Is this a 500 characteristic
Is this a 500 characteristic
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Discussion

zippy500

Original Poster:

1,883 posts

298 months

Wednesday 3rd June 2009
quotequote all
When I pull away in my Griff, I hit what I would describe as a flat spot a low RPM. Initially I thought it was the throttle pot playing up, so I borrowed a used one but it didnt cure, I suppose this one could be knackered just like mine, but the owner of it said it was fine. Then I looked at the vac advance as I dont think it was doing anything, fitted a brand new one but it was no different. I know the 500's are supposed to be lumpy, but am unsire wether I have a problem or if it is just a characteristic of the engine and apart from changing cam etc there is nothing I can do. I am tempted to buy a new throttle pot, just to make sure the other one was not duff, can always return it cant I.

Hard to explain what it feels like, but imagine trying to pull away, then as you get to say around 1500rpm, it stutters ever so slighlty then picks up again, then as you to the change to 2nd process, it does it again so making pulling away a horrible kangaroo experience.

Have checked all my HT leads out and they look fine, resistance checked them all and they are fine. Dizzy cap is fitted correctly and clean inside, rotor arm is ok.

If I do a fast pull away it does feel better and less hesitant, but dont want to drive like a chav everywhere. Cruising around is finem, wouldn't know I had a problem.

Does anyone elses 500 feel like this, or do I have a problem?
It's bugging me now lots.

5.0ltr

2,834 posts

228 months

Wednesday 3rd June 2009
quotequote all
Think you have an issue. Sorry no ideas on the fault but my 99 500 don't do this.

Barkychoc

7,848 posts

233 months

Wednesday 3rd June 2009
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Check that the mechanism inside the distributor that the vacuum advance attaches to is free to move.
My vacuum advance was dead, and I think it had been like this for a long time as the mechanism in the distribitor was seized up.

zippy500

Original Poster:

1,883 posts

298 months

Wednesday 3rd June 2009
quotequote all
Checked all that, cover removed and it's all moving freely. Mech advance moves fine and returns also

Invisible man

39,731 posts

313 months

Wednesday 3rd June 2009
quotequote all
What's the tickover like? I'm thinking MAF, these sons of bhes can cause all manner of probs and not throw any codes up

zippy500

Original Poster:

1,883 posts

298 months

Wednesday 3rd June 2009
quotequote all
Tickover is fine. 900 all day long once warmed up. Checked my stepper motor and base idle incase it was all set wrong, but that is ok too.

Invisible man

39,731 posts

313 months

Wednesday 3rd June 2009
quotequote all
Think it needs a diagnostic in that case.....maybe a dodgy injector or something

Simon.b

1,230 posts

311 months

Wednesday 3rd June 2009
quotequote all
Mine doesn’t do this and presently pulls sweet as ever, but that is not always the case.
Over the years I’ve had various problems like this at differing rev ranges and they usually turn out to be on the HT side.

The best thing I found to help find the problem has been a high voltage low power lamp gismo, that came free with a magazine years ago. It is just held against each lead in turn while the engine is running and it flashes with each pulse by earthing through your body (you don’t feel a thing). By comparing each lead it soon becomes obvious if one is different from the others by brightness and regularity. Then concentrate your efforts on those items, swapping round etc. and repeating the fault.

Unfortunately I don’t know where a modern equivalent of this can be acquired, though I have seen diagnostic LED’s that go in line with the plug to get the same result, just that you need eight.

Good luck,

Simon.

FlipFlopGriff

7,144 posts

276 months

Wednesday 3rd June 2009
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We've just had a similar issue with the 500. Was running on 8 cylinders, then 7, then 8, and not only was it misfiring but there was a hole on acceleration which was dangerous. Anyway changed loads of stuff which did help with the hole situation (mainly putting the proper Lucas rotor arm on), and finally got rid of the stutter at low revs by changing the leads and shrouds. Not sure which one it was but problem now solved and goes like stink again. Must have been deteriorating for some time as the difference is night and day. Hopefully it's something simple.
FFG

zippy500

Original Poster:

1,883 posts

298 months

Wednesday 3rd June 2009
quotequote all
I was very tempted to change leads etc, I dont mind changing anything, provided I know it is at fault. Hate throwing money at things that are not bust. I may just do the leads, cap, rotor an dcoil as they do go eventually anywhow. At least thats a few things more eliminated. Could teh ignition amplifier be at fault?

