I have a '93 f150 5.0 302 w/ 152,000 miles on it. It has been kept well and not run hard. It has problems starting for the past few thousand miles, and has been in the shop but nobody can figure it out. It has a new fuel filter, new idle air control valve, plugs only have about 20k on them, same for plug wires, distributor cap seems okay, and it runs fine overall and never misses. It only has problems starting when it is warmed up sometimes, always starts on first try every morning when it is cold. It always starts eventually when the problem arises, but often takes 3-4 good cranks before firing. First time this happened a couple of years ago, it was the IAC, this time it is the same symptoms but I replaced the IAC and it did not fix it. The throttle body has been cleaned out too. The last guy who worked on it used to be a ford mechanic, told me he thought it could be the fuel injectors, so he cleaned them and it ran well for a month tops. Since then it's been back to hard starting, but he's still not even sure it's the injectors. He quoted me a price on 8 new injectors and labor and it was over $900, more than half what the truck is worth. So that sucks, hopefully that's not the problem. Anyone had this problem, anyone got any ideas on what it is? Know where I can get some injectors cheaper than $98 apiece?

 

Try turning your key to the run pos. for about 10 sec. before you start it
after it has set for a while.
If it starts right up it is not the injectors, more likely the fuel pressure
regulator not maintaining pressure when not running.

 

sub,

thanks for the help. Are you a mechanic, kinda sounds like it? A mechanic told me to try something like that recently, said it primes the engine for starting, and if it did not start then the injectors could be clogged or the fuel pressure could be bad. Anyway, it ALWAYS starts right up first try every morning when the engine has been sitting for hours. The problem occurs when it's been driven and then shut off for a few minutes and started back up. But there's no pattern other than it being at random when the engine is warm, which seems to puzzle everyone as to what the problem is. I have tried your tactic before when the engine was warm and it was having a hard time starting, and this did not seem to help it at all to start up.

 

Sounds like the opposite problem, too rich to burn.
One or more of your injectors is leaking fuel into the intake after you
shut off the truck, flooding the intake manifold.
If you let it set for awhile it will evaporate away to a point that it will start.
You can try holding your foot all the way to the floor while trying to start it,
but do not pause at the on pos. when going to the start pos.

Yes, I worked as a mechanic for a lot of yeas, retired now.

 

very sensible, you sound better than anyone that has looked at it. Actually a while back they originally replaced some kind of sensor that I think controls how rich the burn is because they thought it was bad, charged me $200+ and it didn't fix the problem. The owner of the shop was mad when he found out, said they overcharged me, so he offered to look at it and he actually had it 2 days and had my injectors cleaned. It ran better right after that for 1 month and then back to the problem. I'm wondering why nobody ever mentioned that one of the injectors might be leaking, since someone cleaned them.
What is a fair price for injectors and labor if I have to get any replaced?

 

The sensor they replaced was the Heated Exhaust Gas Oxygen (H) EGO sensor.
This is some times replaced when they see a PCM (EEC) code 42 or 92.
A code 42 or 92 is HEGO sensor circuit indicates system rich.
You can take it Auto Zone and they will read the codes for you.

A 42 or/and 92 can also be a leaking injector or a injector not turning all
the way off when running.

Any auto parts store can tell you the price, just call them.

Labor $$, you will just have to call around.

Good Luck

 

Yeah, the thing is that I took it to auto zone before ever taking it to a mechanic and the truck would not bring up a code on their computers. They couldn't really figure it out. I'm not sure if the mechanic got it to bring up a code or not, I kinda got the impression that the whole time they worked on my truck it was a 100% guessing game, and just from writing w/ you here on the forum, I'd feel much more comfortable w/ you looking at my truck and I don't even know who you are. I felt like they were trying this and that just to see if it was the problem, then charging me a bunch of money and not getting it fixed. So why would getting the injectors cleaned help the problem for about a month, and then it come back? I figured if one was leaking, it would happen even after the injectors were cleaned. Was it just coincidence? How confident are you about it being 1 or more injectors leaking? Those mechanics told me it was a hard job to replace the injectors, and said some of them were in a place where they'd have to pull something first.

 

How confident are you about it being 1 or more injectors leaking?

Without looking at it,
Fuel injectors 35 %.
Bad Ignition Module, 30 %
Bad Ignition Coil, 15 %
Bad Fuel Pump, 5 %
Bad Camshaft Timing, 5 %
Bad PCM (EEC), 5 %
Bad Fuel Pressure Regulator, 5 %


So why would getting the injectors cleaned help the problem for about a month, and then it come back?

Fuel deposits making them not seal or getting stuck.

Those mechanics told me it was a hard job to replace the injectors, and said some of them were in a place where they'd have to pull something first.

Not hard if you have the tools and are able to do it.
Very hard if you do not have the right tools. See 5 below.
A manual for your truck helps too.

Fuel Injector Removal
1. Open hood and install protective covers.
2. Disconnect battery ground cable and secure it out of the way.
3. Remove fuel cap at tank to relieve pressure.
4. Release pressure from fuel system. A valve at the fuel rail is provided for this.
5. Remove upper intake manifold and fuel supply manifold, HARD PART.
6. Carefully remove electrical harness connectors from individual injectors as required.
7.Grasping injector body, pull up while gently rocking injector from side-to-side.

