Strange idle behaviour 2.5-16v

[Cloudini]

Hi everyone,

I hope you guys can help me out,
My 2.5-16v has this strange idle thing going on after i rebuilded the engine,

All new gaskets has been used,
Ive cleaned and checked the vacuum, idle control valve, opend up the fuel pump relay and resolderd every solder point.
But that didnt change anything,

Ive made a video of what is going on, hopefully some one of you has an idea.

https://youtu.be/-Gsjf7GJbE8

Kind regards
Wesley

[Conley]

Hallo,

Ist das bei Kaltem und warmen Motor?

Oder nur bei Warmen?

Gruß
Michael

[Steffen102992]

Oh, that doesn't sound good.... I can hear a mechanical noise coming from crankshaft...
Maybe a mechanical resistance from dry crankshaft bearings?

Please remove the spark plugs and turn/crank the engine around with a wrench if it's turning "normally"
Best is, to remove the flat-belt too...

Remove oil filter and check, if there are some metal peaces in the paper....

It seems like the engine is running against mechanical resistance. That's why it's fighting with idle control...

Did you made a oil pressure startup without spark plugs before real startup?

Did you fix the belt sided crankshaft pulley with the necessary torque? (27mm head Screw)
If not, the oil pump-drive can slip and oil pressure isn't enough.

Or does that noise come from flywheel-housing where the clutch is?

[Cloudini]

@conley, this is only with a hot (warm) engine, cold its running goed !

However, when the car get hotter, it first starts to idle higher rpm out of itself (1500rpm), when i then shut the car off (ignition off) and restart the car, it then runs like in the video of the first post

@steffen, now that i relisten the audio of the video on my iphone it really misforms the audio,im pretty sure bearings are not dry and oil pressure is good, yes i have did an oil presure start before the real actual start ! Oil was pumping in the head ! When the car is running like in the video, that is without applying throttle, but when i just slightly feed the throttle i can make it run idle perfect, by feeding throttle myself,

Everything in the engine is new and measured !
I will try to re record it tonight when the car does this !

Greetings
Wesley

[Steffen102992]

Hi ho...
That's good news!
It was only from bad audio...

Are you able to check the duty cycle? (Tastverhältnis in %)
Engine running too lean?

[Cloudini]

Hey, yes i have checked the car's CO output,

Its running slightly slighty on the lean side but not to much, within proper standards, some where arround 0.4% Vol CO
And arround 100 Vol HC, its got the Katalysator removed, but kept the lambdasonde,

However not as lean to cause this weird idle issue, im trying to find any vacuum system leaks, but so far i can not find any, im going to check the line from the fueltank to the vacuum thermostate sensor tomorrow, weird thing is, everytime the car has run, there is a good vacuum build up in the fuel tank, or, more than im use to with other cars, when i open up the fuel cap you can hear air getting sucked into the fueltank good !

[Cloudini]

I think that i may have found the issue, before i started up the car, i opend up the full fill cap of the gastank, imidiatly there was a vacuum release, then i let the car run for like 10 min, and it started to go to higher idle rpm, i again took of the fuel fill cap, again vacuum was build up in the fuel tank, maybe, the car starts too run bad because the fuel pump is having hard work fighting against the vacuum inside the fuel tank?

Where can i check the fuel tank breathings, and is the fuel tank also connected to the engine vacuum system ?

[Steffen102992]

Hi Coudini!
I didn't mean the CO or other exhaust Gases.
It's good that you checked it, but with a catalyst improved car, it's not a good way to check it out.
Remember that HC and CO behind catalyst are reduced or converted. If you want to check real emissions , you must check in front of the Catalytic converter... For example remove the o2 Sensor and measure there.

What I meant with Tastverhältnis (German) or duty cycle (English) is, that you need a special multimeter with this feature or something that works like the original "Hermann Schließwinkel - Tester) in my case I have both.... I have the Herrmann and from USA I bought a Lambda-checker from MB-codes (name of Company), for the case, that the Herrmann will be broken someday...

The duty cycle gives you many helpful information, if something is wrong.
If some electrical components of the CIS don't work correctly, the duty cycle tells you, where you must start searching.
You must imagine it like a "live monitoring with analog fault display"

The way to check it, is mostly identical to the other CIS engines like M102 8V,M103, M104 300-24v,M119....

How exactly it works is too much for me to explain, but if you search in English-speaking forums (MB-World) for example, you will find it there.

Use search like "how to check duty cycle CIS (Continuous injection system) or KE-Jetronic.

The fuel tank has a breathing line to the inside of the left fender, the is an activated carbon reservoir for the fuel Gases... If you look in engine bay, you see on left side near ABS-hydraulik block a hose coming out of the fender.... From there lines go straight to engine (pneumatic valve)

But for first tell us, what's with the duty cycle.
Leave fuel tank cap open while checking.

[Steffen102992]

You're from Holland or not?
Maybe you should contact Geert from http://www.ferrari400parts.com/
He is specialist in overhauling CIS...
He repaired one of my fuel distributiors last year.