JeepForum.com

JeepForum.com (http://www.jeepforum.com/forum/)
-   Full Size Jeep Forum (http://www.jeepforum.com/forum/f57/)
-   -   91 GW always takes a lot of gas pedal pumping to crank (http://www.jeepforum.com/forum/f57/91-gw-always-takes-lot-gas-pedal-pumping-crank-1494617/)

Macpsk 03-17-2013 04:40 AM

91 GW always takes a lot of gas pedal pumping to crank
 
every time i go to crank my '91 grand wagoneer, i have to pump the gas pedal a bunch of times (AT LEAST 5 times, usually closer to 10 times) before she'll start up. almost like she needs priming. it literally seems like the amount of pumping i have to do to crank her would flood the engine, but instead it's barely enough to crank it up.

also, after i get her started, the engine will be slow to respond to the gas pedal, as if the fuel isn't getting to the engine quickly enough.

any thoughts on what's causing it? does this have anything to do with the mechanical fuel pump? i've read before that installing an electric fuel pump with solve this issue. if anyone has done this, can you provide a little guidance on how to do it? would i install the electric fuel pump in line with the mechanical fuel pump, or would i take the mechanical pump out completely?

Thanks for your help!!

RockRollin 03-17-2013 08:47 AM

if it fires and dies from one pump, is the choke working?
If one pump from the pedal does nothing, then there is no fuel in the float bowl indicating the fuel is leaking past the float valve. You should still get some initial firing from one pump of the throttle. I had the same problem. I had to turn the motor over for about five seconds, then one pump of the pedal and it came to life.
Also check the orientation of the bypass connection on the fuel filter, it should be at 12:00, it could be syphoning the pump dry, it is unlikley but possible. It could be restricting the flow, cheap to replace.
Ok, so yes the mechanical pump is losing prime. Don't overlook the leaking float if the float bowl is empty. It can wash the cylinder wall, and wash past the rings into the oil.

WOLFMAN75 03-17-2013 10:35 AM

What do you mean by 12:00 on filter, I have same problem

RockRollin 03-17-2013 10:55 AM

The output side of the filter has a return nipple to govern fuel pressure. If the right filter is in place it has one line in, two lines out. One from the pump "in" . larger, center to the carb "out" smaller offset to the return. If the return is not at 12:00 position, it can theoretically trap air and reduce fuel pressure, or syphon fuel to the return when not running.
I have seen rigs run with wrong orientation just fine. I have seen wrong orientation be the cause of hard start and poor carb operation. Just a "first thing" to check.

revelc 03-17-2013 10:55 AM

My did the same thing and left me stranded a few times. Finally figured out it was a fuel line that runs under the power steering bracket was dry rotted. After I replaced it I didn't have another problem.

super98lsc 03-17-2013 01:51 PM

also check the lines under the truck there is a small section of rubber line near the t case with all the ethanol in our fuel today your lucky to get a few years out of rubber line. Ptfe lines like all the new cars have won't get eaten up by the alcohol.

jeepdaddy2000 03-20-2013 06:02 AM

Quote:

Originally Posted by Macpsk (Post 15146750)
every time i go to crank my '91 grand wagoneer, i have to pump the gas pedal a bunch of times (AT LEAST 5 times, usually closer to 10 times) before she'll start up. almost like she needs priming. it literally seems like the amount of pumping i have to do to crank her would flood the engine, but instead it's barely enough to crank it up.

also, after i get her started, the engine will be slow to respond to the gas pedal, as if the fuel isn't getting to the engine quickly enough.

any thoughts on what's causing it? does this have anything to do with the mechanical fuel pump? i've read before that installing an electric fuel pump with solve this issue. if anyone has done this, can you provide a little guidance on how to do it? would i install the electric fuel pump in line with the mechanical fuel pump, or would i take the mechanical pump out completely?

Thanks for your help!!

