I was wondering, what oil sending sensor, you use? I have heard that the 88 Fiero oil sensor is the correct one to use. But, I have also been told, that the others sensors are O.K. to use, as well. Are the connectors the same, on all years?
I was wondering, what oil sending sensor, you use? I have heard that the 88 Fiero oil sensor is the correct one to use. But, I have also been told, that the others sensors are O.K. to use, as well. Are the connectors the same, on all years?
If I may give my input. The 88 Fiero sensor gives the best fit and will drive the 85-87 gauges.. However, that style sensor was made in two different resistance ranges ( as it was used on many GM cars) and if its not AC Delco specific to an 88 chances are that the one that you buy locally may or may not work. I purchased one locally and had to add a 300 ohm parallel resistance to calibrate it so it would work correctly. You''ll know if you have the right sensor right away as the wrong one will peg your gauge.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE WILDCAT" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Originally posted by Dennis LaGrua: If I may give my input. The 88 Fiero sensor gives the best fit and will drive the 85-87 gauges.. However, that style sensor was made in two different resistance ranges ( as it was used on many GM cars) and if its not AC Delco specific to an 88 chances are that the one that you buy locally may or may not work. I purchased one locally and had to add a 300 ohm parallel resistance to calibrate it so it would work correctly. You''ll know if you have the right sensor right away as the wrong one will peg your gauge.
Thanks! I will keep that in mind, when I go get my oil sensor, Tomorrow. Do you know if all year Fieros have the same connectors?
The 88's got a different oil pressure sensor with a different mstyle connector which is the same style as the newer cars. You will need to replace this connector to use the 88 sensor also because most 3800's only have a two pin sensor and you need the three pin one. If you can not find a new connector some where the ones from the Astro vans are the same and are easy to come by. You can wire in and run the older style sensor but the newer ones work and fit better and are less prone to leaking. Dan
For the 98 GTP PCm the tan with black wire from the oil pressure sensor goes to PCM C2 (clear) pin 19 and the black with white goes to chassis ground. With a three pin sensor like the 88 Fiero used the third wire is for the gauge. Dan
On the oil pressure sender connector, there is A,B,C,D. Which ones go where for the computer and chassis ground? Looks to me as if A,C and D are where the wires are on the 88 sender connector. My wire colors are all three the same color, I guess its been replaced with a different connector.
If you have the three pin connector with the proper colours the black/white is ground the tan/black straight across from it goes to the PCM and the other tan on top goes to the gauge. Main thing is the two straight across from each other is ground and PCM where the one above goes to the gauge. With the van connector the orange is grounded, the gray to the PCM and again the tan on top goes to the gauge. Dan
Dan is done with harnesses... But seeing how you are in the area.. I could possibly entertain the idea of coming out and doing the harness with you one night.
I have a question. I have been looking at just about all the ECM wiring info that is out there. I find some differences in every setup that I see and the setup that I have. I have been studying the pinouts and what to hook up where, I'm finding that on the harniss that I have that some of the wires that call to be hooked up are not in my harness.
The question I have is, if there is a wire that is called for on the C1- C2 connectors and it is not there am I supposed to add the wire or is that something that isn' going to work.
i.e. C500 pin D3 this is the feed from PCM C1 pin 75 to turn on the the coolant lamp on the Fiero Gauge (I don't have a C1-75 wire)
Unfortunately GM in all their lack of wisdom made wiring differences between the different years of 3800's and models cars for 3800 engines. What is used on a GTP is not on Bonneville or other car. You need to make your harness match the PCM you are using for example the coolant light wire is used on the GTP and not Bonneville so if you are using a GTP PCM add the wire if not don't. Dan
So for the oil pressure Sensor, I have the 2 wire sensor from the 3800sc. One goes to C2 Pin 19, the other is the ground, how or where does the gauge get its reading from?
I want to included the "sport mode" button found in the GTP. It's just one wire that goes to ground right, What Pin does the wire come from?
thanks
Also me and my friends were debating this the other night. Is it better to have two power wires coming from the battery one to the alt and the other to the starter or just to have one that goes to the alt and jumps to the starter. Or does it really matter.
So for the oil pressure Sensor, I have the 2 wire sensor from the 3800sc. One goes to C2 Pin 19, the other is the ground, how or where does the gauge get its reading from?
