Rover V8 EFI Problems
Discussion
This is my first post so hopefully it’s in the right place? I have a Marcos Mantula, which has a 3.9 Rover V8 Tuscan engine. It’s a 1987 vintage classic engine, with 3.5 fuel injection system and a tweaked ECU.
It has been running fine but after not being used for a year, it starts on 7 cylinders. The electrical side of it is all fine so it’s an injection problem. I have run it for a while but it does not clear. I have tried listening to the injectors with a screwdriver and 2 of them make a faint click, whereas the others are fine. So, do I take all the injectors out and try to clean them or is this not possible? Can I send them away to somebody to test them? Any ideas?
Thanks
It has been running fine but after not being used for a year, it starts on 7 cylinders. The electrical side of it is all fine so it’s an injection problem. I have run it for a while but it does not clear. I have tried listening to the injectors with a screwdriver and 2 of them make a faint click, whereas the others are fine. So, do I take all the injectors out and try to clean them or is this not possible? Can I send them away to somebody to test them? Any ideas?
Thanks
There are businesses which you can post your injectors to for testing and servicing. You'll probably find there are local businesses that do it too.
If you have basic electrical skills you can test them electrically to see whether they're being driven properly and whether they have got any internal electrical problems before you go to the trouble of removing them.
You can check the exhaust header temperatures to find whether you have any cylinders which are not firing at all. If you take the plugs out of the cold cylinders you will see whether they are wet or dry. If they're dry you may have a fuel supply problem - since it's only affecting some cylinders the injector is a likely candidate. But you could also have an ignition problem, or just dirty plugs.
If you have basic electrical skills you can test them electrically to see whether they're being driven properly and whether they have got any internal electrical problems before you go to the trouble of removing them.
You can check the exhaust header temperatures to find whether you have any cylinders which are not firing at all. If you take the plugs out of the cold cylinders you will see whether they are wet or dry. If they're dry you may have a fuel supply problem - since it's only affecting some cylinders the injector is a likely candidate. But you could also have an ignition problem, or just dirty plugs.
Hi and thanks for the speedy response. I have checked the resistance of the injectors, which seem to be about 5-6 Ohms or so. I can’t find the correct resistance for these old injectors, which have the hose crimped to them. Will do some more searching now.
I have taken the plugs out and they are all similar – i.e. blackish but not sooted up. I checked the gap was 30 thou and have used a sensor round each plug lead to check there was a spark. Hence my conclusion that its probably a stuck injector. The car has not been used for some years, so I syphoned out the old petrol and added new but there was probably some old petrol still in there.
Will look for a local specialist – thanks
I have taken the plugs out and they are all similar – i.e. blackish but not sooted up. I checked the gap was 30 thou and have used a sensor round each plug lead to check there was a spark. Hence my conclusion that its probably a stuck injector. The car has not been used for some years, so I syphoned out the old petrol and added new but there was probably some old petrol still in there.
Will look for a local specialist – thanks
So have you confirmed a signal at all the injectors ?
Confirmed 12v power to all injectors ?
The injectors are held into the rail with clips ? It would be viable to lift the rail and injectors out of the manifold and crank it to get a visual, taking care for the obvious fuel spray
ASNU can check, test, repair or whatever they need.
Either directly or one of their dealers.
Confirmed 12v power to all injectors ?
The injectors are held into the rail with clips ? It would be viable to lift the rail and injectors out of the manifold and crank it to get a visual, taking care for the obvious fuel spray
ASNU can check, test, repair or whatever they need.
Either directly or one of their dealers.
Thanks for the responses – agree about a clean set of plugs so will get some.
Regarding the 12V to the injectors, somebody else suggested removing the plug from each injector whilst it is running to see the effect and hopefully find the one that is faulty.
A nice suggestion to remove the fuel rail and injectors but as a V8, the fuel rail is a circle running round the plenum chamber, which has to be removed first. Will do some more diagnosis and report back. Thanks for all the inputs.
Regarding the 12V to the injectors, somebody else suggested removing the plug from each injector whilst it is running to see the effect and hopefully find the one that is faulty.