Invisible man

39,731 posts

313 months

Wednesday 3rd June 2009
quotequote all
zippy500 said:
I was very tempted to change leads etc, I dont mind changing anything, provided I know it is at fault. Hate throwing money at things that are not bust. I may just do the leads, cap, rotor an dcoil as they do go eventually anywhow. At least thats a few things more eliminated. Could teh ignition amplifier be at fault?
It's worth fitting those heavy duty blue leads as the heat in the engine bay cooks em pretty quickly, coils tend to go once hot and stay gone till they've cooled off

zippy500

Original Poster:

1,883 posts

298 months

Wednesday 3rd June 2009
quotequote all
It has 8mm Magnecor currently and the effect is not engine temperature dependent, so guessing coil may be ok.

No idea when they were fitted, but do look pretty old, so reckon all of that could do with a change regardless. Its only money after all, arghhhhh

Uncle Fester

3,114 posts

237 months

Wednesday 3rd June 2009
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I've something like the electronic tester described above.

Mine came from an electrical factors. It's a bit like a pen with a battery inside. Touch the tip on the insulation of a wire and the pen lights up if a current is flowing within the wire.

I never thought to use it as described, so I'm not sure if it would do the same thing.

If it's no good for this job on the car, it's useful for DIY.

Get one and try it.

FlipFlopGriff

7,144 posts

276 months

Wednesday 3rd June 2009
quotequote all
Had spare leads and shrouds anyway, as well as rotor arm, dissy cap. Had a new ignition amp as through that wa sthe issue but it wasn't, so got a spare now. Also had a spare coil and throttle pot. Always useful in these intermittent/hard to find electrical niggles.
The leads I had on replaced the Magnecor but the Magnecor have made it as sweet as a nut so I'll defo be getting some more, think they are 8mm too. Don't forget to replace the shrouds at the same time - ACT are reasonably priced (or were).
FFG

sunwharf

152 posts

215 months

Wednesday 3rd June 2009
quotequote all
How many miles has the cam done?

Nick

zippy500

Original Poster:

1,883 posts

298 months

Wednesday 3rd June 2009
quotequote all
Dont know if this helps here, but I have just been for a run, felt st I must say, but on getting back I removed the vac hose from the manifold, covered the hole with my finger and sucked on the pipe, engine note didnt change at all. And this is a brand new vac unit fitted. Could the dizzy be shot? It's only done 42k, cant believe its gone in such a short space of time? It all seemed to move fine inside when inspecting it.


sumoone

352 posts

258 months

Wednesday 3rd June 2009
quotequote all
i had a flat spot and it was the ignition amp.

as you can buy them for approx a tenner on ebay you might want to try a cheap fix if not then you have a spare?

worked for me.

mark

zippy500

Original Poster:

1,883 posts

298 months

Wednesday 3rd June 2009
quotequote all
Was toying of replacing that anyway. May give it a whirl.

Another question. I run it on normal U/L and as far as I know its never been adjusted timing wise to run on this. It was checked a while back at Neil Garners place. Could it just be different fuel type?
I dont get any pinking?

griffith400

90 posts

260 months

Wednesday 3rd June 2009
quotequote all
Phil,

Not sure if this is the exact same but I recently had a problem where I had a 'hesitation' problem with my '97 Griff. All was well and then all of a sudden I started havnig a problem with the car hesitating when I tried to accelerate? It felt like it was over/under fuelling and would eventually pick up and go. The revs were also failing to settle quickly, sometimes sitting up at 2000rpm.

I'd once heard of this and changes the two little silver relays down by the ECU (the common buggers that are infamous for failing). I thought what the hell, change them for my spare set. Problem disappeared and hasn't returned the last couple of outings.

I've since tried the old ones again and they too seem OK. Wonder if it somehow reset something within the ECU?

Anyway, not sure if it's the same as you describe but thought I'd mention it.

zippy500

Original Poster:

1,883 posts

298 months

Wednesday 3rd June 2009
quotequote all
Does sound like that I must say, somehing else to check isnt it. Thanks

It's really pissing me off now. Just makes me not want to drive it or even want it, bloody thing.