hard start after a few days

[DavetheDude]

Thinking of buying a 91MM with injected 2.4l. Guy tells me that it runs great, uses no oil and gets 28 mpg. The longer it is between starting times, the harder it is to start. If he starts it every day, it starts fine. If he waits a few days, it is hard to start. If he waits a long time he uses a shot of starting fluid and it starts right up, runs a little rough for a while and then smooths out. I'm thinking leaking injectors or the fuel pressure is leaking down somewhere. Has anyone out there seen this and could give me some advice? Thanks

[wrngwae]

i would think fuel pump leak down,,,,,,,,,have them cycle the key a few times than try and start it.

[DavetheDude]

The fuel pump and the filter have been replaced. Is the only check valve in the system at the fuel pump or is there another one? I am going to buy it anyway because it runs so well and I think this problem can be fixed.

[pennyman1]

After you get it run fuel injection cleaner through it - i use redline fuel injection cleaner. If it still does it, pull the plugs after it sits for a few days and look for one or more being wet with fuel - signs of leaking injectors. There may be a check valve back by the tank as an anti rollover, but I don't think it is for pressure bleed down

[DavetheDude]

Bought the truck and starting doing a little troubleshooting today. Found that when I cracked the supply fuel line, there was no pressure there and very little gas. This was after the pump ran and I had done a little cranking. Next thing I did was clamp off the return line and the thing fired right up. So, does this point to the fuel regulator leaking?

[TotallyBalistic]

regulator or weak pump man i dunno

[DavetheDude]

plugged off the return line and it has been starting just fine since. I have ordered a fuel regulator and am pretty sure that it is leaking by that. The fuel pump does not come on when you turn the key to on. It comes on when you get to start and then stays on as long as the key is on. Is that normal? Everything I've ever had comes on when the key is turned to on for a few seconds.

[camoit]

When you turn on the key it should prime the system for 3 to 5 secconds and build up pressure in the furl rail. Otherwise you would need to crank for up to 10 secconds for the pressure to build up. I think there is a relay timer that is involved it the system. But yes it should run the fuel pump when you turn the key to on.

[DavetheDude]

Installed the fuel regulator yesterday and the thing started pretty well considering all the fuel pressure had been drained. This morning, same thing. Like not getting any fuel. Either the fuel is draining back into the tank, or some sensor is telling the ECU not to fire the injectors. Runs great after it starts and will start perfectly for a couple of hours after running. I have a switch that runs the pump. Even with the pump running it won't start easily. I'm beginning to think it is electrical. Check engine light is on and the code says it is the motor position sensor, but the sensor checks out. Would that sensor cause it not to start when cold? Still looking for advice. Thanks

[camoit]

Well change out that sensor if it's not too pricy. Pull the battery cable and reset the computer. Unless you have another way. I'm unshure on the procedure for the reset. It's possable that the tempture sensor is faulty. When an engine is cold it needs more fuel. I don't know if you have a cold start valve in that system or not. Many older cars have an injector that dumps fuel into the plenem across all the intakes. Many times that is leaky and fuel psi leaks down over time. Do you still smell gas in the intake after about 10 minutes after shutting down? If so you might want to check it using a peace of white paper under it. That way if it drips the paper is stained some times you can use a shapry and put a black line on the paper. The ink will spread if gas hits it. Also you can check the voltage at the injector during cold crank. A cold start valve will only run for about 5 secconds.