ok ive been doing a lot to restore this car, but i am still having some issues

I have used up 6 cans of carb cleaner so far looking for vac leaks, repaired any i found, so far i cant find any more.. only possible one i can think of would be if the intake manifold gasket has holes or something, the other gaskets were in pretty bad condition so far, which kinda makes me wonder if the intake manifold gasket is crap.. anyways here are the symptoms


Hard to start cold or hot - when i was testing the coil and turning the engine over without spark, and when i pluged the coil back in and started it up, the car started up really fast and great, as if the extra fuel from the sparkless cranks helped it... which makes me think there is a fuel delivery problem...

somtimes it idles high, but i think this is just the engine warming up in its looped mode...

also, the engine seems to be underpowered horribly, when i floored it, the car died. it would be idling, flooring it would make it go "PLoP...PLop......plOp.... *die*"

so something seemed up with the ignition or the fuel there...

if i floor it more gradually i can get it up to speed but very gradually.

i adjusted the TV cable and this seemed to help the problem quite a bit, but it still seems to stutter or hesitate when i floor it, or rev it in park it seems to have some ignition or fuel problem there... i have done complete tune up save for replacing the Coil, the tranny has also been leaking some fluid lately, if that has anything to do with the cars performance...

my friend while riding along commented that when floored, the car seemed to get very high in its RPMs before shifting, very close to redline if not AT it.. He also said that the engine sounded like it was working much harder than the speed being produced... in otherwords, screaming engine, little acceleration..

any help thanks guys!!!!!

 

Have you checked fuel pressure?

As for the shifting, it is normal for it to shift at redline @ WOT, if it didnt you would be shifting out of the max powerband.

 

i bought a fuel pressure guage for 50 bucks but then returned it so that i could buy some other little things like fuses and vac lines, booster air filter, dinner, and carb cleaner lol...

i really didnt want to have to buy a 50$ guage just to test the fuel pressure once....it almost seems like it would be cheaper to just buy the fuel pump and assume that the old ones broke haha
how much should a pump cost??

 

depends what you go with but up here your looking anywhere from 80-300ca for a pump, mechanicals are about $30 lol

You should be able to rent a fuel pressure tester though.

 

could the hard start and the rough WOT be ignition related? sounds like it could easily be a fuel problem too... only thing of the ignition i havent swapped out yet was the coil...

im going to make a fuel pressure guage via instructions i found online.

http://minimopar.knizefamily.net/quickfpg.html

ill test the fuel pressure, if it checks out to spec, does that mean we assume the pump is fine?

then after that i guess i would check the injectors somehow...oh well thats later.. ill post my findings! thanks

 

remember to check the pressures at idle and WOT!

 

i think i am going to buy the pressure tester from autozone for the GM cars with the TBI fitting, where do i hook this up though? do i just attach it to one of the two fuel hard lines going into the back of the TBI?

 

From an inital reading of the problem, I was thinking fuel, but just for reference, I had that exact problem you're describing in my quote above and it was old spark plug boots which were letting the spark arc off onto the heads instead of going through the plugs. New plug wires fixed everything in my case.

 

Have you checked the timing?

 

yeah timing is at about 2*-4* advanced right now, ive played around with it a little bit... I had it at 6* for a little while and at 0* for a while, advancing it didnt seem to help anything but make the idle faster... so i dropped it back down to 2*advanced...

so far ive replaced all of the hoses that lead off of the TBI:
-TBI to MAP sensor hose
-TBI to PCV valve
-TBI to EGR valve
-TBI to Air Cleaner (plugged right now because air cleaner is off for access)


the TBI to Fuel evap canister, there is a plastic hard line that goes into the cab, it attaches to the two way checkvalve that is attached to the cruise control and comes out of the nipple on the intake manifold by the distributor, hasnt been replaced but i havent found any leaks to them, ive also used up about 6 cans of carb cleaner looking for vac leaks...

i found a leak in the TBI gasket, so i bought a rebuild kit and got new orings and stuff for the TBI, the gaskets were in pretty bad shape, sort of makes me wonder how the intake manifold gasket looks, could it be leaking vac?


i hear a super loud hissing at start up when it idles high, the hissing goes quieter a little as the car drops in RPM, it also seems to get quieter when i cover teh TBI with something...


I also replaced the IAC completely after cleaning but then breaking the old one that was really gummed up, i also cleaned the TBI out pretty good with carb cleaner...

the injectors dont seem to be leaking or anything, also, when i turn the key to run, it sounds like the fuel pump relay clicks twice. is that normal? like a "Cli-Click"
really fast, and consistent. two clicks.

