hard start sometimes-fuel pump does not cycle sometimes.

[killerb]

my car is hard to start sometimes.when i turn the key the fuel pump dosent cycle sometimes.do you think my fuel pump relay is shot,or do i have a fuel pump problem?it drives normal once it is started.

 

[Rippin_V6]

The same thing happened to a friends car and it turned out to be the computer. If you have any friends with a TR, borrow their ECM and plug it in. See if that fixes it. I don't know what goes wrong with the ECM, but in my friends car, that was the problem. Hope it helps.....

 

[ijames]

When the fuel pump doesn't run, have you just tried to start it and turned the key off and back on? Once you turn the key on the pump will run for two seconds and then shut off (unless it's getting crank pulses). If you turn the key off you have to wait five seconds before turning the key back on to make the pump run again (this also gives the iac time to reset).

 

[killerb]

the only thing that i can see is that the relay must be bad because it cycles sometimes and not all the times.if the pump was bad it wouldnt run at all.the system has no pressure input for the fuel pressure so it cant sense that there is pressure in the rail.maybe the relay is on the blink.

 

[Geoff87]

I think the FP relay may be bad. While cranking the engine, oil pressure will build. As this happens, the FP relay will be bypassed, which will cause the FP to turn on.

 

[killerb]

ill test the relay today.thanks for everybodys input.

 

[GN Bob]

There is one pin on one of the computer plugs which primes the fuel pump when you first turn the key on. My car leaks water sometimes, water got into the plug and corroded the connection and the pump wouldn't prime.

Replacing the computer may not be necessary since unpluging and reconnecting the plug cleans off the corrosion just enough to get the relay to kick on. I did the computer swap then put my old one back in and it worked OK, thats when I noticed the prime pin problem.

Spray the connector and computer pins with contact cleaner, blow it out and put on a small amount of dielectric grease. This took care of my no start problem.