1800: Wild water temp readings

[sleek lemur]

Thanks Derek. Makes sense. Will check the car out in traffic, but that might be a while, unless I get stuck behind a horse.just revving the engine a couple of 100 seems to make the difference at tickover.

[Ron Kwas]

++ to Derek's info!

[sleek lemur]

Hi Everyone, back again on this thread. There have been some BIG DEVELOPMENTS with my 1800E. I fitted an electric fan and we drove down to Valencia. A round trip of around 3,000 miles. No car issues the whole way, although the temp gauge still rose to close on red in heavy traffic, with the engine showing no signs of overheating.

Since then, I decided to pimp my ride, with a race engine bored and stroked to 2.15ltr by Brian Randall and twin Weber DCOEs with a stainless sports exhaust and 4:1 manifold. Not been able to drive it more than a few miles in the current environment, however it is a completely different vehicle. Brian ran the car in on the dyno and straight away it revs right off the scale and just keeps on pulling.

But we still have the wild water temp readings! In fact the gauge is off the scale even before the thermostat is open. The engine came with a temp sender from Brookhouse, which is probably the same as the item that I ended up returning last time. I'm going to see if they can find the old one, as I do notice that the new one doesn't screw is as far as the old one.

Has anyone ever had any issues with the gauge itself?

[Ron Kwas]

sl;

Symptoms do point to the Sendor and gauge at this point...I did not reread the entire thread, but have you verified function of the Voltage Stabilizer, and cold/hot R values of the sender?

Cheers

[sleek lemur]

Thanks Ron. If my fuel and oil temp gauges are working ok, does this indicate that V Stab is ok ?

[sleek lemur]

.......

[Gaz2]

When I read the post's title, I though it was asking if it's warm enough yet to go swimming in Lake Windermere!

[sleek lemur]

Wiring.jpg

Voltage Stabiliser.jpg

Something unexpected. The voltage stabilizer is not connected and I see green/white wires directly joined to the blue through some sort of sleeve. Hope this shows in the attached pics. Am pretty sure the wires shown should be attached to the voltage stabilizer as one of the blue ones goes directly to the oil temp gauge.

Question is, which wires connect to which terminal on the voltage stabilizer?

I suppose I should expect that the stabilizer is faulty, as I can't think of any other reason why someone would have performed the barbarity described above.

Many thanks in advance.

[Ron Kwas]

sl;

Symptoms of failure of V-Stab are possibly complicated and different for each instrument, because of the different time constants of the instrument (I expect Fuel Gauge has the longest, as it must accommodate a bouncing float due to fuel sloshing)...I have not specifically studied them to give better examples and explanations, BUT... if V-Stab has been bypassed (which someone undoubtedly has done here, by tying Wht-Grn[Input] to Blu[Output]), function of all gauges supplied by this node would be that of the failed (always ON) part of V-Stab ON/OFF cycle, which means that YOU have just found the cause of your "wild" Temp Gauge readings, and at the same time, that "complicated and different " symptom I spoke of...

To address your comment: "fuel and oil temp gauges are working ok" ...former "working OK" can be explained by the super long instrument time constant I spoke of above, and the later's "working OK" is actually not correct...it just seemed to you to be working OK, and you interpreted it as such!...I bet you never verified the calibration and accuracy of the temp indicated...you just got used to the typical readings while gauge was being supplied with a constant 12V, opposed to the 12V for only 83.3% of the time it should have been...I would say you'll have to get used to a new "typical indication" of the Oil Temp gauge (not to mention the Water Temp and probably even Fuel Gauge) after you install a replacement V-Stab!

...now if I can only get you to elaborate and specifically describe what you meant by "wild water Temp readings", because this will be the best possible description of the failed V-Stab symptoms!!

Excerpt of '71 1800E WD showing V-Stab and associated:


Reference: https://www.sw-em.com/voltage_stabilizer.htm

This is without a doubt a unique learning experience for the V-Stab supplied instruments, and I expect to add much of it to the V-Stab page.

That concludes today's CIS Goteborg session!

Cheers!

[sleek lemur]

Thanks Ron. All back together now (apart from one knurled nut for the rev counter, which slipped thru my fingers and has buried itself in the under-dash spaghetti). Now that it's fixed, the cause has become apparent. The car was taken back to bare shell by the people I bought it from in Denmark. Obviously, they joined the WG and Bl wires on dismantling and simply failed to reconnect. This is the latest in a long list of things they bodged.

I'm so grateful for your help. it was you saying in another post to Graham where you told him to chase the WG and Bl leads that unlocked the mystery.

AND now I think of it, when I recently changed the fuel tank as part of the conversion to Webers, the fellow doing the job (123GT on this forum - I will write a post about the great work he did) remarked how there was only a minute drop of fuel left in the tank. Well, I had run it low on purpose, but clearly it was a lot lower than I thought!

Haven't checked the temp gauge yet, as I also have a small issue with the electric fan, but I am sure that this has sorted the problem. Previously, it was right off the gauge within 5 mins of starting the car and before the thermostat had opened.

Thank you, O King of the Voltage Stabilizer and thanks also to 123GT for emailing pics to me this afternoon.