Griffith intermittent misfire/conking out - what could it be
Discussion
I've had my 92 Griff 4.0 Litre for 24 years. It's suffered from an intermittent but annoying problem which nobody has managed to get to the bottom of but it very much spoils my enjoyment of the car nowadays.
An auto electrician a few years ago thought he had got to the bottom of it when he doubled up a wire he couldn't replace which if memory serves went between the ignition timing unit and the ECU I think. The issue did seem to happen less after that - or so I thought! Last night I went out for a drive with my daughter around some back lanes and on the narrow single track road going up a steep hill hit a smallish stone underneath the car just left of center. Instantly the engine conked out and was accompanied by strong smell of fuel. I tried to start it and no joy. Rolled myself back down the hill to the bottom and tried several times to restart. Sometimes it would start but sounded like it was running on only 3 cylinders or something and it would eventually die whether you revved it or not. All the time this was accompanied by strong petrol smell. It's exactly what it used to do years ago and is a problem I hoped had been cured (I haven't used it much in recent years).
Fernhurst tried unsuccessfully to find the problem and sometimes Graham used to take the car for a week and it would run fine for him everyday back and forth to work!!
The problem is with a problem like this I am very reluctant to take the car anywhere really or enjoy it as I just don't trust it. Last night I was lucky and a local good samaritan towed me in his Range Rover back home. Car is sitting outside my house again now and I bet if I go to try and start it this morning it will start immediately and give all impressions of being normal!!
I'm baffled and frustrated and just keen to get to the bottom of it. The suspicion from Fernhurst was that it was undoubtedly electrical but I had the distributor etc all changed and it's had new Magnecor HT leads too! I spent a flipping fortune having it resprayed, new fuel lines, new brake lines, new outriggers etc about 4 years ago and it's not been used much since.
I'd welcome any thoughts from the community as to what it might be. The problem used to happen going over bumps, level crossing etc and that's why I mentioned something has obviously been jolted by the small stone last night - probably a wire. But what wires run down the left center of the car underneath? I suspect the engine used to get flooded by the miss-fire and not all the fuel being ignited hence the strong fuel smell. Sometimes you could restart it 5-10 mins later but last night no joy.
Also fixing this is beyond me so if anybody has any good auto electrical recommendations in the South East Guildford/Petersfield/Portsmouth area that would be good!
Saxon
An auto electrician a few years ago thought he had got to the bottom of it when he doubled up a wire he couldn't replace which if memory serves went between the ignition timing unit and the ECU I think. The issue did seem to happen less after that - or so I thought! Last night I went out for a drive with my daughter around some back lanes and on the narrow single track road going up a steep hill hit a smallish stone underneath the car just left of center. Instantly the engine conked out and was accompanied by strong smell of fuel. I tried to start it and no joy. Rolled myself back down the hill to the bottom and tried several times to restart. Sometimes it would start but sounded like it was running on only 3 cylinders or something and it would eventually die whether you revved it or not. All the time this was accompanied by strong petrol smell. It's exactly what it used to do years ago and is a problem I hoped had been cured (I haven't used it much in recent years).
Fernhurst tried unsuccessfully to find the problem and sometimes Graham used to take the car for a week and it would run fine for him everyday back and forth to work!!
The problem is with a problem like this I am very reluctant to take the car anywhere really or enjoy it as I just don't trust it. Last night I was lucky and a local good samaritan towed me in his Range Rover back home. Car is sitting outside my house again now and I bet if I go to try and start it this morning it will start immediately and give all impressions of being normal!!
I'm baffled and frustrated and just keen to get to the bottom of it. The suspicion from Fernhurst was that it was undoubtedly electrical but I had the distributor etc all changed and it's had new Magnecor HT leads too! I spent a flipping fortune having it resprayed, new fuel lines, new brake lines, new outriggers etc about 4 years ago and it's not been used much since.
I'd welcome any thoughts from the community as to what it might be. The problem used to happen going over bumps, level crossing etc and that's why I mentioned something has obviously been jolted by the small stone last night - probably a wire. But what wires run down the left center of the car underneath? I suspect the engine used to get flooded by the miss-fire and not all the fuel being ignited hence the strong fuel smell. Sometimes you could restart it 5-10 mins later but last night no joy.
Also fixing this is beyond me so if anybody has any good auto electrical recommendations in the South East Guildford/Petersfield/Portsmouth area that would be good!