Might check the accelerator pump. These are classic signs of one that isn't squirting fuel. With the engine off, look down the bore of the carb. When you open the throttle, you should get a nice long squirt of fuel in each barrel.
Also, if the engine has backfired due to this issue, you will want to drop the cover off the power valve to insure it hasn't blown. If there is fuel in the lid, it needs to be replaced.

super98lsc 03-20-2013 09:38 AM

I can almost promise you this will be rotten line related. I still have to drop the tank and replace the lines that feed to the sending unit/pickup on my 90. Replacing the rest of them got it to where she starts but after a night/day of sitting I still have to spin the engine over quite a few revs to reprime the carb/bowl etc. Even though the carb is rebuild and float needle is new and not leaking etc the fuel evaporates out of the bowls overnight. Then the lines loose prime, and I have to crank for 5-10 seconds then I can pump it and get fuel to squirt. Other option is shoot brake clean down the throat of it (the pure methanol kind aka flammable) and she will fire right up and re-prime without cranking the snot out of it. I replaced all the easy to get to lines. The top of tank lines you can check by flipping up the back seat on the driver side and pull back the carpet and remove the access panel. I bet you find lines there that are so rotten that if you touch them they will turn to dust. Unless they were changed in the past 24 months on todays Ethanol excuse for gas the rubber lines just dont last. I change them on my Stingray and 442 Olds every 2 years. This time I am going back with PTFE lines. (teflon doesnt break down)

jeepdj5 03-20-2013 12:16 PM

Check the choke and the fuel filter is in the 12:00 position

Sent from my fsj Cherokee chief using JeepForum

Saul32 03-20-2013 02:46 PM

10 pumps is not bad compared to my 30 pumps every time I start her up. Its the worst. I was told my carb was in rough shape and figured it was that. I will be checking my fuel line when I swap the cam and intake n carb next week.

super98lsc 03-20-2013 02:56 PM

Reality is this:
If the float bowl is full then the accelerator pump should squirt fuel down the barrels when you pump the throttle. I run mine without a choke at all, i mean physically deleted it, and 3 pumps is more than enough fuel to fire it cold. Even in 25-35 temps. The only time I get the long cranks is when the fuel evaporates out of the hot bowl after shutdown and then the pump loses prime overnight. (when i had bad lines) If the pump/bowel is wet and the accel pump is good it should not take much to get it running. Clocking the return line on the filter housing helps prevent the drain back to the tank. I would bet that 99% of the long crank BS starting issues are fuel line/float level issues. Granted if the accelerator pump is bad you will know it by checking for fuel spray down the barrels with the engine off and just looking into them while you hand pump the throttle. If it squirts down both sides its good or good enough. Think of a squirt bottle, if you run it dry how long does it take to get it re-primed? lot of hand pumping eh.

jeepdj5 03-20-2013 03:10 PM

My 258 takes like 5 pumps, when it sits for a month it's a pain in the a$$ cuz you have to pump it like 50 times cuz it looses prime

Sent from my fsj Cherokee chief using JeepForum

super98lsc 03-20-2013 03:16 PM

Brings up a good point, until the fuel pump refills the bowl (primes) then pumping is not doing anything other than wearing out your foot and the accelerator pump piston. They are just rubber pistons and without fuel to lube them your burning the rubber against the metal carb body = wear city. When mine loses prime i hold the starter for 10 seconds without doing anything then let it cool for 5-10 seconds and hit it again, then the bowl is full an 3 pumps BOOM off and running. One thing I love on a Holley DB with 4 corner idle circuits is the EZ cold starts even on my big cammed motors. All 4 barrels blasting fuel usually takes 1 full push to the floor and back and I am running, then i just feather it for a minute or so until the cylinders heat up and she will idle on her own.

super98lsc 03-20-2013 03:20 PM

Here is my 442 with my buddy backing it out..... and my stupid commentary :-)
Holley frankencarb built my me 830cfm ProForm main body, annular boosters, 4 corner idle, no choke, full race setup, some other tricks, high speed and idle air bleeds tuned to match, and of course jetted and tuned by yours truely using my LM2 Wideband to get it on the $$.

https://www.youtube.com/watch?v=_WI1ipmmbSY

RockRollin 03-20-2013 06:42 PM

That off topic 442 sounds awesome LOL. fart cans? I thought those were kazoos:D


The time now is 08:39 PM.

Powered by vBulletin Version 3.8.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.