On-going Problem

[Paul and Judson]

We have an on-going problem with our 72 Series III 88.

The problem is that while it always starts very quickly with only a slight turn of the key, it will, at times, die while at idle or while driving and then it cannot be started again. The engine will turn over very strongly but will not fire and start.

We have replaced the coil, distributer cap, points, condenser, fuel filter, and fuel pump. Sometimes it will operate perfectly for a week or two other times it will not go a day without exhibiting the problem.

As always, your help and advise is greatly appreciated. Other than this frustrating problem, the Rover runs very well.

Thank you

[stomper]

Have you checked to see if you have spark when the engine won't start? I'm guessing you have an intermittent electrical short perhaps.

[Paul and Judson]

Thank you Stomper. This is a good suggestion. I have not checked. I am learning about auto mechanics but not very knowledgeable at the moment. What is the best way to check if there is spark? The engine will not start now.

[LaneRover]

One way is to pull a spark plug, then re-attach it to the plug wire and while holding onto the boot (thick part near the plug) of the wire and keeping the plug where it is dark in the engine bay so you can see a spark try starting the engine. (much easier if you have a friend to do the starting)

The spark should be evident.

[Broadstone]

Do you have an inline fuel filter? I have seen the flow direction wrong and caused a similar problem.

[Terrys]

One way is to pull a spark plug, then re-attach it to the plug wire and while holding onto the boot (thick part near the plug) of the wire and keeping the plug where it is dark in the engine bay so you can see a spark try starting the engine. (much easier if you have a friend to do the starting)

The spark should be evident.

Hold the hex body of the plug against the engine block. You can also pull the center wire out of the distributor cap and hold the end of that wire close (1/8") to something like the valve cover. Spark should be bright blue, not orange/yellow.

[stomper]

Check as Terry described first, and if you are still at a loss, check the other way at the spark plug. The center plug on the distributor will identify anything in the starter switch, coil, and wiring to the distributor, but will omit the rotor button, points, plug wires or spark plug from being the culprit. To check these other items, you have to pull a spark plug to ensure everything is working, and the spark is getting to the cylinder, to ignite the gasoline.

I am guessing the problem is in the ignition switch, or in the wires hooked up to the coil being corroded, so there is no spark when it does not want to start.

[Nium]

Do you have a 25D4 Lucas Distributor? The cap is dome shaped instead of being flat on the top which would be a 45D4 Lucas or a Ducellier distributor.

If you have a 25D distributor then the low tension lead should be replaced as it probably has a break in the wire. The low tension lead is the little bit of wire from the outside of the distributor to the points.

[Paul and Judson]

Thank you all for your invaluable advise.

I checked spark both ways (center wire and spark plug). No spark using either method. I then checked the points and there was no spark or movement in the points when I cranked the engine. I loosened the points and re-set them and the Rover started right up. I let it idle for 15-20 minutes and took it out for a drive. No problems.

The points are new. Why would they get out of adjustment and fail to open and close?

The distributor is a Lucas 25D. Thanks for the most recent posts I will take your suggestions and check out the points you mentioned.

[73series88]

one thing ive learned is when your absolutly positively sure its not something
still check it.
glad it worked
aaron

[stomper]

if the problem was just the points, then you should have had spark at the center wire of the distributor. Unless you fiddled with the low tension lead wire that is attached to the points, I would say the issue might not be fully resolved yet.

I could be wrong, but perhaps someone else will chime in and either verify or disprove what I am saying.

[Nium]

The points are new. Why would they get out of adjustment and fail to open and close?

The distributor is a Lucas 25D. Thanks for the most recent posts I will take your suggestions and check out the points you mentioned.

To answer your question on points closing up. The following arm of the points will wear where the following arm contacts the distributor shaft . A very small amount of dielectric grease on the following arm of the points will help reduce the wear, but it will still wear out eventually. Point gap should probably be checked and adjusted monthly (if a daily driver). Always set point gap to the greater measurement of .016" becasue the point gap will just reduce with wear. If the checked adjustment is between .014" - .016" then they shouldn't need adjustment.

