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PostPosted: Mon Aug 08, 2016 10:10 pm 
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I had a normal one (a Memoscan U581) which also worked on the Range Rover but my daughter bought a Toyota MR-S, the import version of the MR-2 Roadster, which uses JOBD. The Memoscan wouldn't connect to it but the C Reader does all protocols including JOBD so I bought one for that. Since then I've used nothing else and not found anything it won't connect to. If it has an OBD socket, it'll work.

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PostPosted: Tue Aug 09, 2016 11:42 am 
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Gilbertd wrote:
What year is the Jag? Although the OBD standard didn't become mandatory in the EU until 2000, it was introduced in the US from 1996. So anything that was likely to be sold in the US was OBD compliant even though it didn't need to be. I've got a Launch C Reader V1 (http://www.ebay.co.uk/itm/Launch-Creade ... 1882872565) and that reads and displays live data from my 1998 Range Rover perfectly well.


Hi

The Jag is 1996. That reader does look good value, but I will need the Stefanelli kit too as I want to check gas pressure and changeover temperature. At the moment it changes over to gas too early I think.

Glen.


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PostPosted: Tue Aug 09, 2016 11:58 am 
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All good advice regards OBD1 interfaces etc but since vehicle OBD1 systems give varying amounts of info and not all give live data, in the OP's position unless I knew the interface on the Jag would be of decent help in diagnosing the problem I probably wouldn't buy one (but in my position I might buy one based on Gilbert's recommendation). I only ever bought 2 OBD1 interfaces, one for an old V12 BMW and one for an old Honda, both run more complicated engine management systems than the Jag and the average OBD1 car.

There are ways of checking probe function without the interface - the engine can be forced to run leaner by causing a vac leak, make to go richer by squirting butane/propane into the air intake, all the while monitoring probe signal voltage. Engine temp sensors, TPS and map sensor are easily checked, on an older engine really only leaves AFM's (where fitted) un-checkable.

Simon

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PostPosted: Tue Aug 09, 2016 12:10 pm 
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Freebird wrote:
At the moment it changes over to gas too early I think.

Doesn't the Stefaneli system light up progressively more switch LEDs as it approaches changeover temp? If so, the switch could be used to identify a reducer temp sensor problem / if the sensor isn't broke (shorted) could help you determine a suitable resistor to wire in series with the reducer temp sensor to make the system switch to LPG when the reducer is a bit warmer.. Would only advise the latter if your Stef system doesn't have a gas vapour temp sensor (because otherwise it will probably use the reducer temp sensor input for temperature related richening/leaning).

Simon

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PostPosted: Thu Aug 11, 2016 12:10 pm 
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LPGC wrote:
Freebird wrote:
At the moment it changes over to gas too early I think.

Doesn't the Stefaneli system light up progressively more switch LEDs as it approaches changeover temp? If so, the switch could be used to identify a reducer temp sensor problem / if the sensor isn't broke (shorted) could help you determine a suitable resistor to wire in series with the reducer temp sensor to make the system switch to LPG when the reducer is a bit warmer.. Would only advise the latter if your Stef system doesn't have a gas vapour temp sensor (because otherwise it will probably use the reducer temp sensor input for temperature related richening/leaning).

Simon


Mine doesn't light up progressively, the red one flashes then the green ones come on at changeover with a lurch from the car as it struggles to run. Performance is then flat until thoroughly warm. It runs perfectly on petrol.

I have ordered the C reader, so will see what it has to say in due course.

Glen.


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PostPosted: Mon Aug 22, 2016 10:22 am 
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Well, my C reader arrived at the weekend, but unfortunately my car doesn't support the live data side, so I am none the wiser.


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PostPosted: Mon Aug 22, 2016 8:16 pm 
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Freebird wrote:
Well, my C reader arrived at the weekend, but unfortunately my car doesn't support the live data side, so I am none the wiser.


That is a bit of a problem - I've now got one of the same readers and have to say they appear quite good for the money, so at least it may prove useful to you at another point.

I'd suggest your next step is to identify the ECU used - either take some photos of it or find any visible stickers. It may help to get some photos of the engine bay parts as it seems theres a few different setf systems so will help to know which one you have (if you decide to order that lead you need to check it is actually one of the supported systems to get the right lead and software first).

