5.0L XR Shiny Engine Bay Pics

[john keefe]

One positive during this time-out from business is a little extra hobby time, after completing my backlog of Honey-Do remodel projects on our house. Took a few years, actually, to get around to installing everything. Thought it would be a 3hr. job, tops. After all, it was designed to install on basically the stock 5.0L (and 5.8L) block. And, I never really gave it a lot of thought, just kinda' assumed (OK, hoped) it would be almost plug-and-play.

GT40 upper intake, Ford Explorer lower intake modified for appropriate sensors, 65mm TB (stock is tiny, 58mm orifice but it steps down to about a 45mm opening at the sensor), 73mm EGR spacer, 76mm Mass Air meter. Lot of spray painting, and metal polishing. OK, I'm not just cheap, but pretty "detailed" oriented.

Turned out I had to make my own vacuum trees and siphon tubes, a few brackets, the intake tube (3" ABS drain pipe), had to rebuild 24lbs./hr injectors, rebuild the Mass Air meter mount, etc., etc.. Lot's of test fitting to get everything as close to the stock setup as possible, so it would be an easy job to swap it all out for smog testing. Took over a week. Go figure, another XR project with surprises.

Next time, I'll swap on the AFR heads, 1.7:1 roller rockers, main stud girdle, race pan, etc., but at least the work will go a lot quicker then.

Still pondering a way to add a triangulated strut tower brace that bolts the the firewall below the cabin fan.

Huge improvement in performance over the stock setup. But, now I'm following a bog under hard acceleration, around 3K RPM. Works great under smooth acceleration, just not when you really kick it. Reset the idle, and replaced and reset the TPS (thought it might have glitch spot that got magnified during fast opening of the TB), but that's not it. Thinking it's now likely the fuel filter. Walbro 255lph is fine, but the filter is probably clogged enough that rapid demand for 24lbs injectors, vs. stock 19lbs, results in starving. Or, the FPR is not up to the job. Or, a new set of plugs?

Any ideas on chasing this down would be appreciated. CATs and O2 sensors are good.

And, to no surprise, the Power Steering pump decided to blow through the seals, and drained out completely. Replaced the problem seals, but still very heavy steering, and no return to center. Now, if it stops raining, I'll have to cobble something up to vacuum bleed the refilled unit. Unfortunately, the old "turn the wheels stop to stop" isn't bleeding it.

GT40 Intake, TB & MAM 4.JPG (1005.96 KiB) Viewed 3855 times

GT40 Intake, TB & Mass Air.JPG (1 MiB) Viewed 3855 times

GT40 Intake, TB & MAM 3.JPG (1012.82 KiB) Viewed 3855 times

[zxr250cc]

Hi all,

I would say that the symptom of a bogging down on full throttle is like mine when the fuel filter was filled with crud from the tank after sitting a long while. A new filter was an easy fix. It might work for you as well. The overall look of the install looks very good indeed.

Cheers

[john keefe]

Thanks for confirming it could be the fuel filter. This did sit for quite a while with a battery-tender, and only occasional starting. Wasn't noticeable with the 19lbs/hr injectors a couple weeks ago, but makes sense that minor clogging would exacerbate when swapping to 24lbs/hr. Hoping it's not the FPR, as the upper intake has to come off to replace it; my spare is an adjustable FPR, which would be problematic to adjust since there's no room with the intake installed.

[thesameguy]

That looks effing amazing - what a phenomenal engine bay!

I'd be unlikely to suspect a fuel filter... A delivery issue like a clogged filter wouldn't clear up after a second, it should get worse with RPM.

To me it sounds like a mixture issue - specifically an acceleration enrichment issue. I don't know much about EEC, but I'd assume you see mixture set by MAF and modified by load (TPS), and there is a specific enrichment associated with increased load. I'm thinking that bigger injectors are messing up that equation. Was there software to go with the bigger injectors? Maybe this is something you could see on wideband to see whether you're going rich or lean? On other MAF cars I have (I won't lie, they're all Saabs) this *specific* behavior (3000rpm bog) is often associated with MAF, but since you've got a rebuilt that seems less likely.

[john keefe]

Thanks for the comment, much appreciated! Heckuva lot easier to make a clean, neat engine bay when you relocate the battery to the trunk.

As far as all my research, and books on 5.0L builds, there shouldn't be any issue, or need for re-mapping the fuel enrichment. AFAIK, after disconnecting the battery long enough to wipe the A9L EEC-IV memory, start-up with the new combo will have the A9L relearning for the new readings, and everything should be fine after a warm-up. The MAM is a C&L, with the correct tube for 24lbs. injectors.

It's only when I really stomp on it that I get the bogging, and it clears up if I back out of it briefly... going about 85% acceleration rate, no problem at all. Pretty nice punch.

[john keefe]

The more I think about it, I'm less sure it's bogging because of fuel, and maybe just not firing accurately. Can't figure out if it feels like fuel starving, or bogging down from excess fuel not being ignited. If the former, then could be the filter, if the later, than it's spark. Not a misfire, no backfiring, just stumbling along until I back off.

