LUVTruck.com

1979 4x4

I have brought this up before, but I have some new information.

A new fuel pump is $75!

At approx 8-9% throttle, almost just off idle the engine will die unless I rev the motor up slowly. This makes it real hard to get going from a stop. At 7% and 10% the engine responds perfectly. If I put my foot at 8-9% the engine will simply, and immediately, die.

I was getting some gas out and putting it into a can with the fuel pump, and I noticed it was making some weird sounds. The gas was coming out OK, but the pump was sounding really weird and intermittent.

I have a rebuilt motor in this truck, and I have rebuilt the carb. It has done this for 3 motors and before and after I rebuilt the carb. I have also replaced all the vacuum lines and tried rerouting them, and the problem still persists. I do not have a catalytic converter.

Any ideas??

did you buy the $75 pump? if not, don't. I bought one of the generic electric pumps from napa...much cheaper and works just as well as a stock style and much, much cheaper.

_________________
Resident lurker

from another post here viewtopic.php?f=8&t=15817&start=0&st=0&sk=t&sd=a&hilit=purolator



Hope that's some help.

_________________
"If we did the things we are capable of, we would astound ourselves" - Thomas Edison

I have the same kind of problem. But only in the morning on the way to work and it does not die, just have to put the peddle to the floor and wait for the truck to wake up. My fuel pump is new.

Interesting. The odd thing is that the other day while immediately driving it cold, it had zero power. I had to back off the gas then give it more gas and suddenly it came to life. I have no idea what to think.

I don't know these stock carbs well but that sounds typical of an accelerator pump problem. On some models you can adjust pump linkage. If there's an accelerator pump linkage lever with holes, choose a hole farther out towards end of lever.

If it's not the fuel pump, I agree it may be the carb. When I first got my truck a) I had a sloppy accelerator linkage which meant that I was pushing the pedal with no action on the accelerator pump and b) I have since found that the idle was WAAAAY off.

The linkage is convoluted enough on mine, I see a series of shafts and joints to convert the linear pedal motion into a rotary type motion to actuate the throttle. On mine there is a bushing mounted to the firewall which had worked loose and there was tons of slop in the linkage, so I felt when I was feathering the gas it did nothing. As for the idle, by off, I mean set rich and compensated by opening up the throttle with the idle speed screw.

My view, and correct me if I'm wrong here guys, is that the way the manuals tell you to set the idle (start three turns out from seated, richen until it bogs, turn the screw in until it bogs, set it at halfway between those settings) is misleading because for me it took a helluva lot of turns to go rich, meaning I needed like 8 turns from seated to be in the middle. I think that's too many and it just dumps gas in and so you have to use your idle speed screw to compensate and open the throttle to get enough air in. The your idle is more like throttle and it's just crap and causes all kinds of problems...I decided to over rule the manual, set it at four turns from seated, and adjust the idle speed accordingly. Works fine for now although the speed seems low now, I am going to check dwell, timing, etc. this weekend (I still have points, don't plan to change too soon).

-Evan

Accelerator pump linkage... Eh? I think I will go back to having a tube connected to the intake coming into the passenger compartment, where I have a windex bottle filled with gas. When I want to go, I simply pump the bottle a whole lot until I get to where I am going. Pumping faster makes the truck go faster. Makes gear changes hard, but it works like a champ.

Someone suggested it may be the spark plugs, even though they were new. It was indeed the spark plugs. My engine runs superbly, now, with no hesitation, bog, or whatever. It also idles MUCH smoother, with NO lumpy spots or erratic rough idling. I can actually see out of my mirrors now when I am idling. Not to mention the truck is much stronger, and actually a lot quieter, too. Amazing!!! Gas mileage is up, too.

If it was your plugs fouled up and they where fairly new, then you may want to consider a new EGR. Bad EGR also will make it die when stopping. I had a bad EGR in a truck once and it fouled the plugs up real bad.

If a '74-'75 EGR valve will fit that engine I have one I took of my engine, yours if you need it, just holler. Looks like it says Part Number 5161100010, also has small tag stamped 740905, seems to work okay.

JimmieD

Actually, guys, the problem came right back after less than 35 miles. Now it's doing it all over again, which would suggest to me that the crap that is collecting on the plugs is really messing with things.

It says in the manual that it can be caused by fuel additives-except that I use none. It also says it can be caused by a bad brand of fuel-but I use all sorts of brands.

The only thing I can think of is the oil, which is Moile1 extended performance w/ 1 bottle of Lucas stabilizer, and after that leaked out, one more bottle of Lucas stop-leak and oil stabilizer. Are these oils what si causing my problem?

This truck was running *perfectly*, and was actually a joy to drive, enough power not to have to give it gas to go from a stop, ZERO hesitation, good mileage, a great well-tuned sound.

Thanks for the suggestions about the EGR. The EGR pipe from the exhaust manifold is hooked up, however the EGR valve itself is not connected to a vacuum source. Could this be fouling my plugs? How so?

I don't have much time to do my usual long post, but water in the gas is kind of coming to my mind. My 77 acted very similar to this when I was getting water in the tank from a cracked filler neck hose. It mimics the symptoms of a weak fuel pump and is also a lot like bad points. The only difference I recall was water in the tank meant a rough crappy idle and the other two it would idle pretty much solid. I'm not sure how replacing the plugs enters into it, but most problems the plugs could affect would not return after just 35 miles.