I want to included the "sport mode" button found in the GTP. It's just one wire that goes to ground right, What Pin does the wire come from?
thanks
.
The GTP oil pressure sender won't drive the oil pressure gauge as its a switch not a gauge sensor. You'll need to use the 88 Fiero V6 sender. Also be advised that the temperature gauge will require that you use the early GTP ETS 3 pin sensor. The center pins on thse sensors are the gauge connections. As for the sport mode switch, I don't see this on any of the PCM diagrams that I have. ------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE WILDCAT" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
[This message has been edited by Dennis LaGrua (edited 03-27-2009).]
All of this has gone WAY over my head. I know wiring is very simple for me. I guess I will keep this aside until I know the donor car and then it should be clear. I would like to thank everyone for the input into this very important Fiero piece. Please, in the future be patient as I will be asking these same "stupid" questions. Big thanks to Dan for not being an ass and refusing to help the DIY. I think even with him helping the DIYer he still has more harnesses to build than he has time in which to do them.
------------------ Why fight to be accepted by people you don't actually want to be like?
Its a wire on the pcm that you can send to ground to enable performance shift...... its nothing special if you use a tuned pcm... you pretty much just want the best shift settings at all times.
I use mine for a "severe shift" mode, which puts it into a mode where it wont shift until dang near redline at part throttle.
ok so I found the performance shift Pin. C2 Pin 21 (for a 98 gtp anyways)
quote
Originally posted by Dennis LaGrua: The GTP oil pressure sender won't drive the oil pressure gauge as its a switch not a gauge sensor. You'll need to use the 88 Fiero V6 sender. Also be advised that the temperature gauge will reqire that you sue the early GTP ETS 3 pin sensor. The center pins on thse sensors are the gauge connections. As for the sport mode switch, I don't see this on any of the PCM diagrams that I have.
Now I'm a little confused for the ECT I have 3 wires.
1 Green - C500 C2 1 Yellow - C2 Pin 26 1 Black - PCM Ground
is this not correct?
The oil pressure I don't know why this is confussing me so much. So I replace the 3800sc oil pressure sensor with a 88 oil pressure sending unit (would my 85 iron duke one work?) Then wire it up Tan/Black to C2 pin 19, Black/White - chassis ground, and third wire to the gauge. Is this correct? Where do I hook into the gauge from, C203 Pin E?
Im just curious here, but I was told that I could wire pin A on the oil pressure sender, the sender wire, to the gauge and it should read. Is this correct? I guess it would be like running a single wire oil sender? Ive got some SS Competition gauges and it has a sender hookup, + and -, and then the gauge light. I assume that it will run a single wire. Anyway just kinda wanted to see if anyone might be able to enlighten me here.
ok so I found the performance shift Pin. C2 Pin 21 (for a 98 gtp anyways) Now I'm a little confused for the ECT I have 3 wires.
1 Green - C500 C2 1 Yellow - C2 Pin 26 1 Black - PCM Ground
is this not correct?
The oil pressure I don't know why this is confussing me so much. So I replace the 3800sc oil pressure sensor with a 88 oil pressure sending unit (would my 85 iron duke one work?) Then wire it up Tan/Black to C2 pin 19, Black/White - chassis ground, and third wire to the gauge. Is this correct? Where do I hook into the gauge from, C203 Pin E?
thanks for all the help guys!
As for the ECT. The center pin #C DK Green Wire is the sensing output to the temp gauge (connect to pin C2 on the C500 connector. If you had a Duke engine this wire should be tan). Pin A Or/Bl wire is the ground (low ref) and B Yellow is the temp sensor signal that goes to the PCM.
As for the oil pressure sensor. My wiring uses the GTP fuze box and fuel pump relay wiring so I only connected pin C ( the center pin) of the oil pressure sender to pin E tan wire on the C203 connector. Again use the 88 oil pressure sender which provides a 90 ohm resistive output at full pressure. There are many aftermarket senders out there that are sold as 88 Fiero oil pressure senders but provide a 120 ohm output that will pin your gauge. Use only the AC Delco senders. I wanted to get finsihed and ran down to Autozone and used an aftermarket sender and had to add a 300 ohm parallel resisitor to prevent the gauge from pegging. They sold me a generic 120 ohm sensor!!! Apparently many GM cars use a sender that looks just like the 88 Fiero unit but put out a different resistance. If you can reuse your old working Fiero sender that will work too but if it is that big can type fittiment issues can result.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, 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 "
[This message has been edited by Dennis LaGrua (edited 03-20-2009).]
