6k Limiter Issue, Graphs Inside.

[f0xy]

Thought I would post up in here as im sure many people wont go through the pages on my project thread, far to messy.

Anyway, as you may know, I cant get my 172'd Mk1 to rev past 6k. We originally thought this was down to the ECU not getting a speed reading, but now ive fixed that, and its getting a reading fine, it still wont get past 6k.

Coolant temprature sensor is all good, shows the temprature spot on. Lambda is reading fine (not that it would effect it though I dont think?!).

One wierd thing is, my TPS is reading 10% on idle, and dosent go past 90% even if im flat out, not sure if thats a true reading or what, or if it would even effect the limiter?! Not sure.

Been out for a few runs earlier to log some data....The main one is:

There is around 200 seconds of normal driving, then im stood stationary, and revving it a few times upto 3000, then one blip to 5000ish. I pull away and hit the limiter in two out of 3 gears, then slow for roundabout on my private runway.

Then pull away, hit the limiter in every gear until it tops out in 5th on the limiter, then slow down. Then normal driving until around 425 seconds, then I short shift 1st and 2nd, then full throttle it in 3rd to the limiter, limiter in 4th, then near the limiter in 5th...then slowing down again, and there is a small bit on the end of the data.

As can be seen, im hitting the limiter in every gear over a few runs (for the purpose of the log), and it never gets past 6k really. The car is fully upto temprature, and has no other problem running wise (that I know of) apart from this limiter.

So my question really is, what else effects the limiter on the ECU? I thought I had all bases covered (speed/cts etc), but it seems not. I dont want to re-map it, as there is obviously an issue somewhere, as its a 100% standard 172 Ph1 ECU.

Few other graphs....0-100mph Run...

And one showing the same run inc Throttle Position...

Thanks if anyone has any ideas!

 

[Fred@BTM]

the only cars i've seen that won't hit the limiter have had dodgy cam timing or a snapped rocker

 

[f0xy]

dodgy cam timing, uh oh....the famous words are back

how would it stop it from hitting it though?

 

[Matteh]

the only cars i've seen that won't hit the limiter have had dodgy cam timing or a snapped rocker

it's bouncing off a limiter at 6k though, not struggling to rev

 

[Fred@BTM]

actually bouncing? on just stops rev'ing?

 

[f0xy]

bouncing like it would at 7200, normal limiter action...

http://www.vimeo.com/4174092 - first 30 secs

 

[Fred@BTM]

daft question, but is the mk1 rev counter possibly out of sync because you've put a mickey mouse engine in? or are those graps data logs off an RS tuner?

 

[f0xy]

data logs off rstuner, we have fixed the rev counter after much effort, properly reads and bounces at 6k to match RSTuner

 

[Fred@BTM]

if oil and/or coolant is not upto temp that causes a lower limiter

thermostat opening? mk1 oil temp sender? or 172?

 

[Matteh]

oil temp sensor isnt connected to the ecu is it?

I've got the mk1 oil sensor on mine and it limits higher

on mine, it limits lower depending on coolant temp (like its meant to) - f0xys will limit at 6k regardless. rstuner says his coolant is running at 80-90deg... so spot on

 

[f0xy]

thermostat opens fine yes......coolant is upto temp fine, its on the logs (just not graphed).

good 10-15 mins of driving before hammering, oil plenty upto temp. Running mk1 oil level/temp sensor yeah, not connected to ECU though (just checked pin diagram, no oil related inputs?)

 

[Fred@BTM]

hum, very bizzare then!

i'm not sure on the oil temp sensor, me and electronics = no no

 

[f0xy]

Just double checked, nothing Oil related on the ECU at all...only other thing that sprung to mind is CPS, but it wouldnt run if that was knackered correct? and the knock sensor, but both are giving (what seem to be) normal readings into the logs...

 

[Matteh]

in theory if the CPS wasnt getting a signal at high rpm, it would cause the fuel and spark to be cut, so its a possibility

try moving it closer to the flywheel if possible?

 

[Fred@BTM]

i assume its a 172 crank sensor?

 

[f0xy]

yeah 172 crank sensor...

...matteh, if there is an issue with the CPS the engine wouldnt even carry on firing surely, as people who have faulty ones seem to never get the car to fire into life, just turn over....so surely the engine would cut completely if it was faulty, and not hit the 'limiter'....?!

