Alfa...top end lag...help?

V

verrdann

Full member
Points
21
Location
Eastern Cape - SA
Car
alfa 156 2.0 ts
My alfa 156 2.0 TS currently reaches 180km/h and not the 216 top end attainable (flat road). I ran the vehicle briefly without the air filter, same result. The vehicle has adequate torque, overtaking and hills in 5th gear are a breeze. What I have noticed is an intermittent injector red light on the display that comes on...sometimes under acceleration, sometimes under braking, lingers and disappears.:confused: Any suggestions would be appreciated.:)
 
Top end lag.....any advice?

My alfa 156 2.0 TS currently reaches 180km/h and not the 216 top end attainable (flat road). I ran the vehicle briefly without the air filter, same result. The vehicle has adequate torque, overtaking and hills in 5th gear are a breeze. What I have noticed is an intermittent injector red light on the display that comes on...sometimes under acceleration, sometimes under braking, lingers and disappears. Not sure whether this is related or not? :confused: Any suggestions would be appreciated. :smile:
 
Re: Top end lag.....any advice?

Tyre pressures? How old is the car and what distance has it covered?

It might just need an engine decoke and a good service. As engines wear you will lose some power through compression loss in the engine.

Also try with a higher octane fuel.

Even new cars were hit and miss where not all of them could reach the quoted performance figures.
 
Re: Top end lag.....any advice?

Hi Wayne, thank you for the input. The car was overhauled 16 000 km ago and is a 1999 model, tyre pressures 2.1 all round. I will try the option of a higher octane and get back to you.
 
Re: Top end lag.....any advice?

Run some good injector cleaner through it as well for a couple of tank fulls. Do you get Redex over there?

Engine oil is another consideration and I've seen flat our runs destroy an engine because of the wrong engine oil being used.

PS: We trust you are not doing these highly illegal and dangerous speeds on the road and that you have found a decent track or airstrip to run on. :D
 
Re: Top end lag.....any advice?

Yes I do recall having seen the product in-store a while ago. I'll check whether it's still available. Engine oil is correct.

I decided to inspect the engine bay and found the Cam shaft counterbalancing belt was missing. My wife uses the car to work and she is unaware of any sudden noise from the engine bay, that might have indicated a snapping belt.

I will order a new belt. This might be why the vehicle cannot achieve top end speed. Should have it by next week. I'll let you know once fitted.:D
 
It could be something as simple as a faulty sensor, MAF/MAP or Lambda perhaps. Give the car a full service and include new ignition leads.
 
Hi, I have not received the belt yet. Will let you know when I receive and have fastened.

I am reading up on MAP/MAF and have a better understanding re: testing . I will tackle that this weekend.

I did check the injectors and all were 16.1 to 16.3 ohms. My understanding is that this indicates that all 4 injectors are in excellent condition. I did find a wire half eaten by rats which I assume effects voltage/amperage. The car is much smoother at pull away and between gears. Hardly depress the accelerator between gears.

Red injector light is still on, so I am hoping that testing the MAF sensor might reveal whether or not this is related.:)
 
The balance shaft belt is often removed by "alfisti" because the engine picks up a bit faster and seems a wee bit more agressive on pedal movements...

So it doesn't have to be a broken belt.
I've been mechanic at an Alfa specialist for four years. I've often seen 2.0 TS engines with the balance shaft belt not installed.

I also don't think that would be a problem for hitting top speed.

You'd better bring the car in at an Alfa shop for some ECU engine fault codes read out.

Hope this info is someway helpfull...
 
Thanks Dennis, I will check the wiring on the weekend. The closest Alfa dealer is 500km away. I have bought and received a OBDII device plus cables. I am considering downloading Touch Scan to try and identify the potential problem (fuel injector light), it's the full version for a 2 week trial period. Do you have any other software that you may recommend?
 
Normally the software being used is called: examiner, but this software
can't be used on a regular notebook without a special VCI module..
Don't know how to get a hold on that one

I think your software should do the trick ;)
Good luck and keep us posted :p
 
HI Dennis....any luck?....lol. At the moment I am unable to make any progress on the initial problem. My wife hit a rock on the way to the farm. The impact was on the front of the gearbox. Initially she said she had no reverse, but this seems to have sorted itself out. I checked the vehicle and found gearbox oil leaking between the engine and gearbox, and that the gearbox had moved back about 1mm on its mounting brackets. So at present the car is on stands and I am now going to remove motor and gearbox complete. So this is probably going to happen over the next two weeks, as I get time to attend. Hopefully gearbox and motor will be out by the end of the weekend.

