Which Tps, Mine Causes Overfuelling

[JoshGti 8]

I have fitted my Motronic mp3.1 and am trying to now get the car MOT ready, on advice from a few members on here i decided to convert to a lambda sensor instead of the mixture pot. It has made the conversion better but not 100%.

 

The engine is still over-fueling and when i put my toe down i get a nice big lot of black smoke!! It also judders on idle and cannot hold revs cleanly due to this over-fueling. I decided to wire in the k-light to see if there was any ecu problems, low and behold there is; unplugged all my sensors 1 by 1 and upon unplugging the TPS the light went out and the amount of fuel being used dropped which is good news.

 

What tps are other members with this conversion using? The one i currently have is a proper potentiometer but unsure if the ranges (should it be from 0 upwards or another number?) are correct for the ecu or its just plain faulty, pictures of initial position would also be helpful if possible??

 

Also has anyone got access to the original diagnostic tools for this ecu or know of a way to read the codes without it, making the k-light flash or something?

 

Any help greatly appreciated as always!

[welshpug 1,626]

I'm just using the one I got with the parts from a ZX, I do believe some systems had the orientation reversed which could cause an issue like this.

 

1 is earth on most diagrams I can find, seems that 2 and 3 can often be revesed, one being the 5v signal and the other the variable.

 

mine is not adjustable like the Jetronic unit, simply bolts directly on.

Edited October 10, 2011 by welshpug

[JoshGti 8]

Yeah, i used the one provided with my conversion job lot and is a little square bosh one, but the pins are offset so i had to make a little bracket up to make it sit at Throttle initial position so i assume this would be fine. As from previous posts you have replied to welshpug you know that i have had problems with wiring but i found a breaker phase 2 106 xsi and took the whole loom so the wires are all in the correct position at least.

 

I also have a solex 3 pin one kicking around which i attached and left just lying there with the engine running and it seems to help the idle a lot better but without attaching it by making up a new bracket i cannot tell if it will work under load.

 

Do you know the bosch part no off the top of your head thats on yours? As im watching one in the bay ATM that is listed for use with all MP3.1 Equipped cars.

[welshpug 1,626]

mine is a Solex unit

[[L'e$kro] 2]

The pinout on TPS sensors is not always the same

Try inverting Pins #1 and #2 and see if it works better

Nico

[JoshGti 8]

Its a decent loom that i dont fancy cutting up if i can find a tps that works. Ive fitted a new lambda and temperature sensor (a peugeot one not a patern one) and this is the only thing that i can think of that will cause as much overfuelling as im getting besides didgey injectors, but they have been ultrasonically cleaned.

 

This is the tps that is listed for the motronic equipped cars and this is the tps i have fitted currently. By taking a multimeter to it i get a range between 0.85-2.5k and the solex goes in the opposite direction from about 6.5k down to about 2.5k, i just wish i had some way of reading the fault codes!

[Anthony 1,000]

Is there not a 2 pin diagnostic plug on the loom somewhere? That's how you read the fault codes - you can either buy a reader, or you can do it yourself easily enough as it's nothing more advanced than an LED and a piece of wire (or a switch/button) to short the two pins. It's the same setup used on various early 90's Peugeot and Citroen models and I'm sure a search on Google or similar will reveal something.

 

From memory, Pug_ham had a problem with using the wrong TPS on his MP3.1 conversion due to the wiring differences - I'm sure that he'll confirm as and when he reads this, but the issue showed itself most clearly in that the engine would lose all power when you went to full throttle, as the ECU saw that the TPS was closed (due to the wiring being the wrong way around) and thus went into overrun fuel cut mode.

[welshpug 1,626]

you can extract the pins easily enough from most connectors and swap them around.

[JoshGti 8]

Found this after routing through the 106 owners club as all the 1.4 xsis seem to be the most common car with this ecu fitted it seemed a logical place to start!

 

I will be testing the above method tomorrow to pull the codes and see what happens as it says if there is a fault with the sensor it will just replace it on the ecu with a default value. (might be causing the overfuelling)

 

Unfortunately the 106 loom has those hard rubber/silicone covering up the wire ends in the ports so extracting the pins isnt so easy. I may have to resort to bullet connections to chop/change then solder when its right (worst case).

[JoshGti 8]

So wired in my k-light and used the diagnostic shortcut on the website listed. turns out i have 4 error codes with my ecu!!?! being incorrect micture adjustment from lambda which means the one i bought is faulty, battery voltage incorrect, mixture potentiometer faulty and MAP sensor faulty.

 

Reset the error codes with a new battery attached and only 3 came back (points for guessing which ones)

 

The last one worries me as its built into the ECU, anyone know of a way to test a map sensor, with a vacuum gauge of some sorts???

[welshpug 1,626]

there's no data at all for testing the map sensor, I believe it can be replaced but where you'd get a like for like replacement I don't know, probably another MP3.1, 3.2 or 5.1/2 ecu.

 

have you sorted the TPS?

[JoshGti 8]

Yeah, ive bought a 106 xsi ecu for the map sensor from the same guy i got the loom from so that was easikly sorted. De-soldering it from the ecu board was a bitch tho! If not it gives me an excuse to use my wideband setup as i found a guide to create a adjustable MAP sensor. As the MAP only kicks in at full throttle when in (i think) closed loop? So you just adjust it to the right voltage to get a 14.7 on the lambda.

 

I bought another brand new tps from a chap on ebay and its the same bosch number as mine, whipped a multimeter on it and the ranges are the same so looks like im gonna have to cut up the loom and swap the wires over to see if that helps!