JustJeff

iTrader: (13)

So I pull my intercooler off today and go to test my TPS. The car has been idling rough, thick exhaust, scent of gas, occasional backfire and generally acting suspicious. Quick history on the car, it's a S5 JDM 13B swapped into an 89 vert using the N/A harness with pins swapped.

I didn't complete testing the TPS because I found that the rotary tech who did the swap patched wires. He used speaker wire, which the wiring beneath the insulation became corroded completely from one end to the other. From the pics you'll see it's done with crimps and one of the corroded wires broke off at the crimp as I was testing and was corroded enough that the corrosion seeped into the crimp. It's a bad pic, but you can see a dark spot. That dark spot is under the plastic insulation of the crimp.

http://s191.photobucket.com/albums/z...stjeff_photos/

The testing I did get done showed a resistance of 1.9 at idle. I never did the WOT portion of the test because I figured 1.9 was a bad enough showing and that the TPS needs replaced. Along with needing to solder the wires correctly. It wouldn't be so annoying if this wasn't the 2nd crimped patch that I found with the crimped wiring failing.

The good news is that I have a TII harness enroute and I plan on replacing the N/A one all together. Though be prepared, I may have noob questions of, "wehre does this plug go??"

Speaking of questions, there is a pic on the same link of the firewall side of the throttlebody. The coiled line on the firewall side of the TPS that connects to the throttle cable is VERY loose. This is my first TII I've owned and I'm unsure if there should be any play. I can move the coiled part around quite easily with my finger.

HAILERS

Tell you what. Read the thread I'm attaching. Read the post by the NZ guy at the bottom. Then think a bit about two wires vs buying a EM harness. https://www.rx7club.com/showthread.p...highlight=SWAP

RotaMan99

Isn't the T2 short range TPS assembly adjustable? Why not just get the resistance right if it is? The full range I think reads higher, don't hold me to that though.

JustJeff

iTrader: (13)

I was going to work on it more today. I had to go out yesterday and get some more wiring and such to replace my poor crimps with. I assumed that my corroded wiring and broken crimp was throwing the testing off.

This is what I used as reference for testing
http://fc3spro.com/TECH/HOWTO/TPS/tps.html

Craiger

iTrader: (1)

If there is a poor connection in line with what you are testing then it will throw off your resistance reading. Fix the crimps and then re-do the test.

Plus thoes insulated crimps suck anyway, to put enough pressure on them to properly crimp it you'd break right through the insulation. Used non insulated ones with heat shrink.

Arkiane

Or even better, solder and then heat shrink

JustJeff

iTrader: (13)

Thanks for the heads up Hailers. I had read that post before, I know I'm being a bit hasty with my PO'd post. I'm just frustrated because that makes the second crimped patch that fell apart in my hands.

I really do want to take out the N/A harness and start new with my own work that I can learn with. What's the line from Aliens? "I say we take off and nuke the entire site from orbit; it's the only way to be sure."

JustJeff

iTrader: (13)

So I can adjust the idle resistance?...well in theory if mine isn't too messed up. It makes sense seeing how that's part of the test procedure for testing resistance with WOT. According to FC3spro.com it should read 1k ohm resistance at rest and sweep up to between 4-6k ohmsI assume short range is the same as narrow range? Which is the CEL I've gotten 18 for TPS narrow range. So by using the adjustment screw it won't just adjust resistance on the top end but bottom end also.

JustJeff

iTrader: (13)

I ended up having a lazy day and did nothing but watch the Super Bowl. I was going to solder it all and shrink wrap...but at first I'll recrimp and test/adjust the TPS.

JustJeff

iTrader: (13)

Man I wish I knew how to quote several different posts and reply to them all with one post. I'll have to Google that when I have more time.

Craiger

iTrader: (1)

That works too. I usually crimp and solder before heat shrinking it. Overkill maybe... but I have yet to have any issues with the wireing I've done which is more than can be said about a lot of the previous owner's wireing.

HAILERS

You probably couldn't do this with the hand you were dealt, but it helps to stagger the splices so they're not all bunched up in the same location.

I'm glad you know which wire gets spliced with which wire. humor

well uhhh

Wait... Either i am confused or the op is, the TPS is adjustable. if it reads 1.9 at idle just turn the screw until it reads 1 and then manipulate the throttle to WOT a few times and check again. The olny reason to replace the TPS is if it is BAD not out of adjustment. its a different story if the adjustment doesn't stick or there are dead spots between idle and WOT.

oh **** now i see his post. sorry, im dumb.

JustJeff

iTrader: (13)

No I'm dumb, I didn't know I could adjust the bottom end of the resistance on the TPS. I'm glad I started this thread, I would have been out shopping for a TPS prematurely. I may still end up shopping for one, but time will tell.....

JustJeff

iTrader: (13)

Wow is my resistance all over the place. My choices for ohm settings are 200, 2k, 20k, 200k ohms and up. I've got the meter set on 2k ohm and it shows 1.9 at rest, I tried adjusting it down and it only went higher. The ohm meter jumped all over the place when I moved the throttle to wide open. Sometimes would jump up to 9 ohms...sometimes to 14 ohms.