Saxon
Could be many things but as it's been looked at by Fernhurst i would expect to have checked the usual suspects, immobiliser, ecu relays, etc.
Maybe have a achat with http://www.kenttvr.co.uk/ - they are mobile and I'veheard good things about their skills.
Maybe have a achat with http://www.kenttvr.co.uk/ - they are mobile and I'veheard good things about their skills.
There’s a recent thread running in the Chimaera forum https://www.pistonheads.com/gassing/topic.asph=0&a... that sounds similar to your problem. If your not that hands on it is probably best (as you mentioned) to take it to a TVR specialist or auto electrician for a diagnosis.
My 2 cents are - as your symptoms are the immediate cutting out when travelling over railway lines or when stones hit the underneath you could look into the earthing points to block and chassis. A weak voltage caused by a bad earth could account for your issue.
You could also check the rats nest in the passengers footwell shake the loom, check the ECU is properly connected and relays are pressed fully home.
If you don’t have it Rovergauge is a handy tool as it may show a fault code to point you in the right direction. Blitzracing (a regular contributor on here) sells the cables and the program for your laptop is open source. (Google Rovergauge download) There lots of other information Rovergauge will give you that may also help.
My 2 cents are - as your symptoms are the immediate cutting out when travelling over railway lines or when stones hit the underneath you could look into the earthing points to block and chassis. A weak voltage caused by a bad earth could account for your issue.
You could also check the rats nest in the passengers footwell shake the loom, check the ECU is properly connected and relays are pressed fully home.
If you don’t have it Rovergauge is a handy tool as it may show a fault code to point you in the right direction. Blitzracing (a regular contributor on here) sells the cables and the program for your laptop is open source. (Google Rovergauge download) There lots of other information Rovergauge will give you that may also help.
Maybe worth checking the earth points located on the transmission tunnel below centre of dash, passenger and driver side. Will require whale-tail cover to be removed for access, so a bit of a faff. These earth points have been known to work loose over time and cause intermittent faults.
I had a '92 4.0 and not long after I got it, it would randomly cut out. Checked and changed all the usual suspects. With a bit of help from blitzracing I replaced the ECU. Problem solved. I bought a used Range Rover ECU of the same year and swapped in the TVR 'chip'. Might be worth a try if you haven't done that substitution yet.
As has been said both coil and amp can work fine when cold but fail when used on a longer run. (had a classic RR that would break down about 100 yards from work but would be fine when I walked back to collect it a lunchtime).
Also the Wiring in the foot well could also be a culprit.
Steve
Also the Wiring in the foot well could also be a culprit.
Steve
First thing to do is find someone that will follow your testing instructions
Request that they fit several 21 watt bulbs with holders onto a length of wood that will sit on the passenger seat and be stable so that they can't turn over and burn a hole in the seat when hot
Now ask them to wire those 21 Watt bulbs into the supplies and earths of all the circuits that could cause the problem you are experiencing
Example
Fuel pump
ECU
Ignition Coil
Ignition amplifier
Fusebox supplies
Have each bulb labeled for what circuit it is monitoring
Drive the car and take a look at the bulbs when the fault occurs, there may be a supply or earth fault showing
If the above testing doesn't show a fault at least you will then know what isn't causing the problem
Request that they fit several 21 watt bulbs with holders onto a length of wood that will sit on the passenger seat and be stable so that they can't turn over and burn a hole in the seat when hot
Now ask them to wire those 21 Watt bulbs into the supplies and earths of all the circuits that could cause the problem you are experiencing
Example
Fuel pump
ECU
Ignition Coil
Ignition amplifier
Fusebox supplies
Have each bulb labeled for what circuit it is monitoring
Drive the car and take a look at the bulbs when the fault occurs, there may be a supply or earth fault showing
If the above testing doesn't show a fault at least you will then know what isn't causing the problem
Some great replies here already and I am very grateful - the bulb suggestion is an interesting one actually.
I'm trying to decide whether to contact:
1. Local TVR specialist APM Automotive
2. Local Auto electrician Petersfield Auto Electrics
The plus side of APM Automotive is they know TVR's but the downside is he's probably not an electrical expert. The reverse is true of the auto electrical place.
