I have a 1988 Fiero GT with the L32 swap. The oil pressure gauge is pegged and I found there are no wires going to the oil pressure sensor. Some info I found says I have to run a wire from the C203 Tan wire down to the center pin of the oil pressure sensor. I looked at the C203 and I don't see a Tan wire. Where do I go from here?
Or you could tap into the wire on the chassis side C203 and run it to the OPS, but that wire couldn't be unplugged with the connector if you needed a cradle drop.
The C203 pin designation is 'E' for the OPS signal.
Sounds like your harness builder didn't do a very good job.
Typical swap harnesses also use the OPS circuit as a backup power feed for the fuel pump, utilizing an 88 OPS or similar. This circuit is included in case the Fuel Pump Relay fails.
[This message has been edited by olejoedad (edited 04-23-2022).]
Or you could tap into the wire on the chassis side C203 and run it to the OPS, but that wire couldn't be unplugged with the connector if you needed a cradle drop.
The C203 pin designation is 'E' for the OPS signal.
Sounds like your harness builder didn't do a very good job.
Typical swap harnesses also use the OPS circuit as a backup power feed for the fuel pump, utilizing an 88 OPS or similar. This circuit is included in case the Fuel Pump Relay fails.
Thank you for the information. The previous owner used a 2003 Lasabre wiring harness for some reason. Seems like it makes everything more difficult.
Well it just got worse. Apparently the previous owner must have ripped out the wiring on all the connectors and then just put them in where he felt like it, or trying to match the 2003 Lasabre harness. I went to C203 and where the Tan wire should be for the oil pressure gauge there is no wire at all. I clipped onto the pin below it and that's not the correct wire either. I then moved on to the same problem with the AC not having any wiring and once again at the C203 both the spots where there should be the AC clutch, and AC request, there is no wire at all.
If you want the harness repaired and to be fully functional, we should talk. I build and repair harnesses for Fiero swaps and other vehicles as well.
You wouldn't believe some of the crap jobs I've had to make right.
PM me if you are interested.
Thank's, I'll have to go through the whole thing and see if I can get the last few things working or if the whole harness has to be redone. I just can't quite figure out why they would change all the wire placements, it seems it would make it harder for them to do the swap.
How much do you charge for a full re-work?
[This message has been edited by TurboGN (edited 04-25-2022).]
My memory is that I had to add a pin to the oil pressure connector because the LeSabre has a idiot light, not a gauge.
According to my information: Oil Sender pin A to C203 pin E Oil Sender pin B empty Oil Sender pin C to Engine Block Ground Oil Sender pin D to PCM C2 pin 19
Edited EDIT: I believe that I had to either use the oil sender plug off an 88 motor or pull one off a 91-94 Cadillac 4.9L at the junkyard because the LeSabre only had the 2 pin spots.
EDIT: I have a 1999 LeSabre motor that I just bought Sunday sitting here in the garage... I went and took a picture. Memory is still good.
Also I would recommend Joe if you aren't going to do it yourself. He's been around a long time, hasn't had any issues that I have seen on here and gives plenty of free advice. He and Ryan would be my go-to's.
It is fairly easy to do if you are organized and patient. If you start cutting wires just trying to poke around, you are going to be in worse shape... and better off to pay for it upfront then later...
I pulled the oil pressure gauge and followed the Tan wire which ends at the C203 as a Whiteish wire (maybe color change due to age?) that is in the "C" pin with no wire on the opposite side. I spliced into that wire but still had a pegged gauge. I switched to a 1988 oil pressure sensor and it now works. I seem to think that I am going to be running into this kind of stuff on the last two items, A/C & Cruise control.
I pulled the oil pressure gauge and followed the Tan wire which ends at the C203 as a Whiteish wire (maybe color change due to age?) that is in the "C" pin with no wire on the opposite side. I spliced into that wire but still had a pegged gauge. I switched to a 1988 oil pressure sensor and it now works. I seem to think that I am going to be running into this kind of stuff on the last two items, A/C & Cruise control.
The 'C' pin on the C203 is for the malfunction indicator light in the instrument cluster.
The 'C' pin on an 88 OPS is for the fuel pump relay backup circuit.
The 'A' pin on the 88 OPS should be attached to C203 on the 'E' terminal.
Are you sure your posting doesn't have a typo error in it?
I pulled the oil pressure gauge and followed the Tan wire which ends at the C203 as a Whiteish wire (maybe color change due to age?) that is in the "C" pin with no wire on the opposite side. I spliced into that wire but still had a pegged gauge. I switched to a 1988 oil pressure sensor and it now works. I seem to think that I am going to be running into this kind of stuff on the last two items, A/C & Cruise control.
A friend is running into this same problem with his 3800 swap. His swap was done into an 86 GT. He is having the same issue you are (oil pressure gauge pegs as soon as the car starts up). He confirmed the pressure sender is going to the tan wire.
The oil pressure sensor he installed is for a Fiero. AC Delco part C8020, GM part # 19106700. Which looks like it's for the 87. Besides the connector being different on the one for the 88 (looks like GM part number D1808A?) did you have any other issues with switching to this connector?
After reading all this, I'll check my harness connections again. My oil pressure gauge always read toward max but I recall leaving the oil pressure sensor connection attached on the 2003 GTP harness and just wiring it in. Time to recheck.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
The oil pressure sensor he installed is for a Fiero. AC Delco part C8020,
Thanks
C8020 appears to be a switch, not a sending unit for a guage. That one closes at 9 PSI. Near zero ohms (which is same as shorted like he has) pegs the guage, makes sense he sees that. High resistance (90-100ohm) would put the guage around zero and cause light to come on.
The problem here and it shows on my 3800SC as well may not be the wiring but the sensor itself. Most of the OPS units on Rock Auto show a 2 pin pressure light switch. Although the wiring may be correct you may not have the correct oil pressure sensor but one that just triggers the idiot light.. I am running a 2003 PCM and harness with all the original connections including the power center. Does anyone know the correct sensor part number that will drive the Fiero gauge correctly??? Even the 88 2.8 L OPS have come through wrong.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