One possible problem is that my throttle body is disgustingly gunked up on the outside. I'll check FSM once I get to work, but is it safe to unbolt the spring mechanism and clean those individual parts real good with some break cleaner or gasoline?

I've got 2 spare N/A TPS and so far as I can tell the only difference between N/A and turbo is the plate the sensors are mounted to. Can I simply remove them from their plates and swap them out?

1990TurboII-75K

The FSM gives a procedure for measuring a specified Voltage for both the Narrow and Full range pots (potentiometers) at both Idle and WOT. This is the method that I have used to set the TPS.

I have read that others have measured and set the open circuit resistance to 1K ohms. However, I am not sure as how close this will get to what the ECU wants to see. The ECU measures voltage, therfore adjusting the voltage to specifications seems to me to be the best method.

If you are using an ohmeter and resistance setting make sure your scale on the meter is higher than the max resistnace that you are trying to measure. Check for opens as you very slowy move the throttle from idle to WOT.

EnsenCorp

iTrader: (1)

Good post, helped me out!

Craiger

iTrader: (1)

Did you replace all the crimps or just the ones that came apart in you hand?? If I were you I would replace all of them, since if they were all done by the same person then they probably all aren't that good.

I think why they say to measure resistance is because the voltage that gets sent to the computer is determinded by how much resistance is present at the given condition. There are less variables when he is measureing resistance accross the leads than measureing voltage, plus voltage would only be exact while the car is running and the TPS would be trickey to get at with the car running.

While you are moving the TPS the multimeter will jump all over the place, mostly because it isn't quick enough to pick up quick changes. Just rub the leads together and you will get all kinds of weird readings. When measureing WOT make sure the leads and the throttle are perfectly still or you won't get a good reading.

JustJeff

iTrader: (13)

That is very helpful indeed. Thanks for the post. I was probably moving the throttle too quickly. I took both of my spare TPS into work and tested them for resistance. I did notice much more even scaling of the ohm reading when I used a very light touch. With the meter set on 2k they both showed nearly identical resistance ranging from .4-5.90 or so. I assume that if I can get them off their N/A mounts that once they are in I can turn up the idle/resistance to 1k.

I'll do some reading on voltage testing. I'm assuming that's using the 2 light circuit tester method. I'm using the TMIC though, so making adjustments while the car is idling will be a pain.

JustJeff

iTrader: (13)

I've only replaced the suspect crimps for now. I was waiting till I had a good TPS to solder a better job on all 6...er I guess 12, 1 on each end of the patched in wiring. He had about 1 foot or so of wire creating the patch.

One question, the rotary tech who did the work has the patched wires running between the alternator and UIM. He had it nicely wrapped tight and within one of the flexible plastic cable organizers (can't think of the name of them ATM). Then it was tucked in nicely close to the frontplate and ACV My question is, do I need to worry about electrical feedback coming from the alternator? FC3Spro.com's walkthrough shows a completely different harness than my patched one and their walkthrough also shows the wiring coming off the TPS going straight back towards the firewall.

RotaryEvolution

iTrader: (30)

i've always used heat shrink and solder or at the very least i seal the connection with liquid tape and then wrap it thoroughly if it is in a tight spot. what's with all the backyard shops using speaker wire for engine harnesses lately anyways? jesus....

JustJeff

iTrader: (13)

+1

it's not even quality speaker wire, it's the cheapest of the cheap, with really thin insulation.

Killert2

[QUOTE=JustJeff;7820722]So I pull my intercooler off today and go to test my TPS. The car has been idling rough, thick exhaust, scent of gas, occasional backfire and generally acting suspicious. Quick history on the car, it's a S5 JDM 13B swapped into an 89 vert using the N/A harness with pins swapped.




when you removed the intercooler did you replace it with pvc or just leave it open?

JustJeff

iTrader: (13)

[QUOTE=Killert2;7832973]I'm not following you? It was temporarily removed so that I could get at the TPS. It sits under the TMIC. The diagnostics I've been doing have been with the engine not running.

Craiger

iTrader: (1)

I would be more concerned with the bad crimps right now rather than where the wires are being run. The stock mazda harness runs from the passanger side of the engine bay, over the right side of the engine, around the front and in underneith the UIM. With good crimps and proper insulation I imagine any noise from the alternator would be minimal or at least already accounted for. More than likely the TPS wires would have originally come out of the harness at a different spot than where they come out of your modified harness, and that's why the one on yours looks different. Also keep in mind, you have an S5 and the one in the picture is an S4, so yours is going to look different anyway.

Replace the crappy speaker wire and use good non-insulated crimps to connect the new wire, dab a bit of solder around each end of the crimp and then heat shrink each. After that, put the wire loom back around the wires and try adjusting it again. Keep in mind the stuff your following on FC3Spro.com is for an S4 (single TPS) and you have an S5 (dual TPS) your readings are going to be different since if i'm correct one TPS is for when the throttle is mostly closed and it changes to the other when you move toward WOT (don't quote me on this since i am not familiar with the S5 TPS). Either way, your readings may not be the same. Hope this helps.