Rmyers

I've just installed an EF BBM manifold to my EA 3.9litre. ATM it's running off the EA mpfi comp, uses EF injector rail, injectors, regulator etc and an EF fuel pump. Still using an EA head, cam etc...

What I'm getting is a flat spot when booting it from stand still. The car will hesitate for bout half a second, then make it's way to bout 30k's before the power finally kicks in. What do people think is the likely cause of this. There is an extremely slight puff of smoke from the exaust when it hesitates, then it stops. I'm assuming that it may be running a little rich down low??

ATM the I have not got a dual runner switch hooked up, so i've just cable tied in the valve in the up position. Is this switched to long runners or short runners?? I've had it run in the down position and I'm getting the same flat spot, but low down power is even worse.

Any ideas???

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Soxx

Sounds like ignition timing. Where do you currently have it set?

Rick.

Rmyers

Well, the base timing is spot on, and when I check the timing without diagnostic mode turned on, it's 10 degrees advanced. From what people have told me, this is how it should be...

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Soxx

Perhaps the harmonic balancer has slipped and the mark isn't at true TDC.
Check it and re-time it if necessary.

Rick.

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4L I6, naturally aspirated producing 173.5rwkw.
14.410 @ 96.49mph with street radials.
What's that?..... Did I hear you say TQE power?

Rmyers

The balancer can't slip, it can only go on one way as it has a locating notch where you slide the balancer back on.

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Soxx

Harmonic balancers can, and do slip.
They consist of 2 seperate cast pieces, 1 the center hub which slides onto the crankshaft and is located by the key, and 2, the outer ring which is seperated by a high density rubber. This is to damp out harmonics, hence the name.
The outer ring quite often slip out of adjustment when they get old and the rubber starts to perish.

Check to see if it is on true TDC by removing number 1 spark plug and use a bit of wire to locate exact TDC, then see where your mark is on the balancer.

Rick.

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4L I6, naturally aspirated producing 173.5rwkw.
14.410 @ 96.49mph with street radials.
What's that?..... Did I hear you say TQE power?

NZ

Ive had 2 engine both of them had slipped. We used a spark plug gutted with a steel rod welded in. Screwed it in, turned engine till piston touched, made a mark,turned back till it touched again, made another mark then measured halfway in between. This gives the true TDC. Was suprising at how much one of them had slipped.

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Dot Aye You

galapogos01

He's just fitted an EF balancer - NFI how old it is though?

J

Walkinshaw

Yeah sounds timing related. Also the EL ECU (if you were using one) would use a diffrent spark map down low to work with the long runners. Advance the timing 5deg and take her for a spin, keep on advancing it till you get slight pinging then STOP. retard it a few deg and try again.

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Ive been described as a vault of usless random knowledge.

Ill take it as a complement i think.............

ebs_4l

it should be at 10deg adv when in diagnostic mode dude..