Engine diagnostics ...
Discussion
My car (ZL1) has got a horrible flat spot on the power delivery where the car suffers considerable lag when flooring it at low speeds. Can anyone recommend a good garage that will perform a dyno check or some form of engine diagnistics to find out what the problem is ... and then fix it?
Tappers said:
My car (ZL1) has got a horrible flat spot on the power delivery where the car suffers considerable lag when flooring it at low speeds. Can anyone recommend a good garage that will perform a dyno check or some form of engine diagnistics to find out what the problem is ... and then fix it?
Is it not still under warranty?The ZL1's have not been out too long and im sure they came with a 5 year warranty.
Yes it is still under warranty but I don't trust the mechanics at Chevrolet to look into a problem that could potentially be their liability. I thought I would seek some specialist independent advice first to establish what the problem is and then make a decision on how to proceed once I understand the cause.
Tappers said:
Yes it is still under warranty but I don't trust the mechanics at Chevrolet to look into a problem that could potentially be their liability. I thought I would seek some specialist independent advice first to establish what the problem is and then make a decision on how to proceed once I understand the cause.
Maybes just pop into chevy and get them to do a diagnostic only, they cant mess it up plugging the computer in, then at least once you know the problem can decide where to take it.Could potentially be belt slip on the supercharger, does it have an engine warning light on?
After_Shock said:
does it have an engine warning light on?
No there's no warning light on. It doesn't feel as though there's a mechanical problem with the engine as such - it just has terrible lag at low speed (like a severe turbo lag). You can put your foot down at 40kmh and literally nothing happens until the car changes down a gear .... upon which it goes off like a scolded cat. It's fine at higher speeds but with 580bhp it ought to have power everywhere - it does have a supercharger so I'm wondering whether this isn't working properly.I will do as suggested and get Chevrolet to look at it in the first instance - thanks.
Tappers said:
No there's no warning light on. It doesn't feel as though there's a mechanical problem with the engine as such - it just has terrible lag at low speed (like a severe turbo lag). You can put your foot down at 40kmh and literally nothing happens until the car changes down a gear .... upon which it goes off like a scolded cat. It's fine at higher speeds but with 580bhp it ought to have power everywhere - it does have a supercharger so I'm wondering whether this isn't working properly.
I will do as suggested and get Chevrolet to look at it in the first instance - thanks.
The superchargers themselves are basically bomb proof so it would be highly unlikely to be an internal issue with that. However the belts/pulleys do tend to give some issues, especially the one that runs to the engine crank. I had several belt related issues on LS2 engined cars in the UK over 5 years, I can only assume with the heat here it will be worse with rubber belts.I will do as suggested and get Chevrolet to look at it in the first instance - thanks.
However as shirt says it sounds a bit odd with the kick down, you are right the LS engine supercharged has power everywhere, I only had manuals in the UK but if you put it in manual and hold say 2nd gear see if the power works from low speed.
If no warning light on the computer may well not be recording a fault, which would point to something without a sensor on it i.e belts/pulleys. Try not to drive it too hard as if it is and one slips off you could end up with a broken engine/supercharger.
Key sympton is as follows:
Car is automatic and running in 3rd gear at say 30kmh, slam foot to the floor. Literally nothing happens for 2-3 seconds (car stays at same speed) as though the engine is holding back. Car detects foot down hard so drops a gear ... then it's off like the proverbial. Big problem when trying to overtake as 2-3 seconds can be a lifetime.
If you floor it from a standstill it's fine ... no lag just pulls like a train.
It's also ok if you hold it in gear - it's definitely associated with the kickdown. Forgive my ignorance as I'm not mechanically minded, but does this mean it's likely to be an engine issue or something associated with the gearbox?
Car is automatic and running in 3rd gear at say 30kmh, slam foot to the floor. Literally nothing happens for 2-3 seconds (car stays at same speed) as though the engine is holding back. Car detects foot down hard so drops a gear ... then it's off like the proverbial. Big problem when trying to overtake as 2-3 seconds can be a lifetime.
If you floor it from a standstill it's fine ... no lag just pulls like a train.