You might find it more useful and cheaper to have a word with an installer if you can get to one, though you'd need to pick carefully - the few ones left on here will be able to give a good assessment of what your best option is, others may go straight towards replacing the front end (which if you did that would make the money spent on the lead wasted obviously!)


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PostPosted: Tue Aug 23, 2016 12:19 pm 
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Brian_H wrote:
Freebird wrote:
Well, my C reader arrived at the weekend, but unfortunately my car doesn't support the live data side, so I am none the wiser.


That is a bit of a problem - I've now got one of the same readers and have to say they appear quite good for the money, so at least it may prove useful to you at another point.

I'd suggest your next step is to identify the ECU used - either take some photos of it or find any visible stickers. It may help to get some photos of the engine bay parts as it seems theres a few different setf systems so will help to know which one you have (if you decide to order that lead you need to check it is actually one of the supported systems to get the right lead and software first).

You might find it more useful and cheaper to have a word with an installer if you can get to one, though you'd need to pick carefully - the few ones left on here will be able to give a good assessment of what your best option is, others may go straight towards replacing the front end (which if you did that would make the money spent on the lead wasted obviously!)


Thanks Brian, I agree the reader is good value and I'm sure it will come in handy one day.

Here are some photos of the ECU and injectors, I will upload some of the other hardware once I have taken more photos.

http://s1251.photobucket.com/user/freebird50/library/Jag%20XJ6%20LPG%20system?sort=3&page=1

Cheers

Glen


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PostPosted: Tue Aug 23, 2016 1:22 pm 
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Brian_H wrote:
You might find it more useful and cheaper to have a word with an installer if you can get to one, though you'd need to pick carefully - the few ones left on here will be able to give a good assessment of what your best option is, others may go straight towards replacing the front end (which if you did that would make the money spent on the lead wasted obviously!)
I have some second hand Stefanelli parts here.. reducers, 4 cyl ECU(s), map sensor(s) etc and the proper Stefanelli interface... And, not just for those reasons, I'm a good bet for diagnostics / repairs anyway ;-) But I don't know how far away Glen is.

Even with the Jag not showing live data it's worth checking for trouble codes now you've got the tool... Coming up with anything, Glen?

Have you tried connecting to the Stef system via interface cable yet? (I don't remember if you bought one).

Simon

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PostPosted: Wed Aug 24, 2016 9:00 am 
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LPGC wrote:
I have some second hand Stefanelli parts here.. reducers, 4 cyl ECU(s), map sensor(s) etc and the proper Stefanelli interface... And, not just for those reasons, I'm a good bet for diagnostics / repairs anyway ;-) But I don't know how far away Glen is.

Even with the Jag not showing live data it's worth checking for trouble codes now you've got the tool... Coming up with anything, Glen?

Have you tried connecting to the Stef system via interface cable yet? (I don't remember if you bought one).

Simon


Hi Simon

I would like nothing more than for you to have a look at my car, but you are 206 miles and 3 1/2 hours from me according to good old Google maps. I am still considering the option though. Ironically I bought it from a guy 15 miles from you and drove it home.

There are no engine related codes coming up, just P1621 which is a spurious immobiliser fault.

I have not yet bought the interface cable, that's my next port of call I think. I will probably need help understanding what it tells me though.

Cheers

Glen.


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PostPosted: Wed Aug 24, 2016 9:25 am 
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Freebird wrote:
I would like nothing more than for you to have a look at my car, but you are 206 miles and 3 1/2 hours from me according to good old Google maps. I am still considering the option though. Ironically I bought it from a guy 15 miles from you and drove it home.
I see the irony :lol: I do have customers come from further afield but of course realise travelling long distance for repair would put most people off. I should maybe take a leaf from some websites I've seen (e.g. RIP V8 engineering..) where companies try to persuade people the distance is doubly worth it, such as 'while you're here come and have a look at our beautiful countryside etc etc', a sell method I've never tried! :lol:

