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Allo Allo, Topless French fancy or Pug deux-zero-cinq or how to fix fuel injection without resorting to fire or insanity


Tamworthbay

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I'm not sad that mine has a carburettor. Worst case scenario - new carb. That's comforting. Faults with fuel injection can be hard to track down.

 

Well done for having the to patience to diagnose yours - hopefully you're getting close to a result. I suppose when it's on song it should be faster, better on fuel etc. than mine.

 

:)

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I'm not sad that mine has a carburettor. Worst case scenario - new carb. That's comforting. Faults with fuel injection can be hard to track down.

 

Well done for having the to patience to diagnose yours - hopefully you're getting close to a result. I suppose when it's on song it should be faster, better on fuel etc. than mine.

 

:)

Not sure the gain is worth the pain if I am honest. The simplicity of a carb is hard to beat. That said when it’s going well it’s damn nippy for a 1.4, I imagine the 1.9s must be a real hooligans machine. The driving position is perfect and the handling............. well, even on Chinese specials it is brilliant. It also rides the bumps supremely well and is considerably better over speed bumps than my V70!
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So ALL the manuals, info on the internet, even mother Teresa’s ghost say DON’T undo the TPS as the world will end. But what the hell, on the basis that it’s broke so if I can fix it great, if not, nothing lost is there? A quick clean up and some marks to get it back in the same place and it was off in seconds. The tracks show obvious wear but not sure if that is the problem. I cleaned it all thoroughly and put it back together. Figures haven’t changed though so no idea if it has helped or not. I will drop it back on and see if there is any difference. Then I started looking for the part number and it’s shared across Peugeot, Citroen, Lancia, Fiat, vw and others. I have found one on AliExpress for a grand total of £3.16 from the wonderful workers of the people’s republic of China. Oddly all of them list a load of Peugeot models of that era but not the 205. At £3 it’s well worth a punt. I will keep looking for a complete throttle body but the one in Kent that is breaking has failed to reply despite me saying that I wanted a load of bits, could collect and could remove them myself. This is taking a while but I am learning a lot as I go. Not surprised that strangeangel was frustrated with it as it’s far from a simple fix and the information about these systems is few and far between and mostly inaccurate. If I get chance I will put a post up listing what I have found and some graphs to explain the issue as it’s not obvious at first in case anyone else ever has the same issues.

 

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Looks simple enough - it's basically a big potentiometer as far as I can see. You should be able to test it no problem with a multimeter set to resistance. MUCH easier with an old fashioned analogue meter with a big needle as you can see the resistance change in real time.

 

this sort of idea: https://www.wikihow.com/Test-a-Potentiometer

 

edit: maybe you've done that already looking at your pics. but I don't see what could be wrong with it other than a loss of continuity/intermittent connection, or something mechanical stopping it from turning.

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Looks simple enough - it's basically a big potentiometer as far as I can see. You should be able to test it no problem with a multimeter set to resistance. MUCH easier with an old fashioned analogue meter with a big needle as you can see the resistance change in real time.

 

this sort of idea: https://www.wikihow.com/Test-a-Potentiometer

 

edit: maybe you've done that already looking at your pics. but I don't see what could be wrong with it other than a loss of continuity/intermittent connection, or something mechanical stopping it from turning.

It looks simple, but looks can be deceiving...... the problem is that the ramps on the two tracks start at different points, also the resistance at the end of the tracks has become non linear in a decreasing then increasing ramp. This then means that two throttle positions can feed the same output voltage to the ECU and then to add to the complexity when the second track comes on the same non-linearity occurs which allows a further two positions in which one track is telling the ecu it’s in one place or static and the other is saying it’s in another or changing. A real sod to diagnose. The simple test as per your link is a useful starting point but would not have found that and declared it fit for purpose (it would only really identify a dead pot, and that would be fairly obvious from the ICV actions) thankfully Ronnie had £2ks worth of Fluke test kit where we could map the output range. The measurements above are so that I can set the new piece when it arrives. I can certainly see why Strangeangel couldn’t get to the bottom of it! Of course there could still be other issues........
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I can certainly see why Strangeangel couldn’t get to the bottom of it! Of course there could still be other issues........ 

 

^^ The only bit of that I actually was able to understand.

