Weird ford problem

[pmat1]

Re: Weird ford problem

lol i will probabily loose sleep tonight pondering what could be wrong
(i go to a vocational school for auto mechanics)

 

[Trent]

Re: Weird ford problem

Does this year model have a MAP sensor?

 

[Capt Ron]

Re: Weird ford problem

The only truck that I've driven with dual fuel tanks that worked well was a 1974 F250 w/manual valve. My 1974 GMC w/electric switch and the 1990 F350 both gave me trouble.

Only draw back of the manual was that it was located down on the floor betweeen the seat and door, hard to switch while driving. Just made it a habit to stop and get out to turn the handle.

I'm throwing odds that your valve is the culprit. Or, maybe the alternator threw a voltage spike and the computer is flaky. Have you unplugged/replugged the firewall connector? Also check the grounds.

Somewhere I have a book left over that covers your truck...

Capt Ron

 

[Capt Ron]

Re: Weird ford problem

Ok, I found my book and looked through it last night. I will assume that your truck has EEC-IV but you will have to check the emissions sticker under the hood for your vehicle.

Also, there is a dual tank system that uses a low pressure pump in each tank AND a high pressure pump mounted on the left frame rail. The in-tank pumps feed a fuel reservoir and the dashboard switch operates the pump in the selected tank. The low pressure fuel operates the valve for the fuel and return lines with the fuel flowing to the high pressure pump. The ports for the non-selected tank are blocked off. (Now I see that this may only apply to the 7.5L "Hot Fuel" engines as the book only gives pressure and flow rates for the low pressure pumps under that engine. However in the text they say that it was used on dual tank trucks with the early EEC-IV through '89).
The later model vehicles incorporate an in-tank fuel delivery module.

Pressure test: (engine off) 35 to 45 psi
(engine running-vac hose connected to regualtor) 30 to 45 psi
(engine running-vac hose disconnected) pressure should increase 5 to 10 psi

Low pressure pumps (volume) 6oz minimum in 5 seconds.

Yes, there is a MAP sensor. The PCM uses the MAP sensor to control fuel delivery and timing.

As I was reading this book I realized that I had attended a factory sponsored week long school for this down in Miami about 20 years ago. Somewhere I have that certificate. During a break they showed us a Taurus that was being converted to 4 wheel drive with a protoype kit. About all I remember for some reason...actually now I recall having a cold and turning my brain to mush with pills.
The last time that I worked on an EEC-IV car was in 1999. CRS is becoming more serious with age.

Good Luck,
Capt Ron

 

[cam gear]

Re: Weird ford problem

Timing chain is sloppy, This is a common problem, with all north American engines the stock timing chain is cheaply designed. if it skipped a tooth it would not run. Grab the crank damper and jerk it back and forth, with the distributor cap off, if the chain is sloppy enough, you will not see the rotor move in relative motion. but that could be a guess

 

[Capt Ron]

Re: Weird ford problem

Timing chain is sloppy, This is a common problem, with all north American engines the stock timing chain is cheaply designed. if it skipped a tooth it would not run. Grab the crank damper and jerk it back and forth, with the distributor cap off, if the chain is sloppy enough, you will not see the rotor move in relative motion. but that could be a guess

Unfortunately this test isn't a good indicator of the condition of the timing chain. Since the engine (and chain) only turns in one direction while running then there is slack on only one side. The spec for this slack is 1/2" so even a new chain can give questionable results while jerking the damper back and forth.

The only way to correctly check the timing chain is to remove the timing cover and measure the deflection at the mid point of the chain.

One thought that does come to mind however is the distributor shaft, loose in housing/bearings.

Capt Ron

 

[cam gear]

Re: Weird ford problem

Ok my bad, sorry captain Ron, I have worked with north American v8 engines since I was about 12, I am used to what a worn out timing chain feels like when I jerk the harmonic balancer back and forth. There also could be a problem with the distributor as well.