Well, once you've got the cable we can help you find what's going on. As I remember, the Stef software doesn't allow switching individual cylinders back to petrol so isn't as useful for finding fault with individual injectors as might otherwise be, but will at least show what the ECU is seeing for pressures / temperatures and allow adjustment of calibration. Worth bearing in mind: Already spent money on C reader, about to spend money on interface (which may lead to discovering a faulty component that would need replacing), other components of system already old and Stef not a great system anyway - I'm sure you'll get up and running at less cost and hassle going the repair route but there's the chance that with hindsight and if the car's a keeper you could end up thinking a replacement would have been the better bet (maybe a future failed part will be difficult to get hold of and/or expensive). Offsetting that, you're up for doing your own repairs and have the C reader and interface cable this way so maybe your choice would have been clear cut even if you knew at the beginning what you know now, and since you already started down the repair route...

Simon

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PostPosted: Wed Aug 24, 2016 12:47 pm 
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Hi Simon

Thanks for the advise again, I have sent you a PM to save everyone having to read my drivel.

Glen


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PostPosted: Wed Aug 24, 2016 2:36 pm 
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Why? Without drivel there'd be 75% less posts and it would look like everyone had fallen asleep......

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PostPosted: Wed Aug 24, 2016 8:32 pm 
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Gilbertd wrote:
Why? Without drivel there'd be 75% less posts and it would look like everyone had fallen asleep......
:lol: True...

Glen emailed and phoned me, on the phone I advised he should get lambda to flick while running on petrol as a first step, which might even cure his LPG issues. I just got in from work and have emailed back to say I just got in from work having not eaten all day, so I'll answer the email in full through the day tomorrow and include an explanation of how to check for lambda flick with multimeter (could be dodgy probes yet) - but now you know that you might beat me to the multimeter explanation on forum!

We should probably keep the forum updated on this.

Now, my curry's still warm in the oven... :D

Simon

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Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
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PostPosted: Thu Aug 25, 2016 8:06 am 
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Brilliant stuff.


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PostPosted: Thu Aug 25, 2016 11:42 am 
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I replied to your email Glen.

Simon

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PostPosted: Thu Aug 25, 2016 12:37 pm 
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LPGC wrote:
I replied to your email Glen.

Simon


Just so everyone can benefit from the diagnosis, this was Simons reply.

Will need to get lambda to flick while running on petrol before being able to get the best results from any LPG system (in fact in order to get the best results when running on petrol too, but petrol is far more forgiving regards mixture than LPG so in case of incorrect mixture a vehicle is more likely to drive more normally on petrol than on LPG.

When running on either fuel, following engine warm up (so not just after starting the car but when engine is fully warmed, and perhaps even this will take a bit of a drive in an old Jag), lambda voltage should flick between 0 and 1 volts, or between 0.8 and 1.6 volts, or between 0 and 5 volts continuously with the engine running. The voltage range depends on type of probe used on the vehicle, the correct type to suit the vehicle must be fitted.

We don't know which wire on your probes is the signal wire but it is easy enough to connect to each wire in turn to check for a voltage flick. To check the voltage while driving it is possible to run a wire into the car interior from the probe wiring, drive the car with the multimeter on the passenger seat..

Historical OBD error codes have the potential to make the petrol ECU ignore the lambda probes, i.e. to make the engine run in limp home mode... Disconnecting the battery overnight should make an old (pre OBD2) ECU forget any historical error codes, so should make the ECU start to respond to lambda signal.

If disconnecting the battery makes the lambda start to flick as it should when running on petrol, but then when you switch to LPG we find that lambda stops flicking as it should, then this will point to a problem with the LPG system (perhaps just calibration). This is why I said only run the vehicle on petrol after disconnecting the battery.

We don't know if your Jag has been ignoring lambda signal due to an historical code, or if your lambda probe(s) are broken, or if there is something else wrong with your car (MAF sensor, coolant temp sensor telling the ECU the engine is too cold for the lambda probes to work properly), vacuum leak, throttle position sensor, etc. Lambda probes are the usual suspect, particularly if any coolant has found it's way into the exhaust at some point.

