CasperTZE

TPS adjustment or is my TPS just bad? The car sat for the winter and then I did plugs, plug wires and belts and it wouldn’t run without being on the gas till it warms up and then when it’s warm it idles kinda rough, would not idle if it wasn’t warmed up a bit either

Tried adjusting the tps and could get it up to 0.18 with the idle at 1000-1100 but wouldn’t go anywhere higher, can’t get it anywhere close to where it should be

Just wondering if there’s anything else I should check or if you guys thing my tps is just bad now?

WondrousBread

TPS can go bad, but normally you'll see it as "dead spots" while driving. So if your problem is at idle, it's likely just misadsjusted.

There are a few ways to adjust it. The best way IMO is with the test-light, but in case you don't have it I'll tell you the voltage method:

Warm the car up all the way. Turn the car off, and turn the key back to IGN without starting the car. Take the connector and look into it from the harness side. Without unplugging the TPS, backprobe the black pin with the black multimeter probe, and the green one (I think) with the red probe. The orange wire should always read 5V IIRC.

Now that the multimeter is reading the sensor voltage, adjust it until you get 1V. Then press down on the throttle linkage a few times and let it snap back, and adjust again. Keep doing this until it's reliably returning to 1V or very near it.

It sounds like that might be what you're trying already, but that's the whole process so just make sure you're probing the correct wires and all.

The TPS also shouldn't be related to idle speed, only throttle position. On these cars the throttle-stop should never be adjusted. Idle speed is adjusted with the air bypass screw on top of the throttle body. If you adjust the idle make sure to use the bypass screw as adjusting the throttle-stop messes up the TPS.

CasperTZE

yeah I had the car warmed up all the way but it’s not really the idle it’s when your on the gas the idle isn’t too bad it’s just the tiniest bit rough, but when you touch the gas at about 3-4K rpms it starts to bog and cough or it’ll just die if you hit the gas pretty fast if your just super easy and slow on the gas and work your way up it will rev to 6k or so pretty smooth

but I did pretty much the same test I just used the connector near the airbox and when I tried to adjust it by adjusting the screw on the intake I could get it from 0.12 to 0.18 but not really any higher I didn’t touch the throttle stop one

WondrousBread

Yeah, that hesitation you're talking about is the famous "3800rpm hesitation".

It's usually caused due to poor grounds. The main suspect is the ECU harness ground at the engine, and from there the engine to body ground and the battery to body ground. Check out Aaroncakes grounding article for good pictures.

Basically when you hit 3800rpm, simultaneously the primary injector duty goes to 50% of the current duty and the secondaries come online at 50% of current duty. This transition is supposed to be perfectly smooth, but with poor ground sometimes the primaries react but the secondaries take a moment to catch up.

Hence, the big lean spike that you're feeling.

CasperTZE

yeah I read about the 3800 rpm hesitation I thought that’s what it was at first but found it weird how I could rev past it if I was easy on the gas, does that still happen with the 3800 rpm hesitation? But I’ll clean the grounds and saw something about adding some more grounds so I’ll give that a try too

Turbonut

iTrader: (1)

If no load, the secondary injectors won't come on.

WondrousBread

I would try cleaning the grounds before you add any. I briefly tried adding some grounds and found that it caused worse symptoms.