1993 5.0L HO or Non-HO?

[jakester888]

I have a donor motor from a 93 LX 5.0L Convertible and running EFI. I need to know if this is HO or Non-HO as this factor decides which firing order to use. Either:

1-5-4-2-6-3-7-8 (Non-HO)
1-3-7-2-6-5-4-8 (HO)

63772d1344963247-firing-order.gif

I've tried both and neither sounds real good, alot of back-fire in the passenger exhaust.

[jakester888]

Would I be able to tell from the VIN number?

[jakester888]

Computer is an A9M... if that helps.

[jakester888]

Mystery solved. I looked at this old photo of the engine before I removed it and looks like it is indeed HO.
1-3-7-2-6-5-4-8 (HO)

donor2.jpg

[jakester888]

And the intake cover says, "HO". Duh. I have since swapped the upper & lower intake, so it isn't obvious anymore.

[DaleG]

Just to make sure: 1FACP44E6PF000001. 44 = convertible, E = HO

[Jeff Kleiner]

Use the HO firing order.

Jeff

[jakester888]

I switched from HO order to non-HO order, then back to HO to see the difference. Bad idea. Now I've got a nice BANG instead of a pop in the passenger exhaust. I may have damaged a valve.

[Norm B]

The firing order for the valves on the engine can only be changed by changing the camshaft. You shouldn't have damaged any of the valve train by messing up the firing order. The valve timing would have stayed the same unless you changed the camshaft or its timing on the gears. You may have blown the glass pack out of the side pipe if you ran it for too long and I suppose it is possible to blow a header or intake manifold gasket.

Norm

[Norm B]

Just another thought. Check your valve lash and do a compression check. An exhaust valve with too tight of lash and being held open could result in the symptoms you've described. Hopefully the EFI experts (I'm not one of those) chime in with other info. I know incorrect mixture settings on a carb can result in symptoms like you have described.

Good Luck
Norm

[jakester888]

I've been fiddling around with this problem all summer with nothing to show for it except the problem seems to be worsening. I finally broke down and called a local automotive shop. Met the owner, saw his garage and explained my dilemma. He seems really cool and trustworthy and there were other "project" cars already in his garage. So I have scheduled to tow this beast over there, have him diagnose it and give me his assessment.

It feels like I failed here... disappointed it has come to that.

[rich grsc]

Distributer not installed correctly, out of time? EFI must be installed correctly.

[68GT500MAN]

Sounds to me like a distributer problem. Make certain that #1 cylinder is at TDC of the compression stroke and then make certain the distributer is pointing at #1 post, if not, pull the distributer and re-install so that the rotor is pointing at #1.
Doug

[Jeff Kleiner]

To elaborate on Rich's comment; the distributor has a hall effect sensor wheel with a "window" that the PIP senses and signals the ECU for firing the fuel injectors. You can get the distributor installed improperly and by manipulating plug wires still be able to get the ignition timed correctly yet have the fuel injectors out of time. Another similar possibility is if you have the wires for a couple of injectors crossed. In either case it could run (somewhat poorly) and could cause some backfiring out the exhaust if for example fuel was being injected on the exhaust stroke. I'd expect it to throw some codes because the excessively rich or lean condition the oxygen sensors would be seeing would be driving the computer nuts trying to compensate. Have you checked for codes and if so what were they?

Good luck,
Jeff

[jakester888]

I've tried everything I can to dial this in, I think this problem is beyond me. All points you guys suggest above are appreciated of course - but I've tried them.

I'm sure I found TDC for cylinder one (the finger test with plug #1 removed, you can feel the top of the compression stroke as it pushes air out the hole). Then set the distributor to point to lead #1 at that position just like the photo shows at the top. Then used a timing light to get it to 14 degrees TDC. I've checked several times and know I'm running 13726548. This passenger exhaust BANG has me baffled. The pop that was once there in the passenger side has evolved to a full-fledged explosion to the point I am afraid to turn it over for fear of spitting fire out the exhaust or somewhere else.

I'm taking this in because I really need a 2nd set of eyes on this & I'm determined to get this beast on the road next summer. The mechanic I spoke to suggested he'd start by testing codes as well. I told him about the 19# to 24# injector & corresponding MAF change & the upper & lower intake manifold change from 93 stock to 94 Cobra type. Shared some photos from the forum. He seemed genuinely enthused about this FFR approach. I'll let you guys know what he finds.

Here's a video (without engine running) of the build progress:

[rich grsc]

The distributor and #1 plug wire MUST be positioned as in the photo. #1 is at the 12 o'clock position. (Double click to enlarge picture)



HO_firing-order_zps9626b5e0.gif

[jakester888]

The distributor and #1 plug wire MUST be positioned as in the photo. #1 is at the 12 o'clock position. (Double click to enlarge picture)
HO_firing-order_zps9626b5e0.gif

Great photo. Especially the example for avoiding cross-fire. My #1 is at 1-oclock. But then so is the distributor lead at 1-oclock at TDC.

