Ford Automobiles banner

1 - 20 of 47 Posts

·
Registered
Joined
·
47 Posts
Discussion Starter #1
:mad2:

I've been working this problem for quite some time. I'm in Mexico so I'm on my own on this but a willing participant nonetheless.

99 CV P73, 245000 miles.

Cold start stumbles, coughs, kicks and complains but when I goose it, (Italian tune-up), it seems to run fine with no problems unless it sits for several hours.

Replaced EGR, Idle Control, MAFlo, IAT, plugs, coils. Vacuum lines look good. I checked the fuel pump relay, it works when tested, but I don't hear the pump running when I turn the ignition on (no start).

I get 12 volts at the relay base but I's probably low amp until the computer turns it on. IN any case, it's not coming on. When I jump the contacts at the relay base, I hear the pump and get pressure at the pressure relief. I don't have a pressure gauge however, and I do not get a gush of fuel, just a trickle, whether the car has been sitting all night or when it has just shut down. I did not check it while the engine is running.

The fuel filter was changed a few years ago and there are no performance issues after the engine settles down, so I am not certain about a fuel delivery issue; I think it's OK. (Unplug the relay, engine shuts down.)

I have a scantool program (ScanXL from Palmer with the Ford Enhancement) so I can see all data. I can't see fuel pressure data on the rail however. Maybe someone can tell me if the PID exists for 99.

The gas cap is tight, I can't see a crack in the intake (plastic) manifold, but that doesn't mean there is not one there.

This problem has been going on for several months, maybe a year. I've resorted to the "Italian tune-up" method to overcome the bad starting but I think I need to address this now. I also recently discovered that my right side catalytic converter is probably bad, it rattles now (internally).

This car has been well maintained with all needed repairs done in a timely manner. I've replaced a rear axle, harmonizer pulley, idler tension pulley, alternator, sensors mentioned above, front end components etc. It is entirely stock with no mods whatsoever. I have the shop manual and the Alldata subscription. Access to tech data is not a problem, testing equipment is.

At this point, I'm probably looking at an intake manifold and fuel pump unless someone a lot smarter than me can give me some tips, especially explaining the fuel pressure and pump relay workings, that would help. Like everyone, I'm limited financially but I want to keep the car. I bought it new and I love it.

Let's see what you can do.:confused:
 

·
Registered
Joined
·
798 Posts
Need to know the fuel pressure (FP) to help with the diagnosis.
When the key is turned to run (not start) the FP will run for 3 seconds or so then shut off if the key is not turned to start. After the engine fires the FP will turn on again.
There is a fuse, relay and a crash sensor in line with the FP. The crash sensor may be located in either foot well area behind the kick panel.
No PID for FP, it's checked at the fuel rail with a gauge. You can use a cheap tire pressure gauge but it will be junk after-wards....hence a cheap one.

Does it seem to be running rich right after it fires up? If so the FP regulator may be bad. Pull the vacuum hose...look for raw fuel. If so the FP regulator needs to be replaced.
 

·
Registered
Joined
·
47 Posts
Discussion Starter #3 (Edited)
Need to know the fuel pressure (FP) to help with the diagnosis.
When the key is turned to run (not start) the FP will run for 3 seconds or so then shut off if the key is not turned to start. After the engine fires the FP will turn on again.
There is a fuse, relay and a crash sensor in line with the FP. The crash sensor may be located in either foot well area behind the kick panel.
No PID for FP, it's checked at the fuel rail with a gauge. You can use a cheap tire pressure gauge but it will be junk after-wards....hence a cheap one.

Does it seem to be running rich right after it fires up? If so the FP regulator may be bad. Pull the vacuum hose...look for raw fuel. If so the FP regulator needs to be replaced.
Thanks for the response.

Thanks for explaining the fuel pump relay cycle. Makes sense as to why I could not see a thrown relay after I turned the key on; it took maybe 10 seconds to get out from behind the wheel and back under the hood.

The fuel pump circuit is good. The fuse is good etc., and the car is running after it starts up. The fuel pressure gauge is a must, I'll have to find one. I did pull the vacuum hose of the pressure regulator and got a slight increase in idle RPM. What should happen when I pull the vacuum line off the pressure regulator? Is the slight increase in RPM normal, or should something else happen?

