jonost24 Posted June 30, 2009 Share Posted June 30, 2009 Tried to start the 90 tonight (3.5 v8 Efi flapper). Needless to say it wouldn't . Had this prob before inc. cutting out about 7-8 times on an 8 mile run. Suggestions came back that it sounded like the coil breaking down, so a new coil went on, started fine and ran ok. Tried tonight, but just turning over. I've got a spark, but checked a couple of plugs, and there didn't appear to be any fuel on them. Should they have been wet....wet ?? I disconnected the AFM at the filter, turned the ignition on, and physically moved the flap but couldn't hear the pump. I then jumped a lead across from the battery to the pump and it whizzed like a good-un. Does this mean the AFM is kaput ? Can someone tell me what the AFM does exactly ? ie when starting, running etc.... I've also swapped some realys about which didn't make any difference. I will MS when funds permit, but at the moment I just want to get in, start it, drive it stop it when I want it to. Any help appreciated Thanks, Jon Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted June 30, 2009 Share Posted June 30, 2009 Sounds like a power problem to me. Check the tech archive for the diagnostic procedures for flapper and post up the results. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted June 30, 2009 Share Posted June 30, 2009 Full flapper diagnostics guide & system explanation in the technical archive. AFM contains a switch for the fuel pump which activates the relay, could be as simple as the relay being kaput - be careful when replacing though as some have two "87" terminals (dual) and some have an "87" and "87a" (changeover). Quote Link to comment Share on other sites More sharing options...
jonost24 Posted July 1, 2009 Author Share Posted July 1, 2009 Looks like I need to buy a multi-meter. Can I get a decent one for about £20-£25 ? Any suggestions ? The relay does say 87/87A on the back. How can I check that the relay is clicking ? With the ignition on, and I move the flap, I can't hear a relay click or the fuel pump. James, when you say "power problem", do you mean supply to the pump or relay problem or something else ? The tech archive is useful, thanks for the replies. Cheers, Jon Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted July 1, 2009 Share Posted July 1, 2009 Looks like I need to buy a multi-meter. Can I get a decent one for about £20-£25 ? Any suggestions ? You can get one that's more than up to the job for £2.50, although I'd splash the extra 25p and get a continuity buzzer as well (Maplins usually have the same thing for an extortionate £4.99). You can get a pretty handy AC/DC clamp multimeter for £25 from CPC. The relay does say 87/87A on the back. You need to make sure if you replace it, you replace it with the same thing such as R20BC. How can I check that the relay is clicking ? Get someone to listen while you poke the flap, or get someone to poke the flap while you listen, or replace the word "listen" with the word "touch". Or use your shiny new multimeter. Or a test lamp. With the ignition on, and I move the flap, I can't hear a relay click or the fuel pump. It's either the AFM, wiring, relay or fuse then. or possibly dead fuel pump killing one or more of the above. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted July 1, 2009 Share Posted July 1, 2009 Yes, eBay has many, Maplin has many more. You will probably get one plenty suited to automotive use for £10. You can spend more and get bling functions like RPM readouts, thermocouple readers, transistor testers and all sorts. I'd stick with cheap 'n' nasty - you won't mind when it gets covered in oil then. (Clicky) You should hear the relay click with your head nearby - you will certainly feel it if you have your hand on it. You may need to get someone to stick their fingers into the AFM while you feel the relay. If it isn't clicking, either the ECU isn't turning it on, or the relay has failed. More likely the latter IMO - try running wires to the pump to get the pump running, then try starting the vehicle. If it runs - relay is duff. If it doesn't - something else. The AFM by the way serves two functions - turning on the fuel pump, and measuring the amount of air going into the engine so the ECU can work out how much fuel to put in. Quote Link to comment Share on other sites More sharing options...
jonost24 Posted July 1, 2009 Author Share Posted July 1, 2009 Thanks for your replies. How on earth can they sell a multi-meter for £2.50 ?? Even though I'm still on a 3-day week, I think I can stretch to that, maybe even one that plays music . The relay is real close to the AFM on the bulkhead, and I can't hear it clicking,so that is a cheapo to replace, although I have connected the fuel pump to the battery and it runs, but the motor doesn't start when I crank it. I'll change the relay as a matter of course for the small cost. The relay states 28RA, would this mean 28 amps ? If so, would I be ok with the 20A from VWP ? Thinking down the line, I've read the MS thread for beginners. Is this the way to go to junk all the AFM, dizzy etc etc. I've already got my EDIS8+connectors and a couple of Ford coils with plug-leads. I can see there's a lot of wiring involved, is there a P&P loom available for the RV8 ? I see trigger wheels do the MS ECU and also some wiring deluxe kit. I'm trying to build up the parts I need gradually to try and spread the cost. Any advice welcome Thanks, Jon Quote Link to comment Share on other sites More sharing options...
