OK, got the plenum gasket changed last night, was more of a bitch than I thought it was gonna be considering it just went together! (Note to self, never, ever use the yellow Hi-tack that comes in a tube again) The hardest part was scraping off that damn gasket that the jerk that put the motor together glued down!

So, I had previously cleaned my lower intake up really good with some acid and chemicals before bolting it on the new motor, and rinsed and blew out all the holes afterwards. Well, not good enough, there was some crud in the bottom of the upper-to-lower intake bolt holes, not allowing them to screw down in all the way. About twenty minutes with a pick, some brake clean and brushes, and a 5/16" tap took care of that. The intake was physically tight, and not loose, but there must have not been enough clamp from the bolts to seal the gasket surfaces. I probably could have just re-used the gasket, but I already had the new one and it was like $5 bucks, oh well. I checked the lower intake bolts while I was in there, and they were all still tight.

Got her all buttoned up and fired off, first thing I noticed was that the truck started much better & easier. Barely a crank of the starter and it was purring smoothly. Idle settled right down to about 750rpm and smooth. Hooked the vacuum gauge up again, and still only 16" of vacuum at idle? WTF? I'm thinking at this point, that is either because the rings aren't seated in yet (only about 150 miles on the rebuild yet), or because of the HO cam installed 4 degrees advanced. I really would like if someone with the same combo would measure their idle vacuum and let me know.

I only have the timing set at 10* base so far (spout out OC) I would bet advancing it to 12*-14* would get me another inch or two of vacuum at idle, and it's probably needed anyway, as the cam is opening/closing the valves earlier being advanced. I think I'll try that this weekend and see.

I also noticed that my EGR valve position sensor connector slides on/off a little too easy, I looked down in and the bullet terminals looked a little spread. I used a little pick to tighten them back up, hopefully that takes care of my intermittent EGR codes.

 

Most cams have the 4 degrees adv. built in installed straight up. You probably have the cam 8 degrees advanced.

 

It's not the exact same cam but FWIW my 5.0 only has 16" vacccum at idle as well, that's with the Comp 35-349-8 which is essentially a high lift version of the HO cam.

 

The only way to really know on the cam is if it was setup with a degree wheel. I know the comp's like the one Conanski is talking about has 4 deg. built in. Not sure about the stock h.o. cam, but mfg tolerances and installation tolerances could have it off several degrees.

 

Well, that makes me feel better Conanaski. Your truck is Mass-air though yes? Forgot to mention, but my off-idle stumble is gone as well. 73fomo, I believe, IIRC the mustang cams had a few degrees retard built-in per the specs, how they really end up due to tolerances, who knows. I know a cam should always be degreed, but on this stock-ish rebuild, I figured why bother? I know here and on NLOC, plenty of guys running the HO cam at 4* advanced on the timing set with great success. Seems to be working out OK, as the truck has good off-idle grunt, way more than it did before.

 

Well, the cold start is still hit or miss damnit. 1 out of every three times I start the truck cold it'll stumble, surge, lope, etc. until it idles for about two or three minutes and then it's smooth as a kitty cat. I tested the TPS sensor for S's & G's, it's at .9v at idle, sweeps smoothly up to 4.89v at WOT. The check engine light came on yesterday, and it was a 173 rich code again. I'm about ready to pour gas on this MF'er and set it on fire. I'll pull a few plugs tonight and have a look at them, and hook my voltmeter up to the 02 sensor and see what it's reading also.


On a + note, I bumped the timing up to 14* base from 10* that I started with, and that got me up to about 17.5" of vacuum at a warm idle. I did notice putting the spout back in though, that the timing only advanced about 4* from base at idle, playing around with the throttle I could get it up to about 20*-ish, shouldn't it be advancing more than that? Or does it have to be under load? Seems like my Lightning advances quite a bit more with the spout in, but maybe it has more aggressive timing tables.

 

I would honestly get some miles on that motor before messing with to much more at this stage. get that motor broke in and then see where its at. I would honestly install some regular copper plugs in there also.

I would also suggest running a delo or rotella 15w-40 oil for proper break in.

 

The NGK plugs are regular old plugs bud, they aren't platinum, iridium, or anything like that. Still getting 173 rich codes at cruise. I played with the timing a little bit, and noticed with the spout in, I only get 4 degrees advance from base timing. My Ford shop manual says I should have 20* + or - 3 degrees. I'm thinking I need a new ignition module, or possibly a computer. I think I'll try swapping the TFI module from the Lightning into the '92, I believe they are they same.

I used 15w-40 for assembly lube on the cylinder walls, but with my .0015 rod/main bearing clearances, that's far too tight for winter temperatures, I'm running 5w-30

 

Well, the ignition module on the Lightning was the black one, '92 truck has the gray one of course, so I bought a new one and swapped it out for no difference, there's another $60 down the drain. Took it to my brother's shop tonight, and had it hooked up to the scan tool for some testing and data. Had a KOEO 542 code for fuel pump circuit failure, don't know what the hell that is all about? Looking at the data, everything as far as ECT, ACT, TPS, looks good, fuel trims stayed around zero. The HEGO sensor data is pegged at .970v. What the ****? I couldn't get it to move! I unhooked a vacuum hose to force lean, and it went to.990v. I unplugged the 02 sensor connector at the battery and it went to .008v on the scan tool. The HEGO is reporting as pig *** rich, and when I ran it in the shop I believe it, my clothes still stink. Also, it won't go into closed loop, at all. I'm assuming that's because the computer is waiting for the HEGO to switch and it never does.


I don't know, at this point, I'm down to either the injectors I cleaned and serviced are leaking, or the computer is ****ed.

So, either more diagnostics are in order, or a five gallon gas jug and book of matches are in order. I'm leaning toward the latter at the time...


P.S. I pulled the front four plugs the other day, 1 and 2 are black on one side of the porcelain, and white on the other side, as is #6. #5 is the normal tan color and looks fine. I'm stumped by that, never seen it before.

 

My head cooled off a little last night, and I'm actually thinking I'd be better parting or selling the truck. I think I would take a beating selling it whole, but I could maybe get $1,300 for the motor, complete, a few hundred for the E4OD, few hundred for the box, etc. The body is mint, other than about a nickel-sized rust hole in the Dr. quarter panel of the bed (right at the bottom where the brace is on the inside) The red interior is damn near perfect. Do you guys think I'd be able to make $2,500 at least parting it? If I decided to sell it whole, I'd have to come up with wheels and tires for it, as the Lightning wheels on there now I need to keep for my Gen 1. I will try to listen to the injectors KOEO to see if I can hear them leaking, the only thing going through my head is that I left them soaking in the B-12 Chemtool for over a week, and might have ate up whatever seals them on the inside when they are closed.

 

well didnt you say the last time you tested the fuel pressure it dropped off right away. that would point to an issue with the injectors.

 

Yes, and the truck didn't use to do that before. It used to hold pressure just fine. Also, 1 of the 4 plugs that I pulled being clean and the other three being black makes me suspicious also. I did have the rear fuel pump canister apart too though, thought I might have messed up a check valve while in there...

I've thought about pressuring up the system and then clamping off the pressure/return flex hoses at the pumps to see if it holds pressure, but you can ruin the stainless hoses that way by crushing them....

 

it might be worth heading to the wrecking yard and getting a set of injectors off of a v8 explorer i think the 97/98 models had the better model injectors also.

 

Well, the Lightning is put away for the winter, and the upper intake needs to come off anyway so that I can get the valve covers powder coated, so I'm thinking I'll head over to the shop tonight and steal the injectors out of it.

 

sweet. those injectors out of the lightning 19#'s right