chug a chug

Post by **stevey** » Mon Oct 01, 2007 7:20 pm

i dont really know where to put this but i have a minor problem which is starting to majorly annoy!!!!

My brothers car has this habit of everynow and again chuging to a stop as if its run out of fuel. It does eventually start up again after thumping the pump but its a brand new pump and it did the same thing with my pump which hadnt gave any bother in the last 4 years. the carb is as clean as a whistle, the pipe from the pump to the carb is new. Its had a new coil, condenser, points, rotor arm, dis cap and ht leads. the points gap hasnt closed up and i cant think of anything else.

Any ideas?

Post by **rayofleamington** » Mon Oct 01, 2007 7:29 pm

How long do you need to drive before this happens? is it a similar time/distance or does it happen randomly?

Does the pump start ticking wildly just before it starts to work again? That would indicate a sticking pump.

Did you have an SU pump? Sadly, some of the alternatives are not very long lived. I've found most people get better/longer service with an (old) SU pump than with new pumps.

It could be many things including non-venting fuel tank, blocking (or partially blocked) inlet needle on the carb, and a few other things too.

Post by **rayofleamington** » Mon Oct 01, 2007 7:33 pm

rayofleamington wrote:How long do you need to drive before this happens? is it a similar time/distance or does it happen randomly?

Does the pump start ticking wildly just before it starts to work again? That would indicate a sticking pump.

Did you have an SU pump? Sadly, some of the alternatives are not very long lived. I've found most people get better/longer service with an (old) SU pump than with new pumps. With a new set of points, an old SU pump should be reliable for another ~10 years (do check the points though!)

It could be many things including non-venting fuel tank, blocking (or partially blocked) inlet needle on the carb, and a few other things too.

Post by **MoggyTech** » Mon Oct 01, 2007 10:31 pm

Check tank filler cap is vented and not blocked. Drive a few miles and remove the filler cap and listen for a swoosh of air.
This sounds like the classic leaf or paper in the fuel tank scenario.
Now and again blocking the outlet pipe. Tapping the pump to get it going again would suggest the pump, but as you have tried two pumps it seems unlikely. Wierd

Post by **d_harris** » Mon Oct 01, 2007 10:51 pm

crud in the tank/pump pipe?

Post by **southerly95** » Tue Oct 02, 2007 12:03 am

Have you checked the float level in the carb is correct? If the gap is too big there won't be enough fuel getting through. bEst wishes, John

Post by **stevey** » Tue Oct 02, 2007 9:18 am

thanks for the speedy replies. The distance driven before it happens is pretty random and it doesnt matter if its at 5 mph or 50mph. the pump is a genuine su pump not the electronic one. its brand spanking new in the post last week. surely it couldnt be sticky? the inlet needle was clean the float in the carb was taken out and checked and is adjusted as per the book. the filler cap was cleaned out and seems ok. The only other thing could be rubbish in the bottom of the tank so ill have to get round to draining and cleaning it, but i was hoping there was something else easier to check.

keep em coming

Post by **dalebrignall** » Tue Oct 02, 2007 4:40 pm

have you looked at the filter in the pump as you look at the pump from the frount there is a nut at the bottom,undo take out the filter if its full of crud just wash it out in petrol and refit.i had this problem need to get a new fuel tank,i must check this before the website rally

Post by **MoggyTech** » Tue Oct 02, 2007 6:34 pm

Given work done so far, it's a safe bet it's crud from the fuel tank blocking the fuel line from tank to pump.

Post by **stevey** » Tue Oct 02, 2007 6:42 pm

right thanks guys was hoping i wouldnt have to wash out the tank, but ive got another one here so ill just fit that at the weekend. thanks you all ill keep you posted. isnt modern technology the greatest (the minor and the computer as we all know minors just dont date)

Post by **DanRodd** » Tue Oct 02, 2007 10:09 pm

yes,i reckon it to be crud in the tank,as i had very similar problems on the M6 on the way to the leicester rally!Turned out to be a blocked inline filter,but i was glad it was there as it goes to show how much rust etc can travel up from the tank.

Post by **bmcecosse** » Tue Oct 02, 2007 11:09 pm

Some of the lads on another forum I frequent are great believers in coating the inside of the fuel tank with POR-15 special paint. Seals up the tank and prevents rust particles breaking off in the future. May be worth a punt if the problem is ongoing.

Post by **stevey** » Wed Oct 03, 2007 9:07 am

Some of the lads on another forum I frequent are great believers in coating the inside of the fuel tank with POR-15 special paint. Seals up the tank and prevents rust particles breaking off in the future. May be worth a punt if the problem is ongoing.

right, nver thought of that. I was laways told never to coat the inside of the tank with anything in case that starts to flake off.

Post by **bmcecosse** » Wed Oct 03, 2007 9:58 am

Well - I haven't done this - but they (Triumph TR7 forum) swear by it's effectiveness - even seems to seal up small perforations. I just bought a new tank - cost me £150 (hence why they do anything to save old tank) -but I think it will see me out!

Post by **DanRodd** » Wed Oct 03, 2007 11:00 am

ive used petseal(resin)in motorcycle tanks and in the 6 gallon tank of my old Reliant,for this very purpose,it is designed to put a uniform layer all round the tank of hard resin that seals in rust and obviously being resin cant rust itself.Also helps seal any weeps in the tank.Highly reccomended

Post by **overider** » Wed Oct 03, 2007 8:50 pm

I am thinking it would be better if we could get a plastic tank.

Post by **bigginger** » Wed Oct 03, 2007 9:25 pm

I seem to remember that they're not legal, as they could split in a crash. Could be wrong though, natch.

Post by **MoggyTech** » Thu Oct 04, 2007 1:10 am

overider wrote:I am thinking it would be better if we could get a plastic tank.

Not road legal AFAIK. You can however buy tank coatings for use inside the tank to prevent rot. POR-15 do a tank sealer, and Frost do a couple.

Post by **stevey** » Thu Oct 04, 2007 5:20 pm

still not got round to doing anything yet, put it down as being a lazy student!!!!!!!!

Post by **bmcecosse** » Thu Oct 04, 2007 11:08 pm

Plenty plastic tanks around - my old Panda had one many years ago!