Flat spot at 2000-2300 rpm

[Jukelemon]

Hi all.

My engine has developed a slight flat spot-like as if it was not timed correctly.

Started a couple of months ago and I changed out the plugs, wires, cap. As well, I adjusted the valves and retimed it to a dead on 5 deg.

There is no flat spot in 1st and none after 2300 rpm in all other gears. MPG is still great at 20-22.

Any ideas?

 

[WristPin]

check the timing with and with out the te1 and e1 terminals shorted. does it advance when you do this?

 

[WristPin]

i just realized that we had the same exact number of posts before i posted this one! crazy!

 

[Jukelemon]

LOL!! That is crazy Pin.

I didn't check it AFTER I took out the short. I know the short changes the engine though as I can hear the difference.

Why do you mention that?

Just so you know, this happened before I did any of the other stuff. Really no correlation with work done on the vehicle.

 

[WristPin]

cause we want the timing to advance, and by that rpm it should have already advanced.

use a timing light and wrap it up to the problem rpm to see if its advancing

 

[Jukelemon]

What should it advance to?

It also feels like a fuel delivery issue-like an old carb that is not tuned right.

It definitely stumbles now and seems to be getting worse

 

[WristPin]

unless you have a digital light that gives you actual degrees, you couldnt know where its is advancing to.

its in the neighboor hood of 20 degrees which is about 3.5 inches from the spec of 5 or 8, what ever yours is.

advance is always on the left, retard is always on the right as you look at the pulley

 

[WristPin]

as far as fuel delivery goes. make sure your regulator is operating properly. at idle, disconnect the hose to it, and see if its working

also make sure your fuel filter isnt jacked.

if you feel real ambitious, you can jam a banjo fitting inline with a fuel pressure regulator.

spec is 44 pounds

 

[Jukelemon]

unless you have a digital light that gives you actual degrees, you couldnt know where its is advancing to.

its in the neighboor hood of 20 degrees which is about 3.5 inches from the spec of 5 or 8, what ever yours is.

advance is always on the left, retard is always on the right as you look at the pulley

OK. That makes sense and I follow where it should be. I show 5, 8 and 12 degrees advance on the 22re (I think).

As far as the Regulator, I have no idea what you mean. Where is it and what hose and how do you test?

Here is another fact for you: this issue is only evident when I feather the gas. In other words, if I drive agressively, I do not feel the lag/small sputter.

That is why I was thinking fuel delivery.

I have no clue as to when the fuel filter was changed-if ever. I know I have not changed it since I have owned it (5 years and 40k miles).

I also know it is a pain to change but perhaps something that needs to be done regardless.

 

[Ripper]

Similar problem on my '85. Might be your O2 sensor also.

 

[Jukelemon]

Thanks Ripper.

O2 sensor is fairly new and OEM.

 

[mofer_fj40]

the regulator is on the back side of the fuel rail. its small and round. has a single vacuum hose coming out of it

 

[WristPin]

you get anywhere with this?

 

[Jukelemon]

Nope.

I need to replce the fuel filter-just dont have the time at the moment.

How much time for the fuel filter? Steps?

 

[WristPin]

14mm for the banjo bolts. use a long extention for the front one.
and a flexy rachet on the rear

hold the body of the filter with your 17mm wrench

the ripp off the 12mm bolts holdin it to the bracket

on my truck i mounted the new one to the fender cause its eaiser next time.

time? takes me about 20 mins. but i do it for a living so it may take you longer

dont drop the new filter or over torque it. a dent can cause it to bybass the filter element partially

 

[Jukelemon]

Thanks Pin

 

[WristPin]

yer welcome

 

[Jukelemon]

Just curious Pin.

How did you change the mounting position? Add additional fuel line to one side?

Odd question BUT is there a good way to tell if the filter is bad? It is original so I am assuming it is LOL! 185K+ miles old.

So, 20 minutes huh.

I assume you take off the PS front tire? Access through the wheel well?

 

[Jukelemon]

as far as fuel delivery goes. make sure your regulator is operating properly. at idle, disconnect the hose to it, and see if its working

also make sure your fuel filter isnt jacked.

if you feel real ambitious, you can jam a banjo fitting inline with a fuel pressure regulator.

spec is 44 pounds

Pin: what will happen when I disconnect the hose to the regulator? In other words, to make sure it is working, what do I need to do?

I want to do this prior to doing the fuel filter just to see if if it has any effect.

Will do the filter anyway because it needs it. But want to after I check Regulator

 

[WristPin]

removing the vacuum allows full pump pressure to the injectors causing higher rpm.

change the filter no matter what.

i have a feeling the filter will solve your concern