Luis

Ok... here is the problem:

A few weeks ago my car started playing up. At first the engine started cutting out at 4-5Krpm... then I got a rough idle, then the CEL light came up, and finally the engine wouldn't even hold an idle.

I limped the car into the dealership, who pronounced my TPS dead. They said they reset the CEL code (07.1 according to them, whatever that is), went for a drive and the code came up again with the same symptoms. Requested repair bill: $1000.

I was planning to get a 2nd hand throttle body to save on costs but decided to do some diagnosing myself.

The code that I got from using the SCS ECU procedure was 7 short blinks and 0 long blinks. Looking at modifry's tables ( http://www.baustnet.com/honda/misc/dtc.htm ) it did seem to confirm that the TPS was the source of the problem.

However I decided to try the map sensor "tapping" fix, reset the ECU and go for a drive.

Well... The problem seems to have gone away. No CEL, no stumbling, no rough idle. Nothing but clockwork.

Now my question:

Would a stuck map sensor throw a CEL like the one I read? Would it make the engine die at idle? Or am I just having an intermittent TPS problem?

TIA.

Luis

BTW, I ran the shop manual diagnosing procedure half way thru. I was getting the specified voltage on the female TPS connector. The resistance on the TPS body male connector was a bit off, though. Spec'ed at 4.7kohms I read something like 5.3kohms. Not sure if this sufficiently off to declare it faulty.

I tried to measure voltage at the ECU with closed and open throttle, but it was bleeding impossible. Too much work getting thru all the wires to the right ones. I need better instruments and maybe a monkey to get into those tight spaces in the footwell .

2000celicaspeed

i say go test drive one and swap the tps....just kidding.......if the map whack worked dont worry about it till it comes back....sounds like your fine to me

xviper

Unfortunately, some techs have only "2 dimensional" thinking and can only go by what the diagnostic steps tell them to do. The book says to replace the TP sensor when it is out of spec, meaning to replace the whole throttle body, thus the extravagant price. I can't imagine why you can't just change the TP sensor, but I've not actually worked on it.
Since the "MAP whack" worked for you, continue to use this technique till it no longer works. Then consider a new MAP sensor, since this is a lot cheaper than a new TB. Also see if the TP sensor alone can be changed. At the very least try to clean the contacts for the TP sensor harness. It may just be corroded or dirty and that may be why the voltage and resistance is slightly out of spec.
A THOUSAND BUCKS when a "whack" will do? Geez!!!!!

Turtle

The engine will start and idle with the TPS disconnected. You get a CEL straight away, but the engine will still idle - found this out when I forgot to reconnect the TPS after doing some work once. Oops. Anyway, that might point towards the TPS not causing the stall.

The TPS sensor itself can be removed from the TB. I've done an install of an Erick's racing TB on another S2000. That re-uses the TPS sensor from the stock Honda TB. Both the Erick's and the stock TB allow for the body of the TPS sensor to be twisted. This lets you move the readings around somewhat. Depending if the problem is at the bottom, or top of the range , you may just be able to tweak the TPS position to improve things. You can setup the TPS just by measuring the resistance, but it's easier if you've an OBD-II connection so you can set it be reading what the ECU sees the throttle position as. For example, the TPS reading should be about 5% (up to 7% or so max) with the throttle closed. Also worth seeing if the TPS off another Honda TB will fit - I'm not sure if the sizes/specs are the same, but it's got to be a better option than paying Honda for a new TB should it recurr.

-Brian.