91 V6 Auto.I just replaced my fuel filter with a new one.Now the engine has trouble starting when its hot.It starts but takes a lot of starter time.Before I changed the filter,it would always start right away cold or hot.Now it only starts right away when its cold.Any help would be appreciated.Thanks.

 

Make sure the ECT (engine coolant temp sensor) is still connected. (On the coolant bypass, between the block and the firewall).

Check the ignition timing (not likely to have changed, but you might have been a little off to begin with, and it's so easy to check there's no reason not to).

There is a Fuel Pressure Up system to prevent vapor lock when the engine is hot. But you said "warm," so I assume you're talking San Fernando WINTER temps, and an engine that has been sitting for at least 5 minutes. FPU shouldn't be a factor there.

 

Could I have done something wrong when I changed the filter?I did it by the manual except the pressure relief which I thought was a safety step only.Could the filter change be the reason?It took the engine about 10-15 seconds to start after the install.I checked the coolant temp sensor and it is ok.Also,the truck "bogs" when it is cold and in Drive on the road until I give it a lot of gas and it seems to catch and it's like turbo delay.When it warms up it runs fine and does'nt do that.Thanks for any help.

 

Anyone?

 

Ignition timing? It takes a $20 tool you should have anyway.

The pressure relief on the fuel filter doesn't matter at all. It is possible you knocked some dirt loose that made it's way to an injector, but that should either leave you with a no-start, or maybe a lean code.

 

Just where did you get your filter?

You cleaned all the fittings and lines before installing??

Are you seeing or smelling any leaks.

Now I know on the 92 4Runner the filter is down mounted to the frame is yours also.??

You didn`t kink any of the fuel lines?

It is installed in the correct direction?

Then this hard starting could have nothing to do with the filter install just bad luck that it happened now.

 

I am thinking wyoming9 might be right with it being backwards; changed mine on Tuesday morning along with plugs and wires and no issue.

 

I used a Fram filter and no kinks or install issue or fuel leaks.The truck runs excellent except for a longer start time(when hot) since I replaced the filter.Before I replaced it.it would start right away always.The timing is at 10.I replaced the plugs(NGK) and Cap/rotor but nothing changed.I think it has something to do with the pressure but I'm not sure what to check.

 

Not sure how many I changed over the years with no problems once things were back together.

I only use WIX or Toyota Filters Napa Gold also now made by WIX

Bad day at the Fram Factory??

*****It is installed in the correct direction??
Which you failed to mention .

The filters are directional !!

 

I haven't actually run into this problem, but I've heard and read that when you replace a fuel filter on an electric fuel pump system you should prime the new filter with a little fuel. It's supposed to prevent a pressure shock wave that could damage the fuel pressure regulator or other parts in the fuel system.

 

Please explain How you can prime a Horizontal filter I need to learn 2 more things by day light

 

You just add some gas to the filter. You're not actually bleeding the air out, just getting the filter medium wet. I've been told for decades to do that to keep the initial pressure shock from damaging things. I'm pretty sure the Bosch rep said this also.
Edit: I've done some searching on the internet to substantiate that claim but came up with nothing. Probably an old mechanics tale.

 

I did install in correct direction.I'll get another filter(oem) and see what happens.I'll also look into the pressure regulator.I'll post the results.

 

Good luck !!

Could be just bad luck on the hard starts.

i think the priming of a fuel filter might come from diesel engines where the filters are most often mounted in a vertical position .

Then it might be one of those things like " go to supply and ask for Rotor wash"

Being that the FSM says nothing about priming the system when installing a new pump or filter

In any case there is not all that much pressure and it is just sent back via the return line.

 

Was it only on the first start? Did I read your post wrong? If it was only on the first start that's normal. If I read it wrong that's normal as well. Time for more coffee. Hope you get it figured out.