New Injectors - The Bleeding Edge

Discussion in '308/328' started by Archer911, Jun 13, 2018 at 1:05 PM.

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  1. Archer911

    Archer911 Formula Junior
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    The car is an 84 308GTS QV US version.
    It was running well then poorly and now not at all.

    Replaced the fuel pump, accumulator, and filter about 18 months ago. Many other items replaced too as outlined in another post.

    Replaced the original injectors and seals last week as well as the WUR just before that.
    That all seemed to go well. The first turn started the car after a few seconds but it ran very rough. Shut it down and tried again, and again, and again. No start at all.

    So I found an article by Birdman about injector testing/replacement. Fast forward to the end and purging the air from the lines and injectors. To summarize:

    1) Pull the AMP connector off the fuel distributor.
    2) Turn the ignition switch to the first click to start the fuel pump and wait 30 seconds.
    3) Push down on the flow plate for a few seconds.

    Now the article says to crack open the fuel lines at the injectors to let the air bleed out.

    What the article doesn't make clear is whether to leave the key in the on position letting the pump continue to run and at what point to crack open the fuel lines at the injectors. Do you crack them all at once and then depress the flow plate?

    Has anyone ever done this? I tried doing this the way the article is written but got no fuel at all when opening the lines at the injectors. NOTE: the injectors do make noise when depressing the flow plate.

    Thanks.
     
  2. miketuason

    miketuason F1 World Champ
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    Tim what about sparks, have you confirmed or deny ignition sparks?
     
  3. Archer911

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    Mike:

    After I replaced the plugs, extenders, wires, and distributor caps about 18 months ago I have had no symptoms of bad spark. The can ran well for a while.
    Of course something could have changed...

    But, I need to verify that the injectors are getting gas...air in lines, blocked fuel distributor, etc. Odd how some cars need to purge air from the injector lines and some don't. Can't find a factory procedure on this but maybe it will be in the Bosch book I have on order.
     
  4. spicedriver

    spicedriver Formula Junior

    Feb 1, 2011
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    If the injectors are screeching, they're probably working okay. The best way to test is to pull them out, and let them spray in a plastic bag, or bottle.



    An easy way to test for a spark, or fuel problem is to pull the fuel pump relay, and spray starting fluid into the FD. If the car won't start with starting fluid, you're likely not getting enough spark.
     
  5. Archer911

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    It started the first time but ran so badly I shut it down. Tried 3 more times and nothing. The odds of a failure of the ignition system exactly when I changed the injectors must be astronomical. I think your idea of removing the injectors and, attaching b bags to each, and seeing if they spray is a good one albeit one that will be a major pain.
     
  6. Archer911

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    This may be a piece of the puzzle. Found this on CIS Flowtech site and since I replaced the WUR AND the injectors there may be more to this
    Bosch K-Jet Mixture Setting

    posted on August 31, 2009 by Larry Fletcher | Comments Off on Bosch K-Jet Mixture Setting

    After assembly of the fuel system, run the fuel pump and depress the air flow sensor plate for a couple of seconds to bleed air out of the fuel distributor. Remove one injector line from the top of the fuel distributor, and while looking into the injector port in the top of the fuel distributor turn the mixture adjustment screw clockwise until the port just starts to fill with fuel then turn the mixture screw 1/2 turn counter clockwise. Reinstall the injector line, start the engine and adjust mixture when it reaches operating temperature. This is the Bosch recommended procedure for initial mixture setting and adjustment.
     
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  8. mike996

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    When I replaced the injectors on my 328 and then started the car, it ran well for a few seconds, then sputtered and acted like it was going to to stall for maybe a minute or two, then cleared up and ran correctly from then on. I didn't do any sort of bleeding or anything other than just pull the old injectors/install the new ones and start the car. I assumed that's the way it's supposed to work but maybe I was just lucky. ;) As they say, luck is always better than skill! :)
     
  9. Archer911

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    Thanks Mike, I appreciate the info.
     
  10. thorn

    thorn Formula Junior
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    Mike's non-bleed method above actually makes sense to me; I'm not surprised it worked after the engine coughed for a bit. After all, the injectors arent part of a closed circuit.
     
  11. Ferraripilot

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    check your grounds. Pull them and really freshen everything up well with them. Electrical stuff may appear they are working with a so so ground, but they very often won't work well.
     
  12. SeattleM5

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    Tim, the above described procedure is appropriate if the fuel distributor has been removed from the air flow meter, especially if the distributor has been rebuilt given that the distributor plunger may be in a slightly different orientation relative to the pivot arm of the air flow sensor meter upon re-installation of the distributor. See the included figure (note, however, that the schematic is for a generic updraft air flow meter while your car has a down draft meter).