The good news is that I've just been out to start the car and even the following day it's turning over but not starting (which is the first time ever the fault is sustained) I'm hoping this will make it easier to get to the bottom of it. The downside of course is that I now cannot drive the car anywhere so it will need recovery and that's a one shot operation.
Any thoughts on whether to go the TVR specialist route or the auto-electrician route gratefully received.
Saxon
I'm trying to decide whether to contact:
1. Local TVR specialist APM Automotive
2. Local Auto electrician Petersfield Auto Electrics
The plus side of APM Automotive is they know TVR's but the downside is he's probably not an electrical expert. The reverse is true of the auto electrical place.
The good news is that I've just been out to start the car and even the following day it's turning over but not starting (which is the first time ever the fault is sustained) I'm hoping this will make it easier to get to the bottom of it. The downside of course is that I now cannot drive the car anywhere so it will need recovery and that's a one shot operation.
Any thoughts on whether to go the TVR specialist route or the auto-electrician route gratefully received.
Saxon
Hedgehopper said:
You ask what wires are left of centre underneath the car. How about the fuel pump which has exposed wiring in that position?
Agreed, had this recently where car nearly fired as op described. Jiggled the spade end on fuel pump and fired up. Reterminated wires to spade end and all good. There were a few strands only making contact but the spade end was firmly pushed on. Before this I was getting odd misfire.If it doesn’t start at all now that’s not such a bad place to be comparatively, it’s much easier to fix than an intermittent problem, I would talk to your TVR guy and see how confident he is on electrics, the positive side is he might know where all the various items are and maybe has an assortment of spares to test against, the auto guy will likely be better at electrics but might not have compatible parts to test and might struggle with what is sometimes a slightly strange way of doing things.
But as mentioned, the fuel pump is at the rear left, can you hear it prime when you switch the ignition on ?
But as mentioned, the fuel pump is at the rear left, can you hear it prime when you switch the ignition on ?
This is exactly what my car used to do...….. spent a good three years tracking down the problem, changing nearly every sensor, checking wiring, tried different ECUs and I must say both the garage and me were stumped.
I was on the verge of getting rid, as it was no fun to drive anywhere, and most the miles put on it were to and from the garage.
I ended up getting Power to put in their META electronic ignition system, which got rid of all the issues, and to be honest has transformed the total running of the car.
Looking back I would hazard a guess that the issue may lie in the loom, based on the fact we replaced nearly all sensors and tried different ECU's, the cars are approaching 30 years old now, and the cables have been nicely "cooked" by the 4.0/4.3l V8...…..
I was on the verge of getting rid, as it was no fun to drive anywhere, and most the miles put on it were to and from the garage.
I ended up getting Power to put in their META electronic ignition system, which got rid of all the issues, and to be honest has transformed the total running of the car.
Looking back I would hazard a guess that the issue may lie in the loom, based on the fact we replaced nearly all sensors and tried different ECU's, the cars are approaching 30 years old now, and the cables have been nicely "cooked" by the 4.0/4.3l V8...…..
Hoover,
Your solution is tempting indeed - I presume you mean this unit: http://www.powersperformance.co.uk/store/slug/elec... at £2500. The cost is very offputting right now because I'm currently on 50% pay at work and the firm are making redundancies in volume due Covid (airline). Otherwise if it's a guaranteed fix for an engine ignition fault (which presumably it is because I imagine it replaces everything that could affect the system) I would probably just wop it on a 0% credit card in a last ditch attempt to make the car usable. This is one of the main reasons I haven't used the car much in years - as you say it just is no fun knowing that on any longish run you will break down and indeed it's misfired on the outside lane of the M4 which isn't a place you want to be! I find as I get older my nerve for dealing with such things is diminishing anyway and I end up taking the Toyota GT86 instead. I spent over £11000 on the car getting it put back on the road just over 3 years ago including outriggers and respray and probably should have got rid before that - isn't hindsight a wonderful thing!! It still needs a complete retrim (around £4000) and now potentially a new ignition system (£2500) so I will have spent £17500 on a precat Griff in the past 4 years and if I tried to sell it tomorrow I would probably struggle to get £17500 back. I see Fermies are selling a nice precat for £28000 and at that level I could be very tempted to sort the car and then get rid. I used to think I would never part with it but find myself increasingly asking if I need this hassle in my life for the relatively small amount of pleasure it gives. The GT86 by comparison is flawlessly reliable and returns pleasure in spades and frankly is almost as good to look at and better if less raw to drive!
