EvilGSR1

I just bought a 99 GSR from my friend for cheap and it's throwing a few CEL codes.

17 speed sensor
23 knock sensor
54 crank fluctuation sensor
65 secondary o2 sensor heater

He doesn't know much about the car so I had to do a little research myself.

CEL 17- When I drove home after buying the car, everything worked. Now the speedometer does not work, but the tach does. I took a look at the speed sensor and the only thing I noticed was that the female plastic housing is chipped off on one side. My question is, would this affect the speedometer or do I need to get a new sensor? It's kind of weird that the sensor would crap out on the drive home.

CEL 23, 54, 65 - I'm almost positive that the motor is an OBD1 and swapped bc the dizzy has two sets of plugs and the engine stamp starts with 130xxxx. I pulled the ecu and it looks like it's an OBD2a P72 that has "OBD2 flashed P72" on it. I'm thinking that all three codes are thrown bc of the swap. Am I correct? If so, what would be the easiest and cheapest way to fix these codes? Would running an OBD1 ecu with a jumper harness fix everything?

The engine seems to rev high around 2k at first, then settle a little over 1k. After a light rev, the rpms decrease to 1.5k for a sec and then drop back down. Would this be fixed along with the solution above?

Also, when the engine cranks, its a loud process. Hard to explain, but it's not a normal sound. Another symptom of the swap and CELs?

Thanks in advance!

nicknack25

For your code 17, make sure the plug is still plugged in and check for kinked wires.

You say it's swapped? What motor does it have? He could've just had the wrong dizzy and wired it up to make it run. Does it have vin numbers on the motor? And do you know how to check what year the motor it is?

"The engine seems to rev high around 2k at first, then settle a little over 1k. After a light rev, the rpms decrease to 1.5k for a sec and then drop back down. Would this be fixed along with the solution above?"

-Does that sentence refer to when you first start your car? If so, at cold start, idle should be at 1.5k. Normal operating temp is 750.

"Also, when the engine cranks, its a loud process. Hard to explain, but it's not a normal sound. Another symptom of the swap and CELs?"

-How does it sound when it runs? You should check to see if everything is at TDC. And check ignition timing after.

VegasInvasion

Yeah any and all of those codes will put you in semi-limp mode causing weird idle and crappy driving.

The only sensor the OBD1 GSR engine doesn't have is CKF, but that can be bypassed easily with the CKF hack (search)

He might have used the wrong plug on the VSS. But yeah this sensor pretty much always gets broken when people do swaps, replace it.

Since it's a swap, the car isn't wired for a knock sensor, which also means it's not wired for IAB. Or he broke the knock sensor during the swap, very likely. If either of those are the case, I'd go OBD1, chip it, and disable the codes.
Wire in or remove IAB if you want, OR just get a better intake manifold.

The secondary O2 usually dies during a swap because they dropped the exhaust and ripped out the wires (or it got chopped up on the heat shield which can cause a couple fuses to blow). Replace it, or go OBD1.

Ok just convert to OBD1.