No Decel Valve, no problem? Except a lil popping Options

[nditiz1]

2.0 76 GC motor -

So I went through my entire FI system to find out if any vac leaks were present as well as learn the ins and outs. I did find some things interesting and enjoy what they mean except for a slight popping I get on deceleration. Now, this could be caused by two things, exhaust leak (have new gaskets to be installed) lack of decel valve.

If the car still runs by removing certain items I am all for it, especially ones that are over priced due to NLA. My AAR is in good working order, but if it ever does go belly up I may just remove that too. Currently I have the cold start valve disabled (no connector, no fuel) I was trying to diagnose a rich running issue and read it only kicks in at real low temps. I can always properly test it and hook it back up if need be - one item down.

I was looking for my decel valve and could never find it because I don't have one. Now, how much of a burden is this causing me. The car seems to motor down the road fairly well. It idles great (steady) after being warmed up. I get a popping inside the exhaust on deceleration.

I have gone over the timing was at 27 but put it to 28 after finding out I have a Raby 9550 cam.

So now I have a more simple system without two factory things, but is not having the decel valve causing more issues like the popping or even worse? What say you decel valveless FI guys (I think t_rowle runs his that way).

[jcd914]

One advantage of the decel valve is that it reduces the suden high vacuum spike you get when you decelerate. This extends the life of the diaphragm in the MPS.

As you stated, the cold start valve is only energized at low temps, it is also limited to just while you are cranking the engine over.

Neither item is critical to the operation of the FI system but neither is a common failure item.

Jim

[nditiz1]

One advantage of the decel valve is that it reduces the suden high vacuum spike you get when you decelerate. This extends the life of the diaphragm in the MPS.

As you stated, the cold start valve is only energized at low temps, it is also limited to just while you are cranking the engine over.

Neither item is critical to the operation of the FI system but neither is a common failure item.

Jim

So what you are saying is that the decel valve won't prevent the popping and I should adjust the ecu?

[jcd914]

One advantage of the decel valve is that it reduces the suden high vacuum spike you get when you decelerate. This extends the life of the diaphragm in the MPS.

As you stated, the cold start valve is only energized at low temps, it is also limited to just while you are cranking the engine over.

Neither item is critical to the operation of the FI system but neither is a common failure item.

Jim

So what you are saying is that the decel valve won't prevent the popping and I should adjust the ecu?

I don't know if the decel valve will prevent or reduce the popping in the exhaust or not.
You should get a leaner fuel mixture on decel with the decel valve installed and working.
I don't know if that translates into less popping or not.

I would put the decel valve back on, if only to extend the life of the MPS diaphragm.

I would also make sure the head to exhaust gaskets seal well and get the fuel mixture checked and adjusted.

Jim