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S14 Sr20Det Revs Dropping...help

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Hey guys

When I drive along at any speed then slow down by taking my foot off the accelerator the revs drop until it almost stalls and then it pics back up again.

It ran lean off idle on the dyno so I'm thinking of a manifold leak. So while it was running I sprayed around the inlet manifold and piping with start ya bastard to check for vacuum leaks but I got no change in idle speed and can't find a leak.

Has anyone had this issue before? Any help would be great Cheers


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VTA BOV? ie do you have a Vent To Atmosphere Blow Off Valve? What you describe is the exact symptom of what happens when using one on a hot-wire air flow meter equipped SR

Might also be due to a lack of speed sensor input to the ECU

What ECU are you running?

Can you explain the conditions of lean out (on dyno) a bit more?

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The BOV is a Monza SSQ, I made a fitting and plumbed it back in the hopes it was going to fix my problem but it had no effect.

I had Peter Leibig tune my stock S14 ECU with a piggy back unit making it fully programmable. He did a great job with the tune but i didn't have enough coin to keep him there to pursue the dropping idle problem.

The lean out condition was on idle and we seen the A/F ratios hover around 16. My thought was a manifold leak but i cant find one.

Any idea on how i can test the speed sensor input to the ECU?

The air fuel ratio was up

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Also clean out your IACV. It may be full of oily gunk, stopping the car from idling properly. I had kind of similar issues with my car.

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Thanks Jeff i'm in adelaide but thanks for the offer. Its in the shed at the moment so i wont be driving it for a little while otherwise i'd post a vid.

I'm installing an S15 rear seat at the moment, its a little narrow on the edges of the seat so i may have to add some foam to fill it out a little. Is that what you did on your original SX-510? It looked like you had a sunny coupe rear seat in it and i know they are a little narrower than the stock 1600 ones.

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