I have a hesitation very slight hesitation just as I throttle up. I call it a burp and then go. Not all the time though.

I have read several things here about hesitations and have complete most of the checks to find out why.

Throttle body cleaned/new gasket
ICV cleaned
vacuum checks
AMM check
new hose for brake booster check valve
intake hose removed cleaned

The only new thing I have done recently was to replace the exhaust system from the manifold back and I eliminated the resonator and went with the 2" pipe from the kat to the tail with a turbo muffler. Also a new O2 sensor but it was not the exact replacement #. (due to cost I went with #13942 Bosh cut-n-slpice)
Anyway I am now wondering if the burp and go is due to the larger exhaust pipe and I am getting less back pressure. Is that possible? Maybe this was not worth the effert to change to, although I like the tone.

The other items I need to check are FPR and the Fuel pumps. I know the main under the car is working but have not verified the in tank pump is heard.

If I use a FPR gauge to check pressure, how do I connect it to the system?

BTW are FPR that different from another? I found a BWD for 55.00 rather than Bosh for 125.00..

Any other thoughts or rehash on the topic would be of interest.
Thanks
Judd

You say you checked / tested the AMM, the only reliable test I have found is in the car and how well does it run.

I had an annoying hesitation or burp as you describe while at cruising speed. As you accelerate it would hesitate but let off the gas a little and it would be fine. I swapped in one of my spare AMM and the problem was solved. Just to make sure I put the old one back in and the hesitation returned.
Dan

Yesterday I was checking fuel pump in tank. So far with jumping
Fuse #6Left to Fuse #4 Right I hear nothing in the tank. I am going to pull it and check further.
I do have voltage at the connector in the trunk.

Would I have continuity from the fuel pump to the ground if I disconnect the electrical plug in the trunk and prob the yellow/red wire and then to ground?

Because I did this and I have no continuity between it.

Judd

Take off the gas cap and listen for the in-tank pump with the fuses jumped.

You should have continuity between the case of the sending unit(ground) and the black wire that goes to the pump.

If you do not hear the pump you will need to remove the sending unit to see if it is the pump or failed connections as the wires go through the unit to the motor.


Dan

Ah yes indeed. The in tank pump was bad. found one today and replaced. All is good and seems to be running better from start acceleration.
However, I now have been hearing a vac. leak inside the dash when I throttle up.
So what next??

Thanks
again.
Judd

For me this has usually been a vac hose cracked at a bend. Pull the lower dash bits and see if you can hear it.

But make sure it isn't coming from the 1-way valve on the manifold.
--
240s: 2 drivers and some parts cars

Start a new thread.

...but first do a search. 240 vac leaks that can be heard inside the cabin are pretty simple: Climate control hoses, climate control servos, reservoir, and cruise control feed. Maybe the one-way valve for the line feeding the reservoir before it passes through the firewall.

Mike

Check the vacuum line to the fuel pressure regulator.