first rough idle, now no spark

[gruntfuttock]

a few days ago my wife drove our trusty vl to visit friends some 150ks without problems, came home parked it in the garage, next day wont start for her !! I have a try, get it going but very rough wont idle, just coughs and spluters when throttle op[en, so I disconnect the AFM and it idles ok but still no power at hi revs, plug in the AFM and it dies, same reaction if i take off the air hose to the plenum, off it idles on it dies, so I remove AFM and check output volts, seems to be ok, output volts go up when i blow thru it. reconnect every thing now compleatly dead no start no spark from coil, what gives ? , ive checked the fuel pump seems to put out plenty of pressure on switch on, pumps fuel for 5 secs. all fuses ok. did the poor old thing just want to come home to die ? any hints gratefuly accepted

[hsvpgts]

suspect may be possible crank sensor. easy enouogh to DIY (just taks note of how things come apart)
i think they're about $100 or so from repco. have to pull dizzy cap, rotor button etc off to get to it.

[jimrichards1964]

a few days ago my wife drove our trusty vl to visit friends some 150ks without problems, came home parked it in the garage, next day wont start for her !! I have a try, get it going but very rough wont idle, just coughs and spluters when throttle op[en, so I disconnect the AFM and it idles ok but still no power at hi revs, plug in the AFM and it dies, same reaction if i take off the air hose to the plenum, off it idles on it dies, so I remove AFM and check output volts, seems to be ok, output volts go up when i blow thru it. reconnect every thing now compleatly dead no start no spark from coil, what gives ? , ive checked the fuel pump seems to put out plenty of pressure on switch on, pumps fuel for 5 secs. all fuses ok. did the poor old thing just want to come home to die ? any hints gratefuly accepted

Fuel pumps may be running but is the pressure sensor holding pressure, flow no good without pressure, as far as spark, I bought a lemon, 3 things, cracked coil at the bolt hole arcs straight to block, 2 power transister, without it nothing, no aftermarket either I have tried, 3 carbon pin in dizzy worn out. When you get spark if fuel a problem, clamp off return at pressure sensor, after 3 months of it dying on me and spluttering, I finally discovered the sensor likes to do what it wants at the wrong time. Good Luck. Jimmy PERTH ps the cough and splutter is usually because your injectors are getting very little pressure because of that nasty little pressure unit, make sure you have not accidentally pushed a connector pin back into its holder, they are very fragile.Any air leak from the over rated air flow meter, to the plenum causes hassles, but why do they run when disconnected???? Check for a split under the flexy bit from the afm to the induction tube. Last edit, check the reverse polarity relay hidden behind the battery, the 5 pin one if its cooked as mine was, the injectors wont open as it supplies the voltage, but not the signal. GOOD LUCKagain

[gruntfuttock]

thanks for all the tips but to no avail.... thought the coil was dud as it had big cracks around the mounting so replaced it. $70... still no spark, then took of the connecter to the dizzy, sorry crankshaft position indicator! and presto very green lots of corrosion, cleaned it up now starts again as before.. idles but no power at revs, and will only idle with AFM disconnected. have disconnected hose from fuel pump, plenty flow and seems to have plenty pressure at least I cant stop it when i press my thumb on the hose end, the return fuel hose also plenty flow and pressure about 1 litre every 30 seconds, seems a lot??

[gruntfuttock]

I think Ive found the problem. when I clamp off the fuel return form the pressure regulator it runs fine so it seems like low fuel pressure was the prob all along, the AFM was just a confounder. next step, could a blocked filter cause low fuel pressure ? seems to have plenty of flow 2l / min is the correct amount and it seems to be about that much, filled a 1l container pretty quick and if the fuel comes thru the filter then it seems the filter should be OK?? Ill try to get a replacement regulator tommorow...any tips i'm tempted to take it out give it a whack and put it back in. odd that the car drove 150km OK right up to our garage then no start. the fuel flow is not like in the diagrm I have, the fuel goes into one end of the "injector feed pipe" and out the other then into the regulator with excess fuel being fed back to the tank.

[vlv8vic]

replace the filter while your playing around with the fuel. well worth the extra few mins work.

its often after the long trips that things do play up. they are fine while the car is busy but it gets home and relaxes (for lack of better term) and thats when things crack and break.
by all means give it a whack and put it back on, just remember to do the same thing when it dies at the lights in peak hour traffic.

if you get it running, go to a mech, ask them to test it (should be free), they will hopefully tell you whats wrong, then you come here and ask us how to fix what the mech said was wrong!

[gruntfuttock]

well today I replaced the fuel pressure reg and fuel press reg solenoid valve and it's still the same dammit ! will idle with AFM off but will not start or run with the AFM connected (same effect with AFM connected but no air flo thru it, hook it up to plenum and motor dies) however the motor runs with plent power albeit roughly with return fuel line plugged ie higher than usual pressure ? this is just wierd im about ready to chuck it 3 days stuffing around with this car and no result so far !! and clues ?