I am in the finishing stages of my Explorer serp swap and swaping to the thyphoon intake with a larger TB. So the problem is that when I try to start it, ir is hard to start and runs REALLY rough. It even sounds like it is firing on one of the intake cycles of one of the cylinders. I have tripple+ checked timing at 10*, firing order, all electrical connections. I dont know what else to check. I thought would post it up here to see if any of you have any ideas???

It used to run great before this swap.

thanks!

May be vac leak. Intake and TB change won't really affect idle. You changed injectors too didn't you? Did you test them?

I know you said you checked it but that sounds like a firing order issue. Viper is probably right, as always, but make sure your firing order is right.

I did test the injectors. I also soaked them for abour 2 weeks in injector cleaner, changin it every 3-4 days. They have new seals too. Though they are the 2nd generation of 24# injectors. I bought the adapters to make them work with the factory harness from ford motorsport. I used dielectric grease on all the connections to keep water and corosion out.

I can go back to the old injectors, but after inspecting them, the new ones are in MUCH better shape. I too thought it was a firing order issue, but I have gone ower it many times. When I did the plugs I onle unhooked one wire at a time. Oh, and I installed new plugs gapped to .044".

...the part that sucks is that I am SO close to being done with this swap. I wish I could have it running the the breakfast this month!

Just another thought.... I am not sure about your ford motorsports harness but my rjm harness has a main ground on the back of the lower intake manifold. May want to check that if your harness has it. Vacuum leaks can cause all sorts of issues with efi including backfiring. Also check for leaks between your maf and throttle body.

You changed the maf sensor for the 24# injector calibration right? Maf sensor and injectors need to match. Checking for vacuum leaks without it running is pretty much a visual thing. It isn't good on it to run it while it is messed up but short times shouldn't hurt anything but your eyes if it is running that poorly!

Yes I did pull the Dizzy...and I made 100% sure that when I reinstalled it I had it in the same spot.

I am using a MAS from a donor that has 24# injectors. Though to make sure it wasn't the new MAS I switched it back. There was no difference.

Wish I could help, but I would bet it's something simple. We've all overlooked that stupid silly thing once or twice. Keep at it, you'll get it soon!

J.D.

its got to be something with timing or ignition. unless you do have a huge vacuum leak. it would run even with the maf unplugged

Create a youtube account and upload the vid there and then just send us a link to it.

J.D.

Ryan,
You might try pinching off the vac line to the PCV valve.

Just throwing this out there. Are you running a MAP sensor? If so do you have a vacuum line running to it? When we first started ours I thought it was to sense the outside air pressure like I had seen on the mass air EFI's. As soon as I plugged it to vacuum the truck ran great.

After re reading, sure sounds like the same thing we had. Ours ran super rich and popped like crazy. Here is a pic of what we did not have plugged to vacuum. We figured it out by just hooking a line to it and sucking with our mouth. Here is a pic

My money is on timing. Either the dizzy got a little cockeyed on reinstall or the #1 was not at TDC of the compression stroke when the dizzy was reinstalled. Not questioning your work. Just my guesses.

Any chance you are dealing with and 5.0 HO parts in this thing? IIRC, the 5.0 HO had a different firing order, the same as the 351W.

Guys THANKS for all the help! This is just what I need...outsiders perspective to jog something into that ah-ha moment.

-It is a 351 and I have verified the firing order.
-When I took the dizzy out, I pulled the #1 plug and made sure the piston was up, and that the harmonis balancer read 0*, and I verified that the dizzy was pointing to #1 plug wire that is marked on the cap.
-BFD that looks like me barometric pressure sensor. And no there is no vac line to it... there never has been. any one vote that I need one?
-viper I will try that. Though it does have 2. One in the back of the lower run to a port on the upper, and a second from the TB to the pass side valve cover (where the mustang one connects to the oil filler neck).

If I can keep it running long enough I will try to get a video of it tommorw mid day. I really want to get this posted to get your advice. I would LOVE to drive it this saturday to the meeting!!!

THANKS AGAIN!

You don't need a line to it unless it is speed density efi.

I really wanted that to be it! Dang!

OK, so I got the video of it running uploaded. Please let me know what you think it is....

http://www.youtube.com/watch?v=fipwMr0kyUU

It's got a severe miss. Could be plug wires not connected good or in wrong order. Did you have the valve covers off for any reason? Maybe a pushrod off the lifter.

Run the KOER test and see what you get for the cylinder balance test. That will point you to the missing cylinder. http://sbftech.com/index.php?PHPSESSID= ... opic=849.0

Make sure the coil has a good ground in the new location too.

Thanks Phil!

I will run the Key On Engine Running test tonight. Will it hurt it to run it that long to get the codes?

That sounds like a spark plug is not screwed in.

update:

I pulled #1 to verify that it is all the way up when the pointer is at TDC. It is. I also noticed that the plug was wet with fuel.

I will try to do the KOER test tomorrow when i wont wake the neighbors.

when you put #1 on TDC do you make sure it is on the compression stroke?

sounds like one cylinder is not hitting.
just for kicks here is what my 460 sounds like with MSD ignition killing my digital cameras ignition. LOL
http://www.youtube.com/watch?v=GtKXnLSBaDQ