sft3303

Hey guys,

I just wanted to throw out an issue I've run into after replacing my fuel injectors. And before we get started, I have a done some searching, and also from experience, I'm just going to throw out that I think this is due to wiring and TPS (maybe vacuum?), but I'm just not sure where to go from here.

Anyways, car revs up to about 3500 rpm (higher than normal AWS sequence?) and then promptly dies. like within 5 seconds. can be kept alive (somewhat) by fiddling with the gas pedal. I had the tps (narrow range of course) set to 1000 ohms when the fast idle cam was in "warm" position (the throttle body was off the car, but all the same, it was set as it should be). Regardless, I installed everything back as best as I know how, and this is the issue I'm left with.

What confuses me most though, is that after playing "keep alive" with the engine long enough to get the needle on the temp guage halfway up, when the tps was set to 1000 ohms, the plug on the passenger shock tower wasn't agreeing. I.E., tps set to 1k ohm, niether lights on the mazda tester would be on. Also, the adjustment screw is basically screwed all the way in to get the shock tower plug method right (voltage at one side and not the other). Somewhat confusing...

I think I might go to home depot tomorrow to see if I can get components to test for vaccuum leaks (pipe to replace air filter, tapped/threaded for fitting so i can charge the intake with pressurized air, listen for leaks/spray with soapy water look for bubbles). Anyone have tips for this?

Thanks for any help guys, sorry if it's hard to understand what I'm getting across. You guys are the best.

satch

iTrader: (1)

It's likely a vacuum leak but the TPS should be set after the throttle body is installed and not before so.

sft3303

Okay. Well I went through the whole intake system today, and fiddled with the tps until it was set correctly. Car now (barely barely barely) idles. Revs from 1200 to 1600 back and forth for about 4 cycles, then dies down to like 200 rpm (like it's about to die) then runs right back to life, and repeats. Before I started having all of these issues, it would rev from 1200 to 1600 repeatedly, with no impact on drivability.

Now, with the car idling, i was able to nurse it around the block. There's MASSIVE hesitation whenever i try to rev the car under load (i.e., move the car). Free revving in neutral or with the clutch in is no big deal, but the first 20% of the throttle seems to be non-existent, then you get slapped in the back with 21% throttle.

Could this all be attributed to vaccuum? My tps seems to be fine (resistances and the plug-test values matched up this time, smooth sweep across resistance ranges), my MAF is new (like <1500 miles new), all the injectors are new (put in today). The CEL comes on whenever it's idling, but the instant i tap the gas it goes away. Last I checked was throwing codes for the tps being shorted, but i know it's not the sensor? Very confused. Any help is appreciated.

satch

iTrader: (1)

The code is usually thrown when the connection is poor so check that out.

sft3303

Will do. But would it flicker on and off if this were the case?

Also checked the BAC resistance, which came back fine (11 ohms, which according to Hayne's Manual is fine).

satch

iTrader: (1)

On an S5, pin 2F of the ECU should measure 1 volt w/key to on and the engine as warm as it possibly can get. And there are two error codes for an S5 TPS. Do you know which one you were getting?

sft3303

Both. 12 and 18.

Does pin 2F correspond to a wire on the tps pin? I.E., can I compare the voltage at the tps plug and pin 2F, and if they are different, then I know I have some sort of resistance in the wiring built up somewhere? A short perhaps?

Also, will pin 2F have voltage if I unplug the ECU? Or do I need to somehow measure this with the plug still inserted into the ecu? Sorry if that's a silly question, I'm still learning a lot about this car.

satch

iTrader: (1)

Pin 2F is the Green/Red wire at the TPS. At the ECU you would backprobe for the voltage on pin 2F (Green/Red wire) w/the plugs connected (at the TPS and the ECU), key to on and the engine completely warmed up. And if you have both codes then there is likely a poor connection. Pin 2G (Black/Green wire) is the other TPS wire. The poor connection is most likely at the TPS plug or the ECU as the wires have no intermediate connectors between the TPS and ECU. You could also unplug the TPS and see how the car runs when disconnected and the ECU defaults to a full throttle position though. The Brown/Black wire is the ground wire and it needs to be doing its job and Brown/White needs to have about 4.5 volts w/key to on and this powers the TPS. These also could be contributors to your problem.