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If it starts spitting out soot after warming up a little bit that's a classic symptom of over-fuelling. I've seen at least two causes for this:
a) intermittent/faulty engine temperature sensor
b) dodgy ECU
(a) can be eliminated by replacing the ETS with a 300 ohm resistor and trying again. I've seen these things look good hot, and good cold, but in between instead of varying resistance smoothly they can suddenly go open circuit.
(b) can quite often be solved by re-soldering the ECU circuit boards but sometimes it's the main chip that buggers up in which case a replacement ECU is required.
When running excessively fuelly the engine will not idle. Sometimes you can get it through the warm-up phase by pulling the fuel pump fuse temporarily and letting the pressure die away, which compensates for the injectors opening too much. This can sometimes "get you going" if it happens away from base.
If you have access to an oscilloscope and know how to use it, you can learn a lot by looking at the pulse duration firing the injectors.
a) intermittent/faulty engine temperature sensor
b) dodgy ECU
(a) can be eliminated by replacing the ETS with a 300 ohm resistor and trying again. I've seen these things look good hot, and good cold, but in between instead of varying resistance smoothly they can suddenly go open circuit.
(b) can quite often be solved by re-soldering the ECU circuit boards but sometimes it's the main chip that buggers up in which case a replacement ECU is required.
When running excessively fuelly the engine will not idle. Sometimes you can get it through the warm-up phase by pulling the fuel pump fuse temporarily and letting the pressure die away, which compensates for the injectors opening too much. This can sometimes "get you going" if it happens away from base.
If you have access to an oscilloscope and know how to use it, you can learn a lot by looking at the pulse duration firing the injectors.
@Zig - I will double check what's happenign with fuel pressure - actually you could do me a favour and tell me what your gauge shows at idle and when holding at say 4k and also reving, just so I know my behaviour is same or not.
@Adam - yeah, was never convinced about the resoldering tbh although I did resolder earlier in the year, wouldn't be surprised if ECU was upset by it bearing in mind you've got 30 year caps and resistors just waiting to change their values.
@Wedg1e - will do. Does it matter which injectors? say maybe remove 8 and 4 and 3 and 7 so they're spaced a bit?
@Adam - yeah, was never convinced about the resoldering tbh although I did resolder earlier in the year, wouldn't be surprised if ECU was upset by it bearing in mind you've got 30 year caps and resistors just waiting to change their values.
@Wedg1e - will do. Does it matter which injectors? say maybe remove 8 and 4 and 3 and 7 so they're spaced a bit?
OK so you've resoldered already (couldn't remenmber) The problem isn't just the caps - over the years the semiconducors in there have time for further diffusion to take place. I seem to recall the main ECU ASIC is a Ferranti chip? I've heard of these going wrong.
You'll need someone with a spare ECU to swap out to eliminate this possibility.
Easiest to start with the ETS first. The disconnect injectors method may or may not work - don't forget that each connected cylinder will still be far too rich.
You'll need someone with a spare ECU to swap out to eliminate this possibility.
Easiest to start with the ETS first. The disconnect injectors method may or may not work - don't forget that each connected cylinder will still be far too rich.
smash said:
@Zig - I will double check what's happenign with fuel pressure - actually you could do me a favour and tell me what your gauge shows at idle and when holding at say 4k and also reving, just so I know my behaviour is same or not.
Hi mate...For some reason my adjustable FPR has started to play up!..I hope its not the pump failing again.As far as i can see the fuel pressure at idle is 27psi..I can't see it at 4000rpm without a second pair of eyes but i have set the WOT to 38psi....I still have the ECU and AFM that you borrowed off of Stu...I haven't seen him yet to give it back so if its okay with him i can bring it to the Diner tomorrow?...Ziga
adam quantrill said:
Easiest to start with the ETS first. The disconnect injectors method may or may not work - don't forget that each connected cylinder will still be far too rich.
If you think about it, the manifold is under almost perpetual depression (pulsing, admittedly) which causes the air/fuel mix to swirl around the plenum and inlet tracts. You could in theory have one huge injector straight into the plenum and the next intaking cylinder will draw what it can: just because the injectors are located near a given cylinder doesn't mean only that cylinder draws from it... that would be true if it was direct injection of course.If it were otherwise then the bank firing of the RV8 would mean that every cylinder would get twice as much fuel as it actually needs since the injectors fire twice for every rev but each cylinder only fires once - well, you know what I mean
The injectors fire with every spark but each cylinder doesn't. Er, I think that's even more unclear 
I've driven over 100 miles with half the injectors disconnected and although it sounded like it was misfiring it didn't overheat or break and still kept up with motorway traffic.
