Engine stubbles at idle speed

Some auto parts stores will let you use tools for free. Maybe they have a fuel pressure gauge. It just screws onto the schraeder valve on the fuel rail. I have seen bad pumps do crazy stuff yet still run good at other times. Do you know when it was last replaced? It's just part of trouble shooting problems that you verify the pump pressure just as you know there is fuel in the tank.

Control module should throw code on OBD II.
Did you check to see if both injectors are spraying fuel?
No fuel rail on TBI.

enblethen wrote:
Control module should throw code on OBD II.
Did you check to see if both injectors are spraying fuel?
No fuel rail on TBI.

Maybe not called fuel rail but should have a test port on one of the pipe. I searched but didn't find a pic yet. Any ideas?

Did you check the PCV valve?
Have not seen any Schrader valve on TBI.

I did notice some people on you tube using an adapter in line if a schraeder isn't provided.

May be a pita but it's important to know. How old is the fuel filter?


One example

rjxj wrote:
I did notice some people on you tube using an adapter in line if a schraeder isn't provided.

May be a pita but it's important to know. How old is the fuel filter?


One example

changed filter before trip in June. I was never able to find a Schaefer valve for testing fuel pressure. It is a 95 chassis so it has a tbi with 2 injectors on top on tbi that are electronically controlled. Where do you think this fuel pressure valve would be located?

enblethen wrote:
Control module should throw code on OBD II.
Did you check to see if both injectors are spraying fuel?
No fuel rail on TBI.

. Both injectors spraying a nice cone shaped pattern. It is not an OBD II but is an OBD I .

Gjac wrote:

rjxj wrote:
I did notice some people on you tube using an adapter in line if a schraeder isn't provided.

May be a pita but it's important to know. How old is the fuel filter?


One example

changed filter before trip in June. I was never able to find a Schaefer valve for testing fuel pressure. It is a 95 chassis so it has a tbi with 2 injectors on top on tbi that are electronically controlled. Where do you think this fuel pressure valve would be located?

As enblethen mentioned and the video I put in that link shows. It may not have the schraeder valve so people put an adapter in line near the fuel filter to tap into the line. Probably too much to do on the road and messy.

Crazy idea but what type of fuel cap does it have? Try loosening it and run it. Just for the heck of it.

I always wan to know the fuel pressure is ok because of talking to a buddy who did tons of side work on cars and remember him telling me of one that idled poor but would run out good. We both said it seems backwards because more fuel is needed at high speed. I dont remember if he had a regulator or pump issue with that one.

Also be **** careful if messing with the regulator etc. I remember him saying he had one catch fire. Dont know if it was a bad diaphragm.

Dont want to steer you wrong but I know it's never going to be right if the pressure is wrong and I know a lot of electric pumps fail. Some in very few years and some seem to last forever.

rjxj wrote:

Gjac wrote:

rjxj wrote:
I did notice some people on you tube using an adapter in line if a schraeder isn't provided.

May be a pita but it's important to know. How old is the fuel filter?


One example

changed filter before trip in June. I was never able to find a Schaefer valve for testing fuel pressure. It is a 95 chassis so it has a tbi with 2 injectors on top on tbi that are electronically controlled. Where do you think this fuel pressure valve would be located?

As enblethen mentioned and the video I put in that link shows. It may not have the schraeder valve so people put an adapter in line near the fuel filter to tap into the line. Probably too much to do on the road and messy.

Crazy idea but what type of fuel cap does it have? Try loosening it and run it. Just for the heck of it.

I always wan to know the fuel pressure is ok because of talking to a buddy who did tons of side work on cars and remember him telling me of one that idled poor but would run out good. We both said it seems backwards because more fuel is needed at high speed. I dont remember if he had a regulator or pump issue with that one.

Also be **** careful if messing with the regulator etc. I remember him saying he had one catch fire. Dont know if it was a bad diaphragm.

Dont want to steer you wrong but I know it's never going to be right if the pressure is wrong and I know a lot of electric pumps fail. Some in very few years and some seem to last forever.

. Tried loosening gas cap but it had no effect on the problem. I have a full tank of fuel so I probably can't change fuel pump in the Walmart parking lot. I was hoping for something simple. The fuel pump was changed out at 20,000 miles it now has 113,000 miles on it.

Gjac
Dont replace it on my talking about it. It's just part of the troubleshooting to check the pressure, it could have a bad regulator. If you can drive it home I wouldn't go too far into it