Use an ohmmeter to check there isn't an internal break, inside the insulation, of the low tension lead. Take out the low tension lead and flex it will testing with ohmmeter to ensure the wire retains continuity while flexing. An internal break of the low tension lead will manifest by the engine cutting out while idling or running and then refusing to start again till the low tension lead is bumped or jarred so that the broken wire ends make contact again.

Check to that the distributor shaft doesn't wobble around to much by trying to wiggle by hand. There should be very little movement of the shaft if it is excessive then the points wouldn't operate correctly because of the eccentric rotation of the distributor shaft.

stomper
I respectfully disagree. If the points are closed and not opening then the coil would not produce high voltage because the magnetic field of the coil wouldn't collapse because the points would keep the coil continuously grounded. So there wouldn't be a spark from the coil high tension lead to the distributor or from the high tension leads from the dizzy to the spark plugs. I do agree with your ascertation that the problem isn't resolved I strongly suspect the low tension lead has a break in it.

[stomper]

Thanks for helping me with my thought process Walker, that makes perfect sense.

[Paul and Judson]

Thank you all for your helpful information.

The distributor does not have any play in it when wiggled by hand and the low tension wire is sound.

The Rover started as quickly as usual late this afternoon. I let it run for a while and it stalled after a short while but started right up again. It was a bit cold here in Maine and I possibly pushed in the choke without letting it warm up properly. I checked and there was spark.

I tend to believe you and Stomper that re-gaping the points has not fully solved the problem and with the help of the contributors to the forum I will keep on testing options and learning. Any other thoughts would be appreciated.

[SafeAirOne]

I tend to believe you and Stomper that re-gaping the points has not fully solved the problem...



Why do you say that?

If before, the points were physically inoperative because of an adjustment issue and they have now been adjusted and the engine works normally, I'd say the problem is fully solved.

Not sure why everyone has the feeling there's still a problem... :confused:

[printjunky]

I've had a similar problem recently. Very challenging to diagnose, because some of the time it runs like a top, starting with barely a crank, and other, seemingly random times it's cranking, getting spark, but not kicking over at all. It now seems (now that the things dead in the Dairy Queen parking lot, that is) that the culprit was an intermittent fuel pump. It ABSOLUTELY felt/seemed like an electrics/ignition problem (and I'd been over everything 15 times!). But now that it's dead, the cause seems to have been no fuel flow on crank SOME of the time. And now that (I think) I know that, it does smack of fuel starvation, when it wasn't starting.

I won't be 100% sure until I get a chance to do a temp fix this afternoon (or maybe until I get the chance to do whatever permanent fix I decide on (elec pump or R&R the oem pump.)), but that's what it looks like at the moment.

Also, someone probably already said this, but bad grounds (batt to chassis, starter to block, etc) can cause all kinds of weirdnesses.

[Paul and Judson]

Thank you for your good thoughts. I changed the fuel pump (mechanical) recently because I thought it may have been a fuel related problem. However now that I hear some of the instances of a new pump being defective I will have to watch it and consider it if the problem persists.

Good luck with your repair.

[printjunky]

When it was experiencing the no-start condition (but everything else was fine and triple-checked), I pulled the fuel line off the carb and got nothing. It might not be quite that easy though, as in both our cases the condition seems intermittent. And in my case, seemed to come and go pretty randomly.

Off to throw on an electric pump, at least to get it home. It's a beautiful, sunny 16-degrees out (6 windchill!).


Edit: The electric pump seems to have solved that problem at least. Might be worth it to temporarily plumb in an electric pump, see if the condition still pops up. If it does: $50 wasted, but if it doesn't ...

You can always replace/rebuild the mech pump afterwards if you decide to stick with that. I suspect next shadetree season. I'll put new guts in my mechanical pump and keep the electric in my onboard spares as a backup.