I've recently had a stack of problems, High fuel consumption and appalling idle.

Much has been changed to solve this problem including a secondhand replacement Throttle Body.
Replacing the tb made FA difference and I tried other things to no avail.

Today I pulled the stepper motor out to check it.

It appears to be solid. I would expect this to be quite easy to move with the spring returning it easily to its appropriate place. But, both of mine have been almost impossible to move by hand, even after a good soaking in WD40.

? How easily does the stepper motor move when working correctly. Should I be able to pull it in and out?

? How much are stepper motors and are they easily available aftermarket?

Oh and its a Punto but I'm more likely to get an answer here than on the Punto forum 'cos you lot seem to appreciate the pleasure of getting your hands dirty

davethetrike said:

'cos you lot seem to appreciate the pleasure of getting your hands dirty

Click to expand...

this true *arc wipes the brake fluid/oil/fuel off his hands and starts tpying*

anyhoo. stepper motor shouldn't be able to move. It moves in steps, and then stays there. It isnt a solenoid it has more than two posistions.

You've probably already checked this, but high fuel consumption and bad idle are both signs of head gasket failure, also timing could be out.

If you've not already done it, i'd suggest compression testing, timing check and also getting a vacuum gauge on there to check the manifold pressure.

Have you had the plugs out, are they showing signs of over-fueling - and are they all the same?

Man you're gonna wish you hadn't asked, but, I would appreciate a way forward 'cos I'm stumped.
Changed Lambda (new) no difference
ECU (KNOWN TO BE GOOD,) no difference
whole throttle body (no difference)
fuel pump (no difference)
blown through return pipe (no difference)
spark plugs (no difference)
ht leads (no difference)
coils (no difference)
cam (no difference)
- clearances good
intake sensor

compression 1 2 3 4 175 180 130 165

Plugs at idle, sooty with number 2 flooding hence crap idle.
Idle gets worse the longer it goes.
misfire up to around 3000

Goes like stink once clear of 2000 3000

approx 15 to 20 to the gallon
not overheating

plugs correct colour at higher revs.

Apart from that its fine

SPI 1242 75 CAM (i think) gsr intake 42mm tb (not 40) 421 csc maniold, Mkcritch chip and when I have sorted this I can finish the nos set up ( around 30mins work.

you're compression test results show the problem, a variance of any more than 14 PSI (1bar) is indication of a fault.

whats the deal with the 42mm TB? the inlet manifold central bore is only 40mm - so 42mm is just going to hit a wall.

arc said:

you're compression test results show the problem, a variance of any more than 14 PSI (1bar) is indication of a fault.

whats the deal with the 42mm TB? the inlet manifold central bore is only 40mm - so 42mm is just going to hit a wall.

Click to expand...

hMM maybe 40mm then matches the manifold exactly,

OK,

What is the way forward on this Arc?

Engine,
could be shot rings?
knackered head?

Engine has done 97000
and was meant to be a test bed for a replacement engine.
I have a cinq sporting head in the garage which was meant to be prepared for the new year and all would be finished

to check for rings, you can do a wet and dry compression test. wet compression test is the same as a dry, just drop a teaspoon of oil down the spark plug hole before you do it. If the readings are vastly different, blame rings.

not likely to be rings. likely to be head gasket imo.

carry on as planned, get the cinq head ready and fitted and i suspect it'll be reet after that's been fitted

arc said:

to check for rings, you can do a wet and dry compression test. wet compression test is the same as a dry, just drop a teaspoon of oil down the spark plug hole before you do it. If the readings are vastly different, blame rings.

not likely to be rings. likely to be head gasket imo.

carry on as planned, get the cinq head ready and fitted and i suspect it'll be reet after that's been fitted

Click to expand...

Hey you've nearly cheered me up....

But, how would a knackered gasket (replaced 18 months) ago cause so much richness at idle?

