1999 Mounty 5.0 aka My Great Bad Idea

[97Sandbox]

On the 1960's Ford Mustangs, we have been removing the negative cable from the block then installing directly from the battery to the top starter bolts. It's a simple set-up but takes out the way low stock ground spot issues.

That sounds like how the main negative is ran on 4.0 trucks (at least the two I've owned) except they run the cable to the bottom starter bolt (4.0 OHV below).

I wonder why the 5.0 main negative cable runs to the timing cover. I bet I could swap in a spare V6 negative cable I have if I really wanted to bypass the stock one on the Mounty.

 

[97Sandbox]

I didn't get around to messing with the Mounty grounds last night, but tonight it fired right up, so I opted to drive it around a bit and see if the lean code came back (didn't feel like standing in the cold cleaning grounds anyway). I drove for 10-15 min at various speeds and loads and while there aren't any permanent codes yet, I have pending lean codes for bank 2 (P0174) and bank 1 (P0171) now. Should I keep driving until the codes show as permanent, or should I start testing for vacuum leaks and look into at the fuel system right away?

 

[410Fortune]

Find the leak! Either low fuel pressure or leaky intake somewhere with 171 and 174

This is the best info I could find on the web about why ford may have used a dedicated ground to the starter bolt on the v6 and just use the front of the block on the 5.0

Hot Rods - Grounding a starter

Simple question: Every article you read relating to wiring it stresses good ( grounds.) I usually go overboard and have numerous grounds throughout...

www.jalopyjournal.com

Possibly a ground loop was created or corrosion issue between starter and block? I dunno


I always thought it to be the v6 starter is on the battery side and the 5.0 it’s far from battery so they simply used a shorter wire
We all know stuffing the 302 into the gen ii was an after thought likely to compete w the Cherokee and Durango’s

 

[97Sandbox]

Sounds good. What's the preferred vacuum leak test method? I was reading about using a propane torch (just with gas flowing, no flame) and like the idea of how targeted it would be and the ability to reach the nozzle into tight spots.

If I can't find the leak, I'll need to get a fuel pressure tester. Given that the fuel filter is new and I cleaned all the injectors, I'm suspecting a fuel delivery issue would be due to failing regulator or weak fuel pump, both would show up as low pressure at the fuel rail, right?

Also, if my upstream O2 values are bouncing around in the 0-0.75 range while driving, does that sound normal?

 

[410Fortune]

Sounds like the 02 sensors are switching and doing there job reporting the codes

Fuel pressure test will show what a cold pump is doing

171 and 174 are usually air leaks at intake or intake gaskets
Pcv valve check make sure it’s still seated
Visual inspection of intake gasket make sure it stayed lined up as you smashed it down

Check all hoses, brake booster line, etx
Air is entering the system somewhere after the mas sensor and before the upstream 02s

If this was a ohv 4.0 9 times out of 10 it would be intake 0 rings. If this was a sohc 4.0 9/10 it would also be intake o rings upper and lower plenum
I have fixed a gazillion 171 and 174 codes w new intake gaskets

With an engine that has been running for a while the intake gasket leaks are easy to spot because soot builds up around the base of the intake where air is being sucked in

 

[CDW6212R]

Rent a fuel pressure test kit, and the engine needs at least 55psi, never below that. I had a lean code with my 99 V6 rarely, and early tests showed 55-60psi, mostly with the engine off. Finally one test was 50-52 psi while cranking, and barely 55psi idling. Normal pressure should be at least 60psi, but slightly under that is not terrible.


That's when I replaced the fuel filter, and doing that I found a torn rubber hose, the one between the pump and FPR. That was a small leak that took two years to finally reveal itself with the pressure test. I had already replaced the intake gaskets twice, when I bought it and did the timing chains etc, and later when the lean code popped up a couple of times.

 

[97Sandbox]

Thanks guys.

Sounds like O2 sensors are not the likely suspects. I will visually and propane check the intake gaskets. I won't say I never make mistakes, but I really made a point to use dowels to align everything when I installed the lower and upper intake manifolds, so I'm hoping those gaskets are fine.