A nice suggestion to remove the fuel rail and injectors but as a V8, the fuel rail is a circle running round the plenum chamber, which has to be removed first. Will do some more diagnosis and report back. Thanks for all the inputs.
JohnR27 said:
Thanks for the responses – agree about a clean set of plugs so will get some.
Regarding the 12V to the injectors, somebody else suggested removing the plug from each injector whilst it is running to see the effect and hopefully find the one that is faulty.
A nice suggestion to remove the fuel rail and injectors but as a V8, the fuel rail is a circle running round the plenum chamber, which has to be removed first. Will do some more diagnosis and report back. Thanks for all the inputs.
If any of the injectors aren't working correctly due to a faulty supply or switching signal, disconnecting any of those injectors will make no difference because they won't be injecting due to the electrical faultRegarding the 12V to the injectors, somebody else suggested removing the plug from each injector whilst it is running to see the effect and hopefully find the one that is faulty.
A nice suggestion to remove the fuel rail and injectors but as a V8, the fuel rail is a circle running round the plenum chamber, which has to be removed first. Will do some more diagnosis and report back. Thanks for all the inputs.
Which airflow meter is it using - the 'flapper' type which was common on Range Rover 3.5 EFis of that age or the later 'hotwire'?
http://www.v8wizard.com/Injection_identify_airflow...
Unless you're sure the injector hose are crimped it was common for them just to be pushed onto the injectors relying on the barbs to hold it in place & the little dished metal ring at the bottom just seems to make it look pretty.
My RRC (1986 3.5EFi flapper) was like that, when I replaced all hoses a couple of years back & I used proper fuel hose clamps as well. No leakage issues.
Appreciate this link is Jaguar but the hose attachment is the same: https://jag-lovers.org/xj-s/book/EFIhoseclamps.htm...
I used the soldering iron removal method after cutting the old hose when I removed the fuel rail to ensure no fuel remaining.
Be careful applying voltage directly to the injectors. IIRC the early ones with the 'flapper' are 3 volt not 12. I don't know if the later 'hotwire' is any different.
Worth a read: 'Hotwire' http://www.britishv8.org/Articles/Rover-Hot-Wire-E...
and from the V8 forum on a Disco 3.9: www.v8forum.co.uk/forum/viewtopic.php?f=13&t=1...
http://www.v8wizard.com/Injection_identify_airflow...
Unless you're sure the injector hose are crimped it was common for them just to be pushed onto the injectors relying on the barbs to hold it in place & the little dished metal ring at the bottom just seems to make it look pretty.
My RRC (1986 3.5EFi flapper) was like that, when I replaced all hoses a couple of years back & I used proper fuel hose clamps as well. No leakage issues.
Appreciate this link is Jaguar but the hose attachment is the same: https://jag-lovers.org/xj-s/book/EFIhoseclamps.htm...
I used the soldering iron removal method after cutting the old hose when I removed the fuel rail to ensure no fuel remaining.
Be careful applying voltage directly to the injectors. IIRC the early ones with the 'flapper' are 3 volt not 12. I don't know if the later 'hotwire' is any different.
Worth a read: 'Hotwire' http://www.britishv8.org/Articles/Rover-Hot-Wire-E...
and from the V8 forum on a Disco 3.9: www.v8forum.co.uk/forum/viewtopic.php?f=13&t=1...
Edited by paintman on Wednesday 7th June 12:03
Thanks for all the responses. Regarding the faulty supply, I will try to check this out but the car is a Marcos built as a kit car and has only done 1,900 miles over the years and I have kept it in a dehumidified garage. The problem I suspect is more the old petrol, which I syphoned out and in reality, I now know that I should have removed the tank to drain completely. I therefore assume that the problem is blocked injectors but it could of course be faulty supply as well.
