Steve8091

I have another active post regarding my mini-me, but I thought I'd post new for this specific issue. I have a D16Y7 block with a D16y8 head, intake manifold, and throttle body. I have the original y7 ECU. I get an error code 1509 (throttle speed issue). I have a few issues that I believe are probably all being caused by the same thing.

1. RPM's are high, approximately 1600 at idle.

2. RPM's oscillate between 1500 and 1700, about twice per second, at idle.

3. The car does not accelerate until the idle RPM's are met, at which point it jerks forward, particularly in lower gears. In other words, my acceleration hesitates when I hit the gas, until I reach ~1600 rpm, at which point it lunges forward and acclerates as normal.

Thus far I've cleaned out my IACV, which had no effect. I've seen other threads on which people describe exactly these symptoms, but I never found one that came to a conclusive resolution. Does anyone have any experience with these specific issues?

rick_rabies

was your motor originaly the one with the TB on the top?
if so. the tps sensor

the 3 wires. leave the middle one alone. and switch the outside to around....
because as of right now your motor reads throttle backwards..

l337h4l

TPS needs to be adjusted it probably thinks it is open

Bwill9886

As the others have said, its most likely the TPS.

Adjust your WOT first to about 4.5v (adjusting the whole TPS sensor using the attachment screws).

Then your idle to anywhere between 0.45v to 0.49v (using the idle screw on the TB).

Steve8091

I'm reading different information in these responses.

Yes, my TB originally pointed up, and now it's on its side. Am I reading right that I have to cut, reverse, and splice the two outer wires on the connector? I've not heard of that before, in all of the mini-me posts I've read. Maybe I'll dig into the wiring diagrams in the Helm's manual.

Can you give me more detail or a link as to how to adjust the WOT and idle on the throttle body? I assume that this is only intended to solve the high idle RPM, not the hunting issue.

Thanks for the help, all.

EDIT: I just reviewed Helm's, pages 23-8 (y7) and 23-10 (y8), and both show the YEL/BLU going to reference voltage and RED/BLK going to ground, so I don't think it's a matter of reversing these wires. Also, if it is reading that voltage differential and it was backward, why would that cause the idle to hunt? I'm not trying to discount what you're suggesting; I'm just trying to understand.

Former User

I also think the Y7 and Y8 TPS connectors are the same. Might the TPS connector be swapped with another compatible sensor connector?

Steve8091

I've tried that; there are two adjacent connectors on the throttle body. I switched them, and the car essentially died on throttle, so I am assuming that they are correct as-is. I suppose I could check the wire colors to be certain.

I was surprised to see so many comments on the TPS right away - most troubleshooting guides I've read point at that as a last resort, as those rarely fail. I expected to hear more about vacuum leaks or the IACV (or the FITV, which are only on models prior to 1996).

I'm still wide open to suggestions. I think that when I get a moment, I will check the voltages on the TPS to see if they're in line.

l337h4l

did you reuse the old gasket and possibly have a vacuum leak? Intake or TB gasket double check all vacuum lines

rick_rabies

my friend had a y7 then put a gsr motor in
he swapped the 2 outside pins on the tps plug and it ran so much better

Bwill9886

You are correct that they don't often fail, but your initial post about you having changed the TB and IM is what led me (and maybe some others) to think of the TPS. This sensor often must be readjusted whenever you reinstall it. At least, thats what I've noticed.

Adjusting the WOT is just adjusting the whole sensor counterclockwise and clockwise depending on which way you need the voltage to go (I can't quite remember which way corresponds to up or down in voltage, sorry). Just loosen the screws that attach it to the TB and play with it until you get it right.

Hope that helps. Good luck.

Steve8091

Just thought I'd post a follow up - I was able to solve the issue. It was the IACV - it was bad. I replaced it with another used one, and the issue disappeared. Thank you all for your help.