Tachometer going the wrong way after 5000rpm
Tachometer going the wrong way after 5000rpm
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Discussion

jonlodge

Original Poster:

59 posts

251 months

Wednesday 5th December 2007
quotequote all
Has anyone got any idea why the tachometer starts going the wrong way, madly, at anything over 5000rpm when I've got her well warmed up?
I also recently suffered an inability to start the car on the key; no click or whirr etc, but she did bump start on a slight hill ok. The battery is ok, as were all lights, wipers and anything else electrical I could think to check.
Do you think there may be a link, possibly the immobiliser playing up?
I've replaced the dreaded Transit connector under the dash which had gven trouble for a while. Main battery earth checked, ok.
Any ideas appreciated.
Thanks, Jon.

ketvrin

3,504 posts

238 months

Wednesday 5th December 2007
quotequote all
jonlodge said:
I also recently suffered an inability to start the car on the key; no click or whirr etc, but she did bump start on a slight hill ok. The battery is ok, as were all lights, wipers and anything else electrical I could think to check.

Any ideas appreciated.
Thanks, Jon.
Hi Jon - sounds like you have a sticking starter motor solenoid... does the voltmeter dip when you turn the key ? if not then it may be the supply to your starter motor...

good luck

K wink

jonlodge

Original Poster:

59 posts

251 months

Wednesday 5th December 2007
quotequote all

[/quote]

... does the voltmeter dip when you turn the key ? if not then it may be the supply to your starter motor...

good luck

K wink
[/quote]

No, and the normally there's no reluctance from the starter. She's started fine since this incident.
Does the immobiliser cut the ignition circuit as well as the starter ?
If it does, then the immobiliser can't have been at fault for the non-starting incident.
Jon.

Barkychoc

7,848 posts

233 months

Wednesday 5th December 2007
quotequote all
I'd check the earth connection to the engine - could be this affecting the tacho aswell.

Chris

spivvy

1,535 posts

283 months

Wednesday 5th December 2007
quotequote all
jonlodge said:
Has anyone got any idea why the tachometer starts going the wrong way, madly, at anything over 5000rpm when I've got her well warmed up?
I also recently suffered an inability to start the car on the key; no click or whirr etc, but she did bump start on a slight hill ok. The battery is ok, as were all lights, wipers and anything else electrical I could think to check.
Do you think there may be a link, possibly the immobiliser playing up?
I've replaced the dreaded Transit connector under the dash which had gven trouble for a while. Main battery earth checked, ok.
Any ideas appreciated.
Thanks, Jon.
where did you get the transit connector from?
is this the one that connects the 4 wires through to the car from from the end of the ignition barrel

jonlodge

Original Poster:

59 posts

251 months

Wednesday 5th December 2007
quotequote all

[/quote]

is this the one that connects the 4 wires through to the car from from the end of the ignition barrel
[/quote]

Yes it is, IMHO. I put in some new, different (chocolate block) connectors. There is alot of current going through the earth (black) wire on this connector, which melts the surrounding plastic and causes all sorts of wierd effects.
Jon.

Roy C

4,213 posts

313 months

Thursday 6th December 2007
quotequote all
I had a similar immobiliser problem a few years back: turn the key - nothing.
The (Piranha) immobiliser was playing up. The quick fix was to disconnect a battery terminal and then reconnect to reset the system (although this also armed the alarm).

Edited by Roy C on Thursday 6th December 07:36

jonlodge

Original Poster:

59 posts

251 months

Thursday 6th December 2007
quotequote all
Thanks Chris & Roy, I'll try those tips, and report back.
Jon.

Edited by jonlodge on Thursday 6th December 08:41

V6ish

370 posts

228 months

Thursday 6th December 2007
quotequote all
Just out of interest how many people often take there S over 5000rpm on here?

I tend to back off just before but very very occasionally hit 5k when I'm peddling hard. Not sure it likes it!

jonlodge

Original Poster:

59 posts

251 months

Thursday 6th December 2007
quotequote all
Mine loves it, but not as much as I do! What a noise. Up to 2500rpm she burbles,2500-3400rpm she growls, 3400-5000rpm barking, 5000-6700 howling biglaugh
Jon.

