[Bulldog 61]

Hi all after some advice, I have a g16a that is hard to start after its been stopped for 10 or 15 mins. The problem appears after I have been driving for a bit and every thing is at running temp.

.Runs fine until you stop and let it sit for about 15 mins and then wont start (after its up to running temp)
.After it cools down for 45min or after only short stops of 5 mins or less, it starts ok with a bit of a stutter and a puff black smoke.
.It has an electric fuel pump mounted near the tank which was in place with the old rooted g13a motor and is still plumbed up in series with the mechanical pump on the g16a motor as well.

I tried this afternoon disconnecting the electric pump and running just on the mech pump and the car started ok but blew blue smoke so Im thinking the fuel pump diaphragm might be shot and leaking a bit of engine oil into the fuel (is this possible??) It did run ok for a quick lap around the block though didn't seem to have the same performance, could be my imagination though. Not sure I can run the electric pump without the mechanical for fuel return, or can I ?

I tried a second carbie, has all new filters and vac lines, new plugs and leads. different coil.


Appreciate any advice, the problem is starting to wear me down.

[Bulldog 61]

Still having the same problems, I tried a new electric fuel pump today, checked the timing again.....don't know where to go from here??

Anybody have any ideas?

[Dan`]

sounds to me like you might boiling your fuel in the lines/carb? creating air pockets etc.
you should be able to bypass the mech fuel pump and just use the electric pump, have you tried this?
black smoke is usually fuel, blue/white smoke is usually oil

when you say its not starting i assume you mean its cranking but not firing? if it wasnt cranking once hot its usually because one of the windings in the starter is FUBRed and while it has enough grunt to kick over a cold (and there for gappy) engine once it gets hot and the tolerances close up it dosnt have the grunt any more.
but yea, try with just the elec pump and see how that goes. running twin pumps may also be over feeding fuel/ too much pressure for the carb/float/bypass to cope with?

[Mike57]

I am no expert on this and have never seen this engine but here are some ideas....

It sounds like the mechanical fuel pump needs an overhaul. I would imagine you can get oil into the fuel but you might also can you get fuel into the oil which is more a concern. Just use the electric pump and bypass the mechanical one. It could be blocking the fuel.
I don't see too many issues running an electric fuel pump. I have done this on a few older cars in my time.
Just as something to try loosen the fuel filler cap just to make sure the tank is venting OK and you are not getting a vacuum in there.
The other possibility is a vapor lock in the fuel line. Does the fuel line run near any heat source like near the exhaust manifold? This would be more of a problem with the mechanical pump but not the electric pump though so not the likely problem.
Do you have a distributor or a crank angle sensor? I am guessing it has a distributor but the crank sensor can stop operating when it is hot when it starts failing. Are you still getting a spark to the plugs when it won't start - that is to make sure this is a fuel issue.
Does it have an automatic choke? Is this malfunctioning when the car is hot and restricting air flow. Remove the air filter when you try restarting it and have a look.
Do you have any aerostart. Try spraying some aerostart into the carby and see if it starts on that just to prove it is a fuel issue. You can even spray a little petrol onto the carby and that can work the same as long as you don't put in too much. Get someone else to crank it over for you of course.

If an engine won't start it is either air, fuel or spark that it is missing. You have to work out which one it is in this case by elimination. Once you work out what is missing then you can work out why.

Anyway just a few thoughts.

Mike

[Bulldog 61]

ok so I just had the same issue (no surprise) I removed the airfilter to have a look at what was happening and the fuel is like its boiling in the carb.

[Dan`]

Bulldog 61 wrote:

and the fuel is like its boiling in the carb.

yup, like i said that can happen. removing the mech fuel pump will be a good idea, and having the elec pump at the back, with the lovely cool fuel should help the situation out a lot.

[Bulldog 61]

Dan` wrote:

sounds to me like you might boiling your fuel in the lines/carb? creating air pockets etc.
you should be able to bypass the mech fuel pump and just use the electric pump, have you tried this?
black smoke is usually fuel, blue/white smoke is usually oil

when you say its not starting i assume you mean its cranking but not firing? if it wasnt cranking once hot its usually because one of the windings in the starter is FUBRed and while it has enough grunt to kick over a cold (and there for gappy) engine once it gets hot and the tolerances close up it dosnt have the grunt any more.
but yea, try with just the elec pump and see how that goes. running twin pumps may also be over feeding fuel/ too much pressure for the carb/float/bypass to cope with?