It's also ok if you hold it in gear - it's definitely associated with the kickdown. Forgive my ignorance as I'm not mechanically minded, but does this mean it's likely to be an engine issue or something associated with the gearbox?
Tappers said:
It's also ok if you hold it in gear - it's definitely associated with the kickdown. Forgive my ignorance as I'm not mechanically minded, but does this mean it's likely to be an engine issue or something associated with the gearbox?
Has it always done this or just recently? I know in the UK a lot of people who had the auto LS powered cars were getting the boxes re-mapped due to them being a bit slow witted. But 2-3 seconds is way too long.I am not sure that it helps but I had the exact same on a Subaru SVX that I owned back in Oz.
Put foot down and nothing....nothing....nothing then BAM and off it went. I also described as akin to massive turbo lag.
Turns out there was a crack in an air intake pipe at a flex joint. Under normal driving or acceleration at a constant rate it was fine but under sudden acceleration, the pipe flexed, crack opened up and then the above happened.
Took the owner after me to find the cause and after no end of diagnostics, dealership visits etc.
Put foot down and nothing....nothing....nothing then BAM and off it went. I also described as akin to massive turbo lag.
Turns out there was a crack in an air intake pipe at a flex joint. Under normal driving or acceleration at a constant rate it was fine but under sudden acceleration, the pipe flexed, crack opened up and then the above happened.
Took the owner after me to find the cause and after no end of diagnostics, dealership visits etc.
seems its quite common
http://www.camaro5.com/forums/showthread.php?t=364...
check the vacuum hose but if not its a case of 'they all do that sir' and your solution is an aftermarket remap.
http://www.camaro5.com/forums/showthread.php?t=364...
check the vacuum hose but if not its a case of 'they all do that sir' and your solution is an aftermarket remap.
- ***********Disclaimer I am not mechnically minded whatsoever!*******************
I reckon it could be as simple as reflashing it with a more aggresive gearbox mode, I'd imagine there must be handheld tuners with stock (non OEM) maps out there for these by now.
Only issue will be the dealer will probably flash it back to stock when it's serviced, I was pretty honest that mine had been done, even when under warranty and as long as I told them they kept the aftermarket tune on, they knew it had been played with anyway as the air filter is the size of a small dog.
shirt said:
seems its quite common
http://www.camaro5.com/forums/showthread.php?t=364...
check the vacuum hose but if not its a case of 'they all do that sir' and your solution is an aftermarket remap.
That's an interesting thread. I love the way it's suggested that it's for safety reasons. I've got a better solution ... if you don't want to unleash 580 ponies when you floor it ... buy the V6. Personally I was hoping for Armageddon so it's a bit disappointing to be momentarily outgunned by a Nissan Tilda!http://www.camaro5.com/forums/showthread.php?t=364...
check the vacuum hose but if not its a case of 'they all do that sir' and your solution is an aftermarket remap.
Edited by Tappers on Sunday 10th May 15:06
dxbtiger said:
*************Disclaimer I am not mechnically minded whatsoever!*******************
I reckon it could be as simple as reflashing it with a more aggresive gearbox mode, .
Now this is my sort of mechanics ... I need a widget type thingy to make the gearbox more aggressive then it'll kick down quicker and go like a stabbed rat.I reckon it could be as simple as reflashing it with a more aggresive gearbox mode, .
Tappers said:
Now this is my sort of mechanics ... I need a widget type thingy to make the gearbox more aggressive then it'll kick down quicker and go like a stabbed rat.
Will be a number of maps available for these for the gearbox, the VXR8s back in the UK use basically the same box from memory and owners were getting great results from maps for the box.Tappers said:
That's an interesting thread. I love the way it's suggested that it's for safety reasons. I've got a better solution ... if you don't want to unleash 580 ponies when you floor it ... buy the V6. Personally I was hoping for Armageddon so it's a bit disappointing to be momentarily outgunned by a Nissan Tilda!
i love the post where the guy has to tell people that remapping the transmission software won't provide a power gain. gotta love the yanks and makes it all the more obvious why chevy et al have the ECU make the decisions. same thing on the raptor according to sam, it won't let you have full throttle under a certain threshold. he's got a map to sort the ford v8, has to be options out there for the chev.
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