Ovrclck350

Since I bought the car a month ago it's been extremely hard to start, both hot and cold. It usually has a strong fuel smell as soon as it starts up.

The other day I changed my fuel filter, and although I made the connections tight when I put the new one on, someting didn't seat right so I ended up with a fuel leak. I didn't notice it for about a day. The odd thing is though, it started up almost immediately every time througout that day. I'm assuming it has something to do with pressure, but I dont' know what.

I know some of you have had issues like this, so what's your opinions?

Ovrclck350

And and I have done the Plugs/Wires/Cap/Rotor

CentralCoaster

Is it different after 10 seconds between starts.... or after sitting overnight, or after 1 hour?

Try holding the the throttle to the floor for 20 seconds or so, then letting go... then starting it.

olman

Take the filter loose where it is leaking and redo it correctly. The old filter may have been plugged so that you had low pressure when starting. The pressure is easy to check at the fuel rail shrader valve with a gauge. Should be 38/39 at idle and mid to upper 40's with engine off or WOT.

mikey whipreck

There is a tech tip on this forum how to check in you have leaky injectors.

If you think it's a fuel problem, you should hook up a fuel pressure guage and see what's going on.

I had a terrible hard starting problem on my '85...
The solution was a few different things:
New charging system (alt was shot), new starter (20 yrs old and oil soaked), and new fuel pump (just because the old one was 20 yrs old)...

Ovrclck350

The filter is correct now.

The starting problem is after sitting for about 10 minutes or more. If I kill it and then start it right back up, it'll start up immediately.


I'll hook up a fuel pressure gauge sometime this week. I just thought it was odd that it would start RIGHT up everytime while it had the leak.

viii

Exact same problem on mine. I know that I have at least two leaking injectors, so I purchased a new set of the pink ones and I hope to install as soon as it gets a little warmer. From what I've read, the new injectors should either completely solve my problem or create a couple of new problems - depends what I read on the forum.

org502slow

hi put a fuel pressure gauge on the fuel rail;if ur pressure drops after turning the car off your injections are shot. it is should matain fuel pressure and not drop

rws.1

I agree, leaking fuel injectors are top of my list of probabilities

nonetooclose

Are you getting any fault codes. I ended up with a bad output from the ECM that was not engaging the fuel pump relay appropriately.

Thanks
Richard

olman

A drop in pressure can also come from fuel leaking back through the fuel pump. The pressure in my 85 drops immediately with new injectors. To do a test and eliminate this problem you can pinch the pressure line at the tank with vise grips by removing the rubber boot around the gas cap. If the pressure then leaks down, it is probably an injector(s). With the pressure line pinched, the pressure holds indefinitely on my car. The symptoms you describe would indicate leaky injectors.

Mike_88Z51

Let's look at the symptoms you have observed.

This tends to rule out the early C4 cold start circuit as an issue.

Too much fuel or unburned fuel.

Works better when the fuel lines still have pressure.

As you originally guessed, and others have agreed, this is probably a pressure related problem.

The car started properly when the fuel filter leak existed. Based upon previous observations and the "correct" operation during the period of the fuel filter leak, what change "fixed" the problem while the leak existed?

Well, with the leak you probbly had LESS pressure in the fuel lines. If less pressure made things better, what would be the possible causes of "too much" pressure?

Your fuel pressure regulator could be going bad and allowing the pump to over-pressurize the system. Your return line could be clogged not allowing the pressure to be stabilized properly by the pressure regulator.

It also could be due to a leaking injector or injectors. With the correct pressure leaking injectors would leak into intake manifold causing a hard start. In under 10 minutes they might not leak enough to affect starting. After 10 minutes the excess leaked fule would cause a hard start and the excess fuel smell. So, if the pressure is correct, why would less pressure (due to the filter leak) appear to fix a leaky injector problem?

Assuming that "too much" pressure caused a problem and "less" pressure made it work: Having the pressure leak due to the filter, would allow the fuel to drain out of the filter connection onto the ground and might prevent the bad injector(s) from having enough after shutoff pressure to leak into the intake manifold. With the fuel leaking out of the filter connection there wasn't enough pressure to force fuel to leak through the injectors into the engine. No hard start.

Since you say it was an issue even when cold, I would say that if you had tried to start it when stone cold after 8 hours and it was as bad as when it was hot plus 20 minutes, it is probably a "too much" pressure problem. Otherwise it probably is an injector leak problem.