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New Updates! After swapping 98 gp gtp 3.8 s.c. into a 2002 gp se car

JimSWylie

JimSWylie

New member
NEED HELP! A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se car
Not sure if i want to ever do a swap like this again

1 - The only dtc code ive got is p1651-ran control 1 relay or qdm "B" fault
fan one does not come on but it did when the 3.1 engine was in the car

2 - performance shift works but neither indicators show up

3 - weird one here - low engine oil light is on in all range selections except drive (4rth)

4 - low coolant level light is on with coolant level good - this also worked correctly when the 3.1 was in the car

5 - cruise control also does not work and it worked when the 3.1 was in the car

Do i need to swap the gauge cluster and bcm and or anything else?

5 - abs not working and it also worked when the 3.1 was in the car

6 - gear selector indicator in dash cluster not working

the doner car is a 1998 gp gtp complete car 3.8 s.c.
the car it went in - 2002 gp s.e with a 3.1
During the swap installed the engine with pcm and engine wiring harness, picked up a 4t65e trans and put hd my diff into it, swapped the the fuel tank and pump and evap system
anyone that could chime in on this one would be awesome
 
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Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

Come on someone, 33 views and no ideas
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

isn't there a wire you have to run to the DIC for the performance shift light to work? a lot of these issues seem like wire harness mismatches, I wish I had more info for you...
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

I also swapped out the dics
Ive heard of something about that but have found it yet
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

Do you have the schematics on both engine wire harnesses where they connect into the relay center? That's likely most of the problem. 3.1 probably put a pin in a different place.

Also...if you put an HD diff into a non hd w body trans, the gear ratio is going to be 3.29 instead of 2.93. That might piss off the pcm and cause cruise and abs to not work.
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

I swapped the relay center also, the 3.1 did not have the pins inside for relay #15 - F/PMP SPD CONT, also the bottom side had a lot less pins in there for the engine/pcm harness
also i thought that the only difference between the 4t65e and 4t65e-hd was the diff and axle
 
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Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

okay banging my head on this for the last three days hears what i come up with -
The engine runs great idles smooth, at wot a little cutting out around the 4,000 rpm range and up, but still pulls hard
when this occurs these dtc's pop up - P0134-O2 sensor circuit no activity detected, P0171-system to lean bank 1, P1133-HOS2 B1-S1 insufficient switching, P1115 E CT circuit intermittent high voltage, P0730- incorrect gear ratio = THESE ONLY POP UP AT W.O.T.=
These DTC's will clear and stay cleared until W.O.T. occurs.
D.T.C. that are on constant and do not clear are - P1651-fan control relay or QDM 'B' Fault and P1672- low engine oil level lamp control circuit.
Still the range selector in the dash cluster not working right and temp gauge in dash also not working. Fan 1 never comes on but fan 2 does come on at 226 degrees.
None of this was going on in the doner car.
Ive went through checking all my relays fuses and sensors.
Would it be the best to get a 2002 engine harness, pcm, and relay control center assembly?
Until i get this figured out im using a code scanner that monitors live data to watch engine temp and temporarily wired in a switch, relay, and fuse to manually turn on and off fan 1.
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

Have you gotten pinouts on both the current car and the donor? Gm likes to change around for the hell of it. The cutting out could b from the wrong gear eatio, ask me how i know ;)
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

Did you change out the cruise control cable? And is your abs lite on.
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

1998 gp and 2002 gps engine harness connect differently to the wheel speed sensor wiring.
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

I do have both
i put the 4t65e-hd diff and axle into the 4t65e trans what else in the trans needs swapped for gear ratio?
 


Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

Nothing, just a computer tune to tell it that its got a different gear ratio now.
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

Yes i had to change both throttle and cruise control cable-they both hook up differently to the t.b.
and yes the abs light is on. I did notice wheel sesors go in differently into the harness but i was going to work on that after i get everything else working properly.
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

Kinda sucks for me i want to get a tuner but cant yet and i have no way in my area to tune it.
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

Just curious, why didnt ya just use the complete 4t65 hd from the donor?
JimSWylie said:
I do have both
i put the 4t65e-hd diff and axle into the 4t65e trans what else in the trans needs swapped for gear ratio?
Click to expand...
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

It was fried with 300,000+ miles on it tore it down clutches and sveral hard parts wasted
 


Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

And the engine was still good enuf to b worth swapping?
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

Ya definitely, engine was fully rebuilt around 200,000 miles no oil leaks good compression and runs very well
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

Ya know, if you still have the original 4t65 from the 2002 itll have the right ratio. :)
 
Re: A few problems to work out after swapping 98 gp gtp 3.8 s.c. into a 2002 gp se ca

Ya the original 4t65 is what im using with the diff and axle being the only thing i changed in it to make it hd.
 
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