Misfire under part throttle
Discussion
My Griff 500 seems to have a misfire, I’ve changed the plugs and extenders, leads, cap and rotor arm but the car still feels rough when cruising on part throttle, if i floor it and every thing seems ok once the revs build up. The car feels better for changing the above but still isn’t quite right. Any ideas, would the ignition module cause this?
You've done most things I've had done to cure similar over the years. Typically this has been rough idle, rough around 1600-1800revs and a little cough at 3,800-4200.
Interestingly I noticed yesterday a bit of hesitancy at 5,200-5,400. I suppose I don't go there very often though
The only thing you haven't mentioned, which I keep top of my list, is that the connectors to the ECU were badly corroded on mine and benefitted from a good clean up (we think a previous owner/selling dealer had the engine steam cleaned 
not a good idea). The likelihood of the ECU actually failing would seem to be low - I would have thought it was more likely to go fizzbang than play around - assuming it was previously behaving itself?
Interestingly I noticed yesterday a bit of hesitancy at 5,200-5,400. I suppose I don't go there very often though
The only thing you haven't mentioned, which I keep top of my list, is that the connectors to the ECU were badly corroded on mine and benefitted from a good clean up (we think a previous owner/selling dealer had the engine steam cleaned not a good idea). The likelihood of the ECU actually failing would seem to be low - I would have thought it was more likely to go fizzbang than play around - assuming it was previously behaving itself?I did change the coil about 5 months ago as the old one was leaking but have been told the Intermotor one I replaced it with isn’t a very good make so might go get a Lucas just to be sure.
The car was running ok but had a knocking noise, I had it rebuilt but once it was rebuilt it started using lots of oil, the company then fitted a new engine block as the old bores were too ovalled for the rings to bed in properly.
David Batty, being the top chap that he is has said he’ll check the car over for me but I was just trying to check the obvious stuff first.
I’ll check the ecu plug tonight but I think it was ok when I last looked.
Does anyone know what the timing should be at idle, I think at 4000 rpm it should be about 28 degrees, but I think I may be seeing a bit to much advance from it.
The car was running ok but had a knocking noise, I had it rebuilt but once it was rebuilt it started using lots of oil, the company then fitted a new engine block as the old bores were too ovalled for the rings to bed in properly.
David Batty, being the top chap that he is has said he’ll check the car over for me but I was just trying to check the obvious stuff first.
I’ll check the ecu plug tonight but I think it was ok when I last looked.
Does anyone know what the timing should be at idle, I think at 4000 rpm it should be about 28 degrees, but I think I may be seeing a bit to much advance from it.
If the engine's been removed/refitted then I should think the culprit is one or more of the many connectors to/from the engine electrics which has been replaced carelessly. In overhauling mine so far I have found:
duff injector connector (forced on wrongly)
fuel pump connector only clipped in with half the female spade (hard to explain, harder to imagine how anyone could do it and not notice)
dirt everwhere
Let Dave Batty have a look, otherwise it might be time to systematically check everything.
duff injector connector (forced on wrongly)
fuel pump connector only clipped in with half the female spade (hard to explain, harder to imagine how anyone could do it and not notice)
dirt everwhere
Let Dave Batty have a look, otherwise it might be time to systematically check everything.
The company who fitted the engine seemed to think everything was ok but it still doesn’t feel right.
I will take it to David Batty so he can check it over for me, but can’t get down till after Christmas so hoping to find the problem myself, still should be getting the bible for Christmas and a new tool set so will put it to use straight away
Does anyone know if there is a fault code reader available for the ECU?
I will take it to David Batty so he can check it over for me, but can’t get down till after Christmas so hoping to find the problem myself, still should be getting the bible for Christmas and a new tool set so will put it to use straight away
Does anyone know if there is a fault code reader available for the ECU?
sure it was the cows though!!Ballistic Banana said:
Have you been at the mince pies and Brandy allready Steve
No. Just getting ready for a day thrunging the Shopping trolley round Goodwood as it is the only TVR that isn't in bits. Haven't been thrunging for some time so getting all excited.
520 has the engine back but no gearbox. Cerbera has no rad and cooling system under the bonnet. Lies scatttered around the garage in boxes waiting for me to get round to fitting it. Gassing Station | Griffith | Top of Page | What's New | My Stuff