timing procedure error??

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timing procedure error??

Postby tedtaylor » Tue 28.03.2017, 17:17

I just went through the process for setting the timing. I've never touched it all these past 5 years of ownership.
I followed the Wiki repair section here on LEC and noted an error. The author reports that the "adjustment" to set timing on the CAS required a 6mm hex wrench which is INCORRECT. That wrench is used to replace the hall sensor. The actual adjustment of the CAS is the large housing or body and that is attached with a 12mm hex head bolt. Correct?

Here's what i did: Marked 16 degree mark "white" on the scale. Marked white the "v" notch on pulley. Warmed up to temp, shut off all electrical devices, steering wheel centered, timing light to #1 lead, paperclip to service mode, revved engine slowly up above 2000RPM and back down slowly, found timing at 14 degrees, adjusted CAS body up slightly to 16 degrees. Rechecked, everything OK.

So i have a couple questions:
1) The cycling of Revs slowly up to 2000 RPM and slowly back down to idle. The author mentioned something about this process resetting something?? I have no idea what that is? What does this rev procedure actually do?
2) should the timing mark on pulley fluctuate slightly up and down a degree while checking with the strobe? Was never completely smooth stroking exactly on the same degree mark.
3) my idle (using dash RPM gauge) is 1000 RPM. What is recommended setting? How do you adjust RPM? What should RPM be when checking timing?

Thanks!
TED
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Re: timing procedure error??

Postby Giniw » Tue 28.03.2017, 18:08

IIRC it's indeed a hex wrench but ... not really sure about that.

1) The 2000rmp/idling cycling is supposed to ensure the engine will idle properly at its nominal RMP (which is 950 RPM on the turbo when the engine is warm)
2) Mine fluctuates just a little, mostly steady but from time to times it flickers just a bit. I have read that someone here had a rock steady mark.
3) 1000RPM is a tad high. It should be 950 on a turbo (+- 50 IIRC). The RPM is adjusted by the Idle Air Control (IAC) which is controlled by the ECU. There is an adjustable screw but there should be no need to adjust it in normal operations*. I don't think the RPM while setting the base timing is relevant since you are supposed to set the ECU in diagnostic mode with a paperclip while doing it, and the ECU forces the advance to be 16° BTDC (hence the 16° you should read at the flywheel)

*When:
- base the timing is set correctly to 16°,
- the engine is warm,
- there is no air leak in the intake plenum
- the IAC is checked to be actually moving (see workshop manual) and it's totally closed
- ? (maybe I forgot something ^^)
=> then you might need to turn that idle screw to adjust the idling RPM.
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Re: timing procedure error??

Postby dapinky » Tue 28.03.2017, 18:50

Ted,

Perhaps the Wiki needs amending to reflect the fact that some cars have a 6mm allen-headed setscrew, and others have a hex-head one (I've had both on various cars).
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Re: timing procedure error??

Postby steve matthews » Tue 28.03.2017, 19:30

Ted, make sure your throttle cable is free and not causing the increased RPM. Adjust as said above at the IAC valve. You should have a little cover cap on the screw.

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Re: timing procedure error??

Postby tedtaylor » Wed 29.03.2017, 00:51

Giniw wrote:3) 1000RPM is a tad high. It should be 950 on a turbo (+- 50 IIRC). The RPM is adjusted by the Idle Air Control (IAC) which is controlled by the ECU. There is an adjustable screw but there should be no need to adjust it in normal operations*.
- the IAC is checked to be actually moving (see workshop manual) and it's totally closed


Is the IAC the screw on the right end of the intake plenum? there's two round cylinder features there, one is capped off, the other rearmost has a screw. Mine is 1 1/2 turns out. when i screw it closed, the RPM comes down closer to 950RPM. I don't have a shop manual to go by. Let me know.
TED
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Re: timing procedure error??

Postby Giniw » Wed 29.03.2017, 01:14

The workshop manuals are available in Brit-Car-Nut signature (eg viewtopic.php?f=18&t=12980&p=328921#p328919)

The screw you turned is probably the one I talked about when I was referring to the idle speed screw base setting which shouldn't be altered unless you have good reasons to do it.
The IAC is behind the engine, beneath the plenum, between the engine and the firewall. Not very easy to inspect but it's not a common fault so it should be OK. Again, I would check the advance, look for any intake leaks, check the IAC is actually moving (the procedure is in the manual, you don't have to remove it, just to unhook it electrically).

