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Old 24th June 2019, 08:43   #1
the dutch guy
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Default 2.0 V6 poor running after 30 seconds.

Hello guys.

I had a issue with misfires, replaced the pack on nr.2 and replaced all the spark plugs with the proper stuff. (they were about 100k miles beyond their lifespan)

now it runs perfectly when cold...for 30 seconds.
after that time (its basically clockwork) the ECU seems to switch to a different program and it runs like a wet rag after that.

no errors on the dash, i plan on going to a T4 this week and hope if they see a error but the dash has not given any error so far.

i had a simmiar behaviour with a previous car but that was due to a lambda sensor that had a failed heater. but that one only did that when cold, once the exaust heated up it ran normally.

any idea what can cause this behaviour?


edit: read the codes, none were present.

Last edited by the dutch guy; 24th June 2019 at 11:59..
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Old 24th June 2019, 16:40   #2
Yorkshire GOC
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Faulty or failing crank sensor prior to complete failure can give Uneven Acceleration/Engine Misfires once the sensor has warmed up . Obviously once the sensor fails completely then you wont be able to start her at all .
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Old 24th June 2019, 20:43   #3
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Have had a similar issue after only 2 seconds, now won't start. Done all? the checks including fitting a replacement crank sensor.
I'm waiting for a T4 but in the meantime have used a Pscan with no relevent fault codes showing.
Another thread suggested blocked air filter or collapse shannon tube, but this was renewed, however, it's something else to check
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Old 24th June 2019, 21:17   #4
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Quote:
Originally Posted by p2roverman View Post
Have had a similar issue after only 2 seconds, now won't start. Done all? the checks including fitting a replacement crank sensor.
I'm waiting for a T4 but in the meantime have used a Pscan with no relevent fault codes showing.
Another thread suggested blocked air filter or collapse shannon tube, but this was renewed, however, it's something else to check
Which car ??---
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Old 24th June 2019, 21:20   #5
COLVERT
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Quote:
Originally Posted by the dutch guy View Post
Hello guys.

I had a issue with misfires, replaced the pack on nr.2 and replaced all the spark plugs with the proper stuff. (they were about 100k miles beyond their lifespan)

now it runs perfectly when cold...for 30 seconds.
after that time (its basically clockwork) the ECU seems to switch to a different program and it runs like a wet rag after that.

no errors on the dash, i plan on going to a T4 this week and hope if they see a error but the dash has not given any error so far.

i had a simmiar behaviour with a previous car but that was due to a lambda sensor that had a failed heater. but that one only did that when cold, once the exaust heated up it ran normally.

any idea what can cause this behaviour?


edit: read the codes, none were present.
Guess it depends what a wet rag sounds like when it's running.--


Talking about wet rags-----how's your plenum chamber ???


Go look. Might have fish in it.---
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Old 24th June 2019, 22:07   #6
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Quote:
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Which car ??---

KV6 2 litre
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Old 24th June 2019, 22:24   #7
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Make sure all of the earths are connected on the coil packs

Brian
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Old 25th June 2019, 09:34   #8
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Quote:
Originally Posted by p2roverman View Post
Have had a similar issue after only 2 seconds, now won't start. Done all? the checks ...
Does that include the fuel filter Mike?

Simon
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Old 25th June 2019, 10:44   #9
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Quote:
Originally Posted by COLVERT View Post
Which car ??---
alfa 156, serval versions. and before people start: everything that broke on those cars had a big honking BOSCH MADE IN GERMANY printed on them.
Quote:
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Guess it depends what a wet rag sounds like when it's running.--
Talking about wet rags-----how's your plenum chamber ???
Go look. Might have fish in it.
it sounds like its missing pots randomly and/or misfires and it seriously/uncomfortably jerks at sub 2500rpm.
plenum has a nice little "jingle" in it. i want to rip that apart and remove the valves once it runs properly.
Quote:
Originally Posted by marinabrian View Post
Make sure all of the earths are connected on the coil packs
they all have fixed (metal) connectors, how can i check this?

Last edited by the dutch guy; 25th June 2019 at 10:50..
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Old 25th June 2019, 12:06   #10
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Following this.

I have a ZR K series that does this, starts fine, purrs away, then after 30 seconds, smells rich, lumpy tickover, and missfires under acceleration under 2500 rpm. above 2500 rpm and it's fine.
Once fully hot it runs fine, even below 2500 revs.
Baffled by it.

Pete.
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