Timing and idle

[Casey835]

I’ve been following another thread and digging up old threads trying to learn something. I don’t want to be rude and keep interrupting the other one so I figured I would start my own. My timing is up around 19.5-21 degrees. The lowest I’ve been able to get idle is mid 900s. Is that timing high? It’s 99 explorer EFI on a 351. I’ve had to work at it to get it where it is now. I does the idle surging or searching from a cold start. Just trying to figure out where to go from here.


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[Broncobowsher]

Considering the 99 Explorer is crank triggered and not adjustable, I am at a loss for what you are doing.

I have a feeling that there is a lot more mix and match parts in this build.

 

[BUCKWILD]

Yes what ^^^ he said. Base timing and what a scaner will show is a lot different

 

[DirtDonk]

Explorer, but running a distributor?

 

[DirtDonk]

My timing is up around 19.5-21 degrees. Is that timing high?

If you're running a distributor and reading an initial timing with SPOUT disconnected then yes, that's high.
If you're running full EDIS and reading this from an OBDII scanner or equivalent, then no that's probably right on the money. The computer often runs very high timing at idle and low/no load conditions. Whatever it needs for best efficiency.

The lowest I’ve been able to get idle is mid 900s. It’s 99 explorer EFI on a 351. I’ve had to work at it to get it where it is now. I does the idle surging or searching from a cold start. Just trying to figure out where to go from here.

Still need more details of just exactly how much Explorer you're running. Including the fuel system since I believe a '99 would have been returnless. Correct?

Paul

 

[Casey835]

Running full EDIS.
Comp cam 35-308-8
AFR heads 170cc
Returnless fuel with factory explorer fuel pump in tank
Accufab 70mm throttle body with new TPS to correctly fit and adjusted

When I first got this running and take for a test drive it would try to backfire. I think I’ve adjusted that out(maybe? Doesn’t seem to have done it again) So I worked with it to try to fix. When I say I’ve made adjustments, usually referring to idle control screw and TPS(.98 if I recall) I did all this using info I dug up posted from other members here. Unplug IAC, adjust throttle screw,checkTPS voltage, disconnect battery,etc....Searched for vacuum leaks. I did find some in my intake tube and fixed. Also appears to be one around the oil fill spout. When I did the smoke test it would push oil out around where it connects to the valve cover. I plan to fix this even though smoke didn’t come out. Also it has hesitation if you suddenly punch gas....keep forgetting to mention that and that’s probably my biggest complaint. New IAC and has been checked by using the old one. The explorer computer controls the 4r70w. Whatever it is I feel it’s minor. Would the 70mm accufab cause the hesitation? I was told not to go lager than that because it would cause hesitation.


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[Broncobowsher]

What MAF and injectors?
For the MAF, not just the sensor, they have a lot of interchange. But housing as well. If the housing size is changed, the MAF calibration will be wrong.
I have doubts that the 17Lb injectors will be enough for a 351 with a cam. But that is under high load conditions.

 

[Casey835]

The 99 factory MAF and the factory 19# injectors. However instead of using the old injectors I did use new. So I will look at those again but I do recall having already verifying those once before because the color was different. as I recall there was orange injectors and white injectors that were the same.

I am using the factory housing for the MAF. I will check that and make sure though.


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[Broncobowsher]

The orange 19# injectors are used with the return style fuel rail.
The white body 17# injectors are used with the higher pressure non-return fuel rail.

 

[Casey835]

I have the Bosch injectors #280 155 861 which are the 17#


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[Casey835]

Should I try 19# injectors? Does that require computer work if I swap the injectors out?


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[Casey835]

Could the placement of the pcv in the rear of the lower intake cause an issue with hesitation? I’m thinking of changing this as I appear to have oil getting to the fuel pulse thingy on the fuel rail. Or is this ok/ normal?


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[DirtDonk]

The location of the valve should have nothing to do with hesitation. The valve itself could (defective, worn out or just the wrong one), or an associated vacuum leak, or the routing of the overall plumbing. But usually not the location of the valve.
Even if you have an early 5.0 intake with a poorly designed (under-sized) oil control baffle, the ingestion of excess oil would not normally in and of itself cause a hesitation upon acceleration.
I suppose in theory if you get enough oil into the intake it could mess with things, but I personally have never seen that much collect.

What is your overall setup exactly?

paul

 

[Casey835]

351 with the explorer EFI edis. New pcv in the rear lower intake that is routed to the upper intake. Can’t believe I don’t have a picture. I can post one up later. I thought I recalled there being an issue with the 351 sucking up oil into the upper intake when placing the valve in the lower intake. Then on the pass side the small hose goes from oil filler to tb. Thanks for any help.


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[DirtDonk]

Didn’t realize you could get a 351 lower with the hole for the PCV in it. Would definitely like to see a picture of that.
Did your driver side valve cover have a hole in it for a valve? Or are they aftermarket valve covers?

 

[Casey835]

The hose connects at two points on underside of upper before it goes to the pcv. I also have the appropriate screen in the hole the the valve on top. It’s a new valve. Does not have hole for valve. If I needed to, I was going to see if I could drill it out.

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[DirtDonk]

Great pics, thanks.
It's often a too-tight fit on the valve cover due to the upper plenum hanging down so low over it. But in your case it looks like you have plenty of room if you want to move it. I wonder what the best method for plugging the hole in the back of the lower would be? I know what kind of plug I think I'd like to use if it was mine, but have no idea what they're for or where to get one. I just know I've seen them, and need to think on it for a bit so i can remember where I've seen them used.
In the meantime, i still say it's not a bad location (and it's nicely plumbed already) and should not cause the hesitation.
If you do indeed have an oil control problem with a bunch going into the intake, then that's a good reason for either moving it elsewhere or plumbing in a catch-can to keep it out of the intake.
But a little bit in the intake is not bad, and also will not cause the hesitation. Unless it's so much it's pooling heavily and getting sucked into the engine constantly.

Could be the wrong valve of course. Did you use one for an Explorer, or for the 351's original application? i would think it needs to be for a 351 for sure, but don't know what that might have been.
What's the intake out of? A Lightning maybe?

Paul