LS Engine Problems
Discussion
Guys
Due to a serious engien problem on my crate LS3/480 i have been unable to attend my IVA test.
To say im P****d off is the biggest understatement ever.
Does onyone on this here forum know any LS engine specialists that can visit my poorly motor and diagnose the issue.
The problem thus far is:
Engine has been started and mapped on dyno.
Engine was lumpy and gave a max of 505hp, according to the guys doing this it was a poor result for the engine. as 530hp has been seen.
Since then the motor was dropped into the gtr, all sensor connected etc etc, however it now ticks over and revs for around 2 mins, then becomes extremely lumpy and goes into limp mode before shutting down completely.
With breather pipes and maf sensor connected on the engine it will not start.
We have conducted a compression test and all is ok, rocker covers removed all in order!
Things to note, if looking at the engine bay from the off side, the two banks towards the rear of the car cause the headers to glow cherry red very quickly, however the engine is runnign rich not lean.
All sensors have been checked, re checked, error codes have been checked only one present is a maf sensor error which we are aware of but not concerened as we dont believe this is the reason for the engine issues.
Anybody got any ideas, or had this issue, or know anyone i can turn to.
Due to a serious engien problem on my crate LS3/480 i have been unable to attend my IVA test.
To say im P****d off is the biggest understatement ever.
Does onyone on this here forum know any LS engine specialists that can visit my poorly motor and diagnose the issue.
The problem thus far is:
Engine has been started and mapped on dyno.
Engine was lumpy and gave a max of 505hp, according to the guys doing this it was a poor result for the engine. as 530hp has been seen.
Since then the motor was dropped into the gtr, all sensor connected etc etc, however it now ticks over and revs for around 2 mins, then becomes extremely lumpy and goes into limp mode before shutting down completely.
With breather pipes and maf sensor connected on the engine it will not start.
We have conducted a compression test and all is ok, rocker covers removed all in order!
Things to note, if looking at the engine bay from the off side, the two banks towards the rear of the car cause the headers to glow cherry red very quickly, however the engine is runnign rich not lean.
All sensors have been checked, re checked, error codes have been checked only one present is a maf sensor error which we are aware of but not concerened as we dont believe this is the reason for the engine issues.
Anybody got any ideas, or had this issue, or know anyone i can turn to.
- ***** *****, insist this is an install issue and will do nothing further to assist until i can prove an engine problem exists.
Edited by Mjpmark on Thursday 15th July 14:01
Edited by Stig on Friday 16th July 10:44
I don't know where you are in relation to them, and they won't go to you but :
http://www.monkfishperformance.co.uk/
Do a lot of work for us chaps over on the HSV section.
They'll know their way round the LS engines pretty well.
http://www.monkfishperformance.co.uk/
Do a lot of work for us chaps over on the HSV section.
They'll know their way round the LS engines pretty well.
Were being reliably informed that thi sis due to the cam, and air temp in and around the clip.
During mapping we have a big fan feeding cold air to the engine, it runs fine. Put it into the GTR and it hates the setup.
Ive got a guy coming to look at the mapping. ealry next week.
Standard ls3 works fine on my setup and install. however the more aggressive gm cam will not.
During mapping we have a big fan feeding cold air to the engine, it runs fine. Put it into the GTR and it hates the setup.
Ive got a guy coming to look at the mapping. ealry next week.
Standard ls3 works fine on my setup and install. however the more aggressive gm cam will not.
Not sure where you are based, but this name has come up a lot on here, and if guys on here had work done by him then that would be good enough for me.
http://www.charlesdunn.uk.com/
Good luck mate.
http://www.charlesdunn.uk.com/
Good luck mate.
The symptoms are very indicative of retarded timing. The interesting part is that only 2 cyls are affected. I would carefully check the following.
Coil pack connector wires - It is possible to have two of them switched around.
Also check that the coil pack harness wiring is correct. Below are the wire colours of the unique wire in each coil plug.
