Sydneyjames

Hi guys,

Struggling a little with the RS, (doing my head in now!) if anyone has any ideas I’d really appreciate it!

basically sometimes it’ll start without an issue, other times won’t start at all. Times where it won’t start at all, you can try all day and it won’t start, it tries to but won’t fire up. Leave it a day or two, go back and it’ll start!

if I take off the filter and spray a little fuel into it, it’ll start up and then stay started.
I have changed the injectors as the engine was flooding very quickly, that seems to stopped that. Metering head is fine, have tried another one on the car - still same. No air leaks neither.
It’s obviously a fuel/starving issue, but am at a loss as to what else it could be.
any one had any similar issues or possible advice as to what it could be.

cheers

OAP Pete

Ex Auto sparks fully conversant with Bosch "K & KE " you say spray a little Fuel in Air intake...fires right away...but are you able to drive off normal without lots of "spluttering / poping back / wont pick up properly till warmed up...this tell me something. You see the 5th injector should be doing "what your doing with spraying direct to manifold...So hear is what happens when you first go to start from cold, you turn on ignition, the water Temp sensor [ Yellow ] would adjust the Black ECU as to what voltage to be sent to the "Pressure actuator on the side of the metering unit"... this is so the pressure can be increased...now turning the Key to start fuel is spayed into manifold...so engine bursts into life...to keep it running now on all 4 injectors the pressure will Higher...how high depends on outside Temp as well as water Temp, also the engine idle will be higher 1000 / 1100 RPM this is set by the Idle control valve under manifold, as the engine warms up...idle returns to normal idle 850 900 RPM, so 2 items need Testing...is the 5th injector getting 12v on a Cold start [ only ].....next is the pressure actuator getting Voltage also on Cold start only...what i can say no voltage at pressure actuator, the engine would be a pig to start...firing...then petering out...keep doing this till eventualy runs. so hope of help. Pete .

Sydneyjames

Once it starts, it drives fine (I do wait til it warms up before driving off)

The fifth injector was changed a couple of months ago, but with the weather warming up, I’ve been told the 5th injector doesn’t do much now. with regards to the voltage at the pressure actuator and 5th injector - Cheers, will try this tomorrow and report back!
Thanks again.

OAP Pete

The 5th injector always comes in on a cold start, for information its controled by the "Thermo timer" [ Brown plug ] under manifold....as soon as engine warms up Timer cuts voltage to 5th...these cars need the 5th on start up Cold, as on cranking Cold engine all 4 injectors wont release Fuel, you confirm you let the engine warm up before driving off....should not be needed...but its a sure sign the "Pressure actuator" is not getting a voltage signal...or is faulty...the reading at the actuator itself [ plug off ] is 16 to 21 ohms...do check also on the Black ECU pin 1 [ colour Black/green ] is live when Ignition on, this Black ECU has its own fuse, for infomation the 5th injector is independent wired and nothing to do with ECU, the Black ECU sends the Voltage [ varies on how cold ] to the actuator, which works on the "Bi-metal princeible"...ie resets itself on cooling down. If no power at pin 1 these cars will start eventualy after much cranking....but keep in mind the 5th injector will be shut down after approx 5/6 sessions of cranking, this is the safety side coming in by the "Thermo timer "...then of course it never starts...after 15 mins or so Timer resets...the 5th injector is then back.. Peter

boost monster

My “5th injector” or cold start injector went faulty in the late 90’s and has been disconnected since with no starting issues.

OAP Pete

I can only comment on standard set up....as they were from new,.,... leaking injectors....High Mixture Co set up....Pressure actuator played with...yes they may well start without the 5th Injector connected...see it all in my time.

Sydneyjames

Thanks for the help OAP Pete, apparently the temp sensor was faulty. Was giving some rather silly temp readings. This was changed and all seemed well…or so I thought! Started on the button but after driving it for a few miles today for the first time on the way back from the garage, the revs started hanging at around 1400 rpm from 950-1000. I got it home and switched it off. Tried starting again and didn’t want to know. Left it a minute and tried again, spluttered a little bit eventually started with the revs staying at around 1400 rpm. Switched it off a few times and started right away, few minutes later didn’t want to start again. Gave up and left it for today. Will try again tomorrow but I’m just so confused! 🤔

OAP Pete

Did the garage set the car up after Temp sensor changed, were they "Familiar with the Bosch system "....Hear are the readings for a good " Yellow Temp sensor" ..Cold engine 15-30 c...1.3 K..to..316 K..Ohms........Hot engine...80c & over.....250-390 Ohms...get this re-checked. The engine High RPMs ...first check Throtle is returning fully at the manifold -[ rarely gave trouble] back in the day....under the intake manifold you have the idle control Valve, with the engine running ONLY there must be 12volt at this unit, if not the idle will be very High as you have, at the same time the 2 Hoses on the unit must be inspected fully for leaks / perished hoses as this will cause High revs, to test the Electrical side of unit it has to be removed, once removed 12V aplied to the terminals after 5 / 9 mins one should not be able to "Blow" through it....ie the internal Valve one would see fully closed....... i wonder if the Garage went for road Test after fitting the sensor ??....as you say on driving Home...Revs High....Last i would say get a "Co mixture" check done on a Hot engine only...should be 1.5 to 2.0...get then to watch the readings for "Eratic readings...goes up..then settals...then up again...sure sign of leaking injector, Co must be steady reading, do you feel the garage might want this infomation ?.....with respect to them. Also all Turbo piping must be in good condition, as any leaking will effect engine running. best i can say. Peter

OAP Pete

just an after thought....did they when changed the "Temp sensor."..knock off the plug to the " Idle control unit"...this would give very High idle all the time. Pete