[realaleman]

I know there have been previous threads on this subject. Touch wood, this is the only annoying problem.....so far. My Cloverleaf only had 13500 miles on the clock in less than 5 years when I purchased it. Overall it was almost immaculate. From cold the problem starts after about 15 seconds. It doesn't stall but sounds as though it only firing on 2 cylinders. Once up and running though its smooth and picks up from 1200 revs without hesitation and is linear all the way to the red line. At the end of a blast the tick over is fine. I've had the Alfa specialist over here run full diagnostics which showed no faults. Should I just keep running it and hope it settles down? Your thoughts would be welcome.

 

[piedthepiper]

With my VERY limited knowledge it sounds like it could be a MAF issue?

 

[realaleman]

Thanks for the advice. I've been told the throttle body might be sooted up due to v. low mileage (ie: lots of short runs by previous owner). I think I'll get that looked at 1st. I'll let you know how it goes.

 

[piedthepiper]

How do you clean the throttle body?

 

[realaleman]

I don't know. But I know a man who does (hopefully). I'll let you know.

 

[gibot123]

You remove the air intake pipe at the throttle body then remove and clean the flap and the inside of the air duct that the valve is in you ca see it once you remove the air pipe.:thumbs:
Use some carb cleaner or brake cleaner?
Some times the dirt build up can stop the flap closing properly allowing uneven airflow or insufficient air causing the idle to be un even.

 

[realaleman]

You remove the air intake pipe at the throttle body then remove and clean the flap and the inside of the air duct that the valve is in you ca see it once you remove the air pipe.:thumbs:
Use some carb cleaner or brake cleaner?
Some times the dirt build up can stop the flap closing properly allowing uneven airflow or insufficient air causing the idle to be un even.

You are absolutely spot on That is almost word for word what my guy said although I don't know what cleaner he will use. I will suggest what you recommended. Thanks for that. Really appreciated.

 

[gapfhild]

Hi, did it solved your problem?
I have an Alfa GT 1.8 TS (38800km)with the exactly same problem. Here is what I have done to try solve it:

- New spark plugs
- New full-kit Distribution
- New intake air filters
- Oil Change and filter
- Throttle body cleaned
- Injectors cleaned
- No past errors found in ECU

Until now, no good. All of this was done by Alfa Romeo support. Please, if you found the solution, describe it here.

Thank you!

 

[Willber G]

Erratic idle

Always look on the bright side of life.

 

[scottyf]

I just sold someone a throttle body as they borked theirs when cleaning it.
If you've done the usual adjustments I'd also check for air leaks around the throttle body.

 

[realaleman]

Hi, did it solved your problem?
I have an Alfa GT 1.8 TS (38800km)with the exactly same problem. Here is what I have done to try solve it:

- New spark plugs
- New full-kit Distribution
- New intake air filters
- Oil Change and filter
- Throttle body cleaned
- Injectors cleaned
- No past errors found in ECU

Until now, no good. All of this was done by Alfa Romeo support. Please, if you found the solution, describe it here.

Thank you!

Hi gapfhild, I have carried out pretty much the same work and checks as you have. In addition I had the O2 sensors changed and a full service. I still have some erratic idle but alot less and this disappears completely once the engine has warmed up which is pretty quickly. Overall the engine is running very sweetly and is very willing to rev. I am thinking of adding a RAMAIR Maxflow Induction Kit and, possibly a Ragazzon Stainless Steel Sports Exhaust sometime this year. An excuse to see if this improves the running more. Let me know how you get on.

 

[Leaky 156]

C&P from Grahameo


The problem is cleaning it... You certainly can, but you also don't want to damage the plastic cogs that the throttle position sensor and idle control valve operate by moving the butterfly by hand while cleaning...

Arm yourself with cotton buds, a clean lint free cloth, a helper to operate the throttle pedal, some carb cleaner spray and penetrating oil/ fluid spray.

while the induction pipe is removed out the way, turn the ignition on to MAR and get your helper to press the throttle pedal fully open.

Using the carb cleaner, give the inside of the TB a good spray... being careful not to drop the cotton buds inside the TB, start cleaning up the deposits left behind, you will usually see a ring of dirt and oil. Pay attention to the butterfly valve itself but do not apply too much pressure to it while cleaning it, just light pressure with a cotton bud soaked in carb cleaner will be fine. Around the area inside the TB, use the clean cloth to remove the deposits from the car cleaner and any dropped deposits. again, don't be tempted to move the butterfly.

Using the penetrating fluid, give the spindle bar a quick lubrication where it enters on both sides of the inner TB.
Release the throttle pedal and have a cursory look at you work to see if there is any deposits you have missed. Secure the induction pipe. Turn off ignition...
Do this next:

battery disconnect for 40 mins or alternatively leave for 5 minutes to dissipate charge and touch the two battery cables together (not the terminals on the battery of course)
Reconnect the battery.

Part 1.
1.Turn key to MAR (ignition on for 90 seconds)
2.Turn to stop for a further 90 seconds (leave key in)
3.Turn back to MAR for 90 seconds
4.After the final 90 seconds are up, start the engine but do not press the throttle and allow to idle for 15 minutes.
Your throttle position sensor and gearing is now reset to standard factory values
Part 2
Once the radiator fans kick in and the engine is finally up to optimum temperature (thus the 15 minutes wait on idle), Do not turn engine off, go for a drive right away (spirited and normal style using all gears and all rev range, 20 minutes will suffice) come back home let the car idle again until the radiator fan kicks in and switches itself off... Then turn the engine off.

Your throttle position sensor and gearing has set up for your driving habits

Job done