speedysprocket

Forgot, I did put a new temp sensor for the ECU in. And new FPR because the old one leaked all its fuel through the vacuum line and into the intake... Fuel pressure reads good now.

qdeezie

Ok.....to check the firing order, all you need to do is pull a valve cover and observe the sequence in which the intake valve opens for each cylinder. It's just that simple to be honest.

Chris_1

iTrader: (1)

You're right on that. Pretty sure it wouldn't run at all on the other firing order though.
I'm kinda leaning towards a sensor on that one - just because it has been known to run good at some point .... why not now ?
Am I way off base on that one ?

qdeezie

I will be 100% honest and say that I haven't read the entire thread.

However, I did read the part about the MAP sensor and soot on the plugs. I would take some carb cleaner and spray out that vacuum hose that runs to the MAP sensor. It could be blocked.

Also, when going with a bigger cam in these trucks, in my opinion, an IAC bypass plate is an absolute must to stop surging at idle due to increased airflow demands.

Once again, I have not read the entire thread, so if I'm off base, you know why.

qdeezie

The other thing I vaguely remember was low vacuum. The MAP sensor HATES low vacuum. That would create surging and soot as well.

speedysprocket

When I say it ran good, it was only till it warmed up, or the MAP sensor was disconnected.

qdeezie

I went back and read the thread. Your problem is the camshaft. It is producing low vacuum. Also, any cam other than the stock cam will require an IAC bypass plate for it to idle correctly most of the time.

Sorry, but you're going to have to tear into the engine and replace the cam.

Let us know how it turns out after you install a new cam.

Aktech

I googled it and you r right. It is your cam. Vacuum suffers greatly with a hotter cam. Just a safety note that some brake boosters may need more vacuum then what u have to work properly.

speedysprocket

Yup, going to try to get an explorer cam locally.
So did the original 89 F150 5.0 come with a roller cam?

Aktech

There are others with more knowledge than me about this stuff. I`ll watch the thread from the side lines now.