I will check if the fuel pump is priming but I'm pretty sure it is - I think it had a new fuel pump 3.5 years ago, I'm pretty sure APM replaced everything else apart from the ashtray judging by the bill!
Saxon
Your solution is tempting indeed - I presume you mean this unit: http://www.powersperformance.co.uk/store/slug/elec... at £2500. The cost is very offputting right now because I'm currently on 50% pay at work and the firm are making redundancies in volume due Covid (airline). Otherwise if it's a guaranteed fix for an engine ignition fault (which presumably it is because I imagine it replaces everything that could affect the system) I would probably just wop it on a 0% credit card in a last ditch attempt to make the car usable. This is one of the main reasons I haven't used the car much in years - as you say it just is no fun knowing that on any longish run you will break down and indeed it's misfired on the outside lane of the M4 which isn't a place you want to be! I find as I get older my nerve for dealing with such things is diminishing anyway and I end up taking the Toyota GT86 instead. I spent over £11000 on the car getting it put back on the road just over 3 years ago including outriggers and respray and probably should have got rid before that - isn't hindsight a wonderful thing!! It still needs a complete retrim (around £4000) and now potentially a new ignition system (£2500) so I will have spent £17500 on a precat Griff in the past 4 years and if I tried to sell it tomorrow I would probably struggle to get £17500 back. I see Fermies are selling a nice precat for £28000 and at that level I could be very tempted to sort the car and then get rid. I used to think I would never part with it but find myself increasingly asking if I need this hassle in my life for the relatively small amount of pleasure it gives. The GT86 by comparison is flawlessly reliable and returns pleasure in spades and frankly is almost as good to look at and better if less raw to drive!
I will check if the fuel pump is priming but I'm pretty sure it is - I think it had a new fuel pump 3.5 years ago, I'm pretty sure APM replaced everything else apart from the ashtray judging by the bill!
Saxon
I had similar (92 4.3 pre cat).
Changed the ignition amp and Coil. It cured it for a while. Turned out to be the wire that runs to it across the front of the engine from the coil.
Mine doesn’t have the 100 amp fuse underneath- not sure if pre cats do but worth checking? Maybe that got hit by the stone?
Hope you cure it -I wouldn’t pay £2.5k for a new ignition either!
Changed the ignition amp and Coil. It cured it for a while. Turned out to be the wire that runs to it across the front of the engine from the coil.
Mine doesn’t have the 100 amp fuse underneath- not sure if pre cats do but worth checking? Maybe that got hit by the stone?
Hope you cure it -I wouldn’t pay £2.5k for a new ignition either!
Yep that's the system I've had fitted to mine
I was at the end of my tether with my Griff...…. I just woke up one Saturday, phoned Dom, drove that morning and left it with him..... not looked back since.
There are other systems out there, but I felt the Meta system was in the spirit of the car...….. I got Power to install it, and it is a very tidy install indeed.
My griff would cut out if I hit a manhole cover some times...… scariest moment was over taking on country lane, when mid way through it cut out, car coming the otherway, had to wait until car I was overtaking had gone past so I could slot back in behind..... not good.
If it’s not priming then hopefully that’s not so bad to fix, as it stopped after hitting a stone in that area of the car then maybe checking the cables at the pump is a good place to start, if they look ok then measure the voltage while connected at the time when it should be on, 2 or 3 on after switching on the ignition, if voltage ok then it’s the pump, if not there are several connection points along the way, fuse, relay , immobiliser, inertia switch, connectors behind the door???
It’s not what you want to hear but you can get a drive in drive out Full management conversion for £2000. (Fuel and spark). You will gain a new wiring loom and get rid of all that Tvr mess.
It’s the best money you will ever spend and will make the car reliable, faults like yours are very hard to pin down.
It will also be much easier to diagnose problems in the future.
I decided to junk the original stuff and go Megasquirt after I had an intermittent misfire and the shocking quality of ignition parts, it’s the best thing I’ve ever done.
It’s the best money you will ever spend and will make the car reliable, faults like yours are very hard to pin down.
It will also be much easier to diagnose problems in the future.
I decided to junk the original stuff and go Megasquirt after I had an intermittent misfire and the shocking quality of ignition parts, it’s the best thing I’ve ever done.
Gassing Station | Griffith | Top of Page | What's New | My Stuff