I have a megajolt setup just running the ignition side of things on a Toyota 4AGE engine. I am running Webbers for the fuelling.

I have drilled and tapped each port on the inlet manifold and linked them all together with the silicon hose so that they balance out when running. As standard there is no balance bar on the manifold.

The issue I am having is that the vacuum gauge from the ECU is jumping all over the place when the engine is running, and hence moving the map around a lot.

Has anyone else had this issue? Megajolt talk about using a small reservoir to help balance out the vacuum. Is there any neat solution for this?

Any help would be appreciated!

Thanks

Matt

Usual solution is a reservoir to smooth thr pulses, a fuel filter is quite an easy solution. On my last car with bike cabs and mjlj i used a length of 22mm tube as a balancer fed from each runner then into the jolt and vacuum gauge.

I believe you can get restrictors that have a small orifice to smooth out the pulses. But not too small that it doesn't react fast enough when you stab the throttle. Shouldn't you be using a TPS based map (Alpha-N) anyway?

Will have a look at the fuel filter option.

I did consider the TPS version of the megajolt, but trigger wheels suggested that I didn't bother and use the vacuum take off.

A lot of 1980s Fords had vacuum pulse damper in the vac line.
The diy way to do it is a resstrictor and some kind of volume to act as a vacuum resevoir damper.
You can us cheap small in-line fuel filter as the resevoir and a section of brake pipe as the restrictor.

Ford Pinto OHC Distributor Vacuum Delay Valve 3496787 #5B22

thanks, will give one a go!

Just check it doesn't damp to much
I mistakenly used a vac 1 way valve and just had a fixed vac for a while
My solution was a tube that the 4 vac signals came into with the tube to the map sensor coming out of 1 end, works fine

You should be able to see it clearly in this photo


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I have a similar setup to you with the pipes, they are a lot smaller though. Will give one of the valves a try and make up a small reservoir if not to see how that helps.

Thanks for your help!

I don't know if you've seen this page:

AutoSportLabs - MAP setup

Discussion here.

The rest of the site is very useful!

[Edited on 31/8/16 by David Jenkins]