Key event today..... managed to get the refreshed Sigma engine running with the custom fuel system, Ford Puma engine wiring loom and new coolig
system.
The FORD TIS is an invaluable resource but 100% clear or accurate it is not. Stripping out all the unused stuff greatly increased the complexity of
the task and was not fault free. The engine now runs as sweet as can be expected. One or two gremlins still to sort out.
Next job is to fit the shortened and refurbised drive shafts once they are returned that is, probably not before christmas.
Rolling chassis here I come!
I could not have installed the modified engine wiring loom without help received from this forum.
http://youtu.be/zkfBWldVGw8
http://sylvabuild.blogspot.co.uk/
Does anybody know what that Vehicle Speed Sensor (VSS) does, I appear to have lost mine after stripping out all the stuff from the Puma. Anybody got a
spare?
Thanks again chaps
The Vss is the speed signal and is split between the ecu and the Dash. Im not 100% why the ecu needs the signal but it does show a fault code after a
while if its not there. From reading ive done its all to do with emissions and is said to cut fuel on over run. It stops the engine dumping unburnt
fuel into the exhaust and cat.
Having run with out it and then adding it back in I cant tell any differance. It doesnt seem to affect iva / mot emmisions or even the rev limit. I
also use the sensor to suply a signal to my dash. Its so much smoother than the nasty magnet set up.
the sensor should be in your gearbox there will be a hole if not ? 
[Edited on 15/12/12 by big_wasa]
quote:
Originally posted by big_wasa
The Vss is the speed signal and is split between the ecu and the Dash. Im not 100% why the ecu needs the signal but it does show a fault code after a while if its not there. From reading ive done its all to do with emissions and is said to cut fuel on over run. It stops the engine dumping unburnt fuel into the exhaust and cat.
Having run with out it and then adding it back in I cant tell any differance. It doesnt seem to affect iva / mot emmisions or even the rev limit. I also use the sensor to suply a signal to my dash. Its so much smoother than the nasty magnet set up.
the sensor should be in your gearbox there will be a hole if not ?
[Edited on 15/12/12 by big_wasa]
It has three wires because its a Hall effect sensor.
Power, earth and signal out. (square wave pulse)
It cant be a type of traction control as the ecu doesnt know what gear its in. The ecu would know the speed against throttle position though.
[Edited on 15/12/12 by big_wasa]
quote:
Originally posted by big_wasa
It has three wire because its a Hall affect sensor.
Power, earth and signal out. (square wave pulse)
it cant be a type of traction control as the ecu doesnt know what gear its in. the ecu would know the speed against throttle position though.
quote:
Originally posted by Jenko
quote:
Originally posted by big_wasa
It has three wire because its a Hall affect sensor.
Power, earth and signal out. (square wave pulse)
it cant be a type of traction control as the ecu doesnt know what gear its in. the ecu would know the speed against throttle position though.
Going to beg to differ........
Very quick search......
Click
Click 2
The Puma donor had a cable drive speedo cable and the VSS was a part inbetween the two I imagine something like this:
ebay item: 160922390105
At that sort of price I will be taking a trip around the scrappy I guess.
I love the comments about the Speedo drive. I have a s/h Smiths Telemetrics supplied with a hall effect sensor 3 wire. I was wondering if i could use
the signal from the VSS.
I think two wires provide the speed readout, and the third the signal to the ecu to presumably retard the ignition.....The ecu knows engine speed via the vr sensor, and gearbox speed via the speed sensor, hence possibly knows which gear ( not sure about that, just guessing). Either way, it limits torque to first and second.....
quote:
Originally posted by Jenko
I think two wires provide the speed readout, and the third the signal to the ecu to presumably retard the ignition.....The ecu knows engine speed via the vr sensor, and gearbox speed via the speed sensor, hence possibly knows which gear ( not sure about that, just guessing). Either way, it limits torque to first and second.....
Justs FYI...quite a good write up about the torque limiter and how it works........but to confirm, there is a torque limiter on the later gearbox, and
a very popular mod is to remove it....for our light weight cars, there is very little stress on the gearbox...I will be removing mine without a
doubt....anyway
In answer to various questions on the Pumapeople list, a Pumapeople member back in like 1999 offered the following write up:
1) Torque truncation works by taking the crank speed sensor reading and the road speed reading and by doing a comparison in the ECU it calculates when
it is in first gear. This does not require all gear ratios to be programmed in. It is simply a comparison table. You may not like the sound of it, but
that's how it works :-)
2)As a history, the IB5 started off as the B-4 in 1978 for the 1.0/1.1/1.3 litre Fiestas (max 60HP). The IB-5 program started in 1996, with closed
bearings, bearing D with innering, 1st/2nd and 3rd gear double synchronisation, retuning of 4th/5th gear synchronisation, neutral selection springs in
the transmission and hydraulic clutch actuation.
3) Failures. When the 1.7 Sigma SE161 project began (Puma to non-Fordies), durability testing discovered three main flaws with the gearbox.
a ) Final drive gear tooth failure
b ) Reverse gear tooth failure
c ) Bearing D failure (I have no idea what this is)
Other failures experienced were 4th gear crashing, and 1st gear jumping out.
At this time there were two final drive ratios under test - 4.27 and 3.82. At 4.27 the teeth broke off the pinion gear. This was then shotpeened to
improve the failure rate. This improved it by 20%, but it still failed. Torque truncation was introduced to limit the torque from 157Nm to 135Nm, and
110Nm in reverse gear (as reverse is lower and hence has a higher loading). Someone made a bloody stupid comment on this list about "how does
torque limiting protect the car in 2/3/4/5/ gears". Well, if you have ever ridden a bike with more than one gear, you will know that the torque
multiplication goes down as the gear ratio goes up, and hence torque truncation only needs to be on 1st/reverse gears.
The production final gear ratio was chosen as 3.82. This could not be shotpeened for manufacturing reasons (gear size). Without torque truncation on
the super accelerated life test, there was a 62% failure rate. With torque truncation this became 100% pass rate.
4) In answer to the question about "how does this protect your gearbox if you rev the engine and dump the clutch?" - it does not. There is
no protection on the Puma for this. I asked this question and was told "we expect our customers to have a bit of common sense". The bigger
engined Foci do have this problem as they kept breaking driveshafts during development. The solution was to put a peak torque limiter on the car.
Basically this is a delay valve in the hydraulic clutch line which limits the speed of engagement. During normal driving conditions this is not
noticed, but during stupid driving will allow slip to protect the drivetrain.
5) To a member - whoever told you that the IB5 can take 300 bhp is probably not well informed. If you drive sensibly than your gear box may well last.
The testing carried out during car development is deliberately harsh and represents 100,000 miles + of motoring, so I am not going to say to anyone
that there gearbox will break without a torque limiter because it is not necessary true.It depends on how you drive it.
However, the IB5 gearbox design torque limit is 135Nm. If someone can tell me what they did to the FRP gearbox I would be interested to know. Also if
it is true that the IB5 was used in Fiesta Turbos in the '90s, then I have no answer to that either. The only thing I can think of is that the
gearbox was altered for those models, and what with Ford tightening the belt with the Puma, (developed as a cheap-to-make low-volume car) the program
costs would not allow extensive, expensive, engineering changes to the gearbox, and hence electronic means were used to allow use of the IB5.
Well done for getting the engine running! I know what you mean about the TIS not being 100% accurate, but it surely does help.
I've got a VSS sensor that I've just pulled off a spare gearbox that you can have if you still need one? U2U me your address and I'll
pop it in the post. Looks the same as the one in the eBay link... but that is a ridiculous price!
Ed.