I just have to jump in to say 'thank you'. As I followed this thread, it FINALLY sunk in that the one tan wire at C203, E drives both the gage and the warning light. I am using an '88 Fiero oil pressure sender with my 3800. I had made an 'oil light relay' (similar to the one used in some late 80s GMs, like the Park Ave with the digital dash). I was going to use the switch to operate a relay (rather than a back-up for the fuel pump) that would open the light circuit when the switch closed at pressure. Thanks on this one, especially to Dennis and Dan. This discussion has been very informative and enlightening! John
I just have to jump in to say 'thank you'. As I followed this thread, it FINALLY sunk in that the one tan wire at C203, E drives both the gage and the warning light. I am using an '88 Fiero oil pressure sender with my 3800. I had made an 'oil light relay' (similar to the one used in some late 80s GMs, like the Park Ave with the digital dash). I was going to use the switch to operate a relay (rather than a back-up for the fuel pump) that would open the light circuit when the switch closed at pressure. Thanks on this one, especially to Dennis and Dan. This discussion has been very informative and enlightening! John
I would not worry too much about the fuel pump (back up) secondary circuit on the oil presure sender. I just carry an extra fuel pump relay in the glove box. In the rare case that the relay goes out, I'll just plug in a new relay and get going again.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, 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 "
For the 98 GTP PCm the tan with black wire from the oil pressure sensor goes to PCM C2 (clear) pin 19 and the black with white goes to chassis ground. With a three pin sensor like the 88 Fiero used the third wire is for the gauge. Dan
I'm just wondering about this wire that goes to C2 Pin 19 - In all my pinout diagrams C2 Pin 19 is not used. So what is the point of running this wire?
The 97/98 GTP used it for oil pressure info and the 99 up GTP stopped using it. The Regal as well as many other GM vehicles that have serial data fed gauges continued to send oil pressure info to the PCM but only for feeding the oil pressure gauge. So the oil pressure info is not needed on the GTP PCM's. Dan
ok so I found the performance shift Pin. C2 Pin 21 (for a 98 gtp anyways)
Just for everyones reference; On the 2003 GTP PCM C2 connector, pins 19-21 are not used. Apparently this "performance shift" mode was only used on the earlier 4T65eHD's transmissons. I summize that it was eliminated on the 2003-up trans.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, 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 "
performance shift was actually removed from most cars in 01, but the functionality stayed in the pcm if you put a pin in the connector and grounded it.
This makes sense but in 2003 when the 4T65eHD was redesigned, I believe that the feature may have been completely removed. Regardless if we want a performance shifts we can do it very easily by adjusting the software. My trans is programmed to shift at 5550 RPM at WOT.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, 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 perf shift tables are still in the bin file on a 01-03... it has nothing to do with the actual transmission anyway, its just a shift pressure and shift point modifier.
The perf shift tables are still in the bin file on a 01-03... it has nothing to do with the actual transmission anyway, its just a shift pressure and shift point modifier.
Yes you are certainly correct about this but on my 03 PCM which I believe doesn't have switchable performance shift, the normal and performance shift table settings are identical. I believe this to be GM's answer to saving a 25 cent switch.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, 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 "
Yes you are certainly correct about this but on my 03 PCM which I believe doesn't have switchable performance shift, the normal and performance shift table settings are identical. I believe this to be GM's answer to saving a 25 cent switch.
That and maybe GM didnt like the idea of it shifting the trans harder.. who knows. some of the base shift logic changed in 01+ years too.
I am really sorry to have to do this to anyone but , Caution to anyone thinking of dealling with Dan Mcllmoyle "FIEROFLYER" I sent him $550 dollars along with my 3800 wiring harness and computer over 4 months ago. He told me it would be a couple weeks to do the new harness up and reprogram the computer. He has moved will not answer emails and the phone number he gave me is disconneted. This amounts ot fraud over $1000 dollars in Canada