[Ringo]

The cam my builder used changed the trimming order to 351. Is it possible somebody added a new cam? Maybe check some other cylinders and see if the piston is at the top when they are ready to fire.

[Jeff Kleiner]

The cam my builder used changed the trimming order to 351. Is it possible somebody added a new cam? Maybe check some other cylinders and see if the piston is at the top when they are ready to fire.

The 5.0 HO firing order is the same as the 351; 1-3-7-2-6-5-4-8. The old, non HO 302 is different.

Jeff

[jakester888]

My mechanic has diagnosed the problem. It was first of all badly timed. I obviously don't know how to read a timing light. He said it was about about 24 BTDC and he dialed it back to 10. Then he noted that it was/is running too rich. Here is where the forum was right again and I didn't listen. Under a separate post about 19lb vs 24lb injectors, you guys warned me about this problem... and I didn't listen. Basically the BBK 24# MAF I bought coupled with the 24# injectors I installed are both fine but the computer still thinks these are 19# and thus allows too much fuel. My next step is to send the MAF to Pro-M Racing and have them re-calibrate the BBK MAF, so the A9M computer will react better.

He also noted a leak from the Water Pump. I suspect this again was my fault for a badly formed hand-made gasket on my part. So I'm paying to have them take it off, reseal and bolt it back in.

Incidentally, the garage where the car is has caused alot of buzz. The mechanics have enjoyed working on something other than old taxi's and they even took photos and video posting it on their facebook page. Cool.

[Dan Babb]

The distributor and #1 plug wire MUST be positioned as in the photo. #1 is at the 12 o'clock position. (Double click to enlarge picture)
HO_firing-order_zps9626b5e0.gif

Why does it matter where #1 is located? As long as you have the #1 plug on the right post when you drop the distributor in the hole, I didn't think it would matter if #1 is at 12 o'clock or 3 o'clock (or whatever position).

[Jeff Kleiner]

Technically Dan it does not matter where #1 is as long as #1 on the cap and the rotor stay together. Remember back in the old days when you might have just moved the wires around the clock by one terminal if you got the dizzy stabbed in wrong? Can't do that on these because the PIP has to know when the rotor is at number 1 and with the TFI module sticking out of the front the distributor has a very limited range of rotation before it physically interferes with either the water neck or manifold therefore to be correct #1 being at 12 o'clock is just about the only option.

Jeff

[jakester888]

Mechanic found a dented/crushed oil intake tube while replacing the timing cover gasket. I've since asked him to replace it.

Oil seemed to be working fine during the oil-prime test with the drill, nevertheless glad I caught it now.

[Jeff Kleiner]

Mechanic found a dented/crushed oil intake tube while replacing the timing cover gasket. I've since asked him to replace it.

Like this?





They are all like that. Ford put those dents/dimples there on purpose because without them you could not get a socket and torque wrench on the bolts that attach the tube to the pump.

Jeff

[jakester888]

Doh!

[rich grsc]

Either your mechanic, isn't, or he thinks you don't know the difference, and is just charging for unneeded parts.

[jakester888]

I called him on it. Showed him the pic above and compared it to the part they salvaged. I think the mechanic didn't realize they were made this way. He showed me the replacement part, clearly no dent from photos online. So I suspect the mechanic didn't realize, when he first looked at it with the timing cover off. Nor did I. Erring on the side of caution at the time, I went ahead and authorized them to replace it, reasoning that if it is bent then I'd take the opportunity now to fix it to avoid risk.

Live and learn. I saved the older part.

So the car is back in my garage now. Fires right up and runs great. Except I still have the too rich problem because of the 24# injectors & 24# MAF on the stock 302. Once again, my plan at this point is:
1) Pro-M Racing to adjust the MAF.
2) If that doesn't work, revert back to the OEM 19# MAF and replace injectors with 19#.

[jakester888]

[jakester888]

Just got the MAF back from Pro-M racing. Runs so sweet now! They tuned it so the A9M computer can understand I have a 24# MAF with 24# injectors. They were careful to note that the tuning was particular to the connical filter direct-connect to the MAF, which apparently makes a difference in the tuning. Anyway I'm reporting that Pro-M really does a good job. If you guys tweak your air intake, MAF or injectors beyond stock, give 'em a call. Ask for Chris Richards, he knows 5.0 EFI.

Pro-M Racing.

sct-ba3000_3522.jpg

[skullandbones]

Glad you worked out your gremlins! WEK.