Throttle position TPS replaced and nothing!

[maddog_187]

Ok sense replacing the ecu with a used one I had laying around I have had a cel 14 (Throttle Position sensor). I finally broke down and ordered one and replaced it and still have the same problem I've checked volts at the ecu and set it to .49, I checked resistance between pin 4 and 1 and am getting 6.03 ohms. I even checked my last sensor I was replacing and it too checks out good (should have done it first ) When I use datalogger I show .3% and does not move when you give it throttle. Where else should I start looking?

Thanks

 

[Colt4G63 also]

I'm 100% sure the California ECU does't have a totally different pinout than the federal. It just has two added pins for EGR temp and EGR control. If you want to read what the ECU is seeing, check the signal voltage from the TPS at pin #19 at the ECU. You need a digital graphing meter to get an accurate reading without interfering with what the ECU sees.

Here's a schematic that covers Federal and California:

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It's a 90 diagram, so if you want to make it 91+, just reverse 6 and 14.

Edit: By the way, you may be particularly intrested in pin 23, since all it does is provide power for your TPS and airflow sensor, which happens to be where your BARO sensor resides.

 

[steve]

It looks like steves post says a Federal can't be swapped for the California ecu. Im sure that that is correct even if you swap pins 6 and 14. Pins 6 and 14 are for Federal 91 through 93 in a 90 Federal.

California cars don't seem to mind Federal ECUs but they may not pass California's smog testing.

California ECUs in a Federal car throw EGR CELs and I don't remember off hand if there is a limp mode that could effect performance.

90 ECUs work ok in 91+ cars when you swap 6 and 14 but 91+ ECUs in 90 cars have problems with the tach that require additional work besides swapping 6 and 14.

There are several post on the site by me and others on the correct way to adjust the TPS on 1Gs and 2Gs. DSMLink likes 0.63v but I've never seen a car set to the factory specs of 0.48 to 0.52v that caused a problem with either DSMLink or stock. The TPS VFAQ doesn't take into account that there is a wide range of total (between pins 1 and 4) resistance in the spec for a good TPS than makes a once size fits all resistance measurement for setting the TPS invalid and just dumb luck if it turns up reading correctly. If you have a logger on a 1G just adjust the TPS for 10% or use the sensor check screen on an SAFC to set it to 0.5v. Baring either of those your measuring the voltage between pins 19 and 24 for the TPS.

Keep in mind that what the TPS reads at WOT, assuming a good TPS, is more a mechanical issue than electrical. If the throttle cable has the correct slack per the FSM then closed and opens the butterfly all the way, then what the TPS reads at WOT is what it reads and the factory ECU doesn't really care. DSMLink has additional code for clearing flooded cars by holding the throttle open when cranking but I expect Tom and Dave made provision for the fact than most cars don't read 100% at WOT.

As others have pointed out the Baro and TPS share both the +5 sensor voltage and the sensor ground wires.

 

[maddog_187]

Thanks again for the wealth of knowledge of steve

When I use the datalogger to calibrate the tps to the 10% I can't it will only show .3% no matter where I adjust it to.

I have been reading and tried all that I know of to do. The one thing I did find is I only am getting .3v from the (correct me if wrong) ecu on the harness, which should be 5 volts correct? So would I have a short some where in the wire I checked the maf and it is getting 4.98 volts on the signal wire. (so I assume the ecu is sending correct voltage if they share the same power source (pin 23)? Should I do a continuity test on the three wires then?

Let me know if I got this right:
Terminal 1 on sensor goes to pin 23 on the ecu and should be 5 volts
Terminal 2 goes to pin 19 on ecu and should be set to .48 - .52 volts (if tps is adjusted correctly)

Terminal 4 goes to pin 24 on ecu

Thanks again

 

[steve]

I have been reading and tried all that I know of to do. The one thing I did find is I only am getting .3v from the (correct me if wrong) ecu on the harness, which should be 5 volts correct? So would I have a short some where in the wire I checked the maf and it is getting 4.98 volts on the signal wire. (so I assume the ecu is sending correct voltage if they share the same power source (pin 23)? Should I do a continuity test on the three wires then?

Let me know if I got this right:
Terminal 1 on sensor goes to pin 23 on the ecu and should be 5 volts
Terminal 2 goes to pin 19 on ecu and should be set to .48 - .52 volts (if tps is adjusted correctly)

Terminal 4 goes to pin 24 on ecu

The wire has to be broken somewhere, a short would pull the +5v sensor power down everywhere.

The Green/Red wire on pin 1 of the TPS goes to the MAF pin 4 and ECU pin 23.
The Green/White wire on pin 2 of the TPS goes to ECU pin 19.
The Green/Black wire on pin 4 of the TPS goes to the MAF pin 6, ETC sensor pin 1, EGRT sensor pin 1, and ECU pins 17 and 24.

 

[maddog_187]

Once again thanks for the great information I knew you had the knowledge.

I will start checking wires tomorrow (I hope! ) and post back.

Thanks again Steve and everyone else who has been helping I will hopefully get everything full understood.

 

[maddog_187]

Ok finally had time to get back to this issue and here is what I found I think I have some wires wrong on ecu harness I don't know if I screwed up when swapping pins or what or if someone else had messed with it before but here is what I found:

Pin 6 on ecu is green/red
pin 14 on ecu is Black/Green
Pin 23 on ecu is Green

I don't get continuity on Pin 1 of the tps to ecu pin 23 but I do get it between 6

so my question now is did I swap 14 and 23 around when doing the pinouts for swapping in a 91 ecu?

What color should the ecu pin 23 be?


Ok found a color diagram and off to do some checking but anymore info in the mean time is still appreciated.

 

[steve]

Please review http://www.dsmtuners.com/forums/articles-tuning-ecu/246467-how-identify-ecu-pin-numbers.html

I'm not convinced you have the right pin numbers based on the colors and results.

 

[maddog_187]

Well once again you hit the nail on the head. I always assumed that swapping the pins that the picture showed the harness not the ecu and never bothered to look at the color of the wires. Once again the newbie mistakes attack. Well got all the wires swapped to the positions they should be but now I think from my mistake I fried the ecu because I am only getting around 1 volt out of the ecu for the sensors. I have good continuity between all wires so there is no broken wires or anything like I originally thought. I am going to try swapping in another ecu today just to make sure it is the ecu and if it is I need to find another one, or get the original fixed.

Any other ideas what would cause only 1 volt if it isn't the ecu?

Thanks again

 

[maddog_187]

Well I'm back to square one I need to buy another ecu or have one of my two fixed I swapped in my good computer from my other car and everything works perfect.

Its getting expensive being stupid!

I will learn yet!

 

[Colt4G63 also]

When's the funeral?