It isn’t as bad as it sounds when you get you head around what it should be doing but it is a country wagon full of shitload more complicated than even the four carb setups I have messed around with on bikes. The main problem is accurately mapping what it’s doing to work out what the problem is as the symptoms are all at the ICV with it wildly fluctuating but that was actually because it was working perfectly as was the ecu, but relying on constantly wrong input information they don’t have a hope.
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I composed a long reply and then lost it.

 

Basically the gist was that I reckon cleaning it will fix it, not much else to go wrong IMO...resistive track can't become non-linear, faults are usually down to a poor connection or mechanical issue, but I can see that the wiring of the track and wipers is complex so that readings from the 4 connectors might be apparently all over the place (and could go up as well as down).

 

If you worked out the circuit you could prove it all with a resistance meter but probably easier to clean it and stick it back on the car.

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I composed a long reply and then lost it.

 

Basically the gist was that I reckon cleaning it will fix it, not much else to go wrong IMO...resistive track can't become non-linear, faults are usually down to a poor connection or mechanical issue, but I can see that the wiring of the track and wipers is complex so that readings from the 4 connectors might be apparently all over the place (and could go up as well as down).

 

If you worked out the circuit you could prove it all with a resistance meter but probably easier to clean it and stick it back on the car.

That’s the hope, however the tracks are sooooo thin that normal wear and tear could easily make them do weird things. And the number for sale on eBay and AliExpress suggest they don’t last forever, the £3 one is on its way so no loss in dropping the other back on to see if it’s improved things at all. The original would be better if possible. I also need to find a good pic of an original engine bay a so have far too many pipes with just a bolt in the end which may also not be helping. Two steps forwards and one back.
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Hopefully will be more progress tomorrow. I have a few new bits so can give the cooling system a bit of TLC, I am also going to put the original throttle body back on and see if the strip and clean has improved it at all. Then in the afternoon I am heading off to pick up some trim bits to tart the inside up a bit.

 

I could really do with a decent resolution pic of the engine bay but can’t find one for an injected TU anywhere. There are a few hoses plugged with bolts and I am sure they didn’t leave the factory like that.

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Hopefully you'll fully get to the bottom of the issue. The Early 1.4 single point Zxs featured a similar system. Not sure if this picture is detailed enough but it's from a a 93/4 single point car. attachicon.gifcitroen__citroen_zx_1_4i_1996_5_lgw.jpg

Thanks! It looks like one of the pipes from the end of the air filter to throttle body housing connects back to the throttle body area, do you know if that’s right? It would make sense as I have both of those ending in nothing at the moment. There is also a feed off the back of the throttle body that goes nowhere but a spigot on the carbon filter by the passenger side that has nothing attached.

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Thanks! It looks like one of the pipes from the end of the air filter to throttle body housing connects back to the throttle body area, do you know if that’s right? It would make sense as I have both of those ending in nothing at the moment. There is also a feed off the back of the throttle body that goes nowhere but a spigot on the carbon filter by the passenger side that has nothing attached.

 

Yeah, that pipe is for the primitive mechanism that switches between the hot and cold air intakes.

 

My BX14 (1990MY) had the exact same engine, complete with the Bosch Mono-Jetronic. IIRC the single injector needs an ultrasonic clean every 30-odd thousand miles, or the running really suffers.

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Yeah, that pipe is for the primitive mechanism that switches between the hot and cold air intakes.

 

My BX14 (1990MY) had the exact same engine, complete with the Bosch Mono-Jetronic. IIRC the single injector needs an ultrasonic clean every 30-odd thousand miles, or the running really suffers.

There are two,pipes, one goes to the hot/ cold air intake flap (replaced as non functioning), the other is disconnected on mine but appears to head towards the throttle body on the pic - where it could meet one of my pipes that is presently stuffed with a bolt. And how did you clean the injector? It seems to run sweet as a nut above idle, it’s just getting off the line that’s an issue at mo.
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So more work this morning but not sure on progress. I swapped the throttle body again for the cleaned one and it ran like shit, so took a gamble and swapped the end plate for the known good one. Idled beautifully but runs like shit. I bunnyhopped like a 17yr old on their first lesson around the estate. Presently sat doing a 10 minute idle reset. Despite stalling at every possible opportunity on the test drive out is now sat idling beautifully. I am now beginning to wonder if there are other issues as well, so need to check fuel delivery and if possible get rid of the old fuel.