Yes, there is a raw fuel smell while she is stumbling on start up, so that makes her rich, but I saw no raw fuel. I did hear a "hissing" sound from the FPR however, that was vacuum.

EDIT ADD: On another note, I did a conversion on the pressure spec on the fuel rail with key on, the spec calls for 240 kpa and that translates into 34.8 (or so) psi. There is no way in the world I am getting 34 PSI off the pressure release, NO WAY. I'm getting, about.......zero.
 

·
Registered
Joined
·
4,352 Posts
Sorry, I didn't have time to read this, or give it any thought, but the fuel saftey inertia switch is in the truck driver's side.

You're in good hands with Cuda_Jim ! :)
 

·
Registered
Joined
·
47 Posts
Discussion Starter #5
Sorry, I didn't have time to read this, or give it any thought, but the fuel saftey inertia switch is in the truck driver's side.

You're in good hands with Cuda_Jim ! :)
Thanks for the input. I'm wondering if the emergency fuel shut off (crash sensor) might be partially closed or otherwise jiggy. The car has some rough play in the back seat from time to time, :ihih: but nothing that would have set the inertia cut off switch; she's never been front ended. Could that get knocked around during normal wear and tear?
 

·
Registered
Joined
·
18 Posts
It seems to me that if the car wasn't getting enough fuel, then it would run better at idle than it would at higher RPMs and under a load. I suspect a vacuum leak somewhere.
 

·
Registered
Joined
·
47 Posts
Discussion Starter #7
It seems to me that if the car wasn't getting enough fuel, then it would run better at idle than it would at higher RPMs and under a load. I suspect a vacuum leak somewhere.
It makes sense, but it runs great at 1000 rpm to redline. It even idles fine after 5 minutes. The problem is in the initial startup.

I am having trouble understanding that, if there were fuel pressure issues, how fuel delivery could maintain the load at higher RPMs. I thought that the FP either works or it don't.

The condition seems to self heal after a few minutes of idle time after a cold start, so something is hanging lose at cold start and then settles down after a few minutes at idle.

I am also having trouble understanding why the car runs. I should see 34 psi at the pressure release, I see a mere trickle 5 seconds after shut off; it should shoot a stream of fuel to the engine hood and go all over the place, but it merely runs over like a warm beer; 34 PSI is a lot of pressure.

So the pressure is either NOT being achieved or not being maintained. How could the car run with a few PSI FP?

Sheesh.....I want my mommie.
 

·
Registered
Joined
·
798 Posts
Yes, there is a raw fuel smell while she is stumbling on start up, so that makes her rich, but I saw no raw fuel. I did hear a "hissing" sound from the FPR however, that was vacuum.
Have you checked for a vacuum leak? (Spray Brake Cleaner at suspects while running)

Have you performed a compression test or......better yet, a leak down test?

The fuel pressure is most likely leaking down. This could be a leaky injector or a bad FPR. Try cycling the key 3-4 times before your next cold start. If it fires up OK the fuel pressure has bled off.

Block the vacuum line when you pull it from the FPR, it's a vacuum leak. It will cause a poor idle.
 

·
Registered
Joined
·
798 Posts
Sorry, I didn't have time to read this, or give it any thought, but the fuel saftey inertia switch is in the truck driver's side.

You're in good hands with Cuda_Jim ! :)
Doooh! it's in the trunk...thanks Poppy
 

·
Registered
Joined
·
798 Posts
It seems to me that if the car wasn't getting enough fuel, then it would run better at idle than it would at higher RPMs and under a load. I suspect a vacuum leak somewhere.
I agree on both points.
 

·
Registered
Joined
·
18 Posts
An engine requires a much richer fuel/air ratio when the engine is cold. This could explain why the engine runs fine after it warms up. However, it most likely is running lean which could cause damage if not corrected ie. burned valves, damaged catalytic converter, etc. I think Cuda is on the right track with a bad fuel pressure regulator. Which I think is vacuum actuated (vacuum leak suspect).
 

·
Registered
Joined
·
47 Posts
Discussion Starter #12 (Edited)
Have you checked for a vacuum leak? (Spray Brake Cleaner at suspects while running)

Have you performed a compression test or......better yet, a leak down test?

