Jibs05

the 3 bulk head relay should be on its own loom? Have you c101 pin out? sounds like fuel pump is wired to constant?

Damn that's a clean car.

Thank you

You use the word "fluctuate" if what you mean is it changed progressively then it appears okay , if it fluctuated it means that the change was not progressive. - please clarify.

You should measure 4kohms end to end , you should measure a varying value between an end pin and the wiper (active) as the throttle is operated

If when you measure voltage you had the correct voltage at the hot end and a progressive change on the wiper then it suggests it is okay.

measuring voltage can be more reliable than resistance

OK mate. Just quoting what you said in your words so i could convey an understanding of what i was implying. The change in voltage was progressive.

Ok, did the voltage in situ test

TPS location (has yellow dot on it)

Remove the cover

And with the ignition on (engine not running) I tested the voltage to the TPS while opening the throttle slowly

So i think i have good voltage at the TPS. As 3pedals (Ron) said, there weren't any gaps or inconsistencies when operating the throttle with the multimeter in.

Anything I've missed?

If you have the TPS in situ then you should measure voltage, the operation should be either linear or logarithmic ( don't know specifics)

and you should read a proportional change in voltage as you operate the throttle, no gaps dips or significant variations.

IF you have it out of circuit then you can measure the resistance and you should equally measure a proportional change in resistance as you operate the device through its full range.

Two simple tests just pick the one that is appropriate - for Voltage the key needs to be on .

P.S. measuring with the engine running is sub optimal

"There are 3 prongs on the tps. Put one of the leads on the first prong and one of the leads on the last prong. You should get approx 4K ohms. Next, touch the leads to prongs 1 and 2 while rotating the throttle plate from the fully closed to fully open position. The resistance should flucuate from 1K to 4K ohms."

that's the test i did yesterday, although i didn't get the 4k ohms.

will try the voltage (in situ) test tomorrow afternoon and report back!

cheers!

Just in case it's not a TPS here's a quick "symptoms check" -http://www.bimmerboard.com/forums/posts/1081877 Note the value given in resistance are NOT indicating that there should be a linear or exponential scale between them, just at those positions those approximate resistances may be read. Anything drastically out may signal a problem.

All good with the M50, that was run until early '96? Similar systems I think in terms of TPS technology. Things haven't changed a hell of a lot since then.

Here's what I got from a few pages:

With the IGN ON - Test for +5v on the TPS harness from the engine, if it's not getting a good 5v there is another electrical problem causing the TPS to give out wrong data. Not sure which pin it is, but just take the + lead and probe each one to see what ya get. Get the other pin on a good ground. If you get an out of spec reading then try the - lead on another ground as it might be that that's causing the bad reading. Pays to be sure.

With IGN OFF check resistance between the TPS harness +5v pin and the DME/ECM (again you'll have to check your schematic for this) resistance should be less than 5ohms. Repeat for the common or ground wire on the TPS, if your TPS uses the chassis to ground itself then make sure it's seated cleanly.

IGN ON again - Reconnect TPS to the harness and some how work out how to probe the TPS signal wire with the sensor connected. This can be tricky, might be best to run some jumper wires from the harness to each pin of the TPS minus the signal pin which you'll probe + lead to signal wire, - lead to good ground.

That last one can be done off the car or disconnected if you have a good 5v source. You'll need to work out which pins are +5v and Ground/common and which one is the signal wire. Anyway hook it up and see if you get a nice reading of between 0.5v to 4.5v

IF the voltages are correct then there is a problem elsewhere. Most likely to be with DME/ECM but could be elsewhere. Never assume with these damn expensive computers!

Hope this helps & the info is accurate!

This is a nice write up http://www.enduringautomotive.com/tps/

- None of this info covers a 5 or 6 pin TPS... don't have any info on them

wow all that info! thank you! Obviously my search skill aren't as good as yours!

Impedance (resistance) for sure.

I'm not sure you should be measuring V+ for a TPS, it could work I suppose but it would only be approximate. (I'm open to be schooled here!)

Edit:

Despite everything said above (by everybody) if your sensor is not providing an accurate reading between _any_ range and especially if is providing *no* reading at *any* point then it is faulty. Ohms or V+ is irrelevant in these cases.

It is reading 1-2 ohms just till around half throttle, just past half it will read dead.

Just further to this, does anyone know if the TPS is the same on Vanos and non - Vanos M50B25?

Wondering if this might be the unicorn I've been searching for..........

Im hoping this for me too, if its mechanical... another can of worms.

Mine reads 1.32 - 4.25 over the full range and operates correctly, I've compared it to a known good one.

Ok cool! Is that resistance or voltage?

i was under the impression you tested TPS with voltage (between 0-5v), not resistance?

Oh? The world wide web told me to test resistance?

what engine and how are you testing?

Sorry should have mentioned this is on my project e30 with a M50B25 non vanos and 402 ecu

Yeah, I can't remember the specifics but a TPS isn't a potentiometer or simple variable resistor so simply ready the resistance won't product a nice smooth curve.

I think (as 4th gear suggests) you're supposed to test it under working voltage and measure the received current. If I recall correctly that's not exactly perfect either and a "proper" test involves graphing the resistance and return voltage against each other.