The problem if you just turn the screw is that it might hide some other problems by compensating.
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Re: timing procedure error??

Postby tedtaylor » Wed 19.04.2017, 14:52

just follow up report...
The timing has been set, but my RPMs at idle are 1,000 not 950. I don't know how to adjust the throttle body and don't want to mess anything up. The manuals are not clear on this at all.
What i did do was add Techron to a fresh tank of gas to clean out the injectors. WOW, what a difference! The car is running excellent, zooty, peppy, and smooth. I'm very pleased. I think i'll just leave well enough alone! :)
TED
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Re: timing procedure error??

Postby lotusflasherman » Wed 19.04.2017, 18:22

tedtaylor wrote:just follow up report...
The timing has been set, but my RPMs at idle are 1,000 not 950. I don't know how to adjust the throttle body and don't want to mess anything up. The manuals are not clear on this at all.
What i did do was add Techron to a fresh tank of gas to clean out the injectors. WOW, what a difference! The car is running excellent, zooty, peppy, and smooth. I'm very pleased. I think i'll just leave well enough alone! :)


That's because idle speed is controlled by the ECU as Giniw said further up this thread. Bit of a clue in the Technical Data ... "electronically controlled" means 'you don't do it' ... :lol:

idle.JPG


Wondering how you know it's at 1,000 rpm. Mine runs with the top of the needle on the bottom of the 1000 rpm line so looks very close to 1,000 but Elanscan tells me it's spot on 950 rpm.

If you are running at 1,000, have you got the Anti-Tamper Plug on the Throttle By-Pass Screw fitted? Item 54 in picture ... they do have a habit of 'going walkabout'...

throttle.JPG


Without it there can be some leakage on the engine side of the throttle causing a slightly faster idle speed that the ECU can't compensate for.
If it's not there, try putting your thumb over the hole and see if there's a bit of suction and if idle speed slows a bit...
I just use a small blind grommet, trimmed a bit to replace the proper one.
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Re: timing procedure error??

Postby tedtaylor » Wed 19.04.2017, 23:30

Phil,
i'm only going by the RPM dial on the dashboard gauge, not a separate instrument. I don't have ElanScan to check it with either.
I do NOT have the plug, so i will check to see if it is not sealed or if it is sucking air.
Question: what position is the screw in? closed? 1/4 turn open?? what is the setting?
TED
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Re: timing procedure error??

Postby lotusflasherman » Thu 20.04.2017, 03:26

tedtaylor wrote:Phil,
i'm only going by the RPM dial on the dashboard gauge, not a separate instrument. I don't have ElanScan to check it with either.
I do NOT have the plug, so i will check to see if it is not sealed or if it is sucking air.
Question: what position is the screw in? closed? 1/4 turn open?? what is the setting?


Don't know, never touched it on any of the 3 SE's I've owned. I've run my engine with Elanscan recording data and the graph of idle speed is a flat line at 950 rpm with occasional 'sags' slightly below until I remove that plug and then I still get 950 rpm but with frequent spikes to 975 & 980. There is only a very slight suction on mine so the ECU is able to compensate but it's having to work at it. Replaced the plug (grommet) and spikes have gone.

Tomorrow I'll run my engine and take a photo of my revcounter needle when Elanscan tells me it's at 950 rpm. If I show you how close to the 1,000 rpm line my needle is you may decide you don't have a problem ...
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Re: timing procedure error??

Postby lotusflasherman » Thu 20.04.2017, 11:54

Ted,
Connected Elanscan and started car to take photos as promised and noted idle speed was 1000rpm when cold and drops to 950rpm as it warms up, which it did while I sorted out phone for photos.

Photo of Elanscan screen on laptop at 950 rpm Engine Speed (ringed in red).

IDLE SCAN.jpg


and dashboard tacho' immediately after, engine still at 950rpm but looks very much like it's showing 1,000 !
Yesterday the needle was slightly lower when at 950 rpm, similar to the Elanscan onscreen 'tacho', but that variation is not something I'm going to worry about it...

Think it's called "Engineering Tolerance", and I'm an engineer so I'll tolerate it ... :lol:

idle speed.jpg


Hope that helps ...
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Re: timing procedure error??

Postby tedtaylor » Tue 25.04.2017, 23:30

thanks for posting that Phil.
TED
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