Hi all,
I have a 1990 1.6 and a new exhaust manifold to fit. The hole for the sensor is a lot further down and the wire needs extending or changing. On the US Miata forum loads of people have said they ‘snaked out’ the wire on the loom side of the connector to get more length. Any idea what this means or any other ideas?
Many thanks!
Martin_Young was very helpful in identifying the bits needed for proper plug and play. Other extend the wires on the sensor itself. Don’t solder, use connectors.
Its for 4-wire sensors, which you can fit to 1.6 models, but the process is similar.
This is the single wire sensor with a spade fitting at the end that joins the main loom near the coilpack in the engine bay.
I would recommend extending with solder and heat shrink with either an inserted piece or a longer length of wire added with a similar spade connector at the front that fits into the plastic connector shroud. One involves a single solder/heat shrink, the other two.
The four wire connector solution would work because the extension is a proper seal and waterproof; this could not be easily replicated with the single wire connector.
Would it be easier to extend the car side loom with solder and shrink?
May be better than modifying the sensor should you ever need to change it.
Soldering a O2 sensor is a big no no for 3 reasons. Bosch explains the major reason why you use a proper connector, and its not to do with waterproofing
Interesting but do you think there is a tubular/porous wire on the original single wire lambda sensor?
I sold the spare I had a few weeks ago; have one fitted to the Eunos but will be difficult to check on the car. Just looked at the photos I had of the one sold and the connector is more sophisticated than I remembered and would appear to seal completely.
The other question is whether the wire is copper or stainless steel.
Most universal lambdas are supplied with crimp joiners. I suggest that a crimped wire will probably not allow air flow. Why is flow needed anyway; if there is air present where it is needed for reference, surely that is enough. I also think that in order to grip the stranded wire sufficiently, the bosch connector would likely lock air out through pressure.
Quite a lot of references to successful soldering of lambdas, so presumably there is room for a difference of opinion on this
You just need to cut it and extend it with good quality gauge wire with a strong solid solder connection, heat shrink and heat tube ,which by the sounds of it ,you have it off the roadster to be easily done on the bench/table.
If you are unsure with a soldering iron there are also some easy solder,heat shrink and seal all in one joiners that can be used with a simply lighter only, they are good and quick to use. but still use a good heat shrink and heat trunking regardless.
Just for reference:- 800Pcs Waterproof Solder Seal Heat Shrink Sleeve Wire ■■■■ Terminals Connectors | eBay
Please do not use crimp connections, the number of times we have had to chase electrical faults from crimp connections is large.
M-m
The more I have been thinking about this supposedly porous/tubular cored wired for reference air, the more I am thinking it is a pile of tosh!
a lambda sensor has no processor chip for intelligent comparison; it is simply a dumb sensor.
The sensor simply detects voltage changes in the exhaust gases it is presented with, nothing more. Four wire sensors have two wires for a heater circuit, an earth and a signal wire, that is it.
I’m calling this bosch, supposed three reasons why video, complete hogwash. Aside from anything else there is only one reason given and that makes no real sense on analysis.
Reasons why these wires cannot be soldered are twofold, potentially…
This kind of sironing marketing from Bosch is very annoying to me because I question its logic and for a while doubted my own reasoning. A total crock in my opinion; I look forward to others putting me right.
Appreciate your input here Wayne; some sanity in an otherwise insane, delusional world:-)
If the wires are steel I agree about the difficulties of reliable soldering. Fortunately, with most steels there is much less of a risk of the crimp inducing work-hardened stress fractures than when crimping copper.
I always prefer to solder and sleeve copper wire-to-wire, adhesive-lined heat-shrink is wonderful stuff.
Copper wire can be crimped reliably, BUT this is only if applying the correct pre-set-tension crimp tool to the correct terminal gripping BOTH the correct conductor and its insulating sleeve, ie good grip with no sharp edges and least stress.
It then also needs a ‘gas-tight seal’ somewhere to prevent corrosion/tarnish, fortunately the rubber bungs in modern connector bodies are usually sufficient if they fit the wire size correctly.
Unfortunately, most people using the nearest-to-hand crimp-tool tend to enthusiastically over-crimp the mismatched terminals and wire.
The copper is now work-hardened and brittle, and therefore walking wounded, ready to fail after some unexpected movement or pull.
And M-M is then asked to pick up the pieces.
Extending a wire some couple of inchs is not going to make a slight bit of difference in the signal…
OP , bring it to me and i’ll lengthen it for you.
M-m
O2 Sensors are electrochemical devices that generate a small voltage that corresponds to the difference between the amount of oxygen in the exhaust and the amount of oxygen in the atmosphere. They need a sample of clean atmospheric air for a reference.
Some get atmospheric air via a vent in the sensor, but it appears these Bosch ones aim to reduce the risk of using contaminated atmospheric air by getting it from the gaps between the individual strands of wire in the cable. If you solder the strands of wire together there is a risk that by creating a solid joint and, perhaps melting the cable insulation around the strands of wire, the source of atmospheric air will be blocked. The air in the cable may also be contaminated by flux/plastic/metal fumes generated by the soldering operation.
Good summary.
If anyone wants full chapter and verse, the Wiki entry Oxygen sensor is well written and comprehensive.
It is worth a read, especially the parts about sensor operation and later on the diagnostics of faults and how they might occur.
It does not specifically address the question of extending the wire, but I guess the information will help one to apply common sense when doing so, ie make sure contaminants cannot reach the sensor.
Well done that man, common sense plague on its way to you.
OP extend it the couple of inchs needed and enjoy your roadster before this chapter of war and peace continuous for ever.
M-m
Haha thank you! I am thinking of just taking it to some, so if you’re near Reading at all…