Fiat Coupe Club UK

Another weekend of 16v injector light misery ahead

Posted By: Blueboyracer

Another weekend of 16v injector light misery ahead - 08/06/2018 06:27

So yet another weekend will be spent by me taking something else off the car to see if I can diagnose the injector light.

Car not running lumpy at all in fact sounds and runs like a dream 99% of the time - but emissions (CO only) too high, very rarely stutters when pulling away, cold idle set to 600 having turned the brass screw which results in slightly elevated warm idle at 900 ish, but if I bring the warm idle down to 750-800 with the brass screw cold idle cannot be sustained and have to use accelerator to keep car alive when cold.

Maybe there is an air noise like blowing under acceleration which I do not recognise in my 20vt - but when I say blowing it is more like a faint poofing noise whose frequency increases with revs.

startrek still says lambda and cam sensor faults with both having been replaced.

Checked/replaced so far: -
Plugs
Leads
Cap
Rotor arm
Filter(s)
Map sensor pipe
All induction pipes
Catalytic converter
Posted By: Anonymous

Re: Another weekend of 16v injector light misery ahead - 08/06/2018 12:26

If it's still flagging sensor errors after the sensors have been replaced and errors cleared then I'd suspect the wiring to the sensors, or grounds, or the ECU itself, or maybe even dodgy new sensors. Just cause the sensors have been replaced doesn't mean the problem is gone if the errors are appearing again.

Is the 16v perhaps different from the 20v where a cam sensor error doesn't cause a non-start but causes the ECU to inject fuel on exhaust and compression strokes just to get the engine running?

ECU faults are very rare but strangely I just had a guy on ebay with a 20vt running very rich and failing on emissions and literally every sensor, pipe and fuel component had been changed with no improvement, swapped out ECU and it then ran fine... an extremely rare problem.

Or what about the fuel pressure regulator or coolant temp sensor?
Posted By: barnacle

Re: Another weekend of 16v injector light misery ahead - 08/06/2018 17:14

For the brass screw setting:

- get engine to running temp
- remove idle control connector
- tweak screw to give around 700rpm
- reconnect idle controller

revs should rise to around 850rpm. If they don't go up, then the ICV is open circuit or stuck closed. If they rise lots, then the ICV is stuck open, or a possible fault in the throttle position valve.
Posted By: Blueboyracer

Re: Another weekend of 16v injector light misery ahead - 08/06/2018 19:31

Thanks GrahamL, I can’t clear the codes with startrek on the 16vna. I will double check rest and replace sensors you suggest and double check those already done again.

Cheers for th3 walk through Neil, being lazy where is the icv?
Posted By: Anonymous

Re: Another weekend of 16v injector light misery ahead - 08/06/2018 20:17

On the 20v I think it clears any stored codes if you disconnect the battery for a minute so that's worth a try.

One way or another, I'd definitely get the codes cleared before doing any further diagnosis.
Posted By: Blueboyracer

Re: Another weekend of 16v injector light misery ahead - 09/06/2018 10:20

Ok so removed icv having found a pic of it online.
Cleaned it and put back together again.
Injector light still on.

Car ran better, no lumpy, no bunny hops, no revs dipping at junctions and pulling away.

Tried steps Neil gave re idle speeds
Disconnecting and/or reconnecting icv makes no change to idle speed.
Used brass screw to set to around 800 warm.

Will try and connect startrek console version when laptop charged to see what codes present now. Especially as disconnected battery for a fiat few minutes.
Posted By: G_Man

Re: Another weekend of 16v injector light misery ahead - 09/06/2018 13:30

Fingers crossed for you - must be a real source of frustration frown Hope I don't hit anything similar with mine in due course! Keep us posted.
Posted By: barnacle

Re: Another weekend of 16v injector light misery ahead - 09/06/2018 18:16

If it's any consolation, I've been trying to sort a hunting idle on my 16 for, ooh, ten years?
Posted By: G_Man

Re: Another weekend of 16v injector light misery ahead - 16/06/2018 11:58

BBR - any update on the injector light and did you finally get passed the MOT omissions problem .. confused
Posted By: Blueboyracer

Re: Another weekend of 16v injector light misery ahead - 29/06/2018 08:12

Spot the difference photo competition...
Experiences: the injector is on, it doesn't cold idle, the CO emissions are high, low rev pull away stumbles, fuel consumption high.