GM Ignition Coil Wiring LS7 - Control Pack Wiring
Ignition Coil Control (Pin # C)
1 Purple
2 Red
3 L-Blue
4 L-Green
5 L-Green
6 L-Blue
7 Red
8 Purple
Coil pack connector wires - It is possible to have two of them switched around.
Also check that the coil pack harness wiring is correct. Below are the wire colours of the unique wire in each coil plug.
GM Ignition Coil Wiring LS7 - Control Pack Wiring
Ignition Coil Control (Pin # C)
1 Purple
2 Red
3 L-Blue
4 L-Green
5 L-Green
6 L-Blue
7 Red
8 Purple
I installed the Ls376/480 engine in my Aspira. The engine as it stood could not be mapped on its standard Gm plug and play ECU to meet emissions.
We attempted this IVA emissions test 3 times. RapidGB and ANother could not Map this on EFIlive and was way over on a ceratin aspect of the test. The UK importer stopped promoting this engine as Euro whatever compliant last year due to the hot cam.
However we did manage to get this engine through with piggy back software on GMplug and play and an engineer "IVA present with laptop"
I now have 540bhp on this engine without mods except air intake and exhaust.
exact same issues as me to start with that cost me months!!!
pm me
oh yes and cancel mapping man for now, unless he has a magic wand........ :-)
as it happens, i am out tomorrow with a guy sitting aside me with a laptop (weather permitting) to fine road tune as this still hasnt been done yet....
We attempted this IVA emissions test 3 times. RapidGB and ANother could not Map this on EFIlive and was way over on a ceratin aspect of the test. The UK importer stopped promoting this engine as Euro whatever compliant last year due to the hot cam.
However we did manage to get this engine through with piggy back software on GMplug and play and an engineer "IVA present with laptop"
I now have 540bhp on this engine without mods except air intake and exhaust.
exact same issues as me to start with that cost me months!!!
pm me
oh yes and cancel mapping man for now, unless he has a magic wand........ :-)
as it happens, i am out tomorrow with a guy sitting aside me with a laptop (weather permitting) to fine road tune as this still hasnt been done yet....
Edited by craig7l on Thursday 15th July 20:30
Limp mode/Shutdown - O2 sensors working overtime and pouring fuel into the engine?
"With breather pipes and maf sensor connected on the engine it will not start" - Does that mean you're unplugging the breather pipes and allowing tons of air into the manifold to get it runnng?
Cherry red - if yes to the above that's your problem (effectivly a manifold air leak) if not then I'd lean towards the leads on the wrong coil packs.
MAF Sensor error - why would you have one on such a new engine? eitherway, unplug it and the ECU should go into SD mode and ignore the MAF anyway.
You need someone with EFILive and log a start/run sequence (log STFT's/LTFT's to see what's happening with fueling).
Rgds
Jim
"With breather pipes and maf sensor connected on the engine it will not start" - Does that mean you're unplugging the breather pipes and allowing tons of air into the manifold to get it runnng?
Cherry red - if yes to the above that's your problem (effectivly a manifold air leak) if not then I'd lean towards the leads on the wrong coil packs.
MAF Sensor error - why would you have one on such a new engine? eitherway, unplug it and the ECU should go into SD mode and ignore the MAF anyway.
You need someone with EFILive and log a start/run sequence (log STFT's/LTFT's to see what's happening with fueling).
