Help needed Interpreting ECUMate readings
Discussion
I took the plunge and ordered the Steve Heath ECUmate as a last ditch attempt to fix my car before consigning
it to a local garage and the subsiquent weeks off the road! Ive now run the tests and found the following:
At idle everything checks out ok. The cars running a bit more lumpy than normal. No faults shown
from the ecu's fault codes
However, out on the road, the Lam A and Lam B indications are OK upto around 2800 rpm where the Lam B
starts flashing Lean. Over 3000 rpm the indication from Lam B is lean while Lam A remains Ok throughout the run.
Significant Engine power loss occurs around 3000 rpm and at around 3800-4000 rpm the engine stagnates regadless of full throttle.
Once the throttle is lifted, the Lam B stays at lean while Lam A indicates OK . When the car is accelerated again, Lam B indicates OK until over 2800 rpm where the above is repeated. At no time has the ecu generated any fault codes as none were shown on the ECUmate afterwards.
AFM / throttle pot readings appeared to be as expected through all revs
Fuel pump and filter were recently replace. As it appears that only one side of the cylinder bank are affected, I presume
that fuel pressure and supply to the rail is ok?
The online guide doesn't state which side lanA and Lam B represent, unless I've missed it somewhere.
Any help suggestions appreciated !
Without wanting to jump to assumptions, how should I continue the fault finding process? I'm thinking a faulty injector, or
manifold leak at the higher rpm.
it to a local garage and the subsiquent weeks off the road! Ive now run the tests and found the following:
At idle everything checks out ok. The cars running a bit more lumpy than normal. No faults shown
from the ecu's fault codes
However, out on the road, the Lam A and Lam B indications are OK upto around 2800 rpm where the Lam B
starts flashing Lean. Over 3000 rpm the indication from Lam B is lean while Lam A remains Ok throughout the run.
Significant Engine power loss occurs around 3000 rpm and at around 3800-4000 rpm the engine stagnates regadless of full throttle.
Once the throttle is lifted, the Lam B stays at lean while Lam A indicates OK . When the car is accelerated again, Lam B indicates OK until over 2800 rpm where the above is repeated. At no time has the ecu generated any fault codes as none were shown on the ECUmate afterwards.
AFM / throttle pot readings appeared to be as expected through all revs
Fuel pump and filter were recently replace. As it appears that only one side of the cylinder bank are affected, I presume
that fuel pressure and supply to the rail is ok?
The online guide doesn't state which side lanA and Lam B represent, unless I've missed it somewhere.
Any help suggestions appreciated !
Without wanting to jump to assumptions, how should I continue the fault finding process? I'm thinking a faulty injector, or
manifold leak at the higher rpm.
Edited by chris2002hk on Monday 6th February 08:16
Just unplug one of the lambda probes and see which (A, or B) stops reading to start with to determin the side. A highly lean mixture reading can also be caused by a severe misfire, as unburnt fuel looks like a lean mixture due to its high oxygen content in the exhaust, so you get a fake reading. Once you know which side A and B are, then pull all 4 plugs from that side and check the condition across all 4. Id expect a blocked injector or a misfire will change the colours. Bad misfires will soot the working plugs up as the ECU over fuels the engine trying to make the mixture correct. Any highly lean plugs (low flow injectors) will be white.
You are correct that if on side is OK the basic pump, filter and fuel rail will be OK. In terms of vacume leaks in the manifold, they tend to make things worse at low throttle settings, as the vacume is high, and amount of fuel low, quite the opposite to what you have.
[
You are correct that if on side is OK the basic pump, filter and fuel rail will be OK. In terms of vacume leaks in the manifold, they tend to make things worse at low throttle settings, as the vacume is high, and amount of fuel low, quite the opposite to what you have.
[
Edited by blitzracing on Monday 6th February 12:21
Edited by blitzracing on Tuesday 7th February 12:29
Thanks Blitz for the suggestions. I will get onto soon and maybe post so pics here of the plugs. Most my ignition parts are a year old or so old but ill re test every lead, plug adaptor for a break or high resistance. I've never heard of a faulty spark plug, although they were changed to the correct NKG ones in Dec, anythings possible I've some HT plug testers which I'll connect up again.
My hunch is that the lambda sensor is doing it's job correctly and indicating a high amount of uncombusted air .
Not at home right now, but I will try a run with sensors disconnected to see if any makes any difference. From reading about the ECU , doesn't it ignore the lambda sensors over 4000 rpm and also when they are cold? My problem is most apparent at higher revs.
I wasn't aware that the layout of the HT leads could be a potential problem! I'm using the spacers supplied with the leads from one of the major TVR suppliers and all leads are numbered, so even I can't F#%^ this up ( but then again .. lol)
I've been reading a lot online about trouble shooting a misfire , starting with ignition basics then moving on to fueling n injectors . Will report back . tks for the hints .
Finally, is there any reason why the ECUs not generating any fault code for this problem? When Interrogated, it says no fault codes found.