Edited by Wedg1e on Friday 29th August 14:52
mrzigazaga said:
.For some reason my adjustable FPR has started to play up! .....As far as i can see the fuel pressure at idle is 27psi..
At idle one expects to have near enough the maximum vacuum (otherwise known as 'depression') of about 10 psi. The FPR senses this and reduces the fuel rail pressure by the same amount. As you have set the WOT pressure to 38 psi, then the idle fuel pressure is therefore approx 28 psi (in your case 27). By doing so the pressure across the injectors remains constant at all times.I would say your FPR is working OK. If needed, you can review how the FPR is supposed to work on my web page. Open this archive -- http://www.vintagemodelairplane.com/pages/Rover_Te... -- of all Efi (flapper) components and go to the section on FPR. Although an adjustable FPR may have some different characteristics, the principle is the same.
mrzigazaga said:
Hi mate...For some reason my adjustable FPR has started to play up!..I hope its not the pump failing again.
As far as i can see the fuel pressure at idle is 27psi..I can't see it at 4000rpm without a second pair of eyes but i have set the WOT to 38psi....I still have the ECU and AFM that you borrowed off of Stu...I haven't seen him yet to give it back so if its okay with him i can bring it to the Diner tomorrow?...Ziga
yes please if Stu's OK with that but can't get down today but can do next weekend if that's OK. Will bring the Alpine as wellAs far as i can see the fuel pressure at idle is 27psi..I can't see it at 4000rpm without a second pair of eyes but i have set the WOT to 38psi....I still have the ECU and AFM that you borrowed off of Stu...I haven't seen him yet to give it back so if its okay with him i can bring it to the Diner tomorrow?...Ziga
smash said:
mrzigazaga said:
Hi mate...For some reason my adjustable FPR has started to play up!..I hope its not the pump failing again.
As far as i can see the fuel pressure at idle is 27psi..I can't see it at 4000rpm without a second pair of eyes but i have set the WOT to 38psi....I still have the ECU and AFM that you borrowed off of Stu...I haven't seen him yet to give it back so if its okay with him i can bring it to the Diner tomorrow?...Ziga
yes please if Stu's OK with that but can't get down today but can do next weekend if that's OK. Will bring the Alpine as wellAs far as i can see the fuel pressure at idle is 27psi..I can't see it at 4000rpm without a second pair of eyes but i have set the WOT to 38psi....I still have the ECU and AFM that you borrowed off of Stu...I haven't seen him yet to give it back so if its okay with him i can bring it to the Diner tomorrow?...Ziga
Stu
I think your FPR is set too high.
It should be 27psi at idle with the vacuum line disconnected, as I recall.
As HJ2 says when you connect the vacuum line it should drop.
This is obviously adding to the "too rich" phenomenon, because at idle the plenum vacuum is adding to the pressure drop across the injectors.
It should be 27psi at idle with the vacuum line disconnected, as I recall.
As HJ2 says when you connect the vacuum line it should drop.
This is obviously adding to the "too rich" phenomenon, because at idle the plenum vacuum is adding to the pressure drop across the injectors.
My mistake, it's around 27 psi idling with the vacuum line connected.
So your setting of 38 (engine not running) is correct, and you've measured it coming down to around 27psi with the vacuum connected, so that sounds like the FPR is broadly working.
If it didn't come down you would be in trouble, but yours does, so let's forget that one. (It pays to think through all this stuff though).
If you haven't got access to an oscilloscope I wonder if you might be able to borrow a dwell meter? That could be OK for measuring the injector pulses, although the dwell at idle might be extremely short (last time I connected a 'scope they were well under 10% mark/space ratio - very narrow pulses) I have the Lucas Pocketune I picked up at the BBWF auction, I'll try it on mine and see what it says.
So your setting of 38 (engine not running) is correct, and you've measured it coming down to around 27psi with the vacuum connected, so that sounds like the FPR is broadly working.
