2012 | 12:02 AM
  #1  
cubby-5056's Avatar
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From: edmonton alberta canada
Car: 1991 Z28
Engine: 350 LT1
Transmission: T 56 (converted from 700r4)
Axle/Gears: 4.10 from a 2000 TA
Just swapped in LT1 running like crap

Hey just running this by you guys. I just got my LT1 started up. It is running like absolute crap. Rpms are super high and there is no power at all/ bogs
I haven't got the O2 sensors connected yet and it's open headers right now. I'm just wondering if this explains how it's running.
I thought it would run in safe mode(sort of half assed) but a lot better than this
It's running like I have a couple of spark plug wires mixed up. Even though I was very careful not to mix them up ,or timing is way out
Is there a way to prove if it's the O2s or bypass them??
She's going in for exhaust next Monday but I'm not sure the car will make it there or if I should drive it there with the way it's running
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Old Oct 10, 2012 | 12:26 AM
  #2  
cubby-5056's Avatar
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Joined: Jun 2010
Posts: 93
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From: edmonton alberta canada
Car: 1991 Z28
Engine: 350 LT1
Transmission: T 56 (converted from 700r4)
Axle/Gears: 4.10 from a 2000 TA
Re: Just swapped in LT1 running like crap

Also the PCM is out of an automatic 95 camaro. I have it running a t56 with no vss as yet
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Old Oct 10, 2012 | 12:00 PM
  #3  
torque_is_good's Avatar
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Re: Just swapped in LT1 running like crap

OK, so it's a 95 which is OBD1 and only 2 O2 sensors

there is no CPS either and you don't adjust the timing. The computer does that so you may have wired the plugs incorrectly or installed the optispark incorrectly or even have a bad one. Yes, the opti can be forced on with the 95 and up opti's if you really try hard enough.

It's not a good idea to run w/o O2's but the car will run rich without them

have you checked the MAF and the coolant temp sensor? About the idle, you may be looking at an issue in the throttle body be it the IAC or tps
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Old Oct 10, 2012 | 07:22 PM
  #4  
cubby-5056's Avatar
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Joined: Jun 2010
Posts: 93
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From: edmonton alberta canada
Car: 1991 Z28
Engine: 350 LT1
Transmission: T 56 (converted from 700r4)
Axle/Gears: 4.10 from a 2000 TA
Re: Just swapped in LT1 running like crap

Ya that's the fun with a whole new engine/computers. I'm definitely going to check those things. I'm really hoping its just the O2s

Is it possible that the no vss or the fact that it is not plugged into the Automatic could affect the way it runs???
I mean it sounds like its running really good until you try to start driving and then the rpm goes all over and the car bogs like crazy
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Old Oct 10, 2012 | 07:31 PM
  #5  
redneckjoe's Avatar
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From: Spring Hill, Fl.
Car: 87 iroc-z
Engine: 454
Transmission: th350
Axle/Gears: 3.73
Re: Just swapped in LT1 running like crap

Originally Posted by cubby-5056
Also the PCM is out of an automatic 95 camaro. I have it running a t56 with no vss as yet
hmmmm,....... i agree the o2 sensors should be installed,....3 of them? wasnt 93 the last year for OBD1? 95 would be OBD2 i believe? after you get the O2 sensors working, id properly adjust the TPS and take it from there.
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Old Oct 10, 2012 | 08:10 PM
  #6  
vetteoz's Avatar
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From: Not in Kansas anymore
Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
Transmission: T400
Axle/Gears: QP 9" 3.73
Re: Just swapped in LT1 running like crap

Originally Posted by redneckjoe
wasnt 93 the last year for OBD1? 95 would be OBD2 i believe?
'96 was first year for OBDII ;
even though the 16 pin OBDII style ALDL connector was used on earlier years

Originally Posted by redneckjoe
adjust the TPS .
TPS is not adjustable on LT1 ( without mods )
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Old Oct 10, 2012 | 08:21 PM
  #7  
redneckjoe's Avatar
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Joined: Sep 2011
Posts: 2,080
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From: Spring Hill, Fl.
Car: 87 iroc-z
Engine: 454
Transmission: th350
Axle/Gears: 3.73
Re: Just swapped in LT1 running like crap

yeah, confussing years.
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Old Oct 14, 2012 | 08:21 PM
  #8  
cubby-5056's Avatar
Thread Starter
Junior Member
 
Joined: Jun 2010
Posts: 93
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From: edmonton alberta canada
Car: 1991 Z28
Engine: 350 LT1
Transmission: T 56 (converted from 700r4)
Axle/Gears: 4.10 from a 2000 TA
Re: Just swapped in LT1 running like crap

Update found the issue. The guy who built it didn't set the rockers and they jumped out of position. Now to see if any damage was done :-(. One rod is missing ???
Time to start taking things apart
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