The fuel pressure is most likely leaking down. This could be a leaky injector or a bad FPR. Try cycling the key 3-4 times before your next cold start. If it fires up OK the fuel pressure has bled off.

Block the vacuum line when you pull it from the FPR, it's a vacuum leak. It will cause a poor idle.
Compression test, no. I sense no compression issues as there are no power issues under load. In other words, it hauls ass and has no problems in that regard even with 200+ pounds in the trunk.

It sounds like you're suggesting that an injector or injectors are not closing or not closing tightly after shut down causing a gradual loss in stored fuel pressure and leakage of fuel into the cylinder, is that right? CAn I check the injector cycle with a meter? The scantool shows no issues, should I get a code if there is an injector malfunction?

If the injector was leaking at the seals, should I see a fuel stain on the rocker arm covers or around the injector body? I'm not talking about a wet stream, perhaps a vapor stain like an oil leak. Ever see that before? How can I get to that without testing equipment and without blowing myself to smithereens.

The vacuum leak will get checked out with brake cleaner spray.
How about I post images of the plugs I took out last week? I put them in the plug box numbered as to what position. Will that help? I also don't understand the relationship between the FPR and stored fuel pressure after shut down. Does the FPR seal the rails from the supply if there is no vacuum?
 

·
Registered
Joined
·
798 Posts
A compression test is not the total answer to poor engine perf, a leak down test is.

Yes, a leaky injector or FPR would cause a very rich condition during startup. The scan tool will not tell you if it's leaking...only how long the injector is open. The pintle and seat wear out after time (245,000 miles). It's just like a needle and seat on a carburetor. It would throw a code if that particular cylinder was misfiring...not just leaking down, monitor your front o2 sensors during start-up, it should show a very rich condition if there is fuel leaking into the cylinder(s). This will help determine which side of the engine the offending injector is located....if you have a bad one that is.

The leak is internal, you would not see any it.

Not sure where the check valve is located in this particular system, hopefully someone else will chime in for that.
 

·
Registered
Joined
·
47 Posts
Discussion Starter #14
OK, I'll monitor the startup in the AM and record the O2 sensors values. Sounds like the injectors might need replacing anyway after 245000 miles, especially with the last 50k or so burning Pemex gas. The gas is OK, but not as clean as State-side, that's for sure. I don't want to waste money on "injector service," especially here.

I have a feeling that the problem is on the left bank, the left catalytic converter is rattling and if I remember right, plug #8 looked a bit rich.

Everything else on the car is great, no overheat issues, no oil consumption issues blah blah blah. I really want to get this car back to baseline.

I think you're on the right track though. All the symptoms are there. We'll have to look closer. Would you recommend injector replacement anyway? Seems to me it should be done after 11 years and 245000 miles. What do you think? Of course, if I get a positive rich on the O2 sensors at start up, they'll all go.
 

·
Registered
Joined
·
4,352 Posts

·
Registered
Joined
·
47 Posts
Discussion Starter #17
You should not hear hissing at the FPR. There is your vacuum leak.
I ran out and listened again to the engine, particularly the FPR, and that hissing sound was the air passing through my skull. I used a medical stethoscope with a hollow rod and checked carefully around the FRP, vacuum lines etc. and there is no hissing, the pipes are tight as a drum. I did get a hit in the back of the intake but could not isolate a leak source, I think I'm hearing the suction inside, the steth is very sensitive.

I'm thinking I might not have put the vacuum tube back on the FRP correctly although I did double check these connections before I buttoned it up on Sunday.
 

·
Registered
Joined
·
4,352 Posts
I'm thinking I might not have put the vacuum tube back on the FRP correctly although I did double check these connections before I buttoned it up on Sunday.
Did that fix your cold start problem?
 

·
Registered
Joined
·
2,028 Posts
check the hoses themselves. there may be a leak in like the middle, and you wouldn't know it. usually if mine had a cold start problem, it was the IAC, but that was on my 89 with a 302. i don't even know if the 4.6 has one, but should...
 

·
Registered
Joined
·
4,352 Posts
Yep... the 4.6 has one.
Here's a picture of that bad boy :)

And the TPS is a little easier to get at than on your's
 

Attachments

1 - 20 of 47 Posts
Top