    Upon installation of new injectors you don't need to crack the fuel lines to bleed them. Just pull the safety switch on the distributor (the blue AMP connector), put the ignition in position II, and depress the air flow meter plate for 10 or so seconds which should be enough time to bleed the lines and injectors. I wouldn't do it much longer than that as you will be pumping raw fuel into your cylinders which will make for an interesting start up situation if you have too much raw fuel in the cylinders when the car attempts to fire up. Note that if the distributor has been off the car and is empty of fuel the bleeding procedure will take quite a bit longer (30-40 sec). In that situation I would run the same bleeding procedure but I would pull the injectors from the manifolds and place them in a visible container so you can see when they start spraying fuel consistently at which point you know the system has been bled.

    As far as your current situation it's pretty hard to determine exactly what the cause is without having my hands on the car. Mechanical fuel injection works very well provided everything is set up correctly. In particular, it requires that flow to all of the cylinders is balanced and there are several areas in the system where things can get out of whack. These imbalances can be intrinsic (i.e. malfunctioning fuel injector, corrosion in the fuel line, deposits in the fuel distributor restricting flow, etc.), or they can be extrinsic (adjustment of the the A/F mixture screw, manipulation of the individual fuel distributor outlet ports adjustment screws, etc). Over time, especially if the cars are not run regularly, intrinsic variables result in poor running situations that prompt mechanics (professionals and DIY'ers) to make adjustments to the extrinsic variables to counter act those effects. It's only speculation but it's possible that over the years your car has been adjusted in such a way that any change in components (i.e. new fuel injectors, WUR) may throw everything out of balance. I have some other ideas but it will take too long to write them all here. Please feel free to send me a PM if you'd like to chat by phone

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  13. cmt6891

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    The new Bosch brass injectors have assembly lube inside and should be cleaned out with solvent prior to installation. So that could be part of the problem, flushing that out with gas will do the job. With that said the system needs a bit of time to pressurize and upon initial start will most definitley stumble and sputter. I don't know how much time you spent on tryting to get the engine running well but it can take at least 5 attempts.
    As Ettore says, the mixture screw might have been adjusted previously to make up for poor performance, possible due to lack of good injector spray or leakage. Although mixture adjustment is a routine to perform after new injectors are installed, I would not touch the fuel distributor screw unless you have a exhaust gas analyser to check the CO. Messing with that will open another can of worms. Good Luck
     
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  15. Archer911

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    I greatly appreciate all the responses I have gotten vis-a-vis my 308 problem.

    You guys nailed it on NOT needing to "bleed" the system as a previous post stated. By doing that I now know that I most definitely flooded the engine.
    I removed the flexible duct between the fuel distributor and the throttle body earlier only to find puddled fuel in the throttle body.. After wiping it out I reattached the duct and gave it another go. I left the cold start injector disconnected and gave it a go. Started first time. See video (watching paint dry).

    Now I have an odd 1000rpm increase in idle when blipping the throttle and then a backfire as shown in the video. (BUT at least it's running again.)
    The Ferrari trouble shooting chart D21 and N21 seems to point toward control pressure issues. I ordered a pressure tester from Pelican that was supposed to arrive today but it didn't.

    The video is a bit like watching paint dry but it does provide some information.

    Thanks again everyone for the support as I greatly appreciate it.

     
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  16. Brian A

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    AWESOME!!!! Glad its running again. What a battle!

    Will you be able to take it out for a long run some time in the near future?
     
  17. Archer911

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    Not until I get the idle under control and find out why it's backfiring.
    Looks like my fuel pressure test kit won't be here until next week now.

    Hoping someone here will have an opinion. I think the new WUR, that replaced the old one of the wrong model number, will play into it and possibly some crud in the lines yet to be extracted. I also have a working throttle position switch now that I didn't have before so that should play into it.
    It's almost like I need to learn how to balance an entirely new equation.

    I would like to send both the WUR and FD to Flowtech so they could match them up but hate to write another month off waiting.

    Hoping to blend some luck with hard work to drive my 308 soon. I'm not a mechanic, I'm a marketing guy so I expect to stumble and fall.
     
  18. cmt6891

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    You mentioned in an earlier post that you replaced the WUR. Was it new or rebuilt by Larry?? The WUR controls the fuel pressure and the Bosch part number is specific to the car, so I would recommend having the WUR rebuilt. The FD is a bigger job and probably not needed .
     
