I see you still have your white HVAC vacuum line at the heater box.
After messing around under the hood those original vacuum lines should be inspected and replaced if they look questionable.
The white vac line is notorious for cracking and disintegrating.

Maybe you should try capping off all your vacuum sources temporarily and seeing if it fixes the drivability issue?

 

Thanks for the help, sounds good I will certainly check that too when I get home. Just to reiterate, it is just when I tip in from idle, in or out of gear, it surges down, almost dies and then takes off. Also, when taking it out of gear, coasting to a stop, it surges a little between 500-800ish RPM and then it settles out really nice. And obviously before I did any of this work it was fine. I will keep digging, thanks guys!

 

 

Okay more juicy info for anyone following or helping...

I took the TB off and there is a decent amount of oil in the upper intake, enough to coat the bottom and then drip out when I took the TB off. Mind you, this was NOT the case before i did all of this work to the truck (new heads, cam, etc.) Obviously the only place the oil could be coming from is the PCV. I guess it kind of makes sense, very light tip in maybe the oil is choking me down?? Then when i overcome it its fine?? Not sure, maybe this is unrelated but just wanted to post it to further the mystery!

 

It may be coming from the pcv valve but the valve may not be the problem.
Sometimes excessive blow by will be the root cause of the oil traveling to the intake manifold via the pcv.

If I remember correctly, you put a whole new top end on a high mileage bottom end.
Any chance the rebuilt top end is too much for your old piston and rings?

Just an idea- I may be way off base.

 

And some times the manufacturer of the component that the PCV valve is inserted into (intake manifold, valve cover, etc) will skimp on the baffle and you'll get excessive oil getting to the valve and up into the intake.

And regarding the TPS and other sensors that are new, is there an easy way to test the? As you may have seen mention of often around here "new does not mean it's good" comes up often, and is not practically a mantra!
If you happen to have your old ones still, and they worked before, you might try them on for size.

But back to the basics, will this system even support headers and a cam without some tweaks to the programming? It might be as simple as eighty-sixing some of the components and running a big cam.
Not sure that's the case of course, because I have not dealt with it personally. But some of the EFI systems had very little leeway with regard to cam changes.

Good luck.

Paul

 

This is probably a good example of posting an issue related to another thread is not a good idea. The OP is using stock heads, an Edelbrock truck EFI manifold, Crane 444232 cam and shortie headers. All of those pieces, even combined, are within the range of operating with a stock Ford Speed Density EFI system.

 

Hello, no worries, good thing to point out. Well the truck supposedly has 80k on the clock and when I had the heads off there was not ridge in the cylinders so I could assume that it is a low mileage engine but who knows...

 

1Ton, thanks for the suggestions but like RLA pointed out it should be fine with the stock heads and mild cam and intake. I will however follow your suggestion to try the TPS that was on there before I did all of this. I am almost 100% certain I didn't have any vacuum leaks. I have the upper intake off now, I cleaned it up and am waiting on some new gaskets. Once I get the gaskets and put the stock TPS back on I will reply and update.

Thanks all. I will welcome anymore brainstormed ideas if they should arise

 

If anyone is still following, this could be the issue, not sure. I just checked my voltage at the battery at idle and it is 12.8-13.4, now its my understanding that it should be about 14. This being said, I have a brand new alternator. I did have a full set of underdrive pulleys, I left the ones on the crank and water pump but changed back the one on the alternator and its the same.

Any suggestions?

I have the two body grounds that were going previously to the intake going the the back of the heads now. All other grounds were fine and untouched. The alternator is an 80a brand new AC Delco.

Thanks

 

 

You're right that this is too low for a modern(ish) vehicle charging system.
I think by '90 they were already using the 2G internally regulated alternator? Looks like it from the pic you posted, so I'll go with that.
While not the most powerful alternator Ford has offered, it was healthy enough to keep things going for many years until they finally changed it out for the newer 3G. They did have trouble with melted wiring with the 2G's odd design (the wiring and connector, not the alternator itself) and maybe you're suffering from an old corroded plug not getting all the signals to the right places?
Of course, a "new" alternator does not mean it's a good one as we've said many times here. Too bad too, because we often need to throw parts at a problem to "diagnose" the issue in the first place!

Did you rev up the engine while testing the voltage to see where it started climbing? If right away, then you might be on to something with the pulley sizes. Might be just over the edge of what the alternator likes to see in shaft speed.
Personally, I would have gone the other way, and changed out the crank pulley first, but either way, I think you may have to try the larger crank pulley again anyway. There's nothing guaranteed at this point, other than the fact that most trucks don't benefit from the 3-10hp that an underdrive pulley set frees up. It's just not worth it in other words, if your charging system suffers.

But was it running this way, with the under-drive setup with no problems? Guess I'll have to re-read this thread to remind me of what you've already done and discussed.
In the meantime though, at least test the alternator's output when you raise the rpms and note where it starts to read 14v and above. And make sure it doesn't go much above 15v or you'll have other issues to deal with too.
While you're at it, measure voltage at the Yellow w/white wire (I think that's the color) on the alternator's connector. Should be the same as the battery at all times. If it's more than half a volt less, find out why. Wire is likely deteriorating, but could be a loose or corroded connection.
Same for the Green w/red wire when the key is in RUN. Should see as close to battery voltage as it can be. Unlike the Yellow wire it does not have to be full battery voltage (it's just turning on a switch in essence) but should not be more than half a volt less either, just because that means that there is a problem with the wire as well.
These wires are not very long (probably less than three or four feet maybe?) so they should not be seeing very much in the way of a voltage drop.

The 2g main connector was notorious for corroding and also having heat reduce the ability of the terminals to grip each other over time. And a loose and/or corroded connector can be a very bad thing.
Heat buildup would literally melt the connector sometimes. And in situations where one main output terminal was not able to do it's job, the other one (the root of Ford's bad idea with the 2g I believe) had to do double the work it was designed for and melted the wire, either at the connector, or further up the line in the harness.
So if you don't see anything obvious, you would do well to test resistance on the two main charge wires to make sure that they're not compromised.

See? And here you thought you were almost done!

Good luck.

Paul

 

Oh, I meant to mention that while low voltage out of the alternator may not, in itself, be able to cause the tip-in issue you're experiencing, if left alone long enough and the battery is slightly low to begin with and the alternator is not keeping up it's end of the job, the low-voltage condition could certainly mess with the way the engine runs. Perhaps weakening the ignition spark, or signals to the injectors and sensors, or stuff like that.
I'm not really sure what goes on inside the full system when low voltage occurs, but it's likely not a happy EFI system when that happens.

Paul

 

 

Yeah, sounds like it. And since the battery is just "storage" and the alternator is what not only keeps it charged, but because of the higher voltage than the battery, also keeps everything working when the engine is running, that voltage should overcome any effect a bad battery would have.
In theory...

In other words, even if the battery has been drained one too many times, getting 14v from the alternator is keeping the system at a reasonable voltage for working.

But in all this, have you verified your fuel pressure? I don't remember if you said or not, but will go back and re-read just to make sure.
But with all those new parts, maybe something like the regulator is not doing it's job correctly. Is it adjustable AND still vacuum controlled like the factory? Or is it strictly adjustable and no longer has the vacuum function? What brand and model is it by the way?

Paul