VTS, poor idling on catcam 708

24th August 2013, 20:26

2000 VTS, 708s, 4 branch manifold, standard ecu.

Mates VTS AX on 708s, timed to standard marks. Idle is pretty bad,hunting quite a bit. Tried to retard the exhaust cam but if anything it seemed to make the idle worse.

Any ideas?

24th August 2013, 20:28

Quote:

Originally Posted by Gabbastard

2000 VTS, 708s, 4 branch manifold, standard ecu.
Mates VTS AX on 708s, timed to standard marks. Idle is pretty bad,hunting quite a bit. Tried to retard the exhaust cam but if anything it seemed to make the idle worse.

Any ideas?

This...

24th August 2013, 20:48

IT needs a map, you FOOLS

Have you tried adjusting the inlet cam?

If retarding the exhaust cam made it worse, you're going the wrong way

24th August 2013, 20:56

Quote:

Originally Posted by MartinObviously

If retarding the exhaust cam made it worse, you're going the wrong way

As above, retarding the exhaust cam (or advancing inlet cam) will make combustion stability at idle worse, due to the increased overlap increasing internal EGR.

First steps would be to time them to catcams suggested settings and get the map looked at.

24th August 2013, 20:59

timing should be standard. Only needs playing with if you have throttlebodies. Map it basically. Its not meant to run without

24th August 2013, 21:03

I must have misread on here as im sure someone said to retard the exhaust to get the idle sorted. The mapping has been sorted by a Dastek, but they cant adjust anything idlewise.

24th August 2013, 21:17

I had 708's on mine and I retarded the exhaust slightly and it idled a lot smoother than on standard marks. Also mapped and dyno run at 155bhp so must have worked

24th August 2013, 21:37

no knowing the dastek very well, but im assuming that because it is a piggy back, the ICV is still retained?

24th August 2013, 21:46

Yeah thats right, ICV is retained but Dastek cant change any of the idle settings.

24th August 2013, 21:52

Try raising the idle a touch - there's a throttle stopper bolt you should be able to move. Sounds daft, but when remapping the standard ECU, the idle is usually raised electronically.

25th August 2013, 10:36

my first question would be "how well did it idle on std cams "
cos if it didn,t idle smooth on std cams --then you have other problems
as all these cars are 10year+ things wear ,like I am guessing you didn,t fit new lifters with the new cams +are they new?
cat went through a period when the grinds were not very accurate ,so you could end up with a "scatter cam"---maybe 6 years ago
which is one of the reasons for me getting my ow cams made --inconsisitancy of results on dyno.
.
is cam belt tension correct?
on older cars fitting a 4.5 fuel reg will cure idle porblems -stops the lambda swinging form rich to lean too quickly --also gives you extra fuelling above the closed loop area --so remap may not be needed .
but yes pulling cam forward on ex cam from std a few degrees usualy will make the idle better .assuming no other problems
is it single or 3 plug ecu?
what efr is it idling at
what is manifold pressure +is it stable ?

25th August 2013, 10:39

Quote:

Originally Posted by Liam_

Try raising the idle a touch - there's a throttle stopper bolt you should be able to move. Sounds daft, but when remapping the standard ECU, the idle is usually raised electronically.

soory --yes that is daft as raising the idle can cause the steeper motor to stop working --tps should be no more that 0.65v ,no less than 0.5v for a std ecu ,could even be a dodgy tps sensor
I notice its a transplant job --check voltage to injectors --old looms = poor main power feeds
If voltage on injector supply drops more than 1v on revving it --then you have supply probs ,should be over 12v at idle ==could be 13+ dependoing on alternator duty at time --which can do all sorts of things
i,ve seen cars at 2 years old with this problem --never mind 10+.
bad earthing can cause the same ,so triple check all these

25th August 2013, 11:53

Thanks John.

Car ran perfectly on standard cams. Car has had a full Saxo loom transplanted, using a single plug ECU. New lifters too. But its interesting what you say about the scatter cams, as these are older 708s and would fall into the age range you describe. I recall someone else mentioning poor manufacturing tolerances with the catcams.

It has a 3.5bar FPR fitted already, prior to 708s being fitted and it ran ok.

Ive a Lexia reader handy, Im assuming they can pull live data. If so, Ill connect that up to the car and check for manifold pressure etc.

No idea on AFR at idle though I have a wideband and gauge on the way so should be able to check that out soon.

Thanks all for the help so far.

25th August 2013, 14:32

you mean it ran perfectly in THIS car or the one it came from?

25th August 2013, 14:38

Yeah, the engine and loom -completely standard- was removed from a Saxo, and put in the AX. Everything ran perfectly. I then changed the cams to 708s, idle became terrible.

Its putting me off putting in the Piper cams I have for mine now haha

25th August 2013, 16:32

Quote:

Originally Posted by Gabbastard

Yeah, the engine and loom -completely standard- was removed from a Saxo, and put in the AX. Everything ran perfectly. I then changed the cams to 708s, idle became terrible.

Its putting me off putting in the Piper cams I have for mine now haha

man the fuck up, it's only a poor idle.

Why worry? unless it's stalling.

25th August 2013, 16:34

Well, at least its not my car! But Ill get a video. Its pretty effing lumpy lol

25th August 2013, 17:05

Maps probably poo who did it?

Shouldn't be too bad after a map my idle was raised when I had mine done too. Also i set mine to the timing recommendations you get given, had a little play about with them on the RR and found them to be the best.