Speedo playing up, especially when cold.

[GRPABT1]

Hey guys over the last few days I've noticed my speedo isn't working properly. When the dash is warm (not the engine) ie: in the afternoon when parked in the sun, it seems to work ok. But in the morning and at night it is rediculously slow and reads way under what it should. If I give the gauge a tap the needles flys up to about where it should be then drops back down. The needles don't seem to be bent or fouling on anything.

The car in question is a 1989 sierra with 1988 swift gti twin cam, running 235/75/15's. It has always been a little out because of the tyres but I can compensate for that but not for this.

So anyone know if it's an easy fix or am I destined to drive of the tacho revs forever?

[ScrawnC]

Possibly bearings/bushings in speedo head. Try finding another cluster to stick in, may need to fiddle with the odometer though

[Lil'Loki]

I agree with Scrawn. I've replaced the speedo cable twice in 18 months and I am starting to believe that it's in the dash/cluster.
My fuel gauge is also playing up to… It reads empty until I get down to about a third of the tank then it starts to read the level again.
If I remember rightly Gwagensteve has worked on these in another post. He'd probably be cluey to what is the problem.

[ScrawnC]

That fuel gauge problem sounds more like a sender problem rather than a dash fault

[Lil'Loki]

I should have probably mentioned that's what the gauge is doing now…
It has done other things as well, erratically reading the correct level sometimes and empty others. (eg full, empty, half full, empty, quarter).
Have spoken to a few people and they think it's the gauge side.

But hey the trip meter works fine… just have to remember to reset it when I fill up, and fill up before I reach 400km.

[ScrawnC]

Wow!! You get 400kms out of a tank? I'm lucky to get 300... It was closer to 200 when I first got it.

[GRPABT1]

Possibly bearings/bushings in speedo head. Try finding another cluster to stick in, may need to fiddle with the odometer though

I guess these are just a plug in swap, no soldering etc? What models are compatible cause mine is an 89 and I doubt the wreckers here will have many zooks.

[ScrawnC]

Should just be plug n swap with most, not sure if the later ones went electronic speedo or not?

[Lil'Loki]

Not sure, but my 1990 and 1995 both had the same style dash. Can't be too sure what year prior to 1990 they changed the dash design.

Re: the 400km range… I was only getting 345 to 350km's per tank before getting my reconditioned engine. I only had a 2" sports exhaust on the old motor. I now have Lukey extractors and 2" exhaust on the new engine. Motor's only 5000km old now. Still getting small improvements with economy and power.

PS. That 400km range is odometer reading only. With my larger tyres it's probably around 8-9% more.

[gumtree]

300km per tank is normal. either your engine is running lean or u have a really good engine.

[Lil'Loki]

Mixture's A1.

You'll find most Sierra 1.3 engines in good nick and tuned should do 10L/100km.

[GRPABT1]

On a perfectly flat road with no wind. With these things it varies to much depending on conditions to get an accurate fuel consumption measurement.

[Lil'Loki]

I drive mine hard!
I drive it in strond winds!!
I drive it up hills!!!
I still get great economy 10/100!!!!

GO THE ZOOK!!

[GRPABT1]

I drive mine hard!
I drive it in strond winds!!
I drive it up hills!!!
I still get great economy 10/100!!!!

GO THE ZOOK!!

Lucky you, what mods does it have?

[rustyvit]

300km per tank is normal. either your engine is running lean or u have a really good engine.

My 1.0L , and 1.3L ( when I had it) Sierra and my 1.6L vitara all get 10L /100 year in year out and thats all town driving .

[Lil'Loki]

I drive mine hard!
I drive it in strond winds!!
I drive it up hills!!!
I still get great economy 10/100!!!!

GO THE ZOOK!!

Lucky you, what mods does it have?

1995 WT Softtop Sierra -
Lukey Extractors with 2" sports exhaust,
235/75 R15's,
Autotechnica Racing Seats.

To come 2" LIFT and looking in to a roof rack setup for my longboards.
Re: Racks for the softtop - Have seen a few on other sites - still looking for something I like.

[Sammyboy]

my holden drover used to get 350-400km per tank (the most that I have ever driven is 410km). I've got extractors and 2" exhaust, with 235/75 15 MTR's. Driving it fully loaded from Melbourne to Tamworth (1200km) with 2 adults, 1 child and luggage: 8.5 l/100km. Driving with 1 adult, 1 child and not much luggage: 8.1 l/100km. These figures are amazing (to me) but were recorded years ago when the car was running at it's absolute best. Nowadays, I have had the distributer repaired and I wonder if the carby needs looking at again , but I reckon it gets in the low 9's on a good day and as high as the low 13's on a bad day. I want to play around with it and get my fuel figures back in the low 8's

[ScrawnC]

Oops, I think I steered this one slightly off topic.
How are you getting on the problem GRPABT1?

[GRPABT1]

Yeah lol. Bit of a case of CBF right now, after finding out my speedo is going to be waaaaaaay out when I get my 33's and put the new gears in anyway. So I just drive by the tacho revs when the speedo decides it's not going to work and stick to traffic speed.

[Lil'Loki]

Solution to your problem…

My Dad got one of those TomToms (GPS's) for Christmas from Mum because he keeps getting lost. (He's got CRAFT's disease!)
They're only a few hundred dollars (I'm sure some are cheaper). They have a speed reading. Get yourself one of these. They're probably more accurate than most speedo's as well!

[GRPABT1]

Yeah perhaps oneday, maybe when I get my little lockbox I plan to mount on top of the trans tunnel under the dash to keep valuables secure.