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Rough running NA Headache


Richie_k83

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Hey guys,

 

Kinda looking for some advice, my NA-Auto had been off the road for almost 6 months now whilst I have been converting to a W58 gearbox.

 

Install is all done and ok, but the idle is shockingly crap and all over the shop.

 

It was fine before. Now its running very very rich and lumpy.

 

Small video below to show how erratic it is;

 

https://vimeo.com/184191570

 

Only changes have been the manual conversion and a set of Magnecor 8.5mm HT leads.

 

No fault codes or anything, still using the auto ecu too.

 

Anyone had a similar problem?

 

 

 

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Managed to unplug/disconnect the vacuum from the map sensor? Sits on the bulkhead up behind the intake manifold.

 

I checked it, still ok, wasnt touched since being off the road tbh.

 

Could it be the leads? 8.5MM are for TT's, the red ones. And the blue ones are for NA's 8MM, used wrong plugs? or are the leads in correct order?

 

I dont think it would be, mine has a distributor and single coil pack. I think all TT's are wasted spark?

 

The lead colour only relates to the thickness, not application (Red=8.5mm, Blue=8mm, Black=7.5mm)

 

Going to try an ECU, sure i have read other guys ECU's have dies after being so long without the batter hooked up... :(

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TPS maybe?

 

Will take a look at that tonight :)

 

Get a vacuum gauge on it and tell us what reading it gives you. Bouncing idle like that sounds like it could be a leak post TB

 

Good shout, i did take the plenum off the other day thinking about it, never changed the gasket though as it seemed ok..

 

Is there a link on how to test the Vacuum system?

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Will take a look at that tonight :)

 

 

 

Good shout, i did take the plenum off the other day thinking about it, never changed the gasket though as it seemed ok..

 

Is there a link on how to test the Vacuum system?

 

Any easy check is to take off the intake, start the engine and block the TB port with your hand/something big enough to restrict all air going in. The engine should stall very quickly, which means you have no leaks post TB.

If the engine doesn't stall then you know you need to find a leak somewhere.

 

With a vacuum gauge, you should be looking to make around 25-27 vacuum at idle on the GE

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Any easy check is to take off the intake, start the engine and block the TB port with your hand/something big enough to restrict all air going in. The engine should stall very quickly, which means you have no leaks post TB.

If the engine doesn't stall then you know you need to find a leak somewhere.

 

With a vacuum gauge, you should be looking to make around 25-27 vacuum at idle on the GE

 

Ahh ok, will give it a go tonight.

 

Is it just a case of T'ing the vac gauge into all the vacuum lines one at a time?

 

 

 

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Probably sucking eggs but there are 3 or 4 of those small 4-5mm vac pipes around the plenum, the two in/under the Y are easy to forget?

 

I did check them, all are on and i used new SFS vacuum hose the other week. Just doubting myself as to whether they are on correctly.

 

Although i did find a PCV valve in one line was on backwords lol it hasnt changed owt though...

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A little strange with mine, on the top of your Throttle Body you appear to have 3x Vacuum ports.

 

On the top of mine, i only have 1x port. (the line with the PCV valve on it)

 

Will check it out tonight, ordered the gaskets i should have changed too, just as a precaution.

 

Ah yeah I forgot, my TB is from a GS300 so I've got the extra ports. In that case, just put the T into the vacuum line going to MAP sensor.

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Is it using any water?

 

Hey Chris, there has been a bit of condensation from the exhaust actually, but nothing out of the ordinary. Although i havent had it running long enough to notice the levels dropping.

 

Its been standing for about 5 months, but was running spot on before I pulled her apart for the manual conversion... wondering if the ECU had died, or if the 8.5mm leads i ordered are duff..

 

God i hope it isnt the head gasket, just want to drive the bloody thing, not do more work! lol :banghead:

 

I have ordered the new manifold Gaskets to change but not sure if it would do anything.

 

I think a compression test is in order whilst the piping was all off and out of the way.

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Hey Chris, there has been a bit of condensation from the exhaust actually, but nothing out of the ordinary. Although i havent had it running long enough to notice the levels dropping.

 

Its been standing for about 5 months, but was running spot on before I pulled her apart for the manual conversion... wondering if the ECU had died, or if the 8.5mm leads i ordered are duff..

 

God i hope it isnt the head gasket, just want to drive the bloody thing, not do more work! lol :banghead:

 

I have ordered the new manifold Gaskets to change but not sure if it would do anything.

 

I think a compression test is in order whilst the piping was all off and out of the way.

 

Did you do that test I mentioned? Takes 30 seconds to do...

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