rsgirl1

hi i have a 4x4 saph cos 1990, have no pulse on number 1 injector, have fitted new injectors,full engine loom,and ecu and the problem is still their, also checked fuel rail for blockage can anyone help please?

mcgoo

you say you have replaced the engine loom, did that include the ecu loom, if not have you checked for continuity from the ecu plug to injector 1?

velocity

which loom did you change, the one from the injectors to the block connectors on the bulkhead or from the bulkhead to the ecu block connector behind the glove box.
all injectors get a 12v supply from the fuel injection relay.but each one has an indivdual earth to the ecu. injector number 1 earths through pin 35 at the ecu.
disconnect #1 injector plug and with ignition on check for 12v at one of the 2 pins in the plug i,m not sure if this times out after a few seconds until you crank over the engine.then go to the other pin and check for continuity between that point and pin 35 in the block connector at the ecu.if your not getting 12v to the injector then there is a break somewhere between the injector and the square 6 pin block connector on the bulkhead (all 4 injectors are supplied from the red wire in this block). if there is no continuity from the other pin to ecu pin 35,then there is a break between the injector and the other block connector (the one with the long pins on the engine side of the loom i think its the one closest to the fuse box) or between there and the ecu pin 35,
hope that aint to much reading

rsgirl1

hi thanks for the advice,have checked the loom and all o.k. when i changed the ecu i used a friends we put it in my car and started the car it still missfired so turned it off and thought my ecu must be o.k. ive since been told that i had to drive the car for at laest five miles(something to do with the memory)is this correct?

Stu @ M Developments

iTrader: (12)

No its not. It should start and run fine.

Please give me a more detailed description of what youve been up to and how you came to change the loom as the symptoms you describe could be ecu or even just phase sensing.

Was she fine one day then broken next? Or did it come after some other work?

rsgirl1

it was running fine then developed a missfire checked for a spark and o.k, so unpluged the injector and this made no diference to the running of the engine so thought the problem was the injector,had new set fitted and still missfireing also tick over went up to 1500 and wont turn down. a friend then checked for a pulse on the injector and there was nothing so they said its ecu or the loom, so borrowed there ecu and still the same then got a new loom both parts of it had that fitted and still the same,had my old loom checked and it is fine. thanks for the help

velocity

no disrespect to your friend but was ther pulse measured correctly and do you actually have a problem with injector at all?
the sudden increase to 1500 rpm is significant as it can be caused by a number of things which in turn can be the cause of your misfire
assuming your engine is idleing on 4 cylinders ok
try this for a few simple pointers
start your engine let it run at 1500rpm,disconnect the plug pluged into the idle speed control valve its the silver cylinder mounted into the throttle body held in by 2 screws,after doing that your revs should drop down to base setting,if not you may have an air leak after the throttle valve like a hose or a dump valve diaphram,manifold gasket,loose manifold bolts etc etc,
depending on the above it could mean a simple fix or a bit more trouble shooting as a sensor may be out of adjustment or failed.but nothing to worry about its all fixable
maybe stu has more to add

rsgirl1

hi cheers for the advice, i disconected the idle speed control valve and the rpm droped, the car runs on 3 cylinders all the time.when first started from cold tick over is about 1200 rpm then drops to 900 rpm for a short time as engine gets warm this rises to 1500 rpm where it stays, have tried another idle speed control valve made no diference.

velocity

ok remove the distributor cap and have a look inside at the phase sensor,move the heel of one of the cams (which are 90 degrees apart) by rotating the engine to line up with the phase sensor heel and measure the gap, it should be 0.2 to 0.3 mm also check for broken wires in and the connector on the side of the dizzy for damage or bad connection.its known for the wires to fray or break at the phase sensor.
its this sensor that more or less sequences the fuel injection so it may be related to the injector problem,although i would thought it would affect them all,but see how you get on

cossied

pull out the injector keep it connected electrically and using a container to catch the fuel fire up the car you will soon if fuel is being injected the voltage supplied to the injector is i think a lot less than 12v

rsgirl1

hi ive had a look at the phase sensor and the wires look o.k still have the sleeving on them,also checked the gap and thats fine. still no voltage at injector plug, do u know if the ecu would turn the idle rpm up to compensate for running on 3 cylinders?

velocity

i dont know if it will,but i dont recall it happening to mine when i disconnected and injector plug.
just to be sure,when u say you have no voltage at the injector do you mean you do not have 12v at one of the pins in the injector plug?
if my wireing diagram is correct if you pull back the sleeve cover at the injector plug end it should reveal 2 wires, one red and the other brown and black.the red one gets a constant 12v supply from the fuel injection relay,and the brown and black wire is earthed in the ecu via pin 35 for #1.the earthing duration gives the injection duration,
so if u do not have 12V at the red wire you could try this
supply a seperate 12v to the correct pin in the injector itself with the plug disconnected and connect the other pin in the injector to its recieving partner in the connector plug,i can only stress that you do not want to send 12v directly into the ecu pin 35 so ensure you connect as above and make sure the tempory connections in the injector DO NOT TOUCH EACH OTHER,
if the colour code does not match up,pull the sleeve back on another injector connector and determin which colour wire has the 12v supply.it might be preferable to start and run the engine and the make one connection to the battery or the earth in the injector plug to see if it alters as its running
let me know how you get on