need cam/distributer/timing expert help

I just swapped a '94 (5.0L) long block into my '84 F150 to replace the busted up 302. I used my carb, distributor, fuel pump set up of the '84. The '94 was fuel injected.

The truck was a California version that used EEC IV and feedback carb. Basically extra pollution control.

Here's the problem: Both engines are timed at 10 BTDC. For some reason, at 10 the engine runs real rough at idle and will back fire some if backing off gas after reving up. Seems to like it better now at 20 BTDC, but it still will die if I put it into gear (auto).

My friend suggested that the distributor from the '94 has a different range of advance so the engine isn't happy with my '84 dist. Unfortunately the '94 dist isn't compatible with the electronics of the '84. But really, advance shouldn't effect anything at idle, so I'm not sure what the problem is.

Do these engines have a different cam that makes this project unworkable? Shouldn't my old dist work just fine?

I discovered today that I have a fuel leak in my carb, so I'm going to rebuild it. But I really don't think that this has anything to do with the poor running issue. Could be wrong though.

Any help would be greatly appreciated. Been busting my ass for two weeks now and would like to wrap this project up. Trying not to spend big bucks cause this is going up for sale when I finish, but will do what I have to-- if it can be done.

If the distribtor/carb setup was running ok on the old 302, it should run ok on the 94 302. The cam is a little different grind but should run ok. Keep advancing the timing and see if it smooths out, but it sounds like it may be a combination of timing and a lean mixture. A timing chain with alot of slack can affect dist timing. Double check for vacuum leaks, and make sure the egr isnt hanging partially open, that could cause your symptoms also. Did you hear the 94 motor run before you put it in, check the spark plugs to see what cond theyre in? Double check your intake manifold bolts to be sure they`re tightened evenly, always go over them 3 or 4 times as the gaskets compress. Just a few things to check.

Thanks Uncle, your info was very helpful. I was waiting to finish checking everything before I got back to you. Here's what I've found out:

Confirmed I had good compression in all cylinders.

EGR stuck shut. Fixed that but didn't make big diff.

New plugs had heavy carbon, running real rich. Cleaned plugs good

So.. discovered power value on bottom of carb not hooked up. Cleaned it out and got a vac line onto it.

Then added new plug wires.. Made a big difference

Now got timing set at proper 10 BTDC and it will idle and keep running while in gear..

Here is where my last final problem lies: I have a miss that I couldn't track down so I bought a good multimeter that has a tachometer. Pulled each spark plug wire and noted the difference in RPM. Base RPM was 460. Four of the cylinders had RPM drop to 410-420 indicating working cylindars. The other four had the RPM rise to 520 when the spark plug wire was pulled. What does that mean? To add to the mystery, is runs in pairs in the firing order. 2 have rpms drop, followed by 2 where rpm will rise. Not sure where to go from here? Warped distributor?

I heard it run in the '94 and seemed fine. Manifold bolts tight, no apparent vacuum leaks using carb cleaner around base. Timing chain seemed tight when I put the front cover on, but didn't really check that close.

Thanks again for your help.

Did you disconnect the plug by the distributor so you are getting the proper base timing. Use a stethoscope and listen to the injectors you can pickout a bad one. I would try cleaning the injectors if you can borrow an injector cleaner. Check you cap and rotor.

Hey javatrooper
The rpm rising when you pull certain plug wires sounds like maybe the firing order isnt right, or the dist cap is cracked or carbon tracked and crossfiring. That could be where your miss is too. Doublecheck to make sure its right, 15426378 ccw. Also on the timing, you can just about forget the factory timing specs except for initial timing to get one running. Those specs were written back when gasoline was sorta still gas instead of the junk they sell us today. Late model injected vehicles have computer controls to monitor timing and fuel delivery and eliminate preignition.With the older carbed vehicles you usually have to play it by ear. Once you get it running smoothly with no skips and misses, keep advancing the timing till it starts detonating and then back it off till it quits. When you get it tuned for best performance check the timing with a light to see what it is and write it down for future reference. Also, just curious, is that the variable venturi carb?? They made good paperweights, not quite heavy enuff for a boat anchor.LOL

Did you connect the ground cable on the back of the motor to the frame? Check your vacuum hoses. put a vac guage on the carb and see what it reads. check the carb pad for leaks too.

Update: Thanks for all of the input.

Rhandwor: yes I unplugged the dist wire and it is converted to 2bbl carb, so no injectors.

Uncle: I had the firing order set 1-5-4-2-6-3-7-8. But a tech from 2 car pros suggested I try a modified firing order 1-3-7-2-6-5-4-8 and I'll be dammed if the truck didn't fire right up. In fact it seems to run even better but only in neutral. Idles fine and revs up great. Took it for a test drive and if I gas it the engine nearly dies and then slowly gains rpm, but is basically powerless. So today I pulled plug wires again. Now rpm rise on all cylinders as follows: Base rpm is 570-580. 1-600 rpm, 3-600 rpm, 7-600 rpm, 2-630 rpm, 6-600 rpm, 5-600 rpm, 4-620 rpm, 8-630 rpm. This leads me to believe my firing order is still not right. I will try your method of setting timing, but I'd like to figure the firing order puzzle first. Are there any other firing orders for a 5.0L out there? The carb is a Motorcraft 2150, 2bbl. Not sure if that is a variable venturi or not.

slash09: Ground cable secure, no leaks from carb pad and hoses seem okay. I don't have a vac guage, but if I go pick one up, what should the reading be?

Overall, I'm convinced my problem lies in my firing order/timing. This is killing me.....Like I said, right now it starts right up, idles fine, revs great in neutral, but bogs in drive and is powerless. Also, I'm using the modified firing order of 13726548 instead of 15426378. Any other options?

Thanks again for your help. Aloha

Hey javatrooper
13726548 is not a modified firing order for the 302, thats the firing order for a 351W which has a different crankshaft configuration, hence the different firing order. 15426378 is the correct one for the 260/289/302 engines and a few others. If it wont run properly with that firing order, you have other problems. There is no other correct firing order for the 302. Did you check the dist cap for cracks/carbon tracking, if you said you put a new one on sorry i didnt see it.?

Hey Uncle,

New cap, rotor, wires, plugs. Not sure if you can view the link below, but it is a diagram titled "modifying firing order and timing marks 5.0 and 5.8L" for 1994 Ford pickup F150. I don't know where this guy found the diagram. I will go back to the 15426378 and see what happens. I tried to cut and past the diagram but didn't work.

http://www.2carpros.com/forum/viewtopic.php?t=65741&start=0

I just got a blow up of the diagram. It says Identifying firing order, not modifying, so I don't know where or what this diagram is about.

I just went out and returned the firing order back to 15426378 and it runs like crap. ????

Hey javatrooper
Are you sure its a 302??? You may have a 351, it would be a bolt in swap and looks very similar, just 3 inches wider!!

The guy who sold it to me said it was a 302. The stamp on the intake said 5.0 EFI. Is there somewhere on the block that I can get some kind of serial/identification numbers?

I think I finally got this figured out.

Apparently 82 and later 302 HO engines use the 351W firing order, 13726548. My 94 block must be an HO cause it doesn't run well on the normal 302 firing order. I then advanced the timing off the scale and got it running fairly well. From a dead stop, if I gas it hard it goes. If I'm already moving and I stomp on it, it pings a couple of times but then takes off. Far better than anything it did up to this point. Once I finally get the timing set to the best location, I will try to figure out what the setting is and post it.

Feels good to finally have this thing running half descent. Thanks for all of help you all gave me.