Thanks Dan, looks like you might be onto something with the boiling fuel, I removed the air cleaner and the fuel looks like its boiling.....I will bypass the mechanical pump tomorrow and re-route the fuel line as it runs between the carbie and the head. Its blows a bit of blue and a shat load of black when it eventually fires up so its definitely flooding.

I noticed on the G16a there is no spacer under the carbie is this normal? I know the G13a had a spacer, thought this might be for insulation.

Your correct it is cranking over just not firing, it generally needs to sit for 45 mins plus before it will eventually start. I will try again tomorrow with just a bit of throttle while cranking as well, it appears easy to flood an engine with the electric pump.

Thanks for your help, appreciate it.

[Bulldog 61]

Dan` wrote:

Bulldog 61 wrote:

and the fuel is like its boiling in the carb.

yup, like i said that can happen. removing the mech fuel pump will be a good idea, and having the elec pump at the back, with the lovely cool fuel should help the situation out a lot.

yeah will give it a go tomorrow, electric pump is at the tank so should be all good.

[Bulldog 61]

Mike57 wrote:

I am no expert on this and have never seen this engine but here are some ideas....

It sounds like the mechanical fuel pump needs an overhaul. I would imagine you can get oil into the fuel but you might also can you get fuel into the oil which is more a concern. Just use the electric pump and bypass the mechanical one. It could be blocking the fuel.
I don't see too many issues running an electric fuel pump. I have done this on a few older cars in my time.
Just as something to try loosen the fuel filler cap just to make sure the tank is venting OK and you are not getting a vacuum in there.
The other possibility is a vapor lock in the fuel line. Does the fuel line run near any heat source like near the exhaust manifold? This would be more of a problem with the mechanical pump but not the electric pump though so not the likely problem.
Do you have a distributor or a crank angle sensor? I am guessing it has a distributor but the crank sensor can stop operating when it is hot when it starts failing. Are you still getting a spark to the plugs when it won't start - that is to make sure this is a fuel issue.
Does it have an automatic choke? Is this malfunctioning when the car is hot and restricting air flow. Remove the air filter when you try restarting it and have a look.
Do you have any aerostart. Try spraying some aerostart into the carby and see if it starts on that just to prove it is a fuel issue. You can even spray a little petrol onto the carby and that can work the same as long as you don't put in too much. Get someone else to crank it over for you of course.

If an engine won't start it is either air, fuel or spark that it is missing. You have to work out which one it is in this case by elimination. Once you work out what is missing then you can work out why.

Anyway just a few thoughts.

Mike

Thanks Mike, The pumps are a throw away unfortunately so cant overhaul them, I will bypass it tomorrow and run just the electric pump. I have been watching the oil and cant smell any fuel in it.....looks normal and the level is not changing. The fuel line runs very near the head, I will re-route this tomorrow as well to try to get it away from the heat. I noticed the fuel is boiling when I try to start it after it has been sitting for 15mins or so. The choke is open, gets fuel when the throttle is depressed although as I said it looks like its boiling. The air intake is just above the extractors as well so I might try sucking cooler air away from the heat source. I did check a couple of days ago and spark is all good when its hot.....it appears the fuel is to hot so Ill try to sort that and see how I go......thanks for your help and advice. I will let you know how I go.

[MrRocky]

Throw the aftermarket pump in bin and just go back to standard components in good order. 99% of the time its aftermarket parts that cause issues

[Mike57]

It could be the petrol over heating or it could have air in it. The failed mechanical pump might be pumping air into the fuel line? Most likely a heating issue if it only happens when hot so check that first but certainly sort out the fuel pump(s). Have you by any chance removed any heat shields, or was one missing when you got the car? Glad you are making progress.

[Bulldog 61]

I by-passed the mech pump and ran off the brand new electric pump, routed the fuel line away from the head with the end result and the same hot starting issues. Its fine if you restart after 5 mins but go much longer and your in for a bit of a wait. I initially cranked it over for maybe 5 secs before giving it about 1/3 throttle but nothing. I removed the air cleaner to have a look, choke is wide open and it gives a squirt of fuel if you work the cable by hand. The carb itself felt relatively cool around the centre section, the base a little warmer but not overly hot. It took about 10-15 cranks of at least 5 secs each over about 5 mins before it finally started (with the air cleaner still off) Was definitely flooded going by the black smoke and took a bit before it ran ok. That's a bit better than previously but may have been just luck because when I got home it would start after a 10 min stop time....left it for 40 mins and fired up first hit.