Fuel Injector Installation
1. Lubricate new O-rings with light grade oil. (10W-30) NEVER use silicone grease as it will clog the injectors.
2. install injector(s) using light, twisting, pushing motion.
3. Install fuel supply manifold.
4. Install electrical harness connectors to injectors.
5. Install upper intake manifold, Tighten to 12-18 FT-LB. HARD PART
6. Install fuel cap at tank.
7. Connect battery ground cable.
8.Turn ignition switch on/off several times without starting engine to check for fuel leaks. System is pressurized to 40 psi.

 

thanks sub! I'll look into some of those things, sounds like just me telling you about it you're more confident that it could be the injectors leaking, which makes sense. I forgot to tell you, just remembered this, once in a while when I lean over the engine to check the oil I can slightly smell a gas smell. That goes along w/ what you are telling me. Do you think if I bought injectors at auto zone if that was the problem, that those would be quality parts for the truck? Maybe they carry motorcraft.

Matter of fact, if you don't mind, you could probably answer the burning questions I have about the truck:
1) antifreeze used to leak in the winter time only from the front left of the vehicle, I assumed the reservoir. Couldn't figure it out. Over the past few years, it began leaking year round, usually takes a few days before reservoir becomes empty when engine is cool. Now I put antifreeze in once a week. I've been told it's probably a bad radiator, but not sure about that, the truck never overheats or anything. What does that sound like?

2)Used to get a chirping sound from the fan belt every 6 mths or less, had to replace the belt even though it wasn't bad. It never went away unless belt was replaced, the truck has never had the same belt on over a year. Finally a mechanic told me it was because the water pump pulley cover was too round in design, and ford sold me a $7 water pump pulley cover that was more squared off in design, kinda fixed the problem. But I still get the chirping noise every 6-12 months now, not sure what that is about and nobody else is either. Belts are never worn down and I don't get them dirty. I've tried all brands of belts.

3) the a/c, defrost, vents seem to have a vacuum problem. Air blows on the floor all the time now, even when switch is off. I replaced the switch in the dash, did not fix the problem. Sometimes w/ a/c on, the air does not come out, so I have to switch it to max a/c or something, or jiggle it on and off. I think a piece under the hood up next to the cab/firewall on the passenger side is broken somehow, not sure what you'd call it. I think it has a crack or the 'lid' on it does not seal off completely when the vents/air are used. I suspect that is the problem, but do you think its the complete problem or do you think there could be a blend door stuck or something way up in there?

 

1. You just have to look real close to see where it is leaking, cracked hose,
cracked reservoir, over full reservoir or leaky radiator.

2. Might look at the idler pulley or tension pully or antifreeze on belt.

3. What switch, Fan?
You have a vacuum leak, maybe the slide control (OFF, A/C Max, A/C Normal).
Check all hoses from the vacuum manifold/reservoir to the slide control and then on to the vacuum diaphragms.

Fixing a bad vacuum leak may fix your starting problem.

 

fixing a vacuum leak could fix the starting problem huh? How's that?

I have replaced the control for the off, a/c max, etc.....whatever that is called behind the dash behind the ****. It did not fix the problem.

 

Bad vacuum leaks and bad grounds have allways been the place to look
when you can not figure something out.

The piston has a hard time pulling in the gas-air mix when you have a
bad vacuum leak, makes them hard to start.

Likewise poor compression will not make enough vacuum to pull in the mix
and you have the same thing.

 

dang, wish you were around here so you could fix my truck. Thanks man, I'll send you a personal email when I get the chance to look at the truck and let you know how it's going because I'm sure this post will eventually die out.

 

do u have to press your foot to the floor to get it to start hot? does it blow smoke after u do this to get it to start? does it seem to not quite run right after its warmed up, not as much power and maybe a little worse fuel milage? if you have answered yes to any of these questions then you may have a bad eng coolant temp sensor. you see when the truck is cold the eng has a set parameter of fuel to add as enrichment. kinda like the computer is adding extra fuel like a choke would do. the problem is after its warmed up this extra fuel is making the mixture too rich and you are having a hard time or impossible time starting because the mixutre is way too rich. the computer does not know that the eng is hot because the sensor is not working right. so it trys to start on the cold schedule and it no worky. its like the choke is sticking closed on a carb. the good news is that its an easy fix the sensor is like 18$ at autozone and it pretty easy to get to. just make sure u tell them its the sensor for the eng computer not the one for the gauge. they are 2 seperate systems. if you even have a gauge that is. even if u only have a warning light they are still two systems. its near the thermostat housing at least it is on my 95 but its a big socket i think like 1 1/8 or 1 1/16 if i remember correctly. at any rate it should take u about a half hour and less than 20 clams so hey thats better than 900$ or even 200$ also if it has been going on for a while you may want to consider changing the o2 sensor again. a whole lotta unburned fuel may not be the best thing for that or your cat converter. also regarding the coolant loss i had a similar problem never saw a leak but it went down slowly and i just kept adding fluid becase that was easier than thinking about a blown head gasket or cracked block or head then i ran some coolant flush through the system at my bi-annual coolant change and then the leak finaly showed up bad enough to leak when sitting and not just when under pressure. 180$ later my new radiator was in and the truck was cooling so much better that i could run my ac on the streets again. sorry for the long post let me know if this does it. its only 20$ so go get one at lunch today and just try it!

 

just currious what altitude u live at the higher u are the worse the artificial "enrichment" would seem. i live in salt lake its at about 4300'