If the petrol ECU is running limp home / open loop mode the lambda signal won't flick like it should, the signal will be much more constant and may even be stuck at one extreme of the probe's signal voltage range. It is still possible to check the probe function: With the engine warmed up and idling - if the probe voltage reflects a lean mixture we can introduce more fuel by squirting propane / butane gas into the air filter to make the engine run richer, enough gas will cause the engine to go very rich, so this should make the probe signal reflect the rich mixture. If the probe voltage reflects a rich mixture we can allow false air to enter the engine by e.g. pulling a vacuum pipe from the inlet manifold. In either case we would be trying to confirm that the non flicking lambda signal wasn't due to a faulty probe.


Me now....I am going to test the lambdas again as last time (see first page) I didn't know that the engine had to be hot.


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PostPosted: Thu Aug 25, 2016 2:48 pm 
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Cheers Glen, should put people's mind at rest that I wasn't just trying to get you to drive 200+ miles to come and see me.. I probably talked you out of that for the moment during our chat yesterday? ;-)

To add to the above..

Following battery removal, old Jags can take some time to steer fuel trims enough for the engine to see correct mixture and lambda flick, could leave car idling a long time and not see the flick - thus the advice to go for a drive after battery disconnection.

In phone discussion, on Glen's 3 wire probes he's seen bat voltage on one wire, near 0v on another, 2.7v on another. We can rule out the bat voltage wire but even if the 2.7V wire is looking likely the signal wire, if flick isn't seen on the 2.7v wire it's worth checking the 0v wire.

If the engine controls fueling based on map sensor input rather than maf sensor input, leaning by introducing a manifold vac leak won't work. The richening method always works - I sometimes use a butane camping cartridge with aerosol type end, a narrow diameter hard plastic CO2 type pipe will fit around the aerosol type outlet, then pushing the pipe towards the bottle sees gas coming out the other end of the pipe.

It is possible that the petrol ECU itself holds the lambda signal wire at an intermediate figure (voltage equating to correct mixture for type of probe - perhaps 2.7v in case of a 0-5v or 5-0v probe...) during engine warm-up and/or when in limp home mode. If the ECU is in limp home mode (only relevant if the pre OBD2 ECU even has a limp home mode..) it would be necessary to disconnect the signal wires from the petrol ECU to check if the lamdba probes are working properly using the richening/leaning methods I described.

Glen - If lambda flick is seen on both pre-cat probes when running on petrol, then move onto switching to LPG and see if flick continues on both probes. The closer LPG calibration is to being correct, the less time it should take for flick to be seen after switching to LPG. Try under various engine rpm/load conditions, though close to flat out is a special case where lambda voltage shouldn't flick but should reflect rich mixture.

Glen's further email questions..
Freebird / Glen wrote:
1. When cold, does the lambda read zero or max flick or is it random? This will help me establish which wire is the signal.
2. Do you know roughly what the frequency of the flick is? Eg every second, 5 seconds…..


1. Could be any voltage within probe's signal range. If the ECU itself holds voltage at a set figure under these conditions, then probably 2.7v in case of a 0-5v or 5-0v probe! Or, if the ECU doesn't hold signal voltage at a set figure during these conditions, probe may start off reflecting a lean mixture (when the probe is too cold to work properly) but then as it warms up and starts to work properly, signal may reflect rich mixture due to the petrol ECU still being in engine warm up mode (ignoring lambda probe and providing rich mixture so the engine gets the injection equivalent of a choke effect).

2. Flick frequency usually increases with rpm and engine load but until the petrol ECU's fuel trims have settled down and been re-learned (after battery disconnection or limp home mode) frequency can be erratic. A flick at idle every 5 seconds wouldn't be unusual, frequency increasing with rpm and engine load.

Simon

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Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
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http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240


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PostPosted: Thu Aug 25, 2016 4:23 pm 
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Thanks Simon

My readings were 4.7, not 2.7 volts mate.

Glen.


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PostPosted: Thu Aug 25, 2016 4:38 pm 
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According to http://www.lambdasensor.com/main/jaguar.htm the 3 wire sensor is a Zirconia which will be 0-1V. From 95 onwards it lists a 4 wire Titania which would be 5-0V with 5V meaning a weak mixture. However, as my Range Rover also uses 4 wire Titania sensors I know from experience that when they fail they will give almost 5V, so that would suggest a dead sensor. 4.7V would be telling the petrol ECU that it is running lean so would cause a rich mixture with the corresponding poor economy.

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'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.


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