If it didn't come down you would be in trouble, but yours does, so let's forget that one. (It pays to think through all this stuff though).
If you haven't got access to an oscilloscope I wonder if you might be able to borrow a dwell meter? That could be OK for measuring the injector pulses, although the dwell at idle might be extremely short (last time I connected a 'scope they were well under 10% mark/space ratio - very narrow pulses) I have the Lucas Pocketune I picked up at the BBWF auction, I'll try it on mine and see what it says.
Still no flowchart?
Flow rate for an injector on a known good 390 at full operating temperature and idle speed would be useful for Smash to compare with. Have the return wires from the injectors to the ECU been checked? If damaged and earthing this will lead to injectors being fully open. Also voltage change for coolant temperature sensor output as the car warms up.
For injector pulse length, would it be possible to fit an LED across the injector, video it and then slow the frame rate on "play" to measure injector pulse length?
Flow rate for an injector on a known good 390 at full operating temperature and idle speed would be useful for Smash to compare with. Have the return wires from the injectors to the ECU been checked? If damaged and earthing this will lead to injectors being fully open. Also voltage change for coolant temperature sensor output as the car warms up.
For injector pulse length, would it be possible to fit an LED across the injector, video it and then slow the frame rate on "play" to measure injector pulse length?
I fitted LED's to mine and it's pretty tricky to tell the difference until you really hit the throttle hard. For the subtleties of a few milliseconds at good idle, to twice that if it's too rich, I don't think you'll see too much of a difference. An oscilloscope on the other hand show it obviously. If I get the dwell meter on mine to do something sensible I'll let you know.
I've been doing a lot of reading about carb conversions and bearing in mind the frankly abysmal sales values of the two 400's on ebay it seems clear I've caught a cold with this one albeit it has a rarity value lift.
So I'm seriously thinking of junking the the troublesome EFi and going carb. Love the look and throttle response of quad dellortos but fiddly to set up and linkages go out of whack regularly plus marginal power benefit against a 4 barrel but with Gazza's drinking tendencies. Very seriously thinking of biting the bullet on a 4 barrel carb conversion as no power loss against the flapper (obviously keep the EFi for next owner should they want to go back)
So I'm seriously thinking of junking the the troublesome EFi and going carb. Love the look and throttle response of quad dellortos but fiddly to set up and linkages go out of whack regularly plus marginal power benefit against a 4 barrel but with Gazza's drinking tendencies. Very seriously thinking of biting the bullet on a 4 barrel carb conversion as no power loss against the flapper (obviously keep the EFi for next owner should they want to go back)
smash said:
I'm seriously thinking of junking the the troublesome EFi and going carb.
As far as i understand it you stand to lose 30-50bhp by doing that..Please put me right if I'm wrong..Also won't this effect the low down torque?..Just seen your post in the other thread, A good rolling road with an old school tuner who knows carbs is what you need...Is there someone near you like that?...Also what is the cost of the conversion?....
Not sure where that's come from. You won't lose any peak power after the carb is rolling roaded against a flapper. Think about what you're saying - WOT AFR for max bhp will be the same for either carb or Flapper so unless the carb is restricting airflow in comparison to the Flapper there'll be no power loss. In fact there may be a little gain due to the restriction of the flapper itself - it's quite heavily sprung and there's nothing similar on an Edelbrock to overcome - secondaries are weighted but much easier to move. Plus the dual plane manifold gives one primary and one secondary per bank in terms of airflow rather than all flow coming throw that single bore AFM...
Only the latest injection systems give a gain over a tuned carb in terms of peak power and even then I was surprised to hear it was only in the order of 3% (according to a Land Rover R&D engineer anyway) - the real benefits of a modern EFi will be economy and better transitional response where it'll be far superior but as we know, the flapper is nothing like a modern EFi!
ATspeed are on my doorstep and they definitely know what they're doing with carbs as Henry will attest to
Only the latest injection systems give a gain over a tuned carb in terms of peak power and even then I was surprised to hear it was only in the order of 3% (according to a Land Rover R&D engineer anyway) - the real benefits of a modern EFi will be economy and better transitional response where it'll be far superior but as we know, the flapper is nothing like a modern EFi!
ATspeed are on my doorstep and they definitely know what they're doing with carbs as Henry will attest to
Edited by smash on Sunday 31st August 19:40
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