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Technical Cold start problem but no problem when warm, 1.6 16v petrol

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Technical Cold start problem but no problem when warm, 1.6 16v petrol

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nemilosul01

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Hey i am new and i just buyed my second stilo 1.6 16v 2001.
And i have a problem that won't let me rest.
The problem is that when the engine is cold no matter of outside temperature the engine won't start ONLY if i spray fuel or put half my hand to suck less air in throttle body for like 20 seconds than car stays on idle but only after 1 minute i can press accelerator pedal without engine dying.
I came to realize that the spark is good but the car does not get fuel when cold when is warm it RUNS like new.

Things i had done so far:
-checked fuel pump pressure that is about 3.5bars exacly like the other stilo.
-changed spark plugs with genuine ones ( solved lots of problems)
-swamped the entire kit of electronics from the other stilo to check if the ecu was the problem ( swamped ecu, BCM and the cip of the key and it had the same problem)
-i changed 3 water temperature sensors ( 1 original, 1 facet, 1 vernet)
-swamped throttle body from the other stilo.
-swamped MAP sensor from the other stilo and still i have the same problem.

My big question is: What does say to the ECU when engine is cold beside temperature sensor and MAP sensor?

The old owner of the car sold the car with this problem because nobody found a solution.
 
As I was reading I was starting to think that the ECU wasn't working out that it needed a rich mixture (old-fashioned "choke") setting... but you've swapped the ECU so it's not that.

I can't remember which sensor the ECU uses to work out the temperature... but there's usually one on the radiatore and one on the thermostat. I think the ECU uses the one on the radiatore, since it has to know when to turn on the cooling fan. The one on the thermostat feeds the temperature gauge in the car (but I might be wrong/thinking about a different car.. :D )

When you took the spark plugs out, what condition were they in? It sounds like the car is running weak.. but your new plugs might show which cylinder has the problem. My suggestion is to take them out and have a look for one(s) which is clean and dry.. the others might be wet and a bit sooty or oily.

You could have one or more dirty, blocked or knackered injectors - you haven't swapped these yet - although you say the car runs "like new" when it's hot and I would expect a duff injector (or two) to make the idle a bit lumpy... or the car would run sluggish if you drove it, since a cold-start/injector problem means the injector can't deliver extra fuel when it needs to.

It's worth looking at the plugs to see if there is a difference between the cylinders. If they're all the same then that's a different problem compared to if one or two look dry and the others look wet.

Ralf S.
 
Ralf S. said:
As I was reading I was starting to think that the ECU wasn't working out that it needed a rich mixture (old-fashioned "choke") setting... but you've swapped the ECU so it's not that.

I can't remember which sensor the ECU uses to work out the temperature... but there's usually one on the radiatore and one on the thermostat. I think the ECU uses the one on the radiatore, since it has to know when to turn on the cooling fan. The one on the thermostat feeds the temperature gauge in the car (but I might be wrong/thinking about a different car.. :D )

When you took the spark plugs out, what condition were they in? It sounds like the car is running weak.. but your new plugs might show which cylinder has the problem. My suggestion is to take them out and have a look for one(s) which is clean and dry.. the others might be wet and a bit sooty or oily.

You could have one or more dirty, blocked or knackered injectors - you haven't swapped these yet - although you say the car runs "like new" when it's hot and I would expect a duff injector (or two) to make the idle a bit lumpy... or the car would run sluggish if you drove it, since a cold-start/injector problem means the injector can't deliver extra fuel when it needs to.

It's worth looking at the plugs to see if there is a difference between the cylinders. If they're all the same then that's a different problem compared to if one or two look dry and the others look wet.

Ralf S.
Click to expand...
hey there Ralf yea it is worth looking for the faulty injectors but i have a better ideea i will pull out the entire injection ramp and plug in the cable with it outside so i can see the power of each one with eye appreciation to see if one or two of the injector(s) will begging to work after 20 secounds or so while i spray fuel into throttle body to check even that problem.
And yea this engine has only one water temperature sensors,one map sensors, one camshaft sensor and one crankshaft sensor so far only the first two were changed i will do the same with the others if injectors are gonna be good.

On the other hand the spark plugs looks good no signs of black near the electrod so far i must check injectors and if the engine does the same problem i wil swamp all the sensors from the other car turn by turn until i see a change if not i will get back here and wait for deckchair5 maybe he can give an ideea if he still exist here in this times...


Anyway Ralf S. Thanks alot for the ideea i will look into it and i will get back here with an answer no matter of the outcome.
 
Last edited:
nemilosul01 said:
hey there Ralf yea it is worth looking for the faulty injectors but i have a better ideea i will pull out the entire injection ramp and plug in the cable with it outside so i can see the power of each one with eye appreciation to see if one or two of the injector(s) will begging to work after 20 secounds or so while i spray fuel into throttle body to check even that problem.
And yea this engine has only one water temperature sensors,one map sensors, one camshaft sensor and one crankshaft sensor so far only the first two were changed i will do the same with the others if injectors are gonna be good.

On the other hand the spark plugs looks good no signs of black near the electrod so far i must check injectors and if the engine does the same problem i wil swamp all the sensors from the other car turn by turn until i see a change if not i will get back here and wait for deckchair5 maybe he can give an ideea if he still exist here in this times...


Anyway Ralf S. Thanks alot for the ideea i will look into it and i will get back here with an answer no matter of the outcome.
Click to expand...


Hello there i am back with my SOLUTION OF THE PROBLEM.

It took lot's of time get new injectors because i found a trusted provider that sold genuine injector for about 35 euros all 4 of them and that was the problem with the car in the end.

Thanks Ralf S. for the help and i wish a happy new year to everybody on this forum.
 
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