Hey all, We're replacing the nozzles on my friend's '83 400i and had a couple questions before we commence.. Before I ask, I will say that we have 12 new Bosch nozzles and 12 of the little green Bosch seals that go around the nozzle body... 1. What is the procedure for removal of the injector itself? Is it simply to disconnect the line and pull the nozzle out? 2. Will the o-ring/seal come out with the nozzle? 3. Is it advisable to replace the nozzle holder as well? It looks like the intake sits just slightly covering the nozzle holder, which means that has to come off before it can be replaced. Any thoughts are always appreciated! Cheers, Aaron '82 GTSi
Hi Aaron, this is one of the few easy jobs on a 400i ! You just grasp the injectors in a large pair of long nose pliers and ease them out. The fuel lines need to be released from their plastic brackets to allow the injectors to come out of the plastic housing and have enough free movement to work on them. I think it is advisable to remove the fuel distributers from the car (a bit tiresome) as it is easier to apply the two spanners needed to unlock the nuts that hold the injectors on. Considerable force may be needed to unlock the injectors from the fuel pipes, and this is more controllably applied on a work bench. The plastic inserts in the head would only need to be changed/removed if damaged, I would leave the intake manifold on unless you need to remove it for another job (valve clearence setting etc). Always replace the rubber 'o' rings around the injectors (mine are black and fat!). When you remove the injectors some of these 'o' rings will come out with the injectors, and some will stay in the plastic holders. Just remove and discard them which ever happens. To refit I recommend fitting them first on the injectors with a smear of grease, positioning the injector (with fuel pipe attached) in the plastic holders, and gently tap home, using a screw driver on the injector top nut and small hammer. Easy!!
Tim, Thanks for the reply. I figured it couldn't be too awful of a job! One other thing; I removed the left side rubber air intake boot that fits over the throttle plenum, and as I pressed the plenum plate down, I noticed that it only moves down maybe an inch or inch and a half, but no more. On Mercedes CIS injection systems, the throttle plate can be moved down maybe four or five inches! Is this the way it's supposed to be on the Ferrari? Cheers, Aaron '82 GTSi
Hi Aaron, the plate you refer to is an air flow sensor. It should be closed normally, and move upwards with the engine running. This movement adjusts the amount of fuel being fed into the injectors to get the correct fuel to air mixture. The plate should lift freely with no friction, and return to the closed position when you release it. Hope that helps, Tim.
bergxu, If these scans from the Ferari 400i iniezione manual are legible maybe they'll help depict the "plenum plate" (Air Flow Sensor in these diagrams) you mentioned. The purpose of the plate is to sense the volume of air flowing from the bottom up thru the mixture control unit on it's way thru the rubber boot on it's way to the throttle plate in the intake. Al Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Al, Ahh, many thanks for that diagram. I was pressing down on "5b" in the diagram. I see now, at least according to the picture, that it does not have a long travel, as it is of a somewhat different design than the Mercedes CIS system is. Cheers, Aaron '82 GTSi
