P38 problems; advice needed
P38 problems; advice needed
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plasticpig

Original Poster:

12,932 posts

249 months

Sunday 3rd January 2010
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Got a few issues pop up recently.

1. Got the wet drivers side carpet problem. Bit of a bugger as I tested this when buying the thing six months ago and it was fine. Is this a dash off and remove steering column job to replace the O rings?

2. The stereo has gone very quiet. I know there are individual amps in each door but is there a pre-amp as well? It's got the Harman Kardon speaker system.

3. The most worrying problem is an occasional sudden loss of power when accelerating. If I accelerate gradually I don't have a problem. If I boot it; it will accelerate to 60ish and then will lose power. I have tried shifting from D to 3 and the revs will change accordingly but this makes no difference. What's strange is if I stop and try booting it again it performs fine.










BLUETHUNDER

7,881 posts

284 months

Sunday 3rd January 2010
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The o rings can be done without dash removel. But its a pig of a job. You say the radio has gone quiet. Has "mute" come up on the display???. If so disconnect the battery to re-set.

plasticpig

Original Poster:

12,932 posts

249 months

Sunday 3rd January 2010
quotequote all
No "mute" showing on the stereo. It appears a third party hands free kit has been fitted at some point and I am wondering if this is causing the problem.

Meeja

8,290 posts

272 months

Tuesday 5th January 2010
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plasticpig said:
3. The most worrying problem is an occasional sudden loss of power when accelerating. If I accelerate gradually I don't have a problem. If I boot it; it will accelerate to 60ish and then will lose power. I have tried shifting from D to 3 and the revs will change accordingly but this makes no difference. What's strange is if I stop and try booting it again it performs fine.
I'd be interested to know what this one is... as very occasionally, mine will do this. (very, very occasionally!)

Doesn't seem to do it on LPG... only when running on petrol.

My indy hasn't managed to replicate it, as it really is that intermittant.... so can't offer an opinion/explanation.

As Bluethunder has said, the O ring replacement is no longer a "dash out" job.... but I think that a main dealer will insist that it is. Indys definately the best option here.

Edited by Meeja on Tuesday 5th January 16:42

eliot

11,988 posts

278 months

Wednesday 6th January 2010
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WRT to #3 I wonder if it’s to do with the throttle pot - as it's used to enrich the mixture on transients (changing throttle) - whereas it would be largely ignored when accelerating progressively.

Found my PDF on the gems setup - you haven't told us what you car is and its not in your profile:

This sensor is mounted on the throttle body in line with the throttle shaft. The signal varies from 0 to 5 volts, and is used (mainly) for acceleration and idle purposes. If it is changed the GEMS closed throttle voltage must be reset.

There is a default strategy. GEMS correlates throttle position with the corrected MAF, which in turn is correlated against the fuel data (injector pulse width, RPM, lambda probedata). If the TP data does not correlate correctly the TP is assumed to have failed and GEMS calculates default data from corrected MAF, which may “adversely affect acceleration performance”. The fault will illuminate the MIL light on NAS vehicles.

Edited by eliot on Wednesday 6th January 20:23

plasticpig

Original Poster:

12,932 posts

249 months

Wednesday 6th January 2010
quotequote all
It's a 99 4.6 with THOR.

eliot

11,988 posts

278 months

Thursday 7th January 2010
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plasticpig said:
It's a 99 4.6 with THOR.
Ignore the above then.
Usual stuff then - check for air leaks, check / replace plugs, leads, air & fuel filters - all of which should be cheaper than get the codes 'pulled at the local dealer.