I'm pretty sure an 88 E30 uses a similar TPS to an 89 E32 - I'll try find the documents on TPS testing and link them, they are for the E32 I think but should be a similar process.

Sorry should have said this was on my e30 with a M50 engine

Hi all,

(copied from my build thread)

So i did some tests the other day on the electrics/sensors with his multimeter that is a lot flasher than mine,

the coils came back reading good, and so did the crank angle sensor and cam position sensor. so i was standing around kinda clueless as to why it did so bad at the dyno.

I checked the TPS, and at close (around 1.3ohm), to half throttle (2ohm) it reads resistance fine until i turned it just past half way. kaka. reads nothing.

Online (because its sooo reliable) has told me to look for 1-4ish ohms. Does this sound about right for a faulty TPS?

Or am i doing it wrong?

cheers!

---------------------------------------------------------- update ----------------------------------------------------------

1/11/2014

Hi all, put in some 21lb injector for my m50b30 stroker. Naturally it would hunt for idle because the tune isn't right(haven't been driving it, maybe one pull up the street then parked up).

So I purchased a chip from Euro-tuning specifying my modifications, installed the chip, reinstalled the ECU and started it up. Waited until it was near operating temperature, but its still hunts for idle. Although it does run more consistent than before and less smoke out the exhaust.

question is could my o2 or AFM be reading wrong(broken)?

I honestly don't think the chip is bad, but then again, I don't know enough about chips to make that assumption.

Here is a video of what is happening at the moment...

you will see at the end of the video i look at some black liquid on the ground, it has the consistency of water but looks black. Is it because it has been parked for a while? (2-3 weeks)

thanks for any help!

e30s are never a half hour job, take what you think it will take and then keep dreaming. haha jk. just my luck haha

nice car btw

I found out a friend of mine did electrical engineering or something or rather! (good when you ask)

So i did some tests today on the electrics/sensors with his multimeter that is a lot flasher than mine,

the coils came back reading good, and so did the crank angle sensor and cam position sensor. so i was standing around kinda clueless as to why it did so bad at the dyno.

I may have come to an answer!

I checked the TPS, and at close (around 1.3ohm), to half throttle (2ohm) it reads resistance fine until i turned it just past half way. kaka. reads nothing.

Online (because its sooo reliable) has told me to look for 1-4ish ohms. Does this sound about right for a faulty TPS?

Also if anyone has any numbers for resistance i can compare to a good working MAF from an M50NV using a 402 (or similar ECU) that would be very helpful!

cheers

Upgrading to a clio booster has made a huge difference to the brake assistance and feel, that and also a bigger MC and SS brake lines. Worth.

Good sh*t! maybe we could go for a cruise when my car is legal haha

Trip to the states anyone? haha

Made things a little bit more presentable under the hood (only presentable part of my car haha!) And also fixed an oil leak from the oil pressure sensor housing!

id like them, but i'm in Auckland

I know exactly whats wrong..it's missing a turbo

Id like to snail it, maybe later

We did some stuff today! Rich and I made a semi diy vacuum leak tester! Made from pipes found at the local hardware store,

(for some reason my s3 hates taking photos of car stuff....)

Thankfully both our cars showed no obvious signs of any leaks.

Did you do anything to address the compression when you installed the 3l crank? Seems to go down to around 9.1:1 in the M50 blocks. 140hp atw is roughly what an M50B25 delivers. Have you had the DME remapped?

haven't done anything other than a head skim, but that was only minimal. I've read that with the internals it would be around 10.1:1? i could be wrong though. The DME wasn't remapped for the dyno run. But a chip is on its way from the states that "should" help. There is something wrong with the motor past 5.5krpm. still need to figure out what. Might invest in a decent multimeter.

sick, mrs oil needs a change

Nice purchases.

If you're unable to use those Hartge rims, I'm sure I can take them off your hands

haha i'm sure! i'm gonna polish the lips and buy new bolts then sell

Did you figure out why the power output from the engine was lower than its meant to be?

one real reason was the bolts holding down the trigger wheel were only hand tight, and 2 missing. So it caused it to misfire and the trigger wheel was flopping around! tested compression which came out quite well. still need to test the coils! When shes road legal, ill be over

m30 turbo?

random touring pic

Not much to update, collecting parts at the moment

Scored these pink top injectors and fitted them, also have a chip tune from the states for this set up

Also purchased this LC-1 wideband for quite cheap!

Bought these hartge wheels, which due to a recent change in circumstances, i will be unable to use them

Because i scored these bad boys for a steal! and i need 17" minimum for them sorry for blurry pic

they are off an e38 728i

on a not so positive note, my car is 2db over the limit for an exhaust cert... with a silencer on it. need a new tip.

wow really nice GLWS

The 320i is superior to the 318i because the extra two cylinders produce a noise that justifies the small amount of extra petrol burnt

Disclaimer: I have never owned a 4 cylinder BMW, and will hand in my man card if I ever do

E30 m3?

from personal experience there are only 2 reasons why you buy the 320 e30 1) you are in the e30 series 2) to throw out the 2L and put something better in.

good working order, came out of my running m50, checked with a el'cheapo multi meter, readings came out fine. m50 had 110xxxkms when pulled from the e34, havent done more than 1500kms since.