Water in the tank can be cured with a bottle of fuel tank drier like HEET, or a bottle of rubbing alcohol. (main ingredient in HEET). I found the Fred Meyers around here carries a 99% solution of rubbing alcohol which works best. It might take a while to work all the water out, but the additive will help it run much better while it is choking it through.

_________________
95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)

MEPR: Man, my 4x4 makes all other LUVs look good

Agree with 800xl. Two things that can cause these symptoms are the carb passing dirt or the carb passing water. You might take some gas from the tank into a jar, let it settle overnight and see if there is water at the bottom in the morning.
The EGR valve unconnected should not affect this.

I finally got around to putting new points, condensor, cap, rotor, plugs, wires on mine and I have not had a stall or hesitation yet. I got a new EGR off eBay for 1/2 the price of a parts store, so I plan to put that in when it arrives too. May not be the carb after all.

"I have a rebuilt motor in this truck, and I have rebuilt the carb. It has done this for 3 motors and before and after I rebuilt the carb. I have also replaced all the vacuum lines and tried rerouting them, and the problem still persists. I do not have a catalytic converter."

There's something wrong with this picture. If it has done this same thing regardless of engine or carb then obviously it is something separate from an internal engine problem or a carb problem.

That leaves fuel delivery, vacuum or electronics or electrical. It could be any combination of these also.

Many vehicles are highly sensitive to a failed EGR, but I don't know the LUV system.

I see on my older '75 LUV that the vacuum system is partially controlled by a solenoid. If you have or can borrow a vacuum gauge that might tell a lot. Connect at various places and see what it says.

Brand new plugs fire more easily than used plugs, and only a little fouling is needed to spoil a plug. If you have a weak electrical system it can pass the buck right down the line. Check that voltage regulator is clean bare metal grounded at mounting.

Bad battery cables, lugs, +/- connections, corroded engine ground strap [or lack of same] can cause most of this as low voltage. Also a bad coil or coil secondary wire, low voltage to primary, bad connections or junk wires can all contribute. All of these problems could conceivably improve for a short time with new plugs as less resistance against a weak spark. All grounds are meant to be clean bare metal.

Improper points gap could contribute, so could a funky vacuum advance cannister. Check that points plate moves easily and smoothly when you put suction on the distributor vacuum hose.

Check distributor cap inner lugs for glazing and carefully scrape with a pocket knife to clean. Don't touch the coil tower wire button in top, but clean connection where coil wire plugs in, and on coil tower too.

Best to do a systematic cleanup and check to eliminate each system: vacuum, distributor, coil, wiring, voltage etc. Overall it sounds to me like electrical and distributor vacuum cannister or vacuum problem.

Le Mans in the 60's: Ferrari is having a very bad time in qualifying. Weak coming out of turns, poor bottom end and midrange down the straights especially Mulsanne. Nothing fixed it.

The guy in the white shirt with Champion on the sleeves wanders into the pits and asks to see the plugs. Because Champion was a sponsor the plug tray was passed to him. He stepped into the sunlight and quietly inspected the plugs with an eye loupe.

"I believe you need to remove centrifugal advance weight of about 1/2 gram...."

Ferarri mechanics did as advised. Ferrari placed 1-2-3 that year.

Even a seemingly little thing can cause a heap of problems and can be the difference between win or lose!

.

i too am having this sort of problem just started today. i decided to give her a chance and drive halfway across the state get halfway there or 80 miles from home and all hell breaks loose. rule no.1 if its working just fine just leave it alone. here's what i did...i bought a CAN OF CARBURETOR CLEANER sprayed 1/4 of a can carb looked good now i have all of the symptoms as said above. plan of action for tomorrow is replace dist. with electronic new plugs wires cap bug if that doesn't work carb rebuild kit if that doesn't work !!!!
FOR SALE 1979 MIKADO nah just kidding i don't give up that easy there would be a lot of cussing right before the for sale sign

_________________
I'm one more LUV away from divorce! at least i don't have to worry about her taking them

On these kinds of driveability problems I find that a step by step troubleshooting is best. This eliminates one system at a time from the list of possible culprits. Also if one particular repair solves the problem you then know exactly what to look for in the future on that or other vehicles.

Basic troubleshooting would be to veify voltage from the battery all the way through to sparkplugs, along with checking all grounds. Battery, cables, switch, coil, ballast, points, condenser, rotor, cap, wires etc. Verify fuel from tank to carb. Then you can test single components against specifications and pinpoint the problem. In adition this can reveal other potential problems you didn't know about, before they cause trouble.

OK guys, this is what I have done.

EGR:No vacuum line connected to it.

Vacuum lines replaced..

New cap/rotor/wires/points/condenser

AND I also isolated the ignition system and soldered all contacts to prevent corrosion.

It runs better, but still wants to stall a "little", now.

I don't think it's water in the gas.. It idles perfectly.

If the fuel pump was going bad, wouldn't it affect more than just a certain spot in the gas? I mean, it hesitates like it is suddenly getting *no* gas and wants to die, but just in one spot, a little after idle. If I go past that spot in the right timing, the engine will VERY SUDDENLY recover, and jerk the vehicle violently forward.