Re: TS hard starting

[David Masters <david@xxxxxxxxxxxxxxxx>]

Hekan is having trouble with a hard starting 4 cylinder Twin Spark:
> 
> I have now for ages tried to sort out why the engine on my Alfa 75 TS -89 gets
> flooded especially by cold start.

How do you know it is flooding?  Does it smell or drip fuel, or does it just crank for a long time?
  
> I must disconnect the injector cables and then it starts and get dry again.I
> have lubricated and checked all the connections. I have changed the temp
> coolant sensor the fuel and air filter.I have checked the injectors. I have
> swapped ECU to an other without any changes. I have changed spark plus and
> cleaned the ignition system. The car has a catalyser.

This sounds good.  Have you checked the Idle Position Switch? It is easiest to check it a t the computer end, but the
pinouts are at home.  You will have to pull the plenum to test the actual switch. Make sure it is working properly at the
closed position.

How did you "check" the injectors?  I have found that a constant diet of Fuel Injector Cleaner is the single most
important thing I can feed the car.  
  
  The other disturbing problem I have had is failed rotors in the distributors.  This  was hard to diagnose, as the other
  distributor would mask the problem.  The simplest test is to use a inductive strobe timing light on the plug wires to
  ensure that there is a spark.  One of the distributors is critical for startup.  I can't remember which one!

  Even with only one distributor the car runs very smoothly with no noticable problems.

> I bulit myself a LED and a trigger to test the error codes.I found out thar
> when I first put the ignition on and then pushed the the triggerbutton, the
> injectors and the idle valve and evaporating valve was tested. In order to
> test the other stuff I had to push down the button when turning the ignition
> to ON and then push it once more.

This is interesting.  There are several of us trying to do this.  Are you using the diagnostic port, and what is in your
circuit?
> 
> First I got out some codes indicating outer limits the lambda sond and that
> the coolant sensor was reading the wrong temperature.
> 
> By the second try all that was gone and the engine indicated 4-4-4-4.
> 
> Nest time it indicated 1-1-1-5. What is that??

I haven't EVER seen a list of the codes.  Where did you find the list?

> Then I swapped the ECU and all went back to 4-4-4-4. I swapped the ECU again
> and the signal remains to be 4-4-4-4-4. So everything is ok but the engine
> still misfires, seems to be slow and easily gets flooded.

I have never heard of a ECU failure, it always seems to be a dirty connection, or perhaps a failed distributor!
  
> So I am back on starting position again.
> 
> I will try to check the Lambda sond now. The car does however not consume more
> fuel than earlier.

Fuel consumption is a good guide, but again, the Lambda sensors usually degrade slowly, and won't effect startup.
Clean the battery terminals, and earth lead.  Clean all the spade connectors and their base on each side of 
the radiator support.

It almost sounds like there is a mix up in the plug lead numbering.  Have you had it all apart and possibly mixed up some
leads?  I would put rough running down to spark rather than fuel.

> Ignition seems to be a little bit jumpy when I check the timing wheel with the
> stroboscope lamp.

Try washing out the Idle Speed Controller with Electrical contact cleaner.  It may be sticky.
Or it could be the TPS as I mentioned earlier.  It can be a real problem.

> I also checked the previous sensor which I removed and that seems to work i.e.
> decreasing resitance when getting warm, although it never went down to 0
> resistance at 90 C.
> 
> The only possibility seems to be that the fuel pressure is to high, therefore
> injecting to much fuel in the engine bt on the other hand wouldn`t the car
> then consume more fuel?

Fuel pressure is also a possibility, but check the vacuum leads.  I have had to replace the 6? that are on the front radiator panel
that go into a vacuum switch, as well as all the vacuum leads on the manifold.  The cracks and leaks were hard to find, so I
have just replaced every pipe.  Fuel pipes will be next.

Vacuum leaks cause hard starting and rough running (as we would expect).

> Any advice is welcome

I hope it is useful.
> 
> Hekan W Sweden(also has a 1300GT Junior 73 and a Giulietta-80 1.8
  
Cheers,
david
-- 
1989 Alfa75 TS
2000 Alfa 156 TS
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