I forgot to check the fuel cap until I got home and there was a slight suck of air when I cracked it but seeing as how it had fuel at the carb and I can drive for 100kms with now issues I suspect the cap is not the issue.

Mr Rocky If I was sure a new genuine pump would fix it I would swap it over in a heartbeat, I replaced an aftermarket pump in my sons coily with a genuine pump and as it wouldnt start after it sat for more than 3-5 days, took about 2 mins of crank time before it would fire up.....$220 later still had the same issues so Im not convinced. We just make sure we start it at least every 2 days now.

So still open to hear everyones thoughts and ideas ......... its frustrating problem.

[Dan`]

i wonder if its leaking fuel from the carb into the manifold and causing it to flood which would explain why when you leave it longer it has time to evaporate the extra fuel? would also explain the black smoke when you do get it started.

and i would tend to agree that its not air causing a problem when you have fuel in the carb already

ive never had an issue running an electric pump on a carby car and ive done it a few times, in fact ive always preferred an electric over the mechanical pumps

only other thing to do is when you know its going to not start is pull an ignition lead off a plug, either pull the plug out or use a spare/old one if you have one laying around and hold the end of the plug against something metalic on the motor and double check you have spark. while its not very likely ive had coils that wont fire when they get hot unless they have the full 14.4v that the system runs on once the motors running versus the 12v or less then your starting it.

[Mike57]

I agree with Dan. Best to double check that you have spark when it won't start but you would think that a lack of spark would be evident when you were driving it as well.

Sounds like there is fuel so I wonder if there is too much fuel? Can't explain why that does not affect the running when it is cold though. Is the float valve in the carby working correctly?

[Dan`]

as i said, ive had it where coils wont charge up and fire at cranking voltage before but will at alternator voltage thus making the car perfectly drivable. in this instance i think its probably a 1 in 1000 chance that its the problem but its a simple problem to rule out and you need to start somewhere.

too much fuel while its running and driving wont be overly noticeable because itwill just be running a little rich, and when he starts it soon after stopping it it starts again but only dosnt when its been stopped for a longer time which is whats making me think that the carb is slowly leaking fuel into the manifold over many minutes. its slow enough that while driving its not noticeable and even when stopping and quickly starting isnt an issue but as it keeps leaking over minutes it finally gets to the point that its flooding the motor, but left long enough the fuel finally evaporates and lets it start again after ~20 mins (i think that was the time he said)
ive never come across something like that happening before but it seems it might explain all his symptoms.
again, its just a theory but i think it connects all the dots of the symptoms.

just had another thought.... if you got it hot then shut it off for long enough that it would normally not start again, then get an air compressor and blow air into the carby (with the cleaner etc off and i guess you would need the throttle wide open) it should blow out any fuel and vapours from the inlet manifold that might have built up. give it a really good blowing out and then see it if starts again. this might be a good way of disproving my idea above.

[Bulldog 61]

Yeah thanks guys just had someone else suggest running a wire direct from battery + to coil + when It wont start and have someone else hit the key. I will try this hopefully through the week if I get time. I will let you know how it goes.

PS. I have swapped the coil for another I had but no change, also checked for spark from coil and plug when it wouldn't start the first time it happened.

Its an interesting problem for sure.

[Scrawny]

MrRocky wrote:

Throw the aftermarket pump in bin and just go back to standard components in good order. 99% of the time its aftermarket parts that cause issues

This ^

Have you checked what pressure the electric pump is putting out? I bet it's flooding the engine

[Dan`]

the electric pump is a carby pump and not an EFI pump isnt it? iirc carby pumps are only a couple of psi but an efi pump can make up too about 100psi fuel pressure

[Bulldog 61]

yeah its a 4-6 psi pump

[Bulldog 61]

Scrawn wrote:

MrRocky wrote:

Throw the aftermarket pump in bin and just go back to standard components in good order. 99% of the time its aftermarket parts that cause issues

This ^

Have you checked what pressure the electric pump is putting out? I bet it's flooding the engine

Gday Scrawn,

Would it not flood the engine when its cold as well?

[Gwagensteve]

The engine can tolerate a much richer mixture when cold - that's what the choke is doing, after all.

I'd still say remove the electric pump, ensure the mechanical pump is functioning properly and start troubleshooting from there.

Steve.

