Misfire on restart

Hello all,

This is my first post so hope I'm in the right place etc.

I've had my series III 88 petrol 2.25 for a couple of months and I thought I'd got it running nicely after plenty of tinkering. However this weekend it has decided it wants to kill me.

When re-starting the engine after a break it all runs fine for a few minutes and then refuses to rev up without a lot of misfireing and kangarooing over about 1500 rpm, changing up stops the misbehaviour but results in loss of accelleration. It did this each time I rejoined the motorway after a fuel stop causing lots of grief, annoyed lorry drivers and near death experiences. A minute later and we're barrelling along at 65 like nothing happened.

Any ideas where to start? I've just fitted new lift-pump and hoses from lift pump up to new in-line filter to carbs. Re built carb with new inlet filter etc. New plugs and dissy.

Dom

As an aside what sort of top-speed should I be expecting on long runs. I've been keeping it below 70 but not sure what to expect...

There's another filter on the bottom of the lift pipe in the tank. What state are the ignition bits in? - misfiring and cutting out could just as easily be an intermittent electrical problem.
70 in a swb petrol isn't bad, but it isn't comfortable to go faster! 45 will give you reasonable fuel economy though.

Hi, thanks for the reply.

I forgot to mention I checked and cleaned the fuel pickup and gauze filter in the tank.

I'm just off to the workshop now. I'll try replacing the last remaining bit of original fuel pipe (though I don't think that is the culprit) and will double check all the ignition wiring, also I'll try a new coil by substitution if I can find a 12V one...

Cheers

Dom

PS: Would an overdrive give me a few more MPH or would that just get the transmission warmer? I'm off over to Germany in a couple of months and don't want to hold everyone up!

Well, after all new fuel pipes, checking all filters, messing about with the carb, replacing the ignition coil it appears that the _new_ lift pump was the culprit. A frustrating couple of days! Seems to be running well now...I actually overtook some cars on the way home. Makes a difference from having to pull over every quarter of a mile to let the tailback clear!

Dom

First of all :welcome2: dominicbeesley.

Pleased to hear that you have got your problem sorted!

OSD

Hi, an overdrive will help with your fuel economy and also lower the revs (and also the engine noise) for the same speed. It does increase the speed, though it doesn't help your brakes at all! Would be good for your trip to Germany if you can find one.

Well I spoke too soon....it started playing up again yesterday.

I've now replaced:
- fuel pick up
- fuel pick up to lift pump pipe
- lift pump (twice)
- lift pump to inline filter pipe
- in line filter
- in line filter to carb pipe
- rebuilt carb (twice) including gauze filter etc
- cleaned out oil breather and pipes
- replaced distributor
- replaced plugs
- replaced coil
- set timing
- set idle mix

I can now get this to repeat symptoms pretty reliably:

Start from cold and can drive around without any problems, straight up to 60-70mph and race round the back roads no problem. Then park up for a few minutes either with engine running or off and after setting off there will be all manner of stuttering when powering up through gears. If I take it steady though it will get up to speed on the flat. Problems will then gradually go away until it left to stand again.

I can still see bubbles being sucked through the sediment bowl occassionally though I've no idea whether this is air or fuel vapour.

I'm wondering if the lift-pump cams in the engine are worn but don't get why this only happens when there car has stood warm....

It's really beginning to do my head in now as the landy runs lovely until it decides to play up...I'd much rather it would break down then I'd be sure when I'd fixed it!

Dom

Just an odd thought - are you losing coolant at all? is the coolant system over pressurised when running? Engine runs, coolant system pressurises, engine stops, coolant is forced back into cylinder, runs rough untll cleared. Doesn't explain why it runs OK from cold, though.
The only other thing I can think to eliminate is the wiring to the coil. Next time it plays up connect the coil directly from the battery and see if the problem disappears.

Hi Oxides,

I've tried replacing all the wiring to the coil including running an extra earthing wire from the dissy and wiring the coil straight up to the battery - electrics was my first thought on this.

I'm now pretty convinced its a fuelling problem.

I tried some more stuff quickly today.

Removing the fuel cap makes no difference and breather is ok.

I tried pressing up on the priming lever with the engine running and can barely feel anything happening with the, I know on my Ford 360T engine with a similar pump you get a good solid feel of the pump working through the lever. So either I've fitted the pump wrong.

I'm pretty sure I didn't but it is awkard so will double check when I'm in oily clothes.

If that doesn't cure it I'm going to reroute the fuel pipes in front of the fan and the inline filter more to the left (away from most heat). Plus I think I may just go for an electric pump as they're only £16 on ebay.

However I'm not sure how best to set this up I'd prefer to run it inline before the mechanical pump then I get the benefit of the sediment bowl, I've already had some water collect in there so don't really want to use it. However I'm not sure that it's a good ideas because if the diaphram goes I'll just fill my sump up with petrol!

Also, these pumps pump up to 6psi so do I need to get myself a pressure regulator too, that will push the price up a bit!

If anyone knows of a good (cheap) set up I'd be grateful to hear how they've done it.

Dom