Regarding the other response, it is indeed a flapper system due to its age. The injector hoses look like they are crimped as there is no obvious means to separate them from the injectors and when you buy new, it all comes as one item as far as I can see (unless you know better). The injectors have a resistance of about 2.5 ohms, so you may well be correct that it’s a low voltage solution. I will look at the links in the next day or so but thanks again for the inputs
John
Regarding the other response, it is indeed a flapper system due to its age. The injector hoses look like they are crimped as there is no obvious means to separate them from the injectors and when you buy new, it all comes as one item as far as I can see (unless you know better). The injectors have a resistance of about 2.5 ohms, so you may well be correct that it’s a low voltage solution. I will look at the links in the next day or so but thanks again for the inputs
John
The injectors have a tiny filter basket in the inlet. We had a lack of power problem on the Bowler race truck and it turned out that lint had collected in each of the baskets and restricted fuel supply.
The inine filter didn't catch the lint and we found a little collection of it in the pickup void of the fuel cell.
The inine filter didn't catch the lint and we found a little collection of it in the pickup void of the fuel cell.
JohnR27 said:
The injectors have a resistance of about 2.5 ohms, so you may well be correct that it’s a low voltage solution. I will look at the links in the next day or so but thanks again for the inputs
John
The old injectors are low impedance and will measure around 2.5ohms. Perfectly normal.John
How old is the fuel ?
As it's a flapper I suspect the ECU is going to be the Lucas 4CU.
Certain notoriety for reliability issues - I'm either on my third or fourth since I got it in 1994.
One suddenly ran very very rich with big clouds of black smoke & another suddenly started misfiring & running like a bag of spanners.
I carry a good spare in the car!
They do crop up on ebay used but you can never be sure that they will be any good although I've only had one duff one.
The 4CU only controls fuelling - length of time the injectors are open - not the ignition.
The injectors open in banks of 4, not individually.
Avilec on the Isle of Wight have a good reputation for ecu repairs.
The Range Rover factory workshop manual for this combination is a big thick book. Unfortunately the later factory CD disc (RAVE) doesn't cover it.
SRR660ENWM. Range Rover All models Petrol & Diesel 1986 to 1989.
Usually on ebay, but generally expensive, esp if you don't need all the Range Rover stuff but it does have all the tests.
I don't know if any of the online download type manuals are any good as I've never tried downloading one.
Expected injector reading is given as 2.4 ohms at 20degC so your 2.5 ohms reading is OK.
Certain notoriety for reliability issues - I'm either on my third or fourth since I got it in 1994.
One suddenly ran very very rich with big clouds of black smoke & another suddenly started misfiring & running like a bag of spanners.
I carry a good spare in the car!
They do crop up on ebay used but you can never be sure that they will be any good although I've only had one duff one.
The 4CU only controls fuelling - length of time the injectors are open - not the ignition.
The injectors open in banks of 4, not individually.
Avilec on the Isle of Wight have a good reputation for ecu repairs.
The Range Rover factory workshop manual for this combination is a big thick book. Unfortunately the later factory CD disc (RAVE) doesn't cover it.
SRR660ENWM. Range Rover All models Petrol & Diesel 1986 to 1989.
Usually on ebay, but generally expensive, esp if you don't need all the Range Rover stuff but it does have all the tests.
I don't know if any of the online download type manuals are any good as I've never tried downloading one.
Expected injector reading is given as 2.4 ohms at 20degC so your 2.5 ohms reading is OK.
Edited by paintman on Thursday 8th June 21:42
stevieturbo said:
The old injectors are low impedance and will measure around 2.5ohms. Perfectly normal.
How old is the fuel ?
OK thanks - so all injectors have continuity. The Fuel is newish as I syphoned out the old fuel and put in Esso Super, which I believe does not have any bioethanol in it. I now understand that I should really have removed the tank to fully drain it.How old is the fuel ?
paintman said:
As it's a flapper I suspect the ECU is going to be the Lucas 4CU.
Certain notoriety for reliability issues - I'm either on my third or fourth since I got it in 1994.
One suddenly ran very very rich with big clouds of black smoke & another suddenly started misfiring & running like a bag of spanners.
I carry a good spare in the car!
They do crop up on ebay used but you can never be sure that they will be any good although I've only had one duff one.