Turn the engine over by hand to TDC, then move to about 30 degrees advance, by hand, this takes up slack in the chain. If its worn at all. Then mark where the rotor is pointing and move the crank dampener back to TDC, if the rotor don?t move the chain is worn out. you can do this a few times at different points, to see how worn out the chain is.

Simple test is all it is. Also I would Pull valve covers and check operation of rockers, are they all lifting at the same height?

 

[StoutMann]

Re: Weird ford problem

in doing so they let the vacuum hoses, and wiring for the EGR valve lay against the EGR tube coming off the exhaust manifold, and it burned the hoses and wires... the check engine light came on, and was throwing EGR codes...

So you had wires laying against a ground. My bet is you are chasing a mechanical problem when you have an electrical problem. Wires getting hot will melt where they are hot. Wires shorting out will possibly cause problems in the circuit somewhere else or possibly another circuit in the harness. Because you have a computer and wiring harness being combined with cut/burned wires laying against an exhaust hot ground, I would verify your harness and computer are good. Checking for codes probably isn't sufficient. Either way it sounds like a real pain. Also sounds like a nice older truck with low miles. Don't give up.

 

[puddle jumper]

Re: Weird ford problem

The only two things that come to mind of what you have described is a plugged exhaust converter (easy way to check this is with a heat gun and the inlet should be about 100 degrease cooler than the out let) or the charcoal canister could be flooded with fuel.

 

[hagers11]

Re: Weird ford problem

had a similar problem w/ a chevy though. Same exact symptoms to make a long story short the problem was sticking valves in ALL cylinders. Compression was great. We removed the valve covers and with a borescope in the spark plug holes we tapped the valves and they hung open. Truck normally sits for awhile.

Thought it might help

 

[cougar1985]

Re: Weird ford problem

my buddies dodge truck had about the same weid problems,it was under the drivers side around the frame if i remember correctly there is a wiring set for the in tank fuel pump and due to snow and rain and the likes it was shorting out and giving him all sorts of fits.he darn near rebuilt the truck till he accidently found out about the wiring!worth a check if it applies to your ford.

 

[dolluper]

Re: Weird ford problem

Me thinks you should check the dis....fast way crank her up on the advance then take test drive iffin lots of power your shaft has siezed on the housings bushings....doesn't advance right....or wrong egr valve ...mixed up bp when should be neg or vise versa

 

[rbh]

Re: Weird ford problem

If this problem started after the alternator was replaced, odds are what ever you found melted is the begining of the problem.

 

[Numlaar]

Re: Weird ford problem

Hey gang,

I know this is an older thread, but in case some of you were wondering what the outcome was (a few had asked).

It was in fact the distributor...

Even though the timing was advancing, something in the distributor module was still borked.

Dropped in a rebuilt one, and she was good to go.

Hope that info helps!

Num

 

[j_martin]

Re: Weird ford problem

Is it possible that when the EGR valve harness got burned, it took out the output driver in the ECU for the EGR valve.

The outputs tend to be optical couplers, so it can burn out without causing any other trouble in the ECU. That said, the OC chips are usually pretty easy to replace, sometimes even socketed.

You need to probe the lead for signal when it's supposed to be there.

hope it helps
john

 

[dolluper]

Re: Weird ford problem

My first think was the dissy glad shes running right ...it's a big flaw with most manu's oil has a hard time going uphill

 

[Vlad D Impeller]

Re: Weird ford problem

Mass air flow sensor?

 

[Candy]

Re: Weird ford problem

Your Ford problem sounds like what happened to my 1999 Ford. I live down a dusty dirt road and one day my ford just started acting like what you described. I took it in to the shop and the problem was, there was too much dust collected up under the plastic protector for my electric fuel senceor.
He took that plastic cover off and took the air hose to it and the cover and I haven't had that problem since. Hope this helps. Good luck, Candy.