94 RR Classic Hard to Start Everytime

[agb2g2]

Hi I ve been reading all kind of post but haven' t solve my problem I have a 94 rr lwb engine 4.2 with 78,000 miles recently I change oil and filter, air filter, clean TB and FM, change water pump and fan cluth it has no termostat installed, today change gasoline filter by the way it was mounted backward from previous owner. The thing is that everytime I start the vehicle takes 40 sec or more to start sometimes a little less but always will start no matter what, did the second position with 5 seg in between and same thing to start, can't check fuel pressure at rail because has no valve, sometimes when vehicle is running it shuts down and light in panel come up but if I push on the gas pedal for some reason revives if done fast enough other wise I have to re start. I try changing the battery and same deal. Before I spent money on things like fuel pump or crank sensor like to hear from guru's. Thanks in advance since my budget is very limited and try to do it my self.

 

[joey]

Have you cleaned the oil trap? This sometimes will cause issues also IIRC there is a T in the in the vacuum line that can get clogged.

 

[agb2g2]

You mean the one on the passenger side valve cover, I already did that was very dirty and cleaned the t union with inlets to manifold.

 

[joey]

Try shooting ether into the intake and see if it starts immediately, if it does it is a fuel problem, if not it is electrical.

 

[agb2g2]

I try spraying and it start right up in 4 seg and again with no spray and ot tpp\\ook quite a bit, so its fuel problem. You reccomend to change fuel pump and if its that would you opt for changing the mass or the entire unit? Thanks for your advice

 

[Disco Mike]

First, replace your t/stat, without it, your engine will run in open loop all the time, basically full rich mode.
As for the starting problem, before starting, turn you key to the 2nd position for 3 or 4 seconds, then off. Do that 3 times and then try starting it, if it starts OK, the your fuel pump back flow valve is shot, allowing all the fuel from your rail to drain back into the tank.

 

[agb2g2]

It took the same long time to start. where is located the back flow valve?

 

[Disco Mike]

On the fuel pump assembly.
You should have a shrader valve assembly on your fuel rail.
You might also try a shot of starting fuel/carb. spray into the t/body before trying to start it, see what that does.

 

[agb2g2]

Already did that and start right up very easy.

 

[agb2g2]

Still waiting, like to know if the fuel pump is related to my problem or the return valve. Any advise is appreciated. Thanks.