BuddyLeeX

ok ok...I tweaked my carb....yaya it ran great...I made some finally adjustments(I tweaked the AV). Three hours later, I went out after about 5 blocks, I was goin 45 on a oen way and all o fa sudden my "check engine" light came on and when I gave it gas it wouldnt go at all. Pulled over, turned the car off(it was idling like crap). Turned it back on...put it in drive tried to drive it but I woudl kill it, I could only put the rpms up to about 800-900, idle is at 600, and I would go about 3 or 4 mph. I tweked the carb back to where I though it was, thinking that was the problem, but I broke the spring on the adjuster so I really couldnt get it back to normal, at that point I could get it up to 10mph. Ok...I heard that there is nothign wrong with the carb...it seems like the engine isnt getting enough gas or something. Now when I start it up it idles so amazingly rough and it struggles to stay on, usually it dies or with the push of the throttle it will shut off. We took off the ignition controll module and took it to autozone, goit tested, and it didnt pass 7 of 8 test, so i bought a new one for 28$ thinking this coudl be it, put it on, no dice, same thing. So we are about to check out the coil. Next place, fuel pump, I need help any suggestions?

Dans91

sounds like a fuel problem to me, you may want to buy a fuel pump test gauge for about 35 bux and hook it to your line going to the carb. Then see if your pressure is about right. To me it sounds like a problem with your fuel pump. I think you fuel pressure is supposed to read somewhere around 9-13 psi, but it has been so long since i have looked at the specs i dont know if that is correct. Give it a shot, you will need that pressure guage in the future anyways, you might as well just get it over with now, also check your fuel filter, in fact check that first before anything else, pull it, turn it upside down and tap it lightly on a piece of cardboard and look at all the crud run out of the filter. hope i could be a help

Dan

8Mike9

You do have the aircleaner lid on, don't you? My buddy called me up the other day when he installed a new carb...ran great while he was dinking around with the mixture screws, revving it up, etc...drop the hood and run like crap, bog, etc.. Pop the hood, rev it up, it was fine.

He hadn't put the aircleaner on yet, and it was sucking the insulation into the carb...I about laughed my butt off when I got there.

BuddyLeeX

ok well we replaced teh fuel filter, the next thing is the fuel pump or pressure, Ill see what we can do, Im not sure about the guage im abotu to run out of money

BuddyLeeX

ok, I noticed a fuel line that was shaking like mad and when i squeezed it it felt really thin. We also checked the fuel pressure and it seemed really low, so we are putting on a new fuel pump and fuel hose tomamrow morning and see if that does it.

BuddyLeeX

how do u adjust fuel pressure?

GreenProStreet

I would go for an aftermarket pump, like a holley. GM cheaped out and put the bare minimum, so even an exhuast upgrade will lean the whole engine out. The pump system is a strange one at best for the Lg4. There is an electric pump side one, to feed the one you see at the passenger side of the engine. So the electric may be inhibiting the mechanical, or vice versa. If you replace the mechanical pump, be careful, it can be tricky; it is attaced to the crankshaft. Fortunately I had a buddy do it, I'll pay for his therapy later in life

eightTfourTA

iTrader: (3)

Is that like a Canadian car feature or something? Never saw both a factory electric and mech. on these engines.

chevymad

My 87 has both pumps. Guess they were trying to get rid of vapor lock.

If you change the mech. pump it is run by a rod that rubs the cam shaft. When you pull the pump off the rod will try to fall out. On the front of the motor there are two holes. The air pump bolts to either one or both(dont remember) If you take a longer bolt with lots of threads and screw it into the upper hole, it will bottom out on the fuel pump shaft. Dont screw in too tight you just want it to hold the shaft up for you. Then after you change the pump, dont forget to change the bolt back to the shorter one. If you left it out completly you'll get an oil leak.

That said, I dont think you have a pump problem. Get somebody to try and keep the motor running. Then look down the carb with a flashlight. I think you'll see alot of gas dumping in up top. The float is either stuck, sunk or maybe theres a piece of trash caught in the needle seat. You can sometimes clear a small peice without pulling the carb apart. Take the fuel line off carb. Then either find something to cap it with or cap with your thumb.(it only has 7psi when running) Then have a buddy start the engine and run it till it dies(carb runs out of fuel) It'll run quite awhile really. After it dies hook the fuel line back up. Then start the engine. When it starts kindof rev it a little right away. This will make the needle open as far as possible and then push fast moving fuel past it to wash it out. If the piece is small enough itll pass through and the car will run better.If not you'll have to take it apart.

Be careful about fire. Have a buddy around and a good fire extinguisher. Dont like telling people to run a vehicle with the fuel line disconnected...even worse when the car is running bad. But if your careful you should be fine.