Help! It's that time of year and my '78 MGB wants to get out of the garage, but it can't!

[Tab]

This is not a post-winter storage problem. Actually, last May I was driving it, stopped at a pedestrian walk, it stalled, and never restarted. Had it towed back, figuring it was minor and I'd have it going, but I never did.

It was a busy summer and I didn't get to spend a lot of time on it. Now it's spring again and it wants to go outside, but I can't get it started.

It cranks but doesn't fire.

Details about it:
- Professionally rebuilt engine with a high-performance engine
- Manual choke, overdrive tranny
- Maybe 20k on the new engine
- Because of the engine, uses high-octane gas (thank goodness I don't drive it THAT much)
- I think it has electronic ignition, but aren't positive

What I've done either in this process or had done in the last few years:
- Replaced the coil with a sport coil. It was probably one of the original coils anyway.
- Replaced the fuel filter. Cheap enough, never hurts.
- Replaced the starter a few years ago
- Replaced the fuel pump a few years ago
- I have verified there is gas getting to the carbs (pulled the hose, stuck it into a jug, cranked for a few seconds, it had gas coming out. Not sure how to trace it beyond that point.
- I think it's more of a spark issue, and I bought a spark tester, but aren't exactly sure what to do if I find a low spark on a plug - replace the wire? What?
- Have trickle charged the battery and also tried cranking while jumped from my Saab (plenty of power there). I replaced the cables to the battery a few years ago, so they're strong.

Presumably with the rebuild new sparks and wires were put in. It could be the electronic ignition - I guess they can flake out without any notice - but I don't want to replace everything on a whim. The fuel filter and coil were cheap enough, but now the diagnostics need to start. I'm not a diagnostician or a serious mechanic. I diagnose things in real life, but they're not engines. I can do stuff like replace cables and water pumps, but I'm still new to the mechanic business.

Any idea on how to proceed? And, hey, if you live in southeastern New Hampshire and want to come over and get it running, I can probably pay you something for your time :) Either money or a case of British ale.

But seriously, I do want to get this thing a'movin... any ideas?

[jimmil]

1. Fuel or Fire

That old of a car will require a bit of thought. It is either fuel or fire. For the fuel two things pop into my mind, fuel pressure or jets. You can pick up a fuel pressure Gage at Autozone easily enough and check that the pumps are working up to pressure. If you already know that then it would be in the carbs and that most likely is the jet is clogged up. However, since it is not hitting it would be unusual that both carbs would be effected. Still, it would be something to look for. Maybe they need to be rebuilt. Also just check the plugs. If, after trying the start the car, you pull the plug and it is wet then the fuel is getting to the cylinders. The final test is just squirt some starting fluid into the carbs and see if it fires. If it does then the carbs are the most likely source of the problem. Don't just keep squirting and squirting the fluid in there if it doesn't fire.

The fire is easily tested for with a timing light. If the light is flickering when you turn the car over then there should be fire. Check each wire with the timing light. Next, pull a plug out and get it right next to a grounded piece of metal and turn the car over. If you see (you can also hear) a spark jump between the plug and metal then you are good to go. If no spark you could ask the people that rebuilt the motor what the wires should ohm out at and test for that just to eliminate that possibility. Also check the wire between the coil and distributer. The other possibility if there is no fire is the coil. It is not unusual for a coil to go bad and you can have that checked.

Finally you can get to the distributer. Take it off and check for cracks as well as the condition of the leads inside. Do a continuity check for each lead going from the contact inside to the plug wire outside. Also check the condition of the rotor. Sometimes it can carbon up so use a wet stone and clean it off just a hair. While you are there check the points to make sure you have the proper gap. Again you friends that rebuilt the motor can provide you with the proper clearances. Also check the condenser in the distributer (it may be outside the distributer) and you may just change that out as it is a five dollar part.

It should take you maybe an hour to do all this. Tell us how it goes.

If all that proves nothing then go to you local Chevy parts counter and order an LS1 crate motor (the one for the Vette as it is all aluminum) and put that in the car. It would work every time and be a screamer. You would probably get better milage too so you could consider yourself an eco friendly driver.

[old mark]

2. There may be a fuel shut off switch

mounted on the gas line from the gas tank. It is supposed to stop fuel flowing from the tank in event of a crash to prevent fires.
I was in an MGB when this switch tripped (driving over RR track) and the engine quit IMMEDIATELY and could not be re-started. Had to tow the car to a MG dealer who simply re-set the switch, but you have to get to it and it is really in a stupid location. The switch on this car seemed to trip at any slight bump or even quick stops. Owner finally sold it in disgust. This was in the late 1970's so I am assuming your car is similarly equipped.

I believe this was added to US imported MGB's as a safety extra to help it pass the import regs at that time.

Good luck.

mark

[Tab]

3. There is such a switch

but we seem to have it narrowed down to electrical. I've enlisted the help of someone more capable of diagnosing this that I. Even he doesn't have it narrowed dow, but we're looking at the rotor/condenser as culprits. It's cheap enough to replace them anyway, but that seems to be the area where it's flaking out.

[jimmil]

4. Replacing the points and condenser is relatively painless

And it is a good insurance policy. Make sure you have the gap set correctly for the points. If I were you I would look around and see if there is an aftermarket CD ignition available for this engine. It should fit inside the distributer and makes the tuning much easier. If there aren't any you will just have to do it the old fashion way. There are no tricks I can give you when setting the points. I trust you and your friend know how it is done. Have the coil tested to be sure it is putting out the proper voltage. Good luck! I know you are foaming at the mouth to get this back on the road. The MG is one of a very few real sports cars there was. They are fun to drive.

[Tab]

5. I was surprised to see this thread still alive

As it turned out, it was the points and condenser. In the meantime I replaced the fuel filter (cheap enough, and not a bad thing) and the coil, but it was the points and condenser.

I've since bought a new battery (the old one had kicked - we were jumping it), will put it in later today, and will get it later today - then I need to sneak it to the shop ('cause it ain't inspected) and get the brake work and current inspection done. Then we're rolling.

I'm psyched. I've had this car for ten years - it has a kick-ass engine in it - the only thing keeping me from driving too fast is that I don't drive ANYTHING over 85 mph if I am paying attention. I'm not convinced the car is safe over 85 mph because of the suspension (when was the last time someone talked about an MG like that?). It has a custom engine with a cross-flow head, tuned exhaust, and it roars. It has bummed me out that it has been stagnant this last year. We're ready to drive!!!

I love this thing. I don't know why you'd want a $50k BMW Z3 which no one is curious about over a 70's MGB at a fraction of the cost.

Damn. I'm psyched.

[jimmil]

6. Attend a driving school with the car.

There may be a driving school near you sponsored by the BMW, Porsche, or even a track itself. These schools let you drive your own car with a driving instructor around a real race course. They are a blast and you will learn how to drive your car the way it was meant to be driven. It will instill in you confidence in your capabilities as well as the car. These courses usually run around $250-$300 a weekend. You drive your car in 20 minute sessions, usually two in the morning and two in the afternoon Saturday and Sunday. I promise you that you will have a great time and come away from it a much better driver in your everyday commute.