Yet another problem...Any ideas??
Discussion
Right, took the Chim down to the rolling road again today and it ran fine this time despite being very lean when it first went on! The timing was checked and found to be spot on and the map was adjusted up to 3k revs to get the AFR up to its optimum. Then when it was run up to 5k revs something rather annoying happened... It got to around 3500 revs and the power dropped off and the AFR went rich, like the engine stopped needing fuel...
The guy at the dynos first thought was cam timing as it seemed like the cam shut up shop just after 4k revs and he'd had a car display exacty the same characteristics before. The cam has been changed from an original unit to an MC1 less than a year ago so perhaps it was never timed in correctly? The power graph returned is below (this was only running the base map tweeked to run correct AFR so the numbers are probably a little low). Does anyone have any suggestion what might cause this other than bad cam timing??
The graph shows 3 Chim runs: my one, a pretty highly tuned one (4L I think) which turned out to have bad cam timing, and a standard 4L.
The guy at the dynos first thought was cam timing as it seemed like the cam shut up shop just after 4k revs and he'd had a car display exacty the same characteristics before. The cam has been changed from an original unit to an MC1 less than a year ago so perhaps it was never timed in correctly? The power graph returned is below (this was only running the base map tweeked to run correct AFR so the numbers are probably a little low). Does anyone have any suggestion what might cause this other than bad cam timing??
The graph shows 3 Chim runs: my one, a pretty highly tuned one (4L I think) which turned out to have bad cam timing, and a standard 4L.
I had my Chim RR'd before I sold it - couldn't stop it pinking at high revs so had Mark Adams look at it. One of the issues turned out to be the air hose that feeds air from the filter to the Air Flow Meter. It had collapsed where it went through the front bodywork so at high revs (high air flow) it was 'sucking' itself closed and thus not enough air was getting to the engine, thus a drop in power. Might be this, might not be, but worth checking with the air hose disconnected if you get a chance.
Nope neither of these... Its got big bore ACT induction hose all the way up, a big throttle, big trumpets, AFM replacement pipe and k&n filter so isn't collapsing at all. Then it has full decat manifolds and y-piece with just twin cherrybombs at the back so can't be an exhaust blockage either!
Nick,
OK - I think there are two thing to check :
1) Fuel pressure - presumably you checked this before you started - most are set at 43 psi and this is in the Emerald software set-up.
2) You can check valve / cam set-up.. I'm not far from you if you want to borrow engine degree wheel / dial guage and stand (only needed if you want to measure lift..)
You need to mark the pulley wheel for TDC (piston at tdc .. to make sure its right) and another 2 making points at 111 degrees After TDC and 111 degrees before TDC.
Here is a cam table for reference (H214, H218, H224) all have the same (almost) set-up.
http://www.btinternet.com/~jon.wolfe/kentcamdata.h...
New turn over the engine and observe the value lift on no.1 cyl Exhaust should be fully open at 111 degrees TDC and Inlet fully open at 111 degrees after TDC.
Now - I've guessed 111 degrees but if it was one tooth out on the chain - it would be massively out.
You can get the exact set-up from V8 Developments.
PS. Taking the timing chain off aint easy or quick...
OK - I think there are two thing to check :
1) Fuel pressure - presumably you checked this before you started - most are set at 43 psi and this is in the Emerald software set-up.
2) You can check valve / cam set-up.. I'm not far from you if you want to borrow engine degree wheel / dial guage and stand (only needed if you want to measure lift..)
You need to mark the pulley wheel for TDC (piston at tdc .. to make sure its right) and another 2 making points at 111 degrees After TDC and 111 degrees before TDC.
Here is a cam table for reference (H214, H218, H224) all have the same (almost) set-up.
http://www.btinternet.com/~jon.wolfe/kentcamdata.h...
New turn over the engine and observe the value lift on no.1 cyl Exhaust should be fully open at 111 degrees TDC and Inlet fully open at 111 degrees after TDC.
Now - I've guessed 111 degrees but if it was one tooth out on the chain - it would be massively out.
You can get the exact set-up from V8 Developments.
PS. Taking the timing chain off aint easy or quick...
Edited by rev-erend on Wednesday 9th January 13:53
Hi Alan, thanks for the quick reply!
The fuel pressure is ok I think as after the power dropped off there was still plenty of fuel going in (the AFR jumped up and it started running rich). Some evidence of this was on the way home, if I took the car a bit above 3k revs (estimated due to no rev counter) and then backed off I would get a bit of overrun pop, but much louder than normal (almost embarrassing!) which I assume would be the unused fuel from higher up getting ignited in the exhaust.
So this brings it down to the cam timing I guess...