I did check the PCV valve and hoses and all were still connected/seated.

One area I'm starting to suspect is the double-male EGR fitting. The threads on the header side were pretty chewed up, but I didn't have an opportunity to grab a replacement at a salvage yard and couldn't find it online.

I also need to re-torque my headers now that I have a couple heat cycles into them. I doubt that will resolve the issue, but maybe there's just enough exhaust slipping past the gaskets to throw the lean codes.

 

[Turdle]

Also, check brake booster hose and grommet

 

[410Fortune]

The egr would usually only effect bank 1 and you would typically get egr flow code

 

[97Sandbox]

The egr would usually only effect bank 1 and you would typically get egr flow code

I thought about this more and have to ask: does an EGR leak usually only affect bank 1 because the exhaust gas is escaping leads to the upstream bank 1 O2 sensor "seeing" less exhaust gas than expected? I'd think if air were sneaking into the EGR tube from a venturi effect, it would cause both banks to go lean because the EGR valve opens to the intake elbow which shouldn't have a bias to bank 1 or 2.

 

[97Sandbox]

Re-torqued all the header bolts I could access (one on right side I couldn't get with the heater box back in). Didn't get much of anything out of the left side bolts. Got maybe 1/8-1/4 turn out of the right side bolts.

I tried the hose-to-the-ear technique and probed around listening for vacuum and exhaust leaks. I may have heard some hissing at the EGR fitting, but it was hard to tell.

I also probed around gaskets and lines with propane and didn't notice anything, but we're experiencing sustained 15-20mph wind right now, so I'm not sure if the propane was actually flowing where I directed it vs. blowing away.

My only new discovery is that this EVAP line wants to delete itself under vacuum:

It's totally collapsed when the engine is running and looks like it's splitting. Leak or not, I'd just assume replace it. Can any old 3/8 ID hose work here? I'm thinking the kind of hose for rubber fuel line would work well.

 

[410Fortune]

You maybe right on the egr thing, I was thinking more along the lines of air entering through the leaky fitting into the exhaust flownon bank one when the egr valve is closed

Yes 3/8” fuel line will work in the Evap system

Why is it collapsing? That is very interesting
Any sucking noises when you open your gas cap after running?

The Evap system consists of a canister vent and canister purge solenoid, at wot both of these are to open and allow the vapors from fuel tank to be burned in the intake. If you have a pinched line or problem here (one stuck open) then it could cause negative pressure on the fuel tank? This can make it hard on the pump and strain the fuel system. An emissions referee once pointed out to me the engine vacuum can actually be enough to collapse a factory fuel tank!
I’m not saying this is happening in your truck, but it is not normal for that hose to collapse

I’ve never had luck finding vacuum leaks in these trucks with propane or ether … smoke machine however pin points them right away. I don’t have one (yet) so I still do it all with a flashlight and trail and error (remove intake have look see)

The intake elbow gasket, egr valve and gasket have also been sources of intake air leaks on the 5.0 when not sealed properly

 

[97Sandbox]

Why is it collapsing? That is very interesting
Any sucking noises when you open your gas cap after running?

I figured it was collapsing because it's under vacuum on the intake side and because it's old, flimsy material. Doesn't that hose (between solenoid and intake) see constant vacuum?

I will check the gas cap situation.

The Evap system consists of a canister vent and canister purge solenoid, at wot both of these are to open and allow the vapors from fuel tank to be burned in the intake. If you have a pinched line or problem here (one stuck open) then it could cause negative pressure on the fuel tank? This can make it hard on the pump and strain the fuel system. An emissions referee once pointed out to me the engine vacuum can actually be enough to collapse a factory fuel tank!
I’m not saying this is happening in your truck, but it is not normal for that hose to collapse

I thought the solenoid under the battery tray was the purge solenoid -- is that correct? If so, I'd think it would be closed at idle, in which case the collapsed hose would be under vacuum. Only when the solenoid opens would that vacuum be able to continue back to the fuel tank, which I think your saying is the correct function.