Not at home right now, but I will try a run with sensors disconnected to see if any makes any difference. From reading about the ECU , doesn't it ignore the lambda sensors over 4000 rpm and also when they are cold? My problem is most apparent at higher revs.
I wasn't aware that the layout of the HT leads could be a potential problem! I'm using the spacers supplied with the leads from one of the major TVR suppliers and all leads are numbered, so even I can't F#%^ this up ( but then again .. lol)
I've been reading a lot online about trouble shooting a misfire , starting with ignition basics then moving on to fueling n injectors . Will report back . tks for the hints .
Finally, is there any reason why the ECUs not generating any fault code for this problem? When Interrogated, it says no fault codes found.
Edited by chris2002hk on Wednesday 8th February 02:41
My hunch is that the lambda sensor is doing it's job correctly and indicating a high amount of uncombusted air .
Not at home right now, but I will try a run with sensors disconnected to see if any makes any difference. From reading about the ECU , doesn't it ignore the lambda sensors over 4000 rpm and also when they are cold? My problem is most apparent at higher revs.
I wasn't aware that the layout of the HT leads could be a potential problem! I'm using the spacers supplied with the leads from one of the major TVR suppliers and all leads are numbered, so even I can't F#%^ this up ( but then again .. lol)
I've been reading a lot online about trouble shooting a misfire , starting with ignition basics then moving on to fueling n injectors . Will report back . tks for the hints .
Finally, is there any reason why the ECUs not generating any fault code for this problem? When Interrogated, it says no fault codes found.
Not at home right now, but I will try a run with sensors disconnected to see if any makes any difference. From reading about the ECU , doesn't it ignore the lambda sensors over 4000 rpm and also when they are cold? My problem is most apparent at higher revs.
I wasn't aware that the layout of the HT leads could be a potential problem! I'm using the spacers supplied with the leads from one of the major TVR suppliers and all leads are numbered, so even I can't F#%^ this up ( but then again .. lol)
I've been reading a lot online about trouble shooting a misfire , starting with ignition basics then moving on to fueling n injectors . Will report back . tks for the hints .
Finally, is there any reason why the ECUs not generating any fault code for this problem? When Interrogated, it says no fault codes found.
Edited by chris2002hk on Wednesday 8th February 04:01
The ECU will only report a fault if it detects something it doesn't expect. In other words it will not report a code if the information it is receiving is valid but not necessarily correct.
A bit philosophical but if it sees a temp of 80C when the real temp is 40C it will not report a fault. If it sees a temp of 200C it will. It does not see or control anything from the ignition side except the coil input. If the ignition side is misbehaving it may not see any fault. The lambdas will report back that the mixture is not right, the ECU will try and compensate which may or may not make the problem worse but the ECU doesn't have any information on why the lambdas are reporting lean for example.
I would strongly recommend resetting the ECU by unplugging it for 30 secs or so so that everything is reset. The ECU may have adjusted itself incorrectly and needs to be reset.
Start the car and then check that the tune resistor is correct. This selects the map and may be pointing the ECU to the wrong map.
On the ignition side, both the coil and the ignition AMP can cause bad running at high revs.
A bit philosophical but if it sees a temp of 80C when the real temp is 40C it will not report a fault. If it sees a temp of 200C it will. It does not see or control anything from the ignition side except the coil input. If the ignition side is misbehaving it may not see any fault. The lambdas will report back that the mixture is not right, the ECU will try and compensate which may or may not make the problem worse but the ECU doesn't have any information on why the lambdas are reporting lean for example.
I would strongly recommend resetting the ECU by unplugging it for 30 secs or so so that everything is reset. The ECU may have adjusted itself incorrectly and needs to be reset.
Start the car and then check that the tune resistor is correct. This selects the map and may be pointing the ECU to the wrong map.
On the ignition side, both the coil and the ignition AMP can cause bad running at high revs.
From experiance I know the lean / rich errors conditions have to be pretty bad before the ECU will pick them up as a fault. It appears that as long as the lambda's are seen to be switching at whatever revs it wont generate a fault code. So if by driving the car you pass through a point where the lambda's stick lean for a period, but then start switching again the ECU wont pick this up. It only seem to generate a fault is say you have a switching signal for a period (it enables the lambda control on the first sign of the signal switching, but not before) and then the signal sticks high or low for a long period- I dont know exactly how long but I suspect its minutes more than seconds. It wont pick up a lambda fault if the probes never start switching in the first place as it never turns the control circuits on and just carries on in open loop happily. I think this stops it flagging errors for cold probes that are not switching. There are fault codes for misfires but I really dont know how the ECU will log these as the lambda control is not precise enough to pick up say one plug misfiring. The lambda control is switched off above 3400 rpm, (open loop) BUT at that point the mixture should be rich enough for both lambdas to stop switching and read somewhere over 1 volt constantly.