Pete Attryde Posted July 1, 2009 Share Posted July 1, 2009 I suspect sending Fridefreezer a pm would be a good idea as I believe he can supply most of what you need to do the conversion including the ECU. Pete. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted July 1, 2009 Share Posted July 1, 2009 I thought the fuel pump relay was under the seat next to the ECU, the one by the AFM is a Lucas bodge to give overrun fuel cutoff. Quote Link to comment Share on other sites More sharing options...
jonost24 Posted July 1, 2009 Author Share Posted July 1, 2009 The one on the bulkhead appears to have a wire that runs to the AFM and another wire that goes to the coil, so I made the assumption that when cranking the coil would activate the relay which in turn would start the fuel pump ??? I do have three relays behind my seat next to the ecu, although one is red - diode pack ??? What does that do ?? The one on the bulkhead defo says 37/37A, while the others are just 37. I'll double check in the morning....... Thanks, Jon Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted July 2, 2009 Share Posted July 2, 2009 The one connected to the coil shuts off the signal from the coil to the ECU based on a vacuum switch on the back of the plenum (teed into the fuel pressure reg vacuum line) to stop the ECU injecting fuel on engine over-run (coast), a factory bodge. The red "relay" under your seat is indeed the steering unit (AKA the bits they forgot to put in the ECU), the other two are main relay (many big brown wires) and the fuel pump relay (will have at least one white/purple wire, that is the fuel pump one). If it's a normal type (4-pin) relay then replace it with a GOOD 40A relay as they can burn out / contacts foul up, especially if the pump is past its best. The overrun relay is not shown, but this is the rest of the system: Quote Link to comment Share on other sites More sharing options...
jonost24 Posted July 3, 2009 Author Share Posted July 3, 2009 Had another tinker today, whether I'm correct in doing it or not I don't know - I took the metal casing off the two relays behind my seat to "see" if the relays were working. Neither relay appeared to operate as I cranked the motor, looking in the Haynes book , as you say one is the fuel pump relay, the other the main relay. The main one has wires going to all 5 connectors, the fuel pump relay only four of the connectors have wires. I'm going to get a couple of new relays and try those. I squirted some easy start into the plenum, and it coughed (but they didn't drop ), tried again but this time jumped the fuel pump to run that, but again it only coughed. By the time it's started, I should have given up and done the MS route !! Keep perserveing though, it's a good job I don't need it for work Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted July 3, 2009 Share Posted July 3, 2009 Taking the tops off relays is not something I'd normally bother with - if it doesn't click it's not working (either it's dead or it's not being switched on). Did you hear the fuel pump run when you jumped it? You may be best off looking at the Flapper EFI diagnostics guide in the tech archive and working through it step by step, if only to save us typing out the instructions here step by step Quote Link to comment Share on other sites More sharing options...
jonost24 Posted July 3, 2009 Author Share Posted July 3, 2009 Yes, the fuel pump did run when I connected it straight to the battery. Hint taken about the tech archive Thanks, Jon Quote Link to comment Share on other sites More sharing options...
Aragorn Posted July 3, 2009 Share Posted July 3, 2009 Connecting the fuel pump streight to the battery doesnt really help, as the fuel and main relay will also power the injectors etc. You need to get the multimeter out and see if the AFM is actually powering up the relays. Quote Link to comment Share on other sites More sharing options...
jonost24 Posted July 3, 2009 Author Share Posted July 3, 2009 Ordered the multimeter off ebay, same as CPC but only £7.44 inc P&P. CPC would have been £10.01. I can get checking then Quote Link to comment Share on other sites More sharing options...
bmhor Posted July 3, 2009 Share Posted July 3, 2009 The relay is real close to the AFM on the bulkhead, and I can't hear it clicking,so thatis a cheapo to replace, although I have connected the fuel pump to the battery and it runs, but the motor doesn't start when I crank it. Jon, A couple of things come to mind; When you first turn on the ignition, the fuel pump should run for a couple of sec's to prime the system, is this happening? If not have a look at the main power relay. From the coil there is a single wire from the -ve connection to a "relay" mounted on the AFM bracket (on a R/R anyway) this is the sense wire that tells the ECU that the engine is turning over and it should fire the injectors and turn on the puel pump. Its not unknown for the "relay" to fail or the wire to fall of the coil. My money is on the main power reley..... Bob Quote Link to comment Share on other sites More sharing options...
jonost24 Posted July 3, 2009 Author Share Posted July 3, 2009 Thanks Bob for your comments. The flapper fuel pump only works when the engine is being cranked, so no pump priming will be heard with just the ignition on. I think the hot-wire system works that way. The wire on the coil is still on. I'm going to try a couple of new relays and also do some checks with my new shiny multimeter whenit arrives. Cheers, Jon Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted July 4, 2009 Share Posted July 4, 2009 What Jon said - flapper does not prime the fuel pump, and the "relay" on the coil (tach) signal wire is just a relay, so you can remove it and jump a wire with two spade terminals across the contact pair of connectors (obviously NOT across the white +12v / black GND wires that turn it on) to eliminate it from enquiries. 1st check would be to measure the voltage across the fuel pump relay coil when you poke the flap, should be ~12v. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.