It may be worth noting, my EVAP monitor is the only emissions monitor that hasn't turned green during my 3-4 drive cycles since I reconnected the battery. I'm not getting a "EVAP purge valve low/no flow" code, but it seems the PCM is not seeing something EVAP-related that it's looking for. Thoughts?

I'll certainly replace the hose, but it sounds like it collapsing may be more of a symptom than it is the problem.

 

[410Fortune]

The hose should be hard nylon inside and a soft coating. Even with regular fuel line I have never seen it collapse
There is also a fuel tank pressure sensor
The pcm should let you know if the solenoids are not working and the pressure builds up
It may take more drive cycles to trigger these codes

Yes that is correct about the purge solenoid but the second “vent” solenoid is all the way back by the charcoal canister.. the two of them work in unison

 

[97Sandbox]

Okay, I'm on the same page then. I've recently been chasing a "EVAP purge valve low/no flow" code on my 2012 Civic (even after replacing the valve) and have needed to generally familiarize myself with EVAP systems. It seems the Ford and Honda implementation are about the same.

The hose should be hard nylon inside and a soft coating. Even with regular fuel line I have never seen it collapse

It definitely doesn't feel like there's any hard nylon tube in there. Maybe the nylon has brittled after years of heat cycles and cracked in several spots. I'm curious what I'll find when I pull the hose off. That hose does see full engine vacuum under normal conditions though, right?

Based on what we're saying, it sounds like it's possible the vent and purge solenoids are in working order, I just have a damaged hose that's "confusing" the purge valve. Wouldn't it be nice if $15 worth of hose fixed my lean code and EVAP system? Probably wishful thinking.

 

[97Sandbox]

I replaced the flimsy EVAP hose with 3/8 fuel line hose and it's still collapsing at idle. No sucking sounds at the gas cap while running or after shutting it off. Not sure what to look at next for this issue, I decided to go for a test drive and see if an EVAP code popped up. Right as I started the drive, an intermittent tapping/ticking sound popped up. From inside the vehicle, it sounds a lot like an exhaust leak, but from the engine bay not so much. It seems like its coming from higher up on/in the engine. It doesn't sound as harsh or metallic as I thought valvetrain noise would. It almost sounds like tapping coming from the intake itself. I tried to get a video with the sound, but I couldn't catch it before it went away. Any thoughts?

 

[donalds]

Check for a cloged pcv

 

[410Fortune]

Egr or exhaust leak will sound like rattle or tapping

 

[97Sandbox]

Pulled PCV valve and it rattles nicely (as it should, it was brand new as of the time I replaced all the engine gaskets). A bit oily, but definitely not clogged.

I turned my shop vac to blow and stuck it in the tailpipe then started poking around with my soapy water.

• Bank 1:
  • No noticeable leaks around head
  • No noticeable leaks at EGR valve
  • Very slight leak at header EGR Bung
  • Slight leak at collector
  • Very slight leak at ball flange
  • No noticeable leak at O2 sensor bung
• Bank 2:
  • No noticeable leaks around head
  • Significant leak at collector
  • No noticeable leak at ball flange
  • Moderate leak at O2 sensor bung

I can probably stop the EGR bung leak with a replacement fitting, just need to get one from a salvage yard. I might be able to tighten the right ball flange a little more, but access to that inside bolt is awful.

Maybe adding a copper crush washer to my O2 sensor will help it seal. This is the one that was loose, so the threads are pretty crusty.

The most significant leak though is the hardest to address. For anyone who followed my header thread, you can probably imagine my disappointment. I don't think I could weld that collector any better than it already is even if I was willing to cut it apart again and strip the nickel (which I'm not). So how to address it? My only idea (which I don't really like) is to clean really well where the 5-6-7-8 primaries join together and then paste some ultra copper along the seams. I could run the shop vac on suck to hopefully draw the ultra copper into the leak. I don't have high confidence in that repair holding up forever, but my motivation to do much else is quite thin.

 

[97Sandbox]

On second thought, ultra copper is only good up to 700F which won't cut it on a header.

I'm looking for any reason left to not give up on these headers, but after months of trying and trying, I think it may be time to cut my losses.