The 4CU only controls fuelling - length of time the injectors are open - not the ignition.
The injectors open in banks of 4, not individually.
Avilec on the Isle of Wight have a good reputation for ecu repairs.
The Range Rover factory workshop manual for this combination is a big thick book. Unfortunately the later factory CD disc (RAVE) doesn't cover it. SRR660ENWM. Range Rover All models Petrol & Diesel 1986 to 1989.
Usually on ebay, but generally expensive, esp if you don't need all the Range Rover stuff but it does have all the tests.
I don't know if any of the online download type manuals are any good as I've never tried downloading one.
Expected injector reading is given as 2.4 ohms at 20degC so your 2.5 ohms reading is OK.
Thanks for the detailed response. It's indeed a flapper and a 4CU ecu. I have a current clamp, so was going to check that the injectors are getting a feed from the ECU in the next day or so. If this points to a faulty ecu, then as you say, I will be looking on eBay.Certain notoriety for reliability issues - I'm either on my third or fourth since I got it in 1994.
One suddenly ran very very rich with big clouds of black smoke & another suddenly started misfiring & running like a bag of spanners.
I carry a good spare in the car!
They do crop up on ebay used but you can never be sure that they will be any good although I've only had one duff one.
The 4CU only controls fuelling - length of time the injectors are open - not the ignition.
The injectors open in banks of 4, not individually.
Avilec on the Isle of Wight have a good reputation for ecu repairs.
The Range Rover factory workshop manual for this combination is a big thick book. Unfortunately the later factory CD disc (RAVE) doesn't cover it. SRR660ENWM. Range Rover All models Petrol & Diesel 1986 to 1989.
Usually on ebay, but generally expensive, esp if you don't need all the Range Rover stuff but it does have all the tests.
I don't know if any of the online download type manuals are any good as I've never tried downloading one.
Expected injector reading is given as 2.4 ohms at 20degC so your 2.5 ohms reading is OK.
camel_landy said:
ISTR the Rover V8 can be very fussy about the HT leads, so might be worth investigating and/or replacing those.
Could it be the start of a head gasket failure?
M
Thanks - the leads are fairly new and I have checked that there is a spark to all cylinders, which seems to be fine, so I will investigate the fuel issues and come back to leads if I can't solve it then. ThanksCould it be the start of a head gasket failure?
M
JohnR27 said:
OK thanks - so all injectors have continuity. The Fuel is newish as I syphoned out the old fuel and put in Esso Super, which I believe does not have any bioethanol in it. I now understand that I should really have removed the tank to fully drain it.
Largely pointless test.Do what I said 2 weeks ago.
JohnR27 said:
Thanks for the detailed response. It's indeed a flapper and a 4CU ecu. I have a current clamp, so was going to check that the injectors are getting a feed from the ECU in the next day or so. If this points to a faulty ecu, then as you say, I will be looking on eBay.
The 4CUs I've got have several different part numbers on the sticky labels - Lucas part numbers & Land Rover part numbers - on them.There was website that dealt with the Rover SD1 & he said he tried a few & did notice differences in performance. Think the site was something along the lines of 'vintagemodelairplane.com' but I can't seem to find it anymore which is a pity as it had a lot of info on 4CU & flappers.
I emailed Lucas some years ago & the reply was that they thought they were all the same & interchangeable.
Can't say I've noticed any differences in performance between them but then again I'm dealing with a vehicle with the aerodynamics of a garden shed not a sports car!
ETA I've just had a quick look on ebay & there is someone - Mark Adams - who advertises remanufactured & upgraded 4CU. Might be worth having a word to see if he could test yours.
www.ebay.co.uk/itm/165236512841
Edited by paintman on Tuesday 13th June 18:57
stevieturbo said:
Largely pointless test.
Do what I said 2 weeks ago.
Looking at the injectors spray pattern etc is on my list but I'm struggling with time. To remove the injectors is not straightforward as I need to remove the plenum chamber to get to them. There is also a circular fuel rail, so you remove all 8 together. Will get to it.Do what I said 2 weeks ago.
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