hesitation under load = fuel presure regulator

ca someone tell me wheres the fuel pressure regulator on a 92 PA ULTRA ?

i got this hesitation when i ask for power and have changed all the plugs and wires, o2, fuel filter... its not constant, it does it one day and stops the next one.

any ideas?

Deadring

ok,

i forgot to add that, the car will get this problem and then the next day it's gone.... now is there something more frustrating than a intermitten problem? like now, the car is OK , it will lauch like a rocket and reach it's speed limiter in no time..then all of a sudden, it will start hesitating...

could there be something in the gas tank clogging up the strainer and when i let it rest for a while is goes back down and everything is alright?

i dont know what to think :(

Deadring

Everything is exactly the same from when the poblem occurs to when it dosen't?

I know what you mean tho, mine will idle like smooth, full power and shift smooth. Then out of nowhere idle gives you a full body massage, increased power (weird huh?) and missed, rough shifts.

Now, I've tried to examine what I asked you, outside & operating temp is the same, baramotric pressure is the same (or close to), same drive route, same or close level of fuel. Nuts

when the problem all of sudden appears, the car still goes well.. but if i ASKED for power, it will shudder and hesitates.. and if i floor and it's in second gear, it will almost hang there shuddering and hesitating till it reaches ther redline and then shift if it feels like it... like now its been 3 days and i have no problem what so ever.. i can burn the tires on the spot and ferociously pass a car at 60 MPH with ease... whats gives ???

this is not something easy to diagnose

Have you tried disconnecting the torque converter lockup solenoid? Almost sounds like it's starting to tweak. Shouldn't set a hard DTC either, so chances are no check light. You could try and jump the ALDL and see if does present the soft code #39?

i dont know if you have a supercharger on yours but i may suspect the boost actuator freeking out.. since if you put boost and remove it and put it back real fast it WOULD do this kind of thing...

i dont think the torque is the trouble since mine does this hesitation under load and at high REVS.. other than that it goes real well
and to top it off this very afternoon it started up again.

Nah, no s/c on mine (yet). Isn't there a gauge for the boost level? If not, there's got to be a way to temporarily install one to moniter if the boost falls off during hard load?

I still say for s n g's of it looking at the TCC a little closely, like any sloppy disengagements. The 89-93 GM's seem to eat these up alot on the 4t60s. So I'd see it going out before the charger.

UPDATE

well still going at it.. now it did something a little diffrent coming back from the supermarket.. i was floorring it and it started to ping like mad. as if the problem was ignition related ?!?!?! since i got new plugs and wires it cant be that.. i had no remorse holding it till it reached the redline and it came to have this pinging sound...could it be a coil pack going bad?? i really don't know what would be the symptoms of it.. but at 50 $ it's worth changing one... it seems to be doing that everytime the outside temperature here goes near 60..

im gonna try changing one just to see.

You can check the resistance of the coils as a means of testing instead of throwing a new one at it. Yours has the coil pack near the alternator? I've heard of those getting water spray from the wheel and slowoly degenerating. Actually somebody on here had a issue but it was at all times and traced it out to the pack, actually the ignition module turned to jelly then baked. Worth a look tho, any signs of white powder kind of like a dirty battery terminal would be a indicator of a prob.

well i got mad and went to a shop i know this morning. got the sucker hooked up to see if there was any codes and there weren't any.. then got fuel pressure gauge on it and stuck on the windshield to see the pressure as i floored it. at idle i hang around 50 PSI and when i floor it it goes below 35 PSI.. then we unhooked the fuel pressure regulator and let the system run a full pressure.. which was 50 PSI and it did the same when i floored it.. it went to approx. 35 PSI above 4000 RPM... so im thinking fuel pump here.

gonna go check the filter and if thats ok im gettiung a new pump in.. my proiblem cannot be ignition.. it has something to do with lack of fuel

hmm, sorry bud, saw that you replaced the filter and omitted it for the possibilty list, also was assuming you already checked pressure, my bad.

I got my whack job problem wrapped too, CTS report off by 10* then erratic at times, so a new CTS for $8 and all s/b right with the world.

hey no problemo


for me, it seems the fuel pump did wonders.. it idles ALOT better and i dont have that hesiation at high RPM neither.. plus the new pump has that corrective strainer that those old PA's needed.. under 1/4 of a tank if you would steer hard enough the car would sputter from lack of fuel. now thats ok too :)

now it just needs a new exaust sometime soon. the shop kinda played with the old exaust from a side to atnother in order to get the fuel tank off the car.. its hard to justify that THEY broke it since it is kinda rusty.. it makes a little noise when its cold but ill get a new one at the end of summer :)

Deadring

Yeah, I snapped the weld at the rear of the cat when I moved mine to do my pump. Stick of JB weld has been holding pretty well now for about year and half.

[QUOTE=deadring]i dont know if you have a supercharger on yours but i may suspect the boost actuator freeking out.. since if you put boost and remove it and put it back real fast it WOULD do this kind of thing...
QUOTE]

Replaced the CTS this weekend and man, what a difference jsut alittle out of spec. can make. Idle smoothed out, stopped jerking off the line and idle is consistant at all temps ( so far)

Trans did slop on me this morning a couple of times from a stop, so I still ahve other issues there.

glad you found yer problem :)


whats a CTS? i can't think as of right now of what it can be

Deadring

Coolant Temprature Sensor,

Input from this bad boy runs a vast majority of the show: MAF, IAC, TCC, and fuel trim.

what size is the fitting that connetcs to the fuel rail? I want to get a tool to check my fuel pressure in my 95 PA

You can buy a fuel pressure hose and guage at most auto parts stores. The hose has a connector with a built in pin to open the schrader valve on your fuel rail so fuel can flow to the guage and read pressure. It will also have a bleed valve to open to bleed out air when first installing and to bleed out fuel when you are finished.

yup! i bought one last night. i had 48 psi with the key on/no start test (spec is 48-55) and 41psi at idle.

but the key on/no start test leaked down after a few minutes. this shouldnt happen according to the manual. The only way to find out why is to put two shut off valve in the supply and return lines. anyone know where to get these shut off valves?

yup! i bought one last night. i had 48 psi with the key on/no start test (spec is 48-55) and 41psi at idle.

but the key on/no start test leaked down after a few minutes. this shouldnt happen according to the manual. The only way to find out why is to put two shut off valve in the supply and return lines. anyone know where to get these shut off valves?


if you wanna know if the fuel pressure reg is messed up just unplug the vacuum hose that to it and put a screw on that hose to the engine side so you wont lose vaccum in the engine. then check the fuel pressure how high does it go.. if it doesnt changge much you might have a faulty pump... mine , with no regulator was close to 50, but at
WOT it was around 35 psi.. so the regulator was not getting enough pressure from the pump.. so when i got a new pump ( btw with a revised strainer that cures that dreaded sputtering from lack of fuel when turning a corner real fast while being low a gas) which is alot smaller and lot better . now the car flies :)


Deadring

It is normal for the pressure to leak down a little over a period of time. You could have a small leak in your test hose or one or more injector leaking a small amount. Your fuel pressure is great. You do not have a fuel delivery or regulator problem.