And, awful lot of engines on ebay at the mo, temptation, temptation, 75 engine ? 85 16v hmmm - and 85 16v with 421 mani and gsr intake , without going turbo what is the optimum? Hey, this feels like xmas shopping Hey after 3 weeks of gloom things look like fun hmmmm turbo. But, back to earth, how come the overfuelling?

because its not combusting properly, and the ecu is trying to make sense of whats going on.

oil in the cylinders will reduce the overal octane rating - so the ecu might be injecting more to compensate.

or its just that engine is using a lot more fuel because it's leaking all over the show and is generally not a happy engine!!

anything other than a 1242 SPI will need work. You could fit a 75 engine and matching ecu etc, but then u could from a 16v too. I dont know how much of a faff it is to swap looms over on the punto.

i didnt bother looking too far into using the stock ECU's for proper power upgrades, i just bought a standalone

arc said:

i just bought a standalone

Click to expand...

Don't worry this isn't endless but, could you expand on the standalone ecu?

I'm an old git who has messed with engines for far too many years but, has messed with motorcycle engines these last 20 years. Returning to cars and ecus was a bit of a shock. Know now how it all hangs together, just, but standalone ecus ?
?extra fuel injector(s)?
able to be mapped via laptop?

cost? worthwhile?

Many to choose from. Mine is OMEX, and, at the moment, it is still spaghetti.

Just a thought though. Cam timing, is it spot on?

Cheers

D

rallycinq said:

Many to choose from. Mine is OMEX, and, at the moment, it is still spaghetti.

Just a thought though. Cam timing, is it spot on?

Cheers

D

Click to expand...

Changed the cam about 6 months ago and I had no problems, do you think it could jump? Seems unlikely..

i think i mentioned cam timing a bit earlier up.

standalone ECU replaces the stock ECU with, well, a better one. Mine cost £325 - it still hasn't turned up yet though.. which tbh i'm getting rather miffed about.

it has more features, and is easier to map with more precise fuel/spark tables.

just a pain in the rectum to make it work

arc said:

i think i mentioned cam timing a bit earlier up.

standalone ECU replaces the stock ECU with, well, a better one. Mine cost £325 - it still hasn't turned up yet though.. which tbh i'm getting rather miffed about.

it has more features, and is easier to map with more precise fuel/spark tables.

just a pain in the rectum to make it work

Click to expand...

And I thought I was a masochist, I mean just leave the thing alone Unfortunately you have to fiddle a little, then a big, and then well why not. Jeez, why can't I leave it alone:devil: Sod it, blown head gasket, chance to upgrade

hmmm now if I sell.(cam the wife etc)...and then (bigger engine cam - new idea ecu).....I could ( get more bhp, torque)... (its the voices in my head).

Gonna have to pull the head now as that 130 psi is bugging me and if I pull the head well I could fit a whole new engine

I'll check timing on the strip down.
jeez I'm a looney

davethetrike said:

And I thought I was a masochist, I mean just leave the thing alone Unfortunately you have to fiddle a little, then a big, and then well why not.

Click to expand...

hehe, seen what i've started?

https://www.fiatforum.com/cinquecento-seicento/85946-christmas-chii.html

arc said:

hehe, seen what i've started?

https://www.fiatforum.com/cinquecento-seicento/85946-christmas-chii.html

Click to expand...

Now thats very funny. Perfectly logical, its working so I'll take it apart Odd thing is, I feel right at home.....
(battery in the boot is a thought, used to do that on the old fords to balance 'em out a bit)

Project punto now back on track
?last? How much should I skim off this cinq head to raise the compression a little. I'll then grind out the lumps and bumps in the ports.
+ Which gasket set, fiat or aftermarket? I must admit I fitted aftermarket with my last gaskets.

my head is skimmed to the max markers on the head, and its in the shop right now actaully being skimmed some more i dont know how much has been taken off, just 'lots'

i use spesso head gaskets. very good - if you remember to skim the head before fitting it..oops

Just been reading through your thread did ydid you take the head off? was the cam timing correct would be great to know what happened next and how it was resolved

the OP hasnt been on the forum for about 5 years according to his profile...

I've not read through the thread though so whats your issue exactly?