I'm not going to pretend I know much about this as it would be the first time i'd attempted such a thing. Getting to the timing cover doesn't look that hard, what else would be involved other than removing the exhaust downpipes, chassis member and crank pulley? I'll have a look at the bible in a bit to see if it has it... Once the cover is off though i'd be in unchartered territory - how easy/hard would you say this would be for me? i.e should I attempt it or should I take it to a garage? If you're close, do you think you'd be able to lend a hand one weekend on the tricky bits under the timing cover for some beer tokens or the like if I do attempt it myself? It sounds like I could probably do with having someone with a little experience on hand...
The fuel pressure is ok I think as after the power dropped off there was still plenty of fuel going in (the AFR jumped up and it started running rich). Some evidence of this was on the way home, if I took the car a bit above 3k revs (estimated due to no rev counter) and then backed off I would get a bit of overrun pop, but much louder than normal (almost embarrassing!) which I assume would be the unused fuel from higher up getting ignited in the exhaust.
So this brings it down to the cam timing I guess...
I'm not going to pretend I know much about this as it would be the first time i'd attempted such a thing. Getting to the timing cover doesn't look that hard, what else would be involved other than removing the exhaust downpipes, chassis member and crank pulley? I'll have a look at the bible in a bit to see if it has it... Once the cover is off though i'd be in unchartered territory - how easy/hard would you say this would be for me? i.e should I attempt it or should I take it to a garage? If you're close, do you think you'd be able to lend a hand one weekend on the tricky bits under the timing cover for some beer tokens or the like if I do attempt it myself? It sounds like I could probably do with having someone with a little experience on hand...
Yes - my money was on that too .. but always worth knowly the fuel supply is OK..
To get to the timing chain is a lot of work and all you want to do is check it's OK.. which is much easier..
To get to the timing chain most of the stuff on the front of the engine has to come off..
Water pump (new gasket needed), belt, crank pulley and anything else in the way .. then the cover can be removed.. and for all that - I think you are just looking for two marks to align ..
Pull of the manual here :
http://www.landrover.ee/est/varia/downloads/engine...
It could be that the cam is knackered .. if one of the valves is not opening properly - then unburnt fuel stays in the inlet manifold and makes the rest too rich.
I'd remove the rocker covers and check visually that all seem to open and close the same amount..
I would not be bothered with the timing chain until I'd done the easier check of the values and valve timing first.
WOuld love to come over but I'm sick as a dog with a bad cold at present.. have been since 21st Dec.. it's getting boring now.
To get to the timing chain is a lot of work and all you want to do is check it's OK.. which is much easier..
To get to the timing chain most of the stuff on the front of the engine has to come off..
Water pump (new gasket needed), belt, crank pulley and anything else in the way .. then the cover can be removed.. and for all that - I think you are just looking for two marks to align ..
Pull of the manual here :
http://www.landrover.ee/est/varia/downloads/engine...
It could be that the cam is knackered .. if one of the valves is not opening properly - then unburnt fuel stays in the inlet manifold and makes the rest too rich.
I'd remove the rocker covers and check visually that all seem to open and close the same amount..
I would not be bothered with the timing chain until I'd done the easier check of the values and valve timing first.
WOuld love to come over but I'm sick as a dog with a bad cold at present.. have been since 21st Dec.. it's getting boring now.
Hmm how could the cam be knackered?? It's been in less than a year and always looked after (valvoline VR1 Racing oil and very rarely left to idle). When it was done, it had new lifters and a new timing chain - could it be that this has stretched or jumped a tooth somehow?
I'm sure I can manage getting to the timing cover then, would just need to drain the coolant I guess and check the marks. I think there's a good chance that it won't be done this weekend though. I'm going to have to leave it until at least next weekend so perhaps you'll be better then..? I think you've probably got the same thing I had - just got over it after 3 weeks!
I'm sure I can manage getting to the timing cover then, would just need to drain the coolant I guess and check the marks. I think there's a good chance that it won't be done this weekend though. I'm going to have to leave it until at least next weekend so perhaps you'll be better then..? I think you've probably got the same thing I had - just got over it after 3 weeks!
Thats the thing, it was running fine beforehand. I was just wondering if when it was running rough before the timing was set up it somehow managed to stretch the chain or something? I would have said it'd be something electrical but the timing is spot on with the crank sensor and everything and it runs and sounds fine now, everything works and talks to everything else... It just has this power loss!
If it was fine before then it's fine now.. problem is with what has been done.
Sorry.
Thinking about this - sounds like the signal at higher revs is a fault so some possibilies occur to me like :
Crank trigger signal at faster revs is poor..
Voltage compensation table has incorrect values (cannot remember what this does but might be worth checking the voltage of the engine and the table..