Edited by jonlodge on Thursday 6th December 16:46

coolcatmaz

3,521 posts

231 months

Thursday 6th December 2007
quotequote all
mine loves being put at 4500/5000rpm, the noise is something else.

seems to hate dawdling along on acceleration and almost begs for you to drive it harder. I of course quite willingly at times obligue biggrin

they don't half shift as well if you get them up there.

Roy C

4,213 posts

313 months

Friday 7th December 2007
quotequote all
Absolutely fine until you bang into the rev limiter 1t 6000RPM. driving

jonlodge

Original Poster:

59 posts

251 months

Friday 7th December 2007
quotequote all
Rev limiter? What's that? Oh, I remember.....my right foot biglaugh
I obviously don't have an electronic one fitted, as, many times I have glanced at the tacho, (when it isn't going the wrong way) to see it well into the red zone; whoops redface I just can't resist.
Jon.

Roy C

4,213 posts

313 months

Friday 7th December 2007
quotequote all
jonlodge said:
Rev limiter? What's that? Oh, I remember.....my right foot biglaugh
I obviously don't have an electronic one fitted, as, many times I have glanced at the tacho, (when it isn't going the wrong way) to see it well into the red zone; whoops redface I just can't resist.
Jon.
The Ford ECU (EEC-1V) fitted to S series with 2.9 V6 has the rev limiter set to 6000rpm.

V6ish

370 posts

228 months

Friday 7th December 2007
quotequote all
Can I be sure I have a limiter on my S3c?

Although I have has my car decatted so the sound may be different to some, does anyone know what I mean when i say there is a raspy trumpetey roaring sound(?) when I loose traction say in 1st or 2nd and the revs suddenly climb high. Its the most awesome sound I have ever heard on a car, but often wonder if it is revving over 6k for a split second. I haven't got the heart to sit there in neutral and rev the car hard until the limiter kicks in

I always seem to forget to glance at the tachometre when the arse is hanging out and I've got opposite lock on! hehe

Barkychoc

7,848 posts

233 months

Friday 7th December 2007
quotequote all
V6ish said:
Can I be sure I have a limiter on my S3c?

Although I have has my car decatted so the sound may be different to some, does anyone know what I mean when i say there is a raspy trumpetey roaring sound(?) when I loose traction say in 1st or 2nd and the revs suddenly climb high. Its the most awesome sound I have ever heard on a car, but often wonder if it is revving over 6k for a split second. I haven't got the heart to sit there in neutral and rev the car hard until the limiter kicks in

I always seem to forget to glance at the tachometer when the arse is hanging out and I've got opposite lock on! hehe
Don't rev the car hard with no load - it is a really bad idea!

Although the rev limiter kicks in at 6000 revs there's inertia and various other laws of physics going on in your engine which if you rev it hard without load even if the ECU cuts the fuel/ignition at 6000 rpm the engine can't stop at 6000 revs - it could well climb much higher momentarily.

Edited by Barkychoc on Friday 7th December 11:35

jonlodge

Original Poster:

59 posts

251 months

Saturday 8th December 2007
quotequote all
Well, if I have a rev limiter, it's not working; I twice today took her into the red zone, up to 6500rpm, in 3rd, and there was no sign of any power reduction/limiter effect. There may be a sudden loss of power if I do this too often! I do wonder if this lack of limiter may be something to do with the tacho's strange behaviour (when she's hot) though.
I haven't located the engine earth cable yet but it may be underneath, or at least only visible from below?
Jon.

V6 Addict

Original Poster:

59 posts

251 months

Wednesday 30th July 2008
quotequote all
Solved the intermittent non-starting at last; bad connection on the main lead on the starter that failed, then welded itself on for a while, then failed again and so on. Must get underneath again and put some copper washers on to stop it happening again.
Tacho still got a mind of it's own occasionally!
Thanks for the help though.

Barkychoc

7,848 posts

233 months

Wednesday 30th July 2008
quotequote all
Be careful working on the starter connections, disconnect the battery live terminal first. Otherwise spanner on main starter terminal, other end touching chassis = short circuit straight across the battery terminals with no fuse!!

SteveOS3

503 posts

220 months

Wednesday 30th July 2008
quotequote all
No problems with my tacho, but the speedo bounces around when driving in 4th. Only with the headlights on though........