  19. SeattleM5

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    First off, I'm glad to hear that you are planning on getting a fuel pressure tester. As a first step I would ensure that the fuel pressures are correct prior to proceeding any further. I suspect you already have this data but for the -083 WUR (which I understand your -132 was calibrated to) you should expect a cold control pressure of anywhere from 1.6-2.0 bar at 10 deg C, 2.0-2.4 bar at 20 deg C, 2.4-2.8 bar at 30 deg C. Warm control pressure should be between 3.3-3.7 bar. If there's a problem with either the CCP or WCP then your WUR is not calibrated appropriately. Primary (system) pressure for the -139 distributor should be 4.8-5.4 bar. If your primary pressure is too low it's either a problem with the fuel delivery (pump, accumulator, distributor inlet lines) or the pressure regulator within the distributor. If the primary pressure is too high it's either a problem with the pressure regulator within the distributor or there's a restriction in the return pipe from the distributor to the fuel tank. Once you have confirmed your fuel pressures are correct you want to ensure that distributor port flows are equal. This is hard without specific Bosch equipment. Bosch made flow meters for this purpose but they are very hard to come by and few shops have them. I use a Bosch KDJE P-200 flow meter which allows you to confirm flow rates at idle, part load, full load (see photo). Ferrari publishes what the acceptable distributor flow variance is within the WSM (around 16% at idle, and 10% at part/full load). While cumbersome, flow testing can be done without the machine but it requires you to pull the injectors from the manifold and measure individual injector fluid volumes over time.

    Once you have confirmed that fuel pressures and flow rates are within spec would I move to the AFR. I see that you have an AFR meter in place in the video. Please confirm how you have that hooked up. Are you measuring via a 'sniffer' from the tail pipe or using a wide band O2 sensor in place of the original precat O2 sensor? Ideally you want to test in the precat location so you are not getting spurious data as a result of cat irregularities. You need to make sure that the system is in 'open' loop which requires you to unplug the O2 sensor harness. Once the car is warmed up adjust the mixture screw until you achieve the stoichiometric ratio (14.7:1). Note that you want to make small incremental changes with the screw (1/8 turn at most) and reassess AFR after each adjustment. Note also that you need to plug the mixture screw access hole after each adjustment before taking the AFR reading as the open hole allows for un-metered air into the system which will affect the AFR. See post #19 for specific details regarding what direction to turn the screw to lean/enrich the mixture: https://www.ferrarichat.com/forum/threads/what-is-the-hole.397630/#post-142084574

    That's it for now. The offer still stands if you want to chat directly, just PM me.

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  20. Archer911

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    I think my best course of action concerning the WUR and FD is to send them to CIS Flowtech. They must have all the right equipment and unfortunately I don't know who rebuilt my WUR as I bought it from TRutlands. I'm taking it all out tomorrow. When I get the units back I can proceed as you suggest with checking for restrictions with my simple test kit.

    In terms of the the AFR it is connected to a Wideband O2 sensor in a Fabspeed cat bypass pipe (original cat on the shelf). I did read about how sensitive adjustment is to the FD and about replacing the plug between changes.

    In the meantime I think I should empty the tanks as the fuel is from last Fall (stabilizer was added then) but I suspect it's going south, and will also change the fuel filter again.

    I did PM you earlier and will take you up on the offer again when I get parts back in the car.

    Thanks again...to be continued...
     
  21. spicedriver

    spicedriver Formula Junior

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    RPM increase could be the plunger in the FD sticking. You can feel the movement with the air vane.
     
  22. mike996

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    FWIW re fuel/stabilizer:

    I routinely store my 328 - unattended/battery disconnected - for at least 5 months and as long as 7 months on some occasions - with some Stabil in the tank, the amount as per the Stabil instructions. Gas was the usual 10% ethanol in the local area. When returning to the car I reconnect the battery and the car starts/runs as if it had been running the day before. So although it's certainly a good idea to put fresh fuel in, I'm thinking that if you put the recommended amount of stabilizer in, the gas is not causing the problem.
     
  23. johnk...

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    Done the same thing with my 308 for 35 years except no fuel stabilizer. Same result, starts and runs like it was never stored. Same with my old Miata for 10 years and 355 for the last 5. And yes, we have ethanol in CT. You do realize that Stabil is 95% heating oil.

    Tim, is it backfiring though the intake or exhaust? You know, it just might be that getting it out on the road under load might clear things out.
     
  24. Archer911

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    The air vane seems to move pretty smoothly.
     
  25. Archer911

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    Yeah, I don't think it's the reason for the problem either but I don't think old gas will help much when I finally get her running again.
     
  26. Archer911

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    John when the car has backfired I have always been in the driver's seat so really can't get a sense of the area it came from.
    I think if I got the car out on the road it would be returning on a flatbed.
    No wonder Stabil smells like heating fuel!
     
  27. Archer911

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    Looking at the video the backfire was enough to move the car/camera slightly and drop the AFR reading by about 2 well into the rich.
     

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