Griff 500 stalls after hot restart
Discussion
Greetings from the Colonies gents,
Working on a Griff (serp motor) for a friend, it s having an issue whereby once it has heat soaked, it doesn t want to idle upon restart unless you apply throttle. Things I ve done thus far;
1. Replaced stepper motor with new Lucas unit, cleaned bore that the plunger sits in. Stepper seems to be working fine.
2. Ohmed out the ECT sensor right behind the distributor and it s reading about 250 ohms at 90C so I suspect it s ok given it s close enough to the 300-400 you d expect to see normally.
3. Depressed Schrader valve on fuel rail and it s got pressure. I ve not yet connected a gauge but that ll happen tomorrow once it s cooled down.
The engine fires fine from cold and has no hesitation or any other issues regarding performance or accelerating. Seems mainly that unless you hold some throttle on it after a hot restart, it just doesn t want to idle until you ve given it some time to stabilize and ease off the throttle gradually after which point it ll idle on its own.
I have Rovergauge as I used to own a Griff 500 myself so I ve attached a link with a picture and a video showing what fault codes were originally stored as well as a two and a half minute video of the symptom. See link below;
https://drive.google.com/drive/folders/1lZSN1MulWP...
Would appreciate any input on this. She s (yes, she) had the car many years and it hasn t given any issues until recently. Was brought here to the US probably 20 odd years ago before they were legal here shhhhh!
Two more points of note; it does have a cat and I did notice that if I switched the lambda reading to watch long term fuel trim, both green bars remained fully filled in to the left and said 100%. Even after 2.5 mins of idling, I never was able to get it to change, for what that s worth. The fuel pump seems a bit noisy but as I recall from my car, that was pretty normal. Of course I ll update with fuel pressure readings but any other ideas would be helpful. And lastly, I don t think it s the ignition amp, the car doesn t show any symptoms of that failing and when it does stall, the tachometer doesn t drop to zero like you d expect to see happen with a dodgy amp. Not ruling it out, but the car isn t behaving as if the amp is bad, I m still suspect of fuel pressure being a problem. Thanks all in advance, hope the video was of some help!
Working on a Griff (serp motor) for a friend, it s having an issue whereby once it has heat soaked, it doesn t want to idle upon restart unless you apply throttle. Things I ve done thus far;
1. Replaced stepper motor with new Lucas unit, cleaned bore that the plunger sits in. Stepper seems to be working fine.
2. Ohmed out the ECT sensor right behind the distributor and it s reading about 250 ohms at 90C so I suspect it s ok given it s close enough to the 300-400 you d expect to see normally.
3. Depressed Schrader valve on fuel rail and it s got pressure. I ve not yet connected a gauge but that ll happen tomorrow once it s cooled down.
The engine fires fine from cold and has no hesitation or any other issues regarding performance or accelerating. Seems mainly that unless you hold some throttle on it after a hot restart, it just doesn t want to idle until you ve given it some time to stabilize and ease off the throttle gradually after which point it ll idle on its own.
I have Rovergauge as I used to own a Griff 500 myself so I ve attached a link with a picture and a video showing what fault codes were originally stored as well as a two and a half minute video of the symptom. See link below;
https://drive.google.com/drive/folders/1lZSN1MulWP...
Would appreciate any input on this. She s (yes, she) had the car many years and it hasn t given any issues until recently. Was brought here to the US probably 20 odd years ago before they were legal here shhhhh!
Two more points of note; it does have a cat and I did notice that if I switched the lambda reading to watch long term fuel trim, both green bars remained fully filled in to the left and said 100%. Even after 2.5 mins of idling, I never was able to get it to change, for what that s worth. The fuel pump seems a bit noisy but as I recall from my car, that was pretty normal. Of course I ll update with fuel pressure readings but any other ideas would be helpful. And lastly, I don t think it s the ignition amp, the car doesn t show any symptoms of that failing and when it does stall, the tachometer doesn t drop to zero like you d expect to see happen with a dodgy amp. Not ruling it out, but the car isn t behaving as if the amp is bad, I m still suspect of fuel pressure being a problem. Thanks all in advance, hope the video was of some help!
Edited by bergxu on Wednesday 10th September 02:10
I would certainly verify the fuel system is ok, when was the last time the filter was changed etc and make sure you have plenty in the tank.
All the info you need should be here really to help.
Aftermarket steppers can be a real problem, Lucas branded stuff is not that great over here.
https://www.actproducts.co.uk/category/lucas-injec...
http://g33.co.uk/pages/technical-fuel-injection.ht...