I also replaced the filter that went to the brake booster, and the brake booster check valve seems to be working because when i turn the car off and pull the chevk valve out, it sucks in air...

and i replaced the two way check valve by the distributor that comes out of the intake manifold nipple.

the vac leak thing seems to be a dying possibility to me, ive replaced so many things with no help, not even the super huge vac leak from the TBI gasket seemed to make any difference at all.. nor the two way check valve that was completely not working (let air go thru all three different ends from any direction)

im beginning to think its something completely different but the signs seem to say vac leak,

just an hour ago i started it cold and watched the rpms and listened to the engine

it idled first at 1500, then it slowly went up to 2300, then it slowwwly started to work its way back down to 1500. after sitting ther for about 20 seconds it went down slowly to 1100 where it sat for a while, sometimes it would fluctuate from 1100 by a few hundred RPM up or down, like just fluctuating a little bit...

so far the symptoms are
-Hard to start
-High Idle
-Fluctuating RPMs
-Lack of power (could just be the 305
-I smell pretty bad of gas after sitting in it or just working on it for a while and it has a new Cat on it.. its not super strong but its enough to make me stink... this could be just normal for a car of its age and what not... just throwing it out there

thanks for your help guys, im going to fuel pressure test it tomarow hopefully witha buddies gauge...

 

Sounds like a lack of fuel. Put the timing back to 6* and check for a lack of fuel. Sounds like you getting air without the matching amount of fuel. It will accelerate smoothly because you have some fuel but when you floor it there is no burst of fuel (lack of pressure) to compensate for the sudden rush of air. Sounds like a fuel pump dying or falling off the sending unit to me.

 

thank you! i am going to check the fuel pressure tonight.

 

Fuel pressure gauge is important, that's a tool you want to hang on to. Think I paid about $30 for mine many moons ago. Can't live without it.

 

ok so i checked the pressure of the fuel, and yay, somethings wrong (im happy that i finally found the problem probably haha)

now, before i get all excited, i got a gauge with the special TBI adapter, i then traced the hard line from the back of the TBI to where it connects to the short length of rubber hose, i disconnected the top set of rubber hose and metal line, i assume that this is the "inlet" or feed line... and im assuming that its the one i am supposed to use...

please verify that this is the right hose, the top of the two by the alternator...


anyways here are my findings

- Turning the key to run causes the PSI to go up to about 4PSI, as soon as the pump clicks done (2-3 seconds after i turn the key) the psi drops down to zero.. is that normal? i cant get it to go over 4 PSI, if i wait a few seconds to prime it again, the PSI has already dropped down to zero.

then i tried the idline pressure...

at idle the gauge reads a steady 7PSI, when i rev the motor, the PSI drops about 2-3 and then returns to 7... the motor does not seem to rev smoothly, very choppy sounding...

then when i shut off the motor, the PSI drops down to zero again, is that normal for it to drop down to zero? i hope not...

also, when i push the button to release the pressure, no gas comes out of the line... is that normal? the instructions say to put the fuel pressure release tube into a certified 2 gallon bucket, but when i release the pressure, no gas comes out... am i doing this right??

thanks guys

 

I believe there's a one-way check valve which should keep pressure in the system. Hopefully that's your problem.

 

ok, tested it again with the same results,

Prime - 4PSI,
drops to 0PSI after the prime is over. (normal maybe? i mean, pump isnt working once it stops, unless theres a check valve for sure then this is probably normal)

Idle - 7 PSI,
below normal, bad sign, but at least i know whats the problem now...

so, i know of two methods to replacing the fuel pump, cut a hatch or drop the tank....


which one is the best way do you guys think? i dont really mind cutting a hatch, it wont be visible ever so its not a big deal to me... however i dont want to be cutting my car to peices trying to make the right hole.

also, what do you guys think about an inline pump? if i just had the hose go into the tank and had the pump along the line maybe in the engine bay somewhere, easier replacement next time perhaps?


I will most likely go with a stock replacement either way... and im thinking im going to go in from the Hatch route..


what is this check valve? I want to make absolutely for sure that it is my fuel pump so that i dont waste time and money.

i have some pictures here of my setup, here is where i attached the gauge.




its on the top line where the rubber hose meets the hardline by the alternator, im assuming thats the INLET hose? it was hard to trace it for sure.

and also, i seemed to be getting bubbles in my purge line when i released pressure on the gauge.. is this normal? and are the bubbles for sure coming from the fuel for sure? im not positive here



very little gas comes out when i press the purge button after the car has stopped running, also, i dont think a very large amount comes out while idling. more though than when not running, makes sense since the pump is pumping fuel...