Intermittent Slightly Sluggish Start 1.8T

[COLVERT]

Originally Posted by Yorkshire GOC

She charged up to 12.65 at rest - smart charger then said fully charged - 4 hours later back to 12.35 volts so not holding charge -will check today again. So a duff battery or possibly the alternator not working properly

But under load the battery gave 14.1 which seems OK.

Smart chargers are not to be believed when they say the battery is fully charged.

And the reason why is---------For sake of argument let's say your battery has only half of its plates working. ( The rest are coated with hard Sulphate. ) Your charger will tell you the battery is fully charged when, in truth, it's only half charged. The charger simply checks VOLTAGE, not CAPACITY.---

However a smart charger can give you a guide to the condition of the plates in your battery.

If your battery is so discharged it will only light a bulb, dimly and after a couple of hours charging your charger say FULL, you will know your battery is near the end of its useful life.

For more on this go to the Really, Really useful thread near the top of the main forum page and read a bit more about battery care. I've put more info in a couple of posts in there.

[Yorkshire GOC]

RAC came out and checked the battery, starter motor and alternator -all fine. Also no OBD codes.

However he detected a 0.6 amperes battery drain -equivalent he said to a small light draining the battery .

Will open a specific thread to see if anyone has any experience of something similar.

[Yorkshire GOC]

Did the test for failing alternator diode as per Google search- ie set multimeter to AC voltage and run the engine - if the diodes are OK there should be no AC going from the alternator into the battery or so I am given to understand - well am getting a reading of 30 AC volts which seems to point to diode failure which could explain battery drain

Yet RAC man and his test says the alternator is fine.

[COLVERT]

Just curious but how did you connect the multi-meter up??

From where to where and did you disconnect any wires ??

[Yorkshire GOC]

Hi -Set multimeter to AC Voltage lower setting- V wavy line - switched engine on - and black multimeter contact to the neg battery terminal and the red contact to the red pos post on the battery - it then gave 29-30 AC volts. Should it be done differently?

[Sheraton]

Originally Posted by Lovel

Very unusually for my runabout, these last few weeks I have been experiencing a sluggish start before the engine catches when the engine is cold. This occurs in very low outside temp and when relatively warm, perhaps 1 in 6 start ups are sluggish.

The engine runs perfectly right up to the redline once running. Excellent fuel pressure reading (not backed off or extruded elastomer at the filter housing) at shraeder valve and before the inlet manifold.

Initially I thought it was the fuel pump relay, due to my perceived lack of prime when turning the engine to ignition switch to position II, but it turns out I was getting prime. I changed the fuel pump relay out as a matter of course but this has made no perceivable difference.

I have not run T4 diagnostics yet, but now I am focusing on the cam or crank sensor. Anybody have any comments on this scenario?

How'do Gary

how much of a spark plug gap are you running ?

I'm assuming it will be reduced from MG/Rover 1.0mm spec - reducing the Gap having a positive affect under full throttle with max boost pressure - could it have a slightly negative affect on start up ignition ? just a thought



Paul.

[Lovel]

Originally Posted by Sheraton

How'do Gary

how much of a spark plug gap are you running ?

I'm assuming it will be reduced from MG/Rover 1.0mm spec - reducing the Gap having a positive affect under full throttle with max boost pressure - could it have a slightly negative affect on start up ignition ? just a thought



Paul.

Hi Paul, I hope your machine is settling in now and chalking up the miles?

I’m running on .6mm gap. I haven’t seen any staring difference with 1.0 or .6mm tbh. Worth a shout at least, I think my battery is on its last legs.

[Sheraton]

Originally Posted by Lovel

Hi Paul, I hope your machine is settling in now and chalking up the miles?

I’m running on .6mm gap. I haven’t seen any staring difference with 1.0 or .6mm tbh. Worth a shout at least, I think my battery is on its last legs.

My Car has been Great - the Engine work and New Front Suspension have Given the Car a whole new lease of life - unfortunately I'm not driving the Car daily as i have a pickup with my current job - I have been making a point of taking her for a Good run on the weekends though


I initially had issues with a standard 1.0mm Gap - slight misfire breakup with full throttle high boost acceleration - reduced to 0.75 (if i remember correct) then down to 0.60mm after i fitted my VVC Alloy Inlet Manifold, as i experienced the same breakup issue.

on a side note.... I'm still convinced fitting the VVC manifold had a positive(?) affect on the Boost I know the port mismatch between manifold/head would suggest a negative impact on airflow/performance - However, i haven't checked to verify, but I'm sure the VVC has a larger volume plenum and with the map sensor located on the Plenum - all the differences will have some affect on the airflow/pressure and performance but is it positive or negative ? I've had a max 15psi reading from my mechanical boost gauge reading direct from the spare vacuum port on the VVC Manifold (generally peaks around 12psi)... not sure what the max boost should expect to read ....... regardless, the VVC Inlet Manifold is still better



Paul.