[Dan`]

does your car have a fuel return like like the sierras do? if you own a compressor maybe you could blow that out (make sure you dont have a full tank of fuel, remove the petrol cap, MAKE SURE NO ONE IS STANDING NEAR THE FUEL FILLER and there is no sources of ignition near by, last time i had to do this i lost about 5L of fuel out the filler caus i had a full tank, then blow down the return hose from the engine bay.) ive had blocked return lines caus overfueling before, tho like you say you would generally notice this with normal driving, specially once the motors hot, you would also notice it in your fuel economy if you suddenly were using twice as much fuel as your used to.

as for the electric pump causing overfueling, pretty much impossible with the return line. any excess fuel goes straight back to the tank.

[Mike57]

When it won't start remove the plugs and see if they are wet with fuel. Just another way to check for flooding.

[Bulldog 61]

Dan` wrote:

does your car have a fuel return like like the sierras do? if you own a compressor maybe you could blow that out (make sure you dont have a full tank of fuel, remove the petrol cap, MAKE SURE NO ONE IS STANDING NEAR THE FUEL FILLER and there is no sources of ignition near by, last time i had to do this i lost about 5L of fuel out the filler caus i had a full tank, then blow down the return hose from the engine bay.) ive had blocked return lines caus overfueling before, tho like you say you would generally notice this with normal driving, specially once the motors hot, you would also notice it in your fuel economy if you suddenly were using twice as much fuel as your used to.

as for the electric pump causing overfueling, pretty much impossible with the return line. any excess fuel goes straight back to the tank.

All good advice but with the electric pump Im not using the return line, there is a relief valve in the pump which I assume opens when the pump hits a dead head ie. line and chamber is full of fuel and needle and seat has closed off.

[Bulldog 61]

Gwagensteve wrote:

The engine can tolerate a much richer mixture when cold - that's what the choke is doing, after all.

I'd still say remove the electric pump, ensure the mechanical pump is functioning properly and start troubleshooting from there.

Steve.

Hi Steve thanks for dropping in here, I have bypassed the mech pump as I think the diaphragm has perished and allowing oil into the fuel stream, was blowing a bit of blue smoke and now isn't, and am running off a new electric pump that I had sitting here. 4-6 psi rated and the same as was fitted to the vehicle when it had the 1.3 engine installed.

[Bulldog 61]

I drove the car for 3 hrs on the weekend with not so much as miss in the engine, highway speeds, locally at 50km and it ran as expected. Stopped it when I got home and restarted after 5mins, no problem, 10 mins no problem, and 20 mins later wouldn't start

[Dan`]

Bulldog 61 wrote:

All good advice but with the electric pump Im not using the return line, there is a relief valve in the pump which I assume opens when the pump hits a dead head ie. line and chamber is full of fuel and needle and seat has closed off.

ahh well i would imagine that this could very well be your problem then. the needle and seat are only designed to have fuel "wash over" them not build up pressure behind it which is why they use a return line as far as i understand it. im an EFI guy not a carby guy, hate the things, so take this advice with what ever grain of salt you wish. in this case tho i would tend to agree with others who have said that plumbing back a stock fuel pump, specially if its not easy to get the return plumbed in, might be your best option.

[Bulldog 61]

Only thing that worries me forking out for a mech pump and its the same issue, when I had both mech and electric pumps plumbed in it was for exactly that reason so I could use the original mech pump return line and it didnt work then. Remember also early on I did run just of the existing mech pump and had the same starting issue.

[Gwagensteve]

I can't think of a reason to run anything other than a mechanical pump on a G16A/G13A/G13BA. They seem to work perfectly for ~25 years, are completely maintenance free, don't add to electrical draw, aren't introducing power wires and connections under the car, don't have safety issues related to pumping whilst the ignition is on (a tachometric relay via the coil is the correct way to install one, not via the IG+ circuit in my opinion) deliver plenty of fuel to a stock engine at the correct pressure, and utilise the return line.

Is your return line free from obstructions? you could have replaced one problem for another.

are you 100% sure you have no damage/tiny weeps in the fuel lines anywhere? This could cause the system to draw air with the electric pump down near the tank as it cools.

Nothing hard and fast, just things to check.

Just a thought, is your carbon canister correctly connected and the vapour system flowing properly? I wonder if you're pulling a vacuum/pressurising the tank? I seem to recall Christover having some sort of problem like this.

Steve.

[ozzycouch]

Try disconnecting the pump and letting it run for a few minutes before turning off.
Then hook it back up to restart at the 20 min mark.
Will at least eliminate fuel getting forced through the carb causing flooding with residual pump pressure.