My apologies for not posting.I I took the plugs out last weekend and took some photos . Can't upload from my Iphone so will do when back home this weekend. I actually found that the ignition leads ( that I bought from a well known clever TVR supplier) are prone to breaking, and 2 had broken internally where they attached to the plug extenders.I dont need Magnacore performance, but wish I'd bought them now!
However after repairing the HT leads, the stagnation of the engine was fixed, but the engine is still uneven and hesitates while running between 2000 to 3500 rpm. Feels like someone is pulling the handbrake ever so slightly every few seconds.Over 4000 rpm the engine revs as normal and power returns.
The rotor arm is not Lucas but the Dizzy cap is. It seems an ignition problem , but then again .....lol
However after repairing the HT leads, the stagnation of the engine was fixed, but the engine is still uneven and hesitates while running between 2000 to 3500 rpm. Feels like someone is pulling the handbrake ever so slightly every few seconds.Over 4000 rpm the engine revs as normal and power returns.
The rotor arm is not Lucas but the Dizzy cap is. It seems an ignition problem , but then again .....lol
Plug Pix, 1/3/5/7
Dodgy Leads, the connectors were breaking when separated from the plug extenders. pi$$ poor quality,
dont buy these from the clevor supplier.
The leads were repaired, fixed the stagnation, but problem still exists, not that im surprised!
Dodgy Leads, the connectors were breaking when separated from the plug extenders. pi$$ poor quality,
dont buy these from the clevor supplier.
The leads were repaired, fixed the stagnation, but problem still exists, not that im surprised!
Edited by chris2002hk on Sunday 19th February 15:20
Edited by chris2002hk on Sunday 19th February 15:21
Its a little difficult to tell as the insulators are not fully visible on all the plugs, but the one on the left looks pretty perfect, although the ones that have purely white insulators could be running hot / lean. None of them look sooted up enough to be the ECU mis interpreting the exhaust gas content due to a bad misfire below 3400 rpm in closed loop. Its needs a bit of a rethink.
To get full power you need:
A good spark at the right time.
The required amount of fuel
The full amount of air getting into the combustion chamber
As I understand it you cant get much more than 4000 rpm under load out of the engine? If its a genuine lean mixture causing this the ECU mate will show the lambda voltage drop to 0 volts and stay there when the issue occurs, (is this the case?) but there are other things to consider. Is the engine starved of air- has the inlet ducting collapsed? Is the ignition timing advancing as it should as the RPM rises- this can be checked with a simple strobe test on the timing marks.
Generally on HT voltages, the voltage needed to ignite the mixture changes quite considerably depending on the amount of air and fuel going into the engine. You need higher HT voltages at wider throttle openings, so if the coil or ignition is poor it will fail when you ask more of it. The coil should produce around 35 kilovolts peak, but normally you wont ever get this high as the plug fires long before this point is reached, so the voltage stops rising once the plugs starts arcing. You can however as a rough test disconnect the king HT lead from the distributor cap, and pull back the rubber cap to expose the connector. Then carefully tape the lead so you have a a 10mm gap between the connector and the chassis and get someone to turn the engine over, having unplugged the injectors or pulled the fuel pump or main relay out. A good coil spark should jump a gap at least 10mm, and ideally 15mm if its really good.
To get full power you need:
A good spark at the right time.
The required amount of fuel
The full amount of air getting into the combustion chamber
As I understand it you cant get much more than 4000 rpm under load out of the engine? If its a genuine lean mixture causing this the ECU mate will show the lambda voltage drop to 0 volts and stay there when the issue occurs, (is this the case?) but there are other things to consider. Is the engine starved of air- has the inlet ducting collapsed? Is the ignition timing advancing as it should as the RPM rises- this can be checked with a simple strobe test on the timing marks.
Generally on HT voltages, the voltage needed to ignite the mixture changes quite considerably depending on the amount of air and fuel going into the engine. You need higher HT voltages at wider throttle openings, so if the coil or ignition is poor it will fail when you ask more of it. The coil should produce around 35 kilovolts peak, but normally you wont ever get this high as the plug fires long before this point is reached, so the voltage stops rising once the plugs starts arcing. You can however as a rough test disconnect the king HT lead from the distributor cap, and pull back the rubber cap to expose the connector. Then carefully tape the lead so you have a a 10mm gap between the connector and the chassis and get someone to turn the engine over, having unplugged the injectors or pulled the fuel pump or main relay out. A good coil spark should jump a gap at least 10mm, and ideally 15mm if its really good.
The colouration around the insulators is not even, and this Im told can be due to fouled injectors where the fuel does not atomise correctly and washes the carbon of the insulator, so first thing is to put some injector cleaner in the fuel. This however is not the reason for such a major loss of power. Two of those plugs are really lean / hot , so you need to take another reading with the ECU mate at over 3600 rpm of the Lambda voltages. If they are 0 volts on both sides you have a fuel delivery problems, such as blocked fuel filter, faulty fuel pump, or faulty pressure regulator. The ECU can make some huge corrections in fueling below 3600 rpm, and may mask the basic fault, so this is why you need to get the ECU in open loop at over 3600 rpm.
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