During the swap, I replaced the cap, and noticed that the carbon track on 3 of the 8 terminal pins were not centered, but retarded (i.e., the carbon build-up was off-center, and sparking after the rotor passed center. I have a billet MSD distributor (didn't want to swap it in, as I wanted to add too many new variables for the shakedown). The stock distributor had more axial play in the shaft. Didn't put 2 + 2 together at that time, but I wonder now if that wobble/play is enough to cause the problem?

I've got my stoichmeter on a dash switch which lets me joggle between O2 sensors (and cylinder banks), and both show the normal switching between lean and rich. Haven't observed the readings during the glitches, but next time out, I'll try to duplicate the fault and watch the stoich.

[andyofcolumbusmerkur]

Looks like it belongs in there.

[john keefe]

Thanks Andy. Amazing what a little elbow grease polishing out AL will do for the bling. Funny, although this intake is big, and sits about the same height as the 2.3L intake, it seems like the whole 5.0L does fit in there visually a lot nicer, and lower. Too bad the stock 2.3L didn't come with the intake stuff devoted to the driver's side, instead of the crossover. I think that's what makes the RS stuff look so good. Still crowded with all the wiring and vacuum harness, but having a bare valve cover with Cosworth bossed on it looks very clean and racey.

[thesameguy]

Yes, unless it's a SHO or something Italian, we'd probably rather see the valve cover than the intake manifold.

[john keefe]

Yeah, an SVO long/short multiple runner for a 5.0L would look SO cool, but nobody's come up with that combo for a 5.0L. It's either long runners like the stock or GT40 intakes for low end TQ and weak high end HP, or short runner intakes for high end HP that drastically drop off low end TQ. It would have to look as nice as the SVO, though.

[andyofcolumbusmerkur]

So what did you use as a donor? Or is it a combination of a little this and a little that?

[john keefe]

I actually found a donor 5.0L Mustang off Craigslist, sitting on a ranch near the coast here. It was the son's car and needed work, but the Dad needed to clear out the barn, and told his son to either sell it, or finish it. For whatever reason, the son didn't have time to finish it. When I had it loaded onto the trailer, the Dad asked his son what he wanted to do with the "built" balanced race motor somewhere else on the ranch, and he decided to sell that too. Overall, pretty cheap.

Didn't want to take a chance trying to pass the smog ref, so I did a complete rebuild on the stock motor, ported the heads. I I laid out the Mustang's wiring harnesses with two XR's to make a third harness that integrated the two. That took a while, laid out on an 8' folding table for a few weeks, as I ended up researching and doing several schematics for all the various components. Had a muffler shop build a stock-looking exhaust with cats that fit under the XR.

The second engine had all Holley Systemax stuff on it (heads, intakes), which is a great combination, but none of it was smog legal. So, for the eventuality when I would drop it into the car and have to pass smog test, I traded all the Holley stuff for the GT40 intake and cash, then used that to buy AFR heads with all the smog ports, a C&L Mass Air, custom billet EGR/TB, CompCams 1.7 rollers, ARP stuff, etc., etc.. Unfortunately, that's motor's been sitting since, and I could only rotate it now and then. Would take too long from my Boss's other remodel projects on this house to make a full swap, but eventually I decided to at least try the intake. Next chance, I'll do the 1.7 rocker swap (from stock 1.6), and see how that works.

[andyofcolumbusmerkur]

I was asking because recently I was learning about all these mustang differences. I started watching that 417 fox guy on youtube, and some of those cars can get pretty rare and valuable. Also I never realized the last year of the foxbody had a less desirable 302. And how the MAF versions tend to respond well to mods. Guess I always thought a 5.0 was a 5.0.

[john keefe]

Almost always do respond well to mods... still have some troubleshooting to do sometimes, like now.

Regarding the stumble under hard acceleration: I changed the fuel filter (good call, anyway), new plugs, cap and rotor, swapped TPS and reset a couple times now (sweeps fine with analog meter), and re-checked the new vacuum tree and hoses. This eliminated the "test" bogging while hand-cranking the throttle plate when parked. It only stumbles under moving load, but otherwise runs very smooth at idle, and accelerates nicely through all gears. If I gradually accelerate and then kick it in above 3500rpm, no problem.

But now, I'm getting minor backfiring to go with the stumbling, which seems to be in the exhaust only. It's almost like opening the TB quickly dumps too much fuel on tap, and it's just getting bogged down.

No CEL, though I'll check for memory codes tomorrow. I retained all the stock control/actuator/sensor components, so basically its only mechanical items which have changed to increase airflow and volume, plus 24lbs injectors. IOW, kept the stock mass air flow (MAF) sensor, good TPS, same distributor, stator and TFI, coil, and wires, same base timing. The new hard components are the upper and lower intake, vacuum trees, larger MAF Air housing, and larger TB. The EGR is newer, but that tested OK for diaphragm movement under vacuum.

Although that seems like a lot of change, it's basically just a larger mechanical air pump version of the stock setup, with the appropriate injectors and mass air tube for 24lbs. injectors; the PCM shouldn't have any problems, and in fact seems to run perfect as long as I don't accelerate full throttle. If I don't get codes, I guess the next step is to go back to a stock coil (have an older MSD coil in it now), and if that doesn't work, then swap in the MSD distributor.

Any more ideas?

[andyofcolumbusmerkur]

Drive a couple tanks of gas through it maybe?