CX trying to be a Model T
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  1. #1
    Fellow Frogger! doggiedog's Avatar
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    Default CX trying to be a Model T

    The CX has been running fine around town, but I took it into the hills, and it has this problem that once you start going up a hill, it looses power, and sort of cuts in and out, ( I thought initially this is an electrical problem), but once its on level ground, it eventually comes good. (I had visions of having to reverse up the hills like the Model Ts had to!!!).
    If it starts missing, by lifting the foot off a bit, it seems to run better, but if you floor it, it looses all power, and a couple of times it backfired. I tend to think it is a fuel problem, and it seems to be getting gradually worse, like I was doing 50km/h
    coming into Mirboo Nth in second gear in the dirt, , yet 5 mins later I was doing 120km/hr on the flat.
    I thought Ah Ha fuel filter, but I cant seem to find it, theres no mention of one in the manuals.
    Any suggestions would be appreciated
    Terry

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    DD -

    When your CX is struggling uphill it needs fuel - lots of it - and may not get enough for 2 possible reasons :
    1) tank ventilation restricted - creating vacuum in the tank
    2) if mechanical fuel pump this may be worn/weak/rotten in membrane

    try a simple remedy as first aid : reverse blow the fuel feed line from engine bay to tank - using a bike pump
    That would instantly tell you if tank is blocked - or the feed line was blocked.

  3. #3
    Fellow Frogger! doggiedog's Avatar
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    Hi,
    I dont think it will be the tank, or its ventilation, as I just had the tank replaced due to the old one leaking, and the new(second hand) tank was cleaned out and a new breather pipe fitted. It may be the fuel line from the tank partially blocked, or the fuel pump though. I will blow through the line tomorrow, and try and test the pump as well. I will take the fuel line off the carby and crank the engine and see what sort of flow there is.
    Thanks for the reply
    Terry

  4. #4
    Moderator Alan S's Avatar
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    Out here, this can be the bane of any CX or carby BX owners life; it's fine particles of black muck that get stuck in the jets of the carby.
    The cause I've heard as being the material the fuel lines plus in the case of the BX, also the material the tank is made of being a black plastic type that begins to degrade with age and washes off as minute particles which are hard to detect with the naked eye but large enough to build up in the jets and bowl.
    The other explanation that Shane gives is that they originally had a filter back near the tank somewhere which could be correct also, but something I've never found so it may be that my cras have all had them removed.
    To effect a permanent cure, take the 4 nuts off the top of the black plastic elbow fitted to the top of the carby and if you shine a light down between the two throats of the carby you'll see 4 jets hiding down there and that's the problem child.
    Slacken each with a flat bladed screwdriver and with either a pair of very fine small needle nosed pliers or a pair of foreceps, remove them one at a time, blow out with compresswed air, blow the air gun down into the hole they come out of (trying not to get a face full of petrol in so doing) and refit. One of those cheap $80/$100 Chinese compressors doing the rounds are ideal for this kind of job. That cures the problem. Now to rectify the cause:
    Go to the local parts place and buy a filter of the variety used in EFi cars; the metal variety with a bit of volume about it. NOT a Ryco plastic throwaway variety. I have found one for a Subaru Forester is ideal, and fit it into the fuel line just before the fuel pump. These are around 5 - 6 times the capacity of the throwaway variety. In extreme cases, I have fitted a Commodore V6 type which would be 10 - 12 times the size of the Ryco. Then if you want to be 100% sure that the problem will be substantially reduced or removed, get a glass type with a removeable and replaceable cartridge and fit that between the pump and the carby.
    There's every chance that you will have a repeat of the problem within the first week of fitting this filtration set up and as it occurs, the carby clean out job as I've described above must be done in total to remove the problem; there's no shortcut. You can of course do a full dismantle which is a fairly long job and entails such little gems as removing circlips so small as to almost needing a magnifying glass to see and wire clips not much larger than human hair, which is why this is only done as a l;ast resort.
    A word of warning; be extremely careful when removing the jets that they aren't dropped down the carby throat and please don't ask why I'm a bit paranoid about this.