Are the fuel values in the fuel map around the load site (3K and above) reasonably near to each other ..
Do they jump up crazily ?
Sorry.
Thinking about this - sounds like the signal at higher revs is a fault so some possibilies occur to me like :
Crank trigger signal at faster revs is poor..
Voltage compensation table has incorrect values (cannot remember what this does but might be worth checking the voltage of the engine and the table..
Are the fuel values in the fuel map around the load site (3K and above) reasonably near to each other ..
Do they jump up crazily ?
When you drive it, can you feel the loss of power, than you had before.
Did you have the new cam corectly broken in, if not they can wear out very quickly.
It's not overly complex to get to the timming cover, just time comsuming, plus your need replacment gaskets.
As alan said would be best to take the rocker covers off to check the cam timing. You can then turn it by hand and make sure all the rockers have the same travel.
Leigh
Did you have the new cam corectly broken in, if not they can wear out very quickly.
It's not overly complex to get to the timming cover, just time comsuming, plus your need replacment gaskets.
As alan said would be best to take the rocker covers off to check the cam timing. You can then turn it by hand and make sure all the rockers have the same travel.
Leigh
TVRleigh_BBWR said:
When you drive it, can you feel the loss of power, than you had before.
Did you have the new cam corectly broken in, if not they can wear out very quickly.
It's not overly complex to get to the timming cover, just time comsuming, plus your need replacment gaskets.
As alan said would be best to take the rocker covers off to check the cam timing. You can then turn it by hand and make sure all the rockers have the same travel.
Leigh
Agreed but if it was OK before changing some electrics then the mechanicals have not changed.. so should be eliminated.Did you have the new cam corectly broken in, if not they can wear out very quickly.
It's not overly complex to get to the timming cover, just time comsuming, plus your need replacment gaskets.
As alan said would be best to take the rocker covers off to check the cam timing. You can then turn it by hand and make sure all the rockers have the same travel.
Leigh
Are you on the resisted plugs - they say that without them it causes problems..
I think Matt said he's ran bad with the non resisted and OK with..
RedTuscan said:
Oh for goodness sake, stop asking people to speculate - could it be this, could it be that......
It's a 10 year old car. If you want it to produce more than the current 180 weedy horsepower that the print out shows, then get it to a garage and get it diagnosed and repaired.
Thanks mate, thats really helpful...It's a 10 year old car. If you want it to produce more than the current 180 weedy horsepower that the print out shows, then get it to a garage and get it diagnosed and repaired.
The reason I was asking was to get some opinions on what to try as I do enjoy doing it myself though I lack a lot of experience. I've got some things to try and if I can't do it then i'll gladly take it to Dave Walker to sort out so I can get it back to more than '180 weedy horsepower'.
@ Alan & Leigh, yes its currently running resistive plugs and does feel massively down on power, i'll check over the map and the trig wheel pickup when I get a chance and see if I can diagnose the problem. After reading your posts and speaking to the guy that put the cam in, it does seem unlikely to be the cam or its timing. I will of course check it if nothing turns up on the electrical side but we shall see...
I'm going back to Brum now though so the car will sit in the garage until i'm next back. I'll let you know when it runs whether I do it or Mr Walker does!
Edit: Its not 180 Weedy horsepower, its 125 even weedier ones!
Edited by thenick on Wednesday 9th January 17:02
Tis time to get a scope on the ECU outputs to check that everything is as expected like crank trigger, coil dwell time etc etc etc. Dwell time problems will cause the graph you see as the coil can't recover and it effectively acts like a rev limiter.
How was the timing checked? The pulley marks are notoriously unreliable and I have also experienced a duff crank pulley where the marks moved and got progressively out of sync. Checked it with TDC from the cylinder. Set up the timing and then within seconds found it to be way out. Put a tippex mark right across the pulley and it split into two lines which gave away the problem. Covered in the appendix in the bible.
Also worth checking the obvious things like spark leads. A couple wrong can prevent it running. You can get away with lead problems with wasted sparks as there are two sparks and not one so in some cases a spark is pretty close. You don't necessarily get the very obvious missfire.
Apart from that it could almost be anything, including the ECU and its mapping software. Might be worth resetting the ECU and reloading it.
One final thing: how are the earths and power supply to the ECU? That can cause some interesting problems if there is a voltage drop. It can end up resetting the ECU and effectively giving you a rev limiter. It can also cause problems with the injector timing. Again, a scope is pretty useful - no essential - in seeing that the actual waveforms at injectors/coils etc are what you expect. Just because the ECU is saying the injector pulse is 5ms, it doesn't mean that it actually is.