Instagram to the rescue - hopefully...
click to enlarge
Posted By: Master_Mariner

Re: Another weekend of 16v injector light misery ahead - 29/06/2018 10:13

Which one is your layout now BBR?

I'm around this weekend if you want a 20vt owner to come over and laugh at your 16vt....Uhm I mean lend a sympathetic ear?

Seriously - if you need a spare set of hands for anything - before your head explodes.

Cap on right angle?/Way?

MM
Posted By: Blueboyracer

Re: Another weekend of 16v injector light misery ahead - 29/06/2018 10:33

MM I love your messages - thanks
I have found the issue I think thanks to an instagram pal
If you look really closely - I have connected the ICV and cam sensors the wrong way round frown
Posted By: Master_Mariner

Re: Another weekend of 16v injector light misery ahead - 30/06/2018 17:20

Lol BBR,

That's what I meant - the Connector/the cap.

As it is-I maintain my 24/7 paranoia that something is just about to go wrong on a coup.

You know-the experience that at any time anything on the coupe can break/turn off/turn on/turn back off again-and then turn on and run fine for the next three years.

In general I've learnt to adopt the old Italian saying - if it ain't broke don't even look at it.

Glad the 16vt is behaving - east meet up due soon. I know several good pubs too!

Regards to you and Mrs BBR as ever,

MM
Posted By: Blueboyracer

Re: Another weekend of 16v injector light misery ahead - 01/07/2018 13:48

Some startrek outputs now everything plugged in properly
But CO emissions still too high frown
Anyone notice anything different to theirs???
Normal Idle - Engine Warm
click to enlarge
Fast Idle - Engine Warm
click to enlarge
This was before I did anything - just after I purchased car
click to enlarge
I have also now taken out the ECU and removed the chip for a bit too just in case that would help but startrek didn't look any different so no shots of that.
Posted By: barnacle

Re: Another weekend of 16v injector light misery ahead - 01/07/2018 16:42

Removing the ECU chip will make no difference; that's just an eprom which isn't altered by the processor settings. The processor remembers its configuration and learned data internally, but would show a CPU error if that wasn't being remembered properly.

Everything there looks correct and as if the ECU thinks things are correct. That implies that the mix going into the catalytic converted is correct and that the problem is after that - i.e. the cat itself isn't doing what it should.

And yet you've changed the cat, no? With a new one, or a s/h spare?
Posted By: Blueboyracer

Re: Another weekend of 16v injector light misery ahead - 01/07/2018 17:49

I replaced it with a new one from a recommended supplier on here.
Although nothing has made any difference to date.
It has to be said though the CO is so high that a cat wouldn't bring it down that much. According to the MOT testers anyway.
Lovely to get a clean bill of health on startrek I must say
Posted By: Master_Mariner

Re: Another weekend of 16v injector light misery ahead - 02/07/2018 08:51

Be interested to see what the MOT test would say if there was no cat BBR?

It does look like the cat is doing nothing at all!

Or that somehow your getting less air in at that throttle angle?

V strange! Do the readings stay the same if you take off any maf/breather pipes??

MM
Posted By: Blueboyracer

Re: Another weekend of 16v injector light misery ahead - 02/07/2018 08:58

That throttle angle does look low doesn't it
ZERO at idle
only 3 degrees at 2200 rpm
(bearing in mind it must get to nearly 90 degrees at full throttle I guess)

There is something else to check I suppose, open the throttle fully by hand and check output, as if not enough air is getting in I suppose the mixture of 14.7:1 will not be achieved, the throttle position sensor is easy to get to as well.

I wonder if anyone else has any startrek images at fast idle for comparison sake

The 16v does not have a maf, but it does have a map which provides the Manifold pressure in the output
Posted By: Master_Mariner

Re: Another weekend of 16v injector light misery ahead - 02/07/2018 09:26

Layman thoughts the more mechanical side BBR:

Blocked air hoses? Throttle too loose/reset screw in too far?

I need to learn more about the 16v's I guess.

The answer's somewhere close to hand- no hair pulling yet?

MM
Posted By: Blueboyracer

Re: Another weekend of 16v injector light misery ahead - 02/07/2018 10:03

From one layman to another, I have no hair left - this is ridiculous now.
Does anyone have comparable startrek outputs they can post up?
Does anyone actually know how to interpret the output?
Or have somewhere references on where to look for them?