    Alan S
    If it ain't broke, use a 12" shifter.....that usually does the trick!!

  5. #5
    Real cars have hydraulics DoubleChevron's Avatar
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    What Alan suggests is a good idea with *any* old car.

    However, hills == cold ..... bloody cold air infact.

    Is this what happens, slowly you find yourself using more and more accellerator to the point where the car will barely run. Cracking the 2nd choke on the carby open suddenly finds a new lease of life .... until it starts to die too.

    You pull over on the side of the road screaming abuse at the car, scratch your head, get out and start testing stuff ..... All seems ok, then suddently the sh!t of a thing starts and runs perfectly ... for no reason

    What is happening is the carby is icing up (mine used to do it to my mother each morning in the middle of winter when she drove it to work). As soon as you stop to look under the bonnet, the heat of the motor defrosts the carby and your away again ..........

    This is worth checking for anyway, you'll be tearing your hair out looking for a problem that doesn't exist if it is carby icing

    seeya,
    Shane L.
    'Cit' homepage:
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    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/citro%EBn-forum/90325-best-project-car-you-have-ever-seen.html
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


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  6. #6
    Fellow Frogger! doggiedog's Avatar
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    Hi,
    Looks like I may have found the problem. I blew through the jets(which were loose), with compressed air, and took it for a spin, and alas it was worse, so I was on the other side of town heading home, and it died at an intersection .

    Pushed it off the road before it sat down, and pondered, tried to start it and it turned over, but wouldnt fire.
    Checked the points, and they were SHUT!!!.
    Did a rough gap, and timing adjustment, and it runs fine, but pinging badly.
    Going out now to reset everything before going to work.
    Thanks for the help
    Terry

  7. #7
    Fellow Frogger! doggiedog's Avatar
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    ps,
    one of the jets did have a bit of crap in it

  8. #8
    Fellow Frogger! doggiedog's Avatar
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    Well I thought I had fixed the problem, but I hadn't, it still doesnt like going up hills, but it has been driving beautifully around town, and to work and back.

    Today I figure there must be a fuel filter somewhere on the car, so up it went on the ramps and there I found a sad looking brown (from the crap inside) ryco type filter covered in grease and stuff.

    I put a new one of the same type (just to prove that was the problem) in its place, and took it for a spin and the car was tranformed. It even goes up hills!!!.

    But ALAS, good things dont last forever, I had to stop at a roundabout, and cough/splutter it stalls and wouldnt start. (2nd time in 2 days I've had to push it).
    CX's are actually quite easy to push I've found out.
    Finally got the thing started but it wont idle, at all. (i fiddled with the idle mixture and idle speed on the side of the road).
    Tomorrow, I will have to blow through the jets again, and possible fit a better filter closer the the carb, and see if that fixes it, other wise I'll be scratching my head again.
    Terry

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    One of your last remedies was replacing the breaker points.
    Did it go with a new condenser as well ?

  10. #10
    Moderator Alan S's Avatar
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    Terry,

    As I said originally, this is a common problem with CXs out here, particularly ones that have been laid up for a while.
    If you've used a Ryco filter, go buy another half dozen because that's about as long as they'll last. It has to be done exactly as I said (based on many years of owning and working on many CXs) and you also have to blow the air down each of the holes the jets come out as they come out because the chance of water in there is also fairly high.
    The two filters are a must; the bigger one pre-fuel pump and the smaller one between the pump and the carby. As good a test as any to see if you've got it is if it does exactly as yours did. (ie) Think you've fixed it, give it a good hard squirt, back off, it starts to run rough, depending on which jet the crap is stuck in, then it will either die at mid range, flat out or on idle.
    There's nothing else wrong, just this, which you'll fix if you persevere and do it properly.
    Just remember that if you're using Ryco plastic small capacity fuel filters, I've found the average life in a contaminated CX at around 10 - 100 klms but this will improve as time goes on to up to around 3000 - 5000klms which is why it's cheaper to use a good quality one in the first place.
    Also check your plugs and see if they are getting covered in thick carbon as a high or low float level can cause some hairy running. When the points were fitted, did you recheck the timng? I found on my car 10 BTDC was ideal with PULP being used. They won't handle ULP and run erratic on LRP whereas the PULP is of consistent quality and you can tune for it.
    Points setting is around 15 thou. dwell angle around 55 degrees.