 

I also started the coolant flush by changing the thermostat but noticed the coolant is OAT and I have none so a full change will have to wait. A really frustrating morning :-(

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I wrote the previous post sat in the car with it idling for 10 minutes which gives the ecu time to ‘relearn’ the idle procedure. I found this out from Ronnie who, as mentioned above, was tasked with implementing this system into Rover cars. I cannot find any mention of this anywhere else on the internet, manuals, forums etc etc. It’s a bloody good job I know Ronnie as after the 10 minutes the car could not have been more different! I have only drove it a couple of miles but it’s like night and day. The bunny hopping has gone, throttle response is crisp with no horrendous lag lag lag FUCKING ELL WARPSPEED type response. I did the same route and every U turn and speed bump where it had stalled on the first run it just carried on perfectly. It’s too early to declare it fixed but I am hopeful at least! I would take it for a run this afternoon but I am off to collect some interior bits for it and don’t quite trust it for a 30 mile motorway run just yet. The morning has gone from frustrating to incredibly hopeful in a very short time :-)

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That's a result... You may want to offer your throttle body changing skills to any F1 teams still using the engine.

:lol: It's not that hard and I think I have had it off more than a dozen times now but wondered how long it was taking add it seemed really quick. As for F1, maybe Ferrari are using it and that's why they are having trouble still.

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The Volvo was put into service for the run around South Derbyshire to collect some pug bits. The guy had about a dozen in various states of repair and loads of spares. On the way back we took a detour to Breedon on the hill for some amazing views and some stunning Anglo Saxon carvings. Then back home and a boot full of random bits, some needing a bit of work, some freebies :-) were transferred into the CJ. If I get chance tomorrow I will take it for a longer run and maybe start on some of the interior tweaks.

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I have spent a bit of time trying to track down the spare pipes in the engine bay. Two I am pretty sure I have sorted - they are the opposite ends of one pipe. I can’t work out what goes to the top of the carbon filter but think it may have been a pipe that goes to the back of the throttle body. The one that really has me flummoxed is one from the front of the throttle body, it’s sits low down near the manifold on the bottom right corner if you look from the front. At the moment there is an inch of pipe with a bolt in it. I can’t work out anywhere likely, or anywhere at all if I am honest. Any ideas from anyone?

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After a run this morning I DECLARE IT FIXED! I took it on a round town trip of the shittiest sort with roundabouts, queuing traffic, contraflows, Lidl car park, tricky right turns where you are waiting and age then have to go when a gap appears and it took it all in its stride. It has been a long trek and the idle issue has taken longer to sort than the entire MoT fail list (and it was a fairly extensive list). There have been a few dead ends where I thought I had sorted it and it just laughed in my face. But a methodical approach and a shit load of luck having Ronnie the SPI expert to hand made all the difference. As with a lot of these problems there was one central issue causing the most serious issues but also a load of other minor little niggles that either masked or added to the problem. Old cars basically, and once you chuck in a large lump of 30 year old French electronics in the mix you know it will take a bit of time and patience to sort. What has been interesting is that information on this system is few and far between on the internet. If I had a problem with a Weber carb I could get everything I needed info wise in minutes. I suppose it comes down to a mix of the complexity and the fact that these were a very short lived motoring evolutionary dead end that were superseded by MPI systems almost before they were in production. It’s a great feeling to have saved a car whose future was looking a bit uncertain for a while. Now to enjoy the nice weather..........

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Now the major jobs are out of the way it’s time to start some subtle improvements. First up was a simple swap of the handbrake console, apart from having to take off parts of the seatbelts it was as easy as expected. The old one was a bit rough so the new one brightens it up a bit. Then off for another drive, this time to Halfords to pick up the correct coolant. I am busy until Thursday but will change the coolant at some point.

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  • 2 weeks later...

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I have to admit to a disgraceful lack of progress. I haven’t even changed the coolant. I have however driven it every day and it is either the ecu learning the fuelling or just the benefit of a bit of use but it is driving better and better every day. Tomorrow I plan a bit longer run as I have to go to Cannock hospital. It is about a 40 mile round trip so will give it a proper warm up.

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