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Black EST 202 pinging so is it a CAS vac leak or the EGR

EYY

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Put a genuine bosch hei on it and never look back. Vac leaks won't have enough of an impact on timing to cause an issue (only part throttle advance is altered - total advance remains the same regardless. You don't need to have the vac advance hooked up if you graph it properly.

If it's running okay otherwise I'd be looking at fuel delivery - fuel pump, carby etc. Air leaks around the manifold are very common too. Your problem doesn't sound like it has characteristics of a failing ignition system. What sort of ignition module do they run with the EST?
 

1985VK

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Yeah she runs ok generally just get some engine rattle (don't know why they call it pinging) when warm under load on 95 and even 98 RON ... i will check her for a manifold leak.

The fuel pump was replaced recently. The carb throat is fairly clean so it doesn't seem to be running rich. I have seen some other varajets that are heavily sooted up and black as night ...
 

VK SL 3800

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I fiddled with mine a lot when i was an apprentice, the EGR system will block up and make it ping.
Remove the carbie and in the top of the manifold are two little bellows that the EGR flows into the manifold below, they are difficult to remove.

To test the EGR, run the engine and pull the valve open with your fingers. Its just a little diaphragm but its a little fiddly to get your fingers in the gaps. If the engine stumbles and drops to a near stall then the EGR ports arent clogged.

But,

What i discovered is that the ECM has a very poor spark timing map, cleaning the EGR out all but fix the problem on normal days but hot days over about 35 it will still ping, but in stages of throttle, so you could add more throttle and the ping will stop when the ECU sees the parameters to wind a bit more timing out. (Lower manifold vac mainly)
Its a very rudimentary ignition system, i would recommend ditching it for a Blue motor dizzy.
Its not adjustable in anyway, moving the Dizzy does not do anything. All it does is point the rotor button roughly at a plug lead and the ECM fires the coil.

About the only thing you could do is move the CAS so the ECM thinks the crank angle is a few more degrees closer to TDC then it is.

The only parts to the system are:
Throttle Position sensor - Open or closed throttle only, no actual position %
MAP sensor - located on the fusebox
CAS - Located on the rear of the head, Crank has only 3 pickups from memory.
Coolant Temp sensor
 

1985VK

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Thanks for that info, that's very helpful. Some have their EGR blanked off, so does that also contribute to pinging? Is it worth taking the EGR valve off and giving the ports a clean before taking the carbie off?
 
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VK SL 3800

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The Spark timing is setup to suit EGR, EGR is for Nox emission as you know.

What it does lowers peak combustion temp creating less Nox and therefore being cooler you can advance the timing further before getting pinging.
Without the EGR its hotter so you get the ping.
Majority of VK commodore 202s will have an electronic dizzy fitted so you can blank the EGR and adjust the timing to suit. (i recommend this).

I cant remember which VAC port you use, a blue varajet II has a specific port but a black one has the port blank. I dont believe that its just manifold vacuum.

You can pull the EGR valve off but you cant really get up in there to clean around under the carbie, and its rock hard carbon that wont come out just by spraying a bit of brake clean around.
 

1985VK

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Remove the carbie and in the top of the manifold are two little bellows that the EGR flows into the manifold below, they are difficult to remove.
I must admit i don't recall seeing that on the manifold ... i should take another good look ... in what way are how are they difficult to remove?
 

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They are stuck in, and not much to grab hold of to prise them out. I cant remember much how i got them out, close to 10 year ago since i had it apart.
 

gtrboyy

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Save yourself the headache & fit hei off blue motor....it was very common thing to do.

Unless it's already been done.
 

1985VK

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Save yourself the headache & fit hei off blue motor....it was very common thing to do.

Unless it's already been done.
Do you mean a second hand HEI or a brand new Bosch unit?
 

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If you want to keep the vehicle with its current engine spec & remain a daily driver, then chuck all the EST components away. It was a disaster from the day it was fitted by GM Aus before their attempt of fuel injection! Datsun's RB20-30's fixed the issue with the VL model.

So, a distributor from a "blue 202" & carb from a Falcon. Run it on 98 & remove all the emission sensors, ECU & wiring associated with EST (don't forget the air pump & ancillary parts). Make sure the cooling system is in good condition & has the correct thermostat & rad cap. It will be as reliable as the old HQ-WB's!

If you are thinking of re-powering it don't invest another cent in to it!

I only say this, as my VK was an EST model originally & spent months & months trying to sort it out & all I did was made it marginally better. The temp sensor had failed in the head & couldn't replace it at the time. Most of the vacuum hoses had failed, EGR valve was clogged up, idle validation switch bracket was broken (micro switch). The 308 couldn't come quick enough!!!!

Here's some info on the EST system, if you want to give it a go!!!

Good luck.

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