All hoses (a lot of them on a 16v) clear.

Throttle seems ok and does effect immediate response when pressed and when at floor throttle body fully open.
Posted By: barnacle

Re: Another weekend of 16v injector light misery ahead - 02/07/2018 11:23

wave I do...

The ECU should be trying to set the appropriate amount of fuel to match the air that is actually measured. Because it has a narrow band lambda sensor, which can only do 'lean/rich' rather than returning an actual number, it does this - when in closed loop mode - by deliberately making things a little lean and then a little rich over a second or so, and adjusts until it gets a 50% lean/rich ratio.

If it does not see this lean/rich signal it will assume - and red light - a lambda sensor fault.

Closed loop mode is set when the throttle is closed - 0 degrees is fine on a sixteen at idle - or when it is close to a constant position; that is, when there is not much throttle movement.

Open loop mode is set when the engine coolant temperature is low, when the throttle is wide open, or when there is a fault detected on the temperature sensors, lambda sensor, or throttle position sensor.

In open loop mode it just uses an internal map of fuel values against air intake against temperature; in closed loop these are further adjusted by an offset set by the lambda sensor action indicated above.

A thought - your TPS may be set too low, so that it thinks it's in open loop mode while the throttle is partially open? Might be worth a check to see that it's set to zero at idle but starts to increase the value (on startrek) as soon as the throttle starts to move. Your mention of 3% for 2000rpm is not impossible but I would have thought a little higher would be more likely.
Posted By: Master_Mariner

Re: Another weekend of 16v injector light misery ahead - 02/07/2018 13:07

Would a crack at the inlet manifold also cause issues Barnacle?

Mind you thinking it through I presume any extra air getting in after the MAF measurement would improve the CO readings....hold on...or would the lambada read it as weak fueling?

And simply try to add more fuel?

Maybe ignore this post - likely far off the beaten track now.

MM
Posted By: Anonymous

Re: Another weekend of 16v injector light misery ahead - 02/07/2018 14:05

Exhaust leak before the lambda sensor can cause bad emissions readings.

The picture on the right (bottom of 1st page) has hose clamp missing from oil breather hose also the hose is taped up further down so may be leaking at either point. With MAF sensor (20v) that would be un-metered air but with MAP sensor (16v) maybe it doesn't matter as far as fuelling goes.
Posted By: Master_Mariner

Re: Another weekend of 16v injector light misery ahead - 02/07/2018 14:14

I am being educated today about 16v's!

Cheers Graham and Barnacle. Maybe I wasn't a million miles off.

Hope with some forum power from those much more knowledgeable then I -this will be resolved BBR!

MM
Posted By: Anonymous

Re: Another weekend of 16v injector light misery ahead - 02/07/2018 14:20

I know very little about 16v's too... have driven a 16vt a long time ago but never driven a 16v NA and have only seen pics of the 16v's engine bays, never seen any in reality. Unlike the 20vt where I think I have every part of the engine bay memorised. smile
Posted By: Blueboyracer

Re: Another weekend of 16v injector light misery ahead - 02/07/2018 17:09

Originally Posted By barnacle
A thought - your TPS may be set too low, so that it thinks it's in open loop mode while the throttle is partially open? Might be worth a check to see that it's set to zero at idle but starts to increase the value (on startrek) as soon as the throttle starts to move. Your mention of 3% for 2000rpm is not impossible but I would have thought a little higher would be more likely.

Startrek says 0 degrees at idle - as pic above says
Startrek says 3% at 2200 rpm
I will plug back in though and check startrek shows movement immediately I move the throttle
Thanks barnacle for the very in depth help, I wish I understood more

Originally Posted By grahaml
Exhaust leak before the lambda sensor can cause bad emissions readings.

The picture on the right (bottom of 1st page) has hose clamp missing from oil breather hose also the hose is taped up further down so may be leaking at either point.


The tape was removed repaired and taped up again tighter for asthestics
The missing hose clip replaced too
As the more recent pic shows on the left

An exhaust leak ahead of the lambda is possible I suppose as the flexy section looks like it’s missing mesh, I can certainly see the spring looking bit inside.

Wish I knew if it was actually leaking here, I can’t hear anything. Maybe I will jack have to jack it up and feel around.

Thanks GrahamL too

Hey MM this is a learning experience isn’t it smile
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