1986 RR Classic Amplifier and Coil test

G'Day all,

I have replaced the coil: made no difference.

I agree that it appears the manual is wrong, I have the same multimeter readings for test 3 as before.

Spark comes from the coil lead to distributor when removed from the distributor and held close to an earth (strong spark).

I have removed 3 different plugs and cranked the engine while they are out but still on the lead (all have sparked). The plugs have been cleaned and had the gap set. They were all black when removed from the engine and black again when removed after it had run a couple of times.

I have tested the throttle potentiometer, airflow sensor, coolant temperature sensor, thermo time, (etc) as per the manual and all come up tops.

Fuel is definitely getting up to the motor, there's a fuel smell quite quickly after starting to turn. The fuel pump clicks in when it is meant to as per the relay tests and the airflow and throttle poteniometer tests.

The injectors have all been removed (except the cold start injector) and individually tested. They all click and none are blocked.

A mechanic suggested I run a jumper lead from the negative on the battery to the block and see if it starts. He thought there may be a serious drop in volts when cranking. It made no difference and there is no significant drop in voltage with the battery (about 1 volt) when cranking.

I haven't tested the fuel pressure regulator. However, from my reading this keeps the pressure up when the engine is starting or running at low speed then opens to reduce pressure when the engine is revving harder. In this case, if the regulator was stuffed and not opening when the engine was running harder, the engine should start but run rich under higher revs. If the regulator was stuck open, it probably wouldn't start or if there was too little fuel, the plugs wouldn't be dark but white. Unless the regulator can cause too much pressure for start as well.

There was an aftermarket immobilizer installed: I removed it; made no difference.

The engine tries to start when it has been left sit for a while. It attempts to fire but if you keep cranking, or stop for a second then have another go, it just turns over with nothing. Leave it sit for 5 or 10 minutes and try again, it will attempt to fire again. The only times it has started (6 times now in total over a week) is after sitting for a while. However, this isn't necessarily the case after sitting over night, when the battery is at highest charge. Hence, it would not appear to be charge related, otherwise my thinking is it would fire best after sitting over night. The plugs being black and the fuel smell suggest too much fuel (thinking about this as I am writing here).

So, perhaps I better check the fuel regulator. It may be too much fuel pressure but when left sit for a while the pressure drops and the engine tries to start when first cranked but when with continued cranking the pressure builds up too much again and drives too much fuel into the system. Aerostart doesn't help, which, if it had too much fuel to start with, it wouldn't.

Keep you all informed. Thanks heaps for you thoughts and assistance. I need this f...ing vehicle going.

Wayne.

Try it after disconnecting the cold start injector which sits on the RH side back of manifold.

I know these were prone to jamming open.

Regards Philip A

Philip,

Done that. Didn't change anything.

Wayne.

what about the relay near the airbox that usually turns the fuel pump on.. if that doesnt work i am sure you get the symptoms you are getting as it affects the injectors as well from memory.

had an 86 with this issue and sorting that relay fixed it, if my memory serves me correctly


if that dont fix it, it sounds like it's time to meter the ecu and pin outs as per the manual test procedure

You haven't removed the distributor cap by any chance and replaced it 180degrees out.
This is pretty easy to do.

The way to check is to put your thumb over No1 and bring up to TDC no1 with a socket and feel if the pressure increases to push your thumb off the plug hole.

If it does and the rotor is pointing to the plug lead to no1 then it is correct. Of course you could have all the leads out by one cylinder also.

If not correct then the engine may start weakly and give you the impression all is OK.

It sounds like this may be the problem as usually an engine will either not start at all or start properly unless the timing is out. Where it starts weakly sometimes it points to ign timing being out.

Regards Philip A

If the fuel pressure regulator is holed it will pass neat fuel into the inlet manifold via the vacuum hose connection. Not an uncommon fault across a wide range of EFI vehicles.

G`day ,

as you describe it`s not an ignition problem but more like too much fuel or a lack of air .

You don`t say what stops it or how long it runs when it has started or what it runs like and if it billows black smoke etc .

More information can narrow it down and not necessarily just one fault can cause .

The fuel reg suggestion means taking the vacuum hose off and if there is any fuel found it would likely mean a hole in the diaphragm and a cause of rich running .

The cold start injector needs to be checked it`s not stuck open . Disconnecting the plug won`t stop fuel if the case .

The relay mentioned has to be a Lucas 28RA for the fuel over run and shut of to work properly some of the other relays are Bosch and interchange with each other but this one is different to them .

If the coolant temp sensor ( not sender ) is open circuit or the wires/connector etc are faulty the ECU makes the injectors open for longer than needed giving too much fuel . If the sensor is suspect a 170 Ohm resister in the connector will give hot run fueling .

Have you physically checked the flap in the airflow meter is moving easily through its arc if not it won`t allow enough air through . A back fire can twist the vane or the time sitting may impede the shaft etc .

The pipework air cleaner etc need to be checked that air can flow and that nothing has been living in it while it was 4 years idle .

Could anything you did with the tank be putting fuel where it shouldn`t be .

Hi all,

There was no fuel in the vacuum hose from the regulator and the cold start injector tested fine. It was not stuck open, tested perfectly with the multimeter, was not powered up when cranking, operated when bench tested and allowed fuel through when open. The thermo time tested perfectly as well, as per the manual. My only observation was that the cold start injector clicked way more vigorously than the normal injectors when 12 v power was supplied. It really cracked and made the battery charger hum, whilst the others all clicked open and closed in a way more passive manner.

So, it looks like the fuel pressure test when I'm back after the weekend.

Thanks for all the input again.

Wayne.

Quote:

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Originally Posted by Scrubwa

Hi all,

There was no fuel in the vacuum hose from the regulator and the cold start injector tested fine. It was not stuck open, tested perfectly with the multimeter, was not powered up when cranking, operated when bench tested and allowed fuel through when open. The thermo time tested perfectly as well, as per the manual. My only observation was that the cold start injector clicked way more vigorously than the normal injectors when 12 v power was supplied. It really cracked and made the battery charger hum, whilst the others all clicked open and closed in a way more passive manner.

So, it looks like the fuel pressure test when I'm back after the weekend.

Thanks for all the input again.

Wayne.

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G`day ,

the cold start may use 12V , don`t know but the 8 other run 3V through the resistor pack .

If able i`d suggest you remove all the plugs while away so any internal fuel dissipates , clean the plugs of carbon etc and start afresh