text: 87 RRC EFI Flapper 4cu trouble shooting wiring / ecu / AFM / regulator /
  Thread: 87 RRC EFI Flapper 4cu trouble shooting wiring / ecu / AFM / regulator /
  29th November 2019, 05:45 PM #1
  RRC James
  G'day, still working away at my EFI system to get the car running properly
  I've made plenty of progress after a mobile auto electrician/automotive engineer made a bunch of mistakes in front of me including ignoring the dealer diagnostic manuals I kept trying to hand him and the dealer workshop manuals. He also pulled out the distributor with out finding TDC on the harmonic balancer first or marking anything and was confused with the 30 degree change when sliding the dizzy onto the oil pump shaft. Yes he was that bad.
  Car is starting and running at idle now when AFM is unplugged. It will rev quite a bit but will cut out if I don't do it a particular way.
  As soon as I plug in the AFM it dies.
  When the car originally died - if you were sitting at the lights idling it would just cut out after about 30 seconds. Even if you caught it cutting out and gave it some gas it still cut out. To keep it running at the lights it just required revving but sometime that wouldn't stop it. Eventually it just wouldn't start again. This happened over the space of 2 weeks.
  I have swapped the AFM over for an apparently reconditioned one, however off a Jag V6. Can't be a reconditioned one as once the fuel pump circuit is closed it won't open again unless unplugged.
  Tried swapping out the ECU for another unit, untested but, seller said it was good. No change.
  I will be working through the diagnostic manuals with the multimeter and going over the relays and wiring tomorrow. Can anyone give advice on what to look out for?
  BTW - new plugs, all HT leads in spec for resistance, new pickup coil magnet with air gap in spec. I've been over the ECU with the microscope and found a cold joint at one of the transistors as it was intermittently firing on one bank before eventually becoming a permanent fault. Thats been fixed. Negative air valve switch has been pinned out and the relay attached to that circuit next to the AFM and attached to the negative on the coil is working.
  I may have done some damage to electrical system during all my poking around trying to learn and fix the EFI system making mistakes as I went, sometimes reversing polarity in coils or putting down a spanner in the wrong spot causing a few sparks and a tiny bit of smoke. It there anything I should look for?
  A couple of other things are happening electrically that seem odd or broken. Could anyone please shed some light on them please?
  There is AUX digital battery gauge, its all over the place some times, anywhere from 7V up to 26 volts. Rest of the time the readings are as they should be.
  The fuel gauge is showing over full whenever the ignition circuit has power. I have pulled the two connections out to the sender in petrol tank. No change. Any suggestions or experiences with the same issue?
  Otherwise mechanically engine is great and even though its not finished its sounding better than ever as that old pickup coil had been gradually going open circuit over the last few years and that cylinder bank fault was dogging the thing.
  Any advice welcome thanks for your time
  30th November 2019, 09:54 AM #2
  My experience is with the earlier "Federal" system which I fitted to a 77RRC.
  In that system the fuel pump is controlled firstly by a time delay relay which energises the fuel pump for about 20? seconds when starting.
  The fuel pump is then energized by the flapper lifting a bit as air flows through.You can check by lifting the flapper a little with the ignition on.
  I think that yours has the same system.
  I would look at the flapper to see if the contact inside for the fuel pump activation is OK, and that the wiring to the fuel pump relay is OK, and that the time delay relay is working.
  30th November 2019, 01:01 PM #3
  Yes this has the fuel pump switch inside the flapper afm which is operating correctly when plugged in with ignition on. I am right now trying to work out which of the relays is responsible for switching the circuitry over to the next system once its started, I'm guessing it cooked. Looks like its happy to sit there idling on the starting circuit with the AFM unplugged indefinitely. I've got all the books just trying to put it together. Thanks for your input the time delay relay makes whats happening make a bit more sense.
  2nd December 2019, 11:58 AM #4
  Under the drivers seat are three relays. Well, two relays and a steering module. The two relays are main ECU power and fuel pump. The steering module is red and is responsible for powering the fuel pump while starting and while running. It essentially switches which circuit powers the fuel pump.
  Upon starting the contacts in the flapper will power the fuel pump until the ECU receives the rpm signal via the cut out switch, which then sends a power supply to the fuel pump via the steering module.
  The fuel pump is not on a timer or pressure delay like newer systems. If the engine isn't being turned over or running, the pump doesn't run.
  To me in your case it sounds like it is either getting too much fuel or not enough. If you haven't already, inspect the fuel pressure regulator and test the fuel pressure. For it to die at idle, but be ok with some revs up, it really sounds like a fuel issue where it is overfuelling.
  What are the plugs like, colour? Smell? Are the vac lines all in good condition? Have you cleaned the earth's at the back of the LH head?
  The other two problems probably aren't related. The volt gauge thing is either a loose connection or poor earth and the temp gauge thing could be the power converter in the dash cluster. My 89 does weird things sometimes, especially when the weather is warmer.
  3rd December 2019, 08:44 PM #5
  Originally Posted by Konradical
  G'day. Thanks I've checked the relays and checked the steering module. Looks like SM was rebuilt with uprated parts at some stage. I think it is a too much fuel problem. Plugs get wet then have to leave it half a day or take out and clean to get it going again. Black smoke is pouring out the exhaust when it is going now and this was a problem for about a year long time before the car stopped running. Never got around to buying a tester for the fuel pressure and its gone into the shop today for a LR mechanic to work it out. I did test the AFM using a multimeter this morning and it tests fine, I used a digital and analog multimeter. Good news is I'll have an answer for everything this week.
  I'll have a look under the dash when I get it back thanks for that. Worst case scenario is that its the gauge and I've got a spare one of those handy
  Looking forward to having the car back sorted. Its been a long journey of break downs and googling to sort out all the intermittent problems.
  3rd December 2019, 09:20 PM #6
  I'd suggest you compare notes with Richard, a few threads down the page.
  1988 RR Classic not running on petrol.
  PA might like to comment............. the injection system you have is not closed loop and can keep loading fuel in when running rich AFAIK.
  The NA Chev in my pos used to run really rich on petrol simply because the fuel return line was blocked where it went into the steel tank.Ran fine on gas.
  Worth checking, DL
  3rd December 2019, 09:46 PM #7
  Originally Posted by RRC James
  Yeah could be a simple thing like the fuel pressure reg. If it doesn't allow a pressure drop in a high vacuum state (idle) it will squeeze more fuel out when the injectors fire causing the flooding effect. Or again if the diaphragm is split, fuel will be drawn into the system unmetered.
  I did fail to mention the ECU, as you said you have already tried swapping and repairing.
  Hope they get it going for you and you can get out and about in it in this soon to be (fingers crossed) good weather.
  4th December 2019, 10:30 PM #8
  G'day. Called in this arvo. Mechanic said some strange things happening, said he was working on it just as I called and had to stop to come and pick up the phone... No fuel pressure when fuel pump pumping fuel, clamped return line, still no pressure but return fuel line working and feeding fuel back into the tank. I said is the fuel regulator diaphragm split, he did didn't bite. He said strange things happening as the car will run without the fuel pump relay... I though cranking circuit runs on its own without fuel pump relay and told him so, he didn't correct me. Just looked it up. I'm wrong. It needs the fuel pump relay for fuel pump to work. They said they will keep working. I've worked it out. What do you think? Cheers James