    Alan S
    If it ain't broke, use a 12" shifter.....that usually does the trick!!

  11. #11
    Real cars have hydraulics DoubleChevron's Avatar
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    Quote Originally Posted by doggiedog
    Well I thought I had fixed the problem, but I hadn't, it still doesnt like going up hills, but it has been driving beautifully around town, and to work and back.

    Today I figure there must be a fuel filter somewhere on the car, so up it went on the ramps and there I found a sad looking brown (from the crap inside) ryco type filter covered in grease and stuff.

    I put a new one of the same type (just to prove that was the problem) in its place, and took it for a spin and the car was tranformed. It even goes up hills!!!.

    But ALAS, good things dont last forever, I had to stop at a roundabout, and cough/splutter it stalls and wouldnt start. (2nd time in 2 days I've had to push it).
    CX's are actually quite easy to push I've found out.
    Finally got the thing started but it wont idle, at all. (i fiddled with the idle mixture and idle speed on the side of the road).
    Tomorrow, I will have to blow through the jets again, and possible fit a better filter closer the the carb, and see if that fixes it, other wise I'll be scratching my head again.
    Terry
    Congratulations on finding that filter ... It took me years to find it (back infront of the fuel tank behind a rubber cover where no-one would think to look ). Now you have replaced it, you need to fit a decent filter further upstream as suggested by Alan (or even put the injected car filter back where you removed the ryco from).

    Oh, and make sure you don't have a foam air-cleaner element breaking up and dispersing foam fragments into your carby (we had that on a BX once).

    seeya,
    Shane L.
    'Cit' homepage:
    Citroen Workshop
    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/showthread.php?t=90325
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


    Modern Junk:
    '07 Poogoe 407 HDi 6spd manual

  12. #12
    Fellow Frogger! doggiedog's Avatar
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    Thanks for the replies guys, well the story so far is, today I got a fuel injected type filter and went to fit it just before the pump. There was a short piece of rubber hose on the suction side of the pump, I undid the clamp, took the hose off the pump inlet, and the other end just fell off the fuel line. I was amazed, that the suction pipe was not even tight on the fuel line (with no clamp), and doubly amazed that the fuel line was plastic!!!!.

    Now I know what Alan means about contamination from the fuel line. I assumed it was steel line. Anyway what a nice job that was installing that filter (I'm sure the neighbours thought I was having sex with the engine!!!.
    I wasn't able to find any sort of filter with a replacable cartridge for after the pump, as yet, I was going to use another fuel injected type filter, but wasnt sure if they were suitable for use after the pump.

    I cleaned out the jets again, and it idled quite nicely. Took it for a spin, 2 ks down the road it stalled at an intersection, started again and hasn't missed a beat since.

    I'm leaving the ryco down the back for now, and will see which filter blocks up first, so as I can tell where the contamination is. As soon as the ryco blocks up I will replace it with a piece of fuel line, and fit another filter before the carby.

    As I was running out of time, I didnt clean out the bowl of the carby, so I think there may still be a bit of crud floating around, so will do that next days off, maybe even put a kit through it.
    I havent as yet lashed out on a dwell angle meter, and have only a very basic timing light, so ive set the points at 0.4mm, and adjusted the timing bit by bit till it stops pinging, and maximises power (like when I was a poor student), but will have to lash out. I went to Autobarn and the sales kid didnt know what I was talking about, and they didnt have any timing stuff anyway.

    As it is at the moment the vacuum capsule on the distributor is cactus anyway, so I will have to source another, then set it up more exactly. For the moment though, when the engine is getting fuel, it runs nicely.

    terry

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