Cold Start Issue

[Micheal Nadeau]

I know everyone is gonna beat me with sticks, but I am going to ask anyhow. 6 days ago, I fired my car up to leave work. It kinda sputtered then smoothed out. My car has always started and idled around 1K for about 20 - 30 seconds and then settled around my set 650-700 rpm range. This time was a little different. When it caught itself, it immediately ran around 700 rpms. I take off from work and its sputtering any time I give it gas. it goes about 3-4 miles and finally settles down. I stab it and hit an undisclosed speed with no issues. Get home, pop the hood and check some wires and vacuum hoses, everything looks ok. Now every day when I start my car cold, it runs like crap. Gets warm and its ready for a track night. I checked my injectors, nothing leaking down into the cylinders. Plugs are maybe a month old (NGK), wires are the same (ford racing), fuel filter maybe 6 months old. Fuel pump is 1 1/2 year old Holley. Dizzy is stock Motorcraft with MSD cap and rotor. Coil is about a year old MSD. Battery is good (Interstate) and I have a hard charging Taurus alt on it. I checked my fuel pressure. Key on engine off, hits about 22psi and plummets. Running its at 42 vacuum removed. I don't have fuel in my vacuum line either. I took my AFPR apart to check the diaphragm, can't see any tears. The gasket where it mounts to the fuel rail was shot, so I replaced it. I haven't, and probably should have, put my stock fuel pressure regulator on to eliminate the AFPR. Timing 14 degrees. Another note, the car didn't seem to break up with the Spout removed. I am on my way back outside to pull my fuel filter to make sure I don't have trash in it or the line. Any ideas, links, knocks over the head would greatly be appreciated as I am stumped, and I do this everyday.

 

[toyman]

Check the voltage to the fuel pump with the engine off and then on. The 22 psi KOEO is suspicious. It should be close to 40 psi. Ground the fuel pump as illustrated to keep it on.

 

[jrichker]

Fuel pump pressure test
Disconnect the larger of the two fuel lines up by the Schrader valve. It is the return line and does not have the Schrader valve on it. Find a piece of rubber fuel hose and clamp it on the return line coming from the regulator. Stick a bolt in the other end of the hose and make sure that all your connections are tight and leak proof as possible. When this powers up, you don't want fuel squirting everywhere. Hook up the fuel pressure test gauge. Turn the ignition switch on and watch for leaks. You may want to use a helper inside the car to cut the switch off quickly if you have a leak. To trick the fuel pump into running, find the ECC test connector and jump the connector in the Upper RH corner to ground.

Caution!!! You have blocked the return line for the fuel pump! Pressure will rise very quickly past safe levels with a good pump
If the pressure goes up past 55 PSI, the pump is good and the fuel pressure regulator is bad. If the fuel pressure does not hit 55 PSI or more in a few seconds, the pump is bad or you have electrical problems.

 

[Micheal Nadeau]

Thanks for the replies, I finally found a thread about a fuel check valve in the fuel pump module. Once I am running good, I have great pressure. Its just that first couple of minutes. I will try blocking off the return line. This test will confirm the check valve. I know I am good every where else. I will update tomorrow when I get home from work as I have Sunday off and can leave the car apart over night!!

 

[Micheal Nadeau]

I got the fuel tank removed and started inspecting parts of the fuel system. On the pump hanger, there is an orange "regulator" rubber piece on the return side. it was completely torn. It slows the fuel return, and the way it was torn, it wasn't doing anything. So my fuel pressure wouldn't get above 20. I replaced it, reattached everything and tested again. Key on Engine off, fuel pressure jumped to 36 psi and fell very slowly. So now I am good there. I fired the car up and it immediately seemed better...................for a few seconds. The car stumbled a little bit and started running like crap again. Rev it up and it breaks up BAD. I pull the spout and it smoothed out. Rev it up and its smooth, no breaking up. I checked my timing the other day and it was at 14 degrees. I checked it after it was hot, not cold. My issue is only when it's cold. Can a TFI cause issues cold?

 

[toyman]

Check the harmonic balancer. Look for rubber protruding from the center on the engine side, wobble or any lateral movement. Common issue as the cars age. Has the timing been changed recently? If it has and the outer ring has slipped the reading will be incorrect. TFI hot or cold could be failing as well.

 

[Micheal Nadeau]

So I started the car to leave work. Had the timing light hooked to it before I started it. Fired the car up and watched. The timing was jumping all over the place. The light was cutting out every couple of revolutions. I pulled the spout and the car immediately smoothed out and showed a constant 14 degrees. I drove it home with the spout out. I didn't have my distributor wrench, but I do have another dizzy. I will pick up another TFI module. I smoked tested the motor, which was beneficial for other reasons (brand new valve cover gaskets leaking which has me concerned about my cobra valve covers) I have no other leaks any where else. I checked all of my grounds. Everything checked out good.

 

[Micheal Nadeau]

I put a new distributor in, no change. I had to order a Motorcraft TFI. I couldn't bring myself to buy a Duralast or BWD (Broken When Delivered) version. I need to check wiring again. With the Spout out, car runs perfectly fine. I need to be sure that I am not missing something and maybe the computer is causing this issue. My only other thought was my remote start. There is a tach signal wire, but I doubt that could be causing the issue.

 

[Micheal Nadeau]

I was off work yesterday and had some time to mess with the car again. Put a new Motocraft TFI module on. Car seemed to have the same issue. I have a remote start on the car, which I havent been using while this issue has went on. I cut the tach signal wire and all seems ok. Started it this morning with no issue. I guess I am getting feedback or something on the wire causing the coil to cut out.

 

[Micheal Nadeau]

BTW, What is a SN Certified Technician. I have seen this under a few members names. Anything related to ASE?