Rgds
Jim
Edited by Happy Jim on Thursday 15th July 21:19
Edited by Happy Jim on Thursday 15th July 21:20
EFI live is s
t (IMHO of course)its clue is in its name...in fact it isnt a live system..each change takes 30secs..? to make, then a reboot and its always fighting to make its way home.
you need to pay a license fee and a decent base map as a starting point.....to go nowhere.....
forget tuning this engine with EFIlive to get anywhere near emission compliant.....
the Ls376/480 GMplug and play ECU is made from the same ingredients as homer simpsons famous cocktail "the flaming mo"
t (IMHO of course)its clue is in its name...in fact it isnt a live system..each change takes 30secs..? to make, then a reboot and its always fighting to make its way home.you need to pay a license fee and a decent base map as a starting point.....to go nowhere.....
forget tuning this engine with EFIlive to get anywhere near emission compliant.....
the Ls376/480 GMplug and play ECU is made from the same ingredients as homer simpsons famous cocktail "the flaming mo"
Edited by craig7l on Thursday 15th July 22:43
Mjpmark said:
- ***** *****, insist this is an install issue and will do nothing further to assist until i can prove an engine problem exists.
- ***** ***** know full well the issues with this engine....crap ecu base map........hot cam not emission compliant......
Edited by Stig on Friday 16th July 10:46
jschwartz said:
That cam in the LS3 480 has the wrong lobe separation to meet emissions, change the cam to a stock LS7 cam, retune it and you will be ok. And you'll still make about 500 hp.
X2 Mark !!Also, when using the e67 ECU with anything much over a stock cam, the software is so complex you end up turning off some of the tables and inputting bogus data just to get the motor to idle and warm up properly. Otherwise the Fly-by-wire throttle and ignition timing chase each other around so much that frequently the ECU throws its hand in and usually the throttle body stops responding. Im sure in very experienced hands all the E67/hot cam issues could be resolved but it seems a very time consuming and costly process as each time you make an adjustment you have to re-flash it over to the box.
Personally I think there are several alternative user-friendly ECU/software packages out there for non-stock LS builds.
Its a shame this combo continues to be sold if its not plug and play, which Im sure most customers assume ?
rgds.
x3 Mark
We have been suffering this problem together and we have decided to swop this awful cam for a standard LS3 one...... to gain the IVA pass.
738 called this 6 months ago stating the cam has much too much overlap and not enough duration!! this showed up on the dyno as well with a very rich factory map and poor results, im annoyed that GM still supply this donkey for guys who are trying to gain an IVA pass!!
We have been suffering this problem together and we have decided to swop this awful cam for a standard LS3 one...... to gain the IVA pass.
738 called this 6 months ago stating the cam has much too much overlap and not enough duration!! this showed up on the dyno as well with a very rich factory map and poor results, im annoyed that GM still supply this donkey for guys who are trying to gain an IVA pass!!
The problem is emissions and the gm ecu. NOT AN AWFUL CAM.
After IVA this set up can be made AF constant, and tuned reliable and drivable. My dyno shows 538bhp.
At IVA it was obviously emission compliant ;-)
i nearly said yes to a cam change, which would have been around £3000 with omex610 as was frigged off with GMecu. welcome to my world last sept/oct/nov :-)
After IVA this set up can be made AF constant, and tuned reliable and drivable. My dyno shows 538bhp.
At IVA it was obviously emission compliant ;-)
i nearly said yes to a cam change, which would have been around £3000 with omex610 as was frigged off with GMecu. welcome to my world last sept/oct/nov :-)
Edited by craig7l on Friday 16th July 09:15
It was increased inlet lift Capt C not more duration....
Craig Im certain that cam can be made to work but to allow the stock ecu/FBW combo to be used I considered a cam with increased inlet-bias would be a solution. Having tried this with success (Mr Hodge) it proved what confusion is caused in the common inlet at low rpm when running an upgraded cam. Just by smoothing out the inlet pulses a little at low rpm allows use of the stock GM components and the software seems to cope well!
Craig Im certain that cam can be made to work but to allow the stock ecu/FBW combo to be used I considered a cam with increased inlet-bias would be a solution. Having tried this with success (Mr Hodge) it proved what confusion is caused in the common inlet at low rpm when running an upgraded cam. Just by smoothing out the inlet pulses a little at low rpm allows use of the stock GM components and the software seems to cope well!
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