All the info you need should be here really to help.
Aftermarket steppers can be a real problem, Lucas branded stuff is not that great over here.
https://www.actproducts.co.uk/category/lucas-injec...
http://g33.co.uk/pages/technical-fuel-injection.ht...
Firstly you need to establish if you have spark at the plugs when it's hot. Do you details how to do that ?
If it doesn't then you need to work backwards through ign system to ID where that fault starts.
Secondly I can help with analysis if RoverGauge data. You'll just need to run a logfile for me. I'll try msg you details.
If it doesn't then you need to work backwards through ign system to ID where that fault starts.
Secondly I can help with analysis if RoverGauge data. You'll just need to run a logfile for me. I'll try msg you details.
Thanks gents, no idea on the prior maintenance on the car. I was thinking a fuel filter certainly isn’t a bad idea but I would think it should run like s
te all the time if the filter were restricted. As for verifying spark, yes I can do that on the hot restarts and make sure nothing is amiss with the coil and amp.
I do agree, the modern Lucas stuff isn’t great unless it’s the ‘red box’ Lucas Classic stuff (which this isn’t) but I’d put more weight in a Lucas stepper motor working better than much of the aftermarket stuff out there these days.
Keep the ideas coming, I appreciate it.
te all the time if the filter were restricted. As for verifying spark, yes I can do that on the hot restarts and make sure nothing is amiss with the coil and amp. I do agree, the modern Lucas stuff isn’t great unless it’s the ‘red box’ Lucas Classic stuff (which this isn’t) but I’d put more weight in a Lucas stepper motor working better than much of the aftermarket stuff out there these days.
Keep the ideas coming, I appreciate it.
Having to open the throttle seems to suggest not enough air in my mind but it could be a number of things.
One other thing to try is to cycle the ignition a few times before trying to restart, Im not 100% sure but I think the system sends a priming pulse every time to the injectors to prime the inlet, if it starts better this can be a sign of lack of fuel.
Rovergauge seems to suggest its removing fuel.
One other thing to try is to cycle the ignition a few times before trying to restart, Im not 100% sure but I think the system sends a priming pulse every time to the injectors to prime the inlet, if it starts better this can be a sign of lack of fuel.
Rovergauge seems to suggest its removing fuel.
Edited by Belle427 on Thursday 11th September 06:31
As an update, I did check fuel pressure. When they key is rolled to the “RUN” position and the pump primes, my gauge shows 40psi and when running settles to 34-36psi and drops to approx 30psi upon switching the engine off, so I think the fuel system is a-ok. I did unplug the MAF and the car seemed to start and idle on its own, albeit still needed a second to stabilize but at least it idled.
Today I’ll scrutinize the MAF a bit more and also might go ahead and set the base idle just to verify that’s good.
Today I’ll scrutinize the MAF a bit more and also might go ahead and set the base idle just to verify that’s good.
Good to see some progress.
Don't assume that the wiring is fit for purpose.
It was poor from the factory and a couple of decades won't have improved it. Let alone someone having moved, altered it in the interim.
Check all connections and the wiring including earths. My Tam recently 'lost' all earths. Earth cable from battery to loom has broken down. I've also found 'temporay' repairs to the looms of all my TVRs which cause intermitent issues.
Don't assume that the wiring is fit for purpose.
It was poor from the factory and a couple of decades won't have improved it. Let alone someone having moved, altered it in the interim.
Check all connections and the wiring including earths. My Tam recently 'lost' all earths. Earth cable from battery to loom has broken down. I've also found 'temporay' repairs to the looms of all my TVRs which cause intermitent issues.
My 1994 pre-serp Griff does exactly the same thing so I’ll be interested to hear what you find!
Mine will idle happily all day but if you turn it off when it’s hot and restart it after a few mins it then it won’t idle and takes ages to settle down again. I’d rather assumed it was the ignition module but haven’t managed to get round to investigating further.
Mine will idle happily all day but if you turn it off when it’s hot and restart it after a few mins it then it won’t idle and takes ages to settle down again. I’d rather assumed it was the ignition module but haven’t managed to get round to investigating further.
Ignition module could absolutely be an issue but in my experience, when they fail, they pretty much conk out completely. That said, that doesn’t mean there couldn’t be intermittent problems internally in the module which would allow the engine to run albeit not well.
I will keep updating the thread with results of tests, at this point however, I am suspicious of a bad MAF or throttle pot. I don’t think we have a fueling issue.
I will keep updating the thread with results of tests, at this point however, I am suspicious of a bad MAF or throttle pot. I don’t think we have a fueling issue.
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