At least I will be able to get stuck into the engine bay and clean it thoroughly. I'll also double check for any damaged wiring, brittle pipes, mountings, bushes etc, etc.

Have a good day and hopefully I'll be as upbeat and cheerful after 2 weeks.....lol.
 
Well, gearbox is out and there is a crack on the bracket housing where its leaking. At low speeds there is no indication of an oil leak, but at higher speeds it starts to flow out from the leak. I have taken the opportunity to send the clutch and pressure plate in to be reconditioned, and to replace the two outer drive shaft seals. Slave unit is bone dry, release bearing still good. Hopefully all will be fitted by next weekend.

1) Does anyone know what the ohm reading across both the MAF sensor and the Lambda sensor is?
2) I have cleaned the MAF sensor with Q20, what can I clean the Lambda sensor with?
 
Hi there.... damn.. that's no luck so far..
I would suggest replacing the slave unit (its the hydraulic pressure bearing for clutch engagement/disengagement?) now you've got the gearbox off.

Replacing it afterwards is a struggle...

1) Ohm-readings I'll have to check somewhere... I'll let you know..
2) What's Q20? Like breakcleaner or some other cleaning solvent?
I wouldn't clean the lambda sensor.. I would do the ohm-reading (whenever one of us finds any readings... lol ) when in doubt, replace it (although it's pretty pricy)

If you have any questions or problems, just ask ;)

Kind regards,
Dennis
 
Hi Dennis.....well the clutch, gearbox all in. Seals replaced and the gear changes are identical to my son's 156, very light and precise. Pleasure to drive.

Any progress on the MAF and Lambda readings. Car starts with a miss sometimes, switch off and then on and it's perfect.

Had initial problems with the temp but I assume that the system was not bled properly. Seems to be stable now, will monitor.
 
I have found some parameters for the lambdasensor:

At lean mixture: 200-450 mV
At rich mixture : 550-800 mV

Ideal would be: 500 mV , but it always goes up and down. Should be in that range..
You have a 4-pin stekker. For this test you should measure between pin #1 and pin #2.
Those are the (if you look at the stekker) the 2 on the right...



Ofcourse everything's gotta be measured with the engine running and at operating temp.


You can also check the resistance of the lambdasensor:

For this test, you've got to measure between pin #3 and pin #4.
These are the (if you look at the stekker) the 2 on the left.

The reading should be inbetween 8,5 and 9,5 Ohms.

IMPORTANT: Ohm readings are done with engine shut off and no ignition, so take your keys out of the car ;)
I have found practically nothing on the MAP sensor...
 
What altitude are you at and do you have a "standard" Rim and tyre setup ? recommended pressure is 2.2....(for a standard size..lower the profile high the pressure needs to be tho')
size possibilities
205/60/15
215/50/16
205/45/17
225/40/18
235/35/19

these are other factors which may influence published top end speed spec.
 
Hi, I have been busy and have not been on the site for awhile and I even forgot my password...lol.... The latest....sold the other car (1999 model) after making repairs to buyers satisfaction. Bought another 156 (2001 model), this had 171 000km but a replacement motor (60 000km) had been placed into the car by previous owner who had put on approx 2 000km. What a different car compared to my older 156! This one revs freely and cruises effortlessly up hills, what a pleasure.

I did have the dreaded injector light after about 3 000km and found that this was caused by a faulty relay for the radiator fan, this also affected the performance of my aircon. Strange that it should reflect via the injector light. No genuine alfa relay was readily available in my area, so I bought a universal unit and modified the fittings as a temporary fix, the rating is identical.

All this car needs is a firmer suspension as she leans into the corners and bottoms out with 2 passengers in the rear, even though the shocks and coil springs are brand new. I am propably going to replace the rear coil springs with firmer coil springs.

Lastly, no problem with this vehicle reaching top end..........never solved this problem in the other vehicle. I assume it was motor related.
 
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