How was the timing checked? The pulley marks are notoriously unreliable and I have also experienced a duff crank pulley where the marks moved and got progressively out of sync. Checked it with TDC from the cylinder. Set up the timing and then within seconds found it to be way out. Put a tippex mark right across the pulley and it split into two lines which gave away the problem. Covered in the appendix in the bible.
Also worth checking the obvious things like spark leads. A couple wrong can prevent it running. You can get away with lead problems with wasted sparks as there are two sparks and not one so in some cases a spark is pretty close. You don't necessarily get the very obvious missfire.
Apart from that it could almost be anything, including the ECU and its mapping software. Might be worth resetting the ECU and reloading it.
One final thing: how are the earths and power supply to the ECU? That can cause some interesting problems if there is a voltage drop. It can end up resetting the ECU and effectively giving you a rev limiter. It can also cause problems with the injector timing. Again, a scope is pretty useful - no essential - in seeing that the actual waveforms at injectors/coils etc are what you expect. Just because the ECU is saying the injector pulse is 5ms, it doesn't mean that it actually is.
Thanks for the ideas Steve, I set the timing by finding true TDC by taking out plug no.1 and measuring the piston's highest point on the compression stroke. I then moved the missing tooth round by 105 degrees and put this value into the software. Then just to be sure I put a timing light on it and it was dead on so I don't know how i'd get it any more accurate?
On the HT lead front, i've checked the connections several times and put in plastic spacers to ensure that no lead is touching another at any point. Its got B6 resistive plugs in at the moment which were in just until it was running to a reasonable level to prevent them becoming fouled and I have a set of new B7ECS' ready to go in when its all set up. The power supply to the ECU runs straight off the main relay and earths to the big earth that fed the old ECU. The whole thing earths through this including the sensors and lambda as it seemed to be a good connection. Would it be worth running it straight to the battery terminal?
The crank sensor green light has been on all the time the engine is running so it is picking up a good signal, i'll recheck this though and test all of the ECU connections to make sure there's nothing obvious. All connections have been soldered and heat wrapped to ensure good connectivity so I guess it's bound to be something trivial somewhere within the software or loom. Having said that, I have a feeling the problem will lie somewhere around the coils. If everything else is set up correctly and the fuel isn't going bang then surely that would dictate a problem with the spark? I'll have a look at the dwell time as you suggested and also at the power feed. Its running on the same one that powers the lambda and injectors so perhaps there is a voltage drop taking place. I'll test its input when running and maybe give it a direct battery feed and see if it makes a difference - It'll be a while before I can do any more work on it but i'll keep you posted on what I find...
Thanks again everyone for your input, i've already learnt a lot this year but it seems there's a hell of a lot still to learn! Despite not everything going to plan i'm still glad I did it, it'll kick ass when it's done
On the HT lead front, i've checked the connections several times and put in plastic spacers to ensure that no lead is touching another at any point. Its got B6 resistive plugs in at the moment which were in just until it was running to a reasonable level to prevent them becoming fouled and I have a set of new B7ECS' ready to go in when its all set up. The power supply to the ECU runs straight off the main relay and earths to the big earth that fed the old ECU. The whole thing earths through this including the sensors and lambda as it seemed to be a good connection. Would it be worth running it straight to the battery terminal?
The crank sensor green light has been on all the time the engine is running so it is picking up a good signal, i'll recheck this though and test all of the ECU connections to make sure there's nothing obvious. All connections have been soldered and heat wrapped to ensure good connectivity so I guess it's bound to be something trivial somewhere within the software or loom. Having said that, I have a feeling the problem will lie somewhere around the coils. If everything else is set up correctly and the fuel isn't going bang then surely that would dictate a problem with the spark? I'll have a look at the dwell time as you suggested and also at the power feed. Its running on the same one that powers the lambda and injectors so perhaps there is a voltage drop taking place. I'll test its input when running and maybe give it a direct battery feed and see if it makes a difference - It'll be a while before I can do any more work on it but i'll keep you posted on what I find...
Thanks again everyone for your input, i've already learnt a lot this year but it seems there's a hell of a lot still to learn! Despite not everything going to plan i'm still glad I did it, it'll kick ass when it's done
Edited by thenick on Thursday 10th January 10:44
Nick, coil 'on' time should be in the order of 3 - 3.5ms for most common specs I'm told. This is also the figure I got direct from the MSD tech guys so prolly a good place to start.
It does sound ign related to me, rather than mechanical.... you seem to have the static timing sorted but how is the advance set up? Anything odd going on in the software that coincides with where you think the problem arises?
It does sound ign related to me, rather than mechanical.... you seem to have the static timing sorted but how is the advance set up? Anything odd going on in the software that coincides with where you think the problem arises?
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