 

[Fred@BTM]

but if its loose or something daft its theoretically possible it loosing signal at high rpm, very unlikely but considering who built the car, entirely possible

what earths are on the box/engine?

 

[f0xy]

its all spot on this one, no rig ups

earths ummm.....main one from the box to the passenger wheel arch, one on front and one on rear of box

 

[Fred@BTM]

can you find out what the MAP sensor is reading?

 

[f0xy]

coming right up

 

[Matteh]

 

[f0xy]

thanks matt......i just had a look at the data itself, at 6000rpm its at like 900odd (mBar?) not sure of the unit...

 

[Fred@BTM]

is that for jord's? what's it at on idle?

 

[Matteh]

that's f0xys, yeh

 

[f0xy]

circa 400.....395-415 ranges from.

 

[Matteh]

400-410ish

 

[Fred@BTM]

from memory thats a bit high, IIRC 300-350 is normal (i maybe way off there)

 

[f0xy]

what could cause that? my throttle position never shows below 10%, but it cant be idling high (ie. creating more manifold pressure) as its normal rpm at idle 750-800ish....

 

[Fred@BTM]

this is where i run out of brains, i would speak to Icarus or Henk next, they know more than me

thinking about it, your throttle butterfly doesn't go through a full 90degrees of movement, maybe 87degrees or something like that, maybe that could explain why you don't see a full 100%? pass, i dunno, i leave all the electronics lark to experts! LOL

 

[f0xy]

LOL...fair enough!

Had enough of this for today, sleep for me!

 

[ben_p]

LOL...fair enough!

Had enough of this for today, sleep for me!

Your throttle cable is going all the way isn't it? TB isn't jammed? Take the elbow off, get someone to hold the pedal to the floor and look to see of the valve is flat!

For the sake of 2 mins, lossen the cps and hold it closer to the box then re tighten. You need to lend soneones oem tps too try too.

Need to start ruling basic thngs out first IMO

You haven't got the cps wires the wrong way round? Or is it all unchopped on the loom?

 

[f0xy]

Throttle cable all the way yes, throttle body isnt jammed, was cleaned and all good when I built the engine up...

Will try CPS closer to the box, wires are untouched for that, only touched what I needed in the engine loom..

 

[JT182]

So, correct me if I'm wrong, the car does rev to the limiter at first, but deteriorates as the journey gets longer? Is that right?

If it is, I had the exact same problem last year with my Trophy. It revved all the way to the limiter for the first half an hour of driving say, but then it gradually got to a stage where it wouldn't rev past 5,500/6,000rpm.

Took it to Renault, and they diagnosed a problem with the fuel pump. It was replaced, and that solved the problem and it has been revving easily each and every time to the limiter ever since.

I'm not mechanically minded at all like some people on here but at first glance your problem sounds very similar to what mine used to have. Just a thought anyway and I hope you get it sorted!

 

[f0xy]

Doesn't deteriorate no. Its just got a set limiter of 6000, where it acctually bounces like it would at 7200 or whatever.

It doesnt struggle to get to 6000, drives fine and revs fine upto that, its just like thats the set limiter and it bounces off it there....

 

[Ali]

How bizarre! :S

 

[Tom@JMS]

Need to start ruling basic thngs out first IMO

Good call: Another silly suggestion but have you tried reinstalling the ecu base software & the reapplying the map? could be a corruption in the file?

 

[f0xy]

Not tried, where is the base map available from? Surely there were different variations depending on specific ECU model etc, not just engine codes?

Ruling out basic things has already been done (Its been like this for 3 weeks or more now, been trying to sort it for that long), the only thing left to try is the CPS...as said, everything else has been, Lambda/CTS/etc

 

[Tom@JMS]

I'm sure Henk would be able to send you a copy of the base software & the standard map; it would almost certainly be worth sending him the readouts as he might be able to spot something we can't.

Other than that there is always Renault :quiet:

 

[fil_b]

have you got RS tuner??

Could use one of henks maps if u know the engine code

 

[Fastchip]

Have seen something like this once, with a stripped out mk1. Airbag related if I recall correctly.
The rev limiter was at 6500 rpm ignition cut. Instead of the usual >7200 rpm Fuel cut.