Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Roadster Bunny hopping

Well it seems I may have been a silly boy.
Anyone had trouble with their st220 (roadster) cutting out. 22K
I flushed the coolant yesterday. Filled it up ran it, topped it up, ran it, (heater on) seemed to be level went for a short run, started to conk out on me, checked the level, thinking common denominator. Just needed 500ml. left over night. Checked this AM looked level, no leaks etc. went for a run not far, 3 miles started to bunny hop last half a mile. I managed to get her back. Checked level and it was fine, temperature gauge showed just over 80.
This has not happened before. Any ideas, would it do that with too little coolant or too much?
Thanks, Paul

Last time I changed the coolant it took a few days to purge the air completely. I had to top it up quite a bit and suspected a leak, but it stabilised after a while.

Have you splashed any water over the coil packs or over the heads, where it might have gone down the plug holes? - or in the loom connectors at the front of the engine?

It could also be an intermittent fault on the fuel pump relay.

I had a similar problem with slight coolant loss this spring after a coolant change on my '92 4/4.
Came down to regular topping up as air purged from system over a couple of runs.
A SLIGHT loss from one joint was found early on but tightening the clip solved that, leaving air opurgeing the only problem to solve.
Fresh antifreeze always seems to find weak spots in the system.
I just missed one clip when checking.
The airlocks are now all gone and water constant again.
Giving the car a quickonce over today/tomorrow before heading to Wicked Welsh Weekend on Friday.
Weather looks good so should be a great weekend up in Mid Wales.
Did the Carmarthenshire Run hosted by Whitland Car Club on Sunday and A4069 yesterday as cobweb cleaners in readiness.

Dave, I was pretty diligent about the water e.g. not splashing it about. Checked the connectors at the front of the engine, all seems fine. It’s most likely coincidence that I flushed and this problem has come along. I have not seen a Management light.
Thought I would see the temperature rise if it was a coolant problem.

The car sat for a good 14 months until April this year, it’s had at least two tank fills (on a half tank of one of those at the moment) done some 450 miles. It’s possible it has dredged up something from the tank as modern petrol does not like to sit.
So thought I would go get some injector cleaner, drop that in.
It’s like she has a lack of power at low speed. I need to gun her to keep her going.
I need to get this sorted as I am away in her to France soon. And need my confidence back in her. I have had no trouble with the 4/4 that seems comparatively easy to diagnose issues!
Would an air block in the cooling system cause this?
Will run her on the drive for a while see what happens.
Thanks both for your thoughts so far.
Paul

Oh, ys forgot to ask, where is the fuel pump relay?
thanks

Re power loss - I had a similar thing after filling up the tank from very low level.
It was debris in petrol.
Symptom was - revving ok to about 2000rpm but then above that engine seemd to be starved of fuel and "hunted" - revs varying up and down. A tank flush cured the problem.During the flushing some debris was found when filtering the petrol. I think this was causing partial blockage and fuel starvation when high demand was made.

I may have found the issue. Put the diagnostic on her no faults showed.
Checked all the connectors. Coolant level fine, as I idled her without the reservoir cap on, a fare bit of air was in there. Anyway out of curiosity I pressed the inertia switch button only to find it clicked, did not seem a full click however. I went for a run with a friend holding the OBD all checked out good while running, temperature up and down with the heater on, trim ok, MAF, etc. etc. The run I went on was the same one that I had the issue arise yesterday. Run absolutely fine.
As I get my confidence up with her I shall further a field, periodically checking that switch, I did have her up on axle stands while I was bleeding the brakes, I may have let the front down a little too harshly which trigged the switch.
So here’s hoping.
Paul

Sospan, my issue was technically the other way round i.e. at lower revs, which is why I at first thought it may have blocked injectors. The injectors open more when giving her some. I put some injector cleaner in her anyway.
Thanks

Just in case, my relay thread is here:
http://www.talkmorgan.com/ubbthreads.php?ubb=showflat&Main=2497&Number=24637#Post24637
Your relays though, may not be over the steering column!!!!

I had a similar problem on a Vauxhall Viva in 1979, I do not know the Roadster engine set up but is the thermostat opening?