Introduction

[bdag]

Hey y'all. I've been lurking this site ever since I bought my 720, almost 2 years ago. I've gained a ton of knowledge and so far done all the fixes myself. My truck is an 86 720 King Cab 2WD. It's got about 130k on the 2.4. A friend helped me replace the head gasket several months ago. This is my first pickup truck and I'm sorry I didn't get one sooner. I was raised a city boy but the country boy is taking over. My mechanical skills are basic but growing.

I'm guessing y'all are waiting to see when this noob is going to complain about my truck's problem looking for a fix. Well, it's true, I'm stymied by a problem at the moment but came up with a punchlist to check. I can't keep the engine running unless I'm constantly feathering the gas. Even when I'm braking I need to keep the edge of my foot on the gas pedal. I can let off the gas if I'm still in gear and be fine but as soon as I push the clutch or pop it into N it dies. Cold, hot, doesn't matter. It works fine when I start it up in the morning, but as soon as I tap and release the throttle it dies. If it dies after driving for 5-10 minutes it sometimes won't start. It wants to but it sounds like the starter isn't getting the juice it needs. Most of my driving is a 7 mile stop and go commute on surface streets in the morning and the reverse in the evening. I tend to be on the freeway about once a month or so.

Oh and sometimes the carb sight glass has no fuel but most of the time it does.

One of the first things I noticed after checking out some of the posts is that my main choke flap is wide open when cold so I assume my choke spring is broken.

Second thing is that the engine is acting worse in the cold weather so I'm thinking either the thermostat or vacuum temp valve in the fresh air intake is shot. I don't think that's the entire problem though.

If that doesn't work I'm going to pull a carb, buy a kit and follow fastboatman's amazing rebuild tutorial. Why not a Weber? Because I live in Oregon in the DEQ parts.

I've visually inspected all the vacuum hoses and they look good enough. I've sprayed carb and choke cleaner into the carb and around the engine and seen no sign of a vacuum leak.

I've considered the fuel pump but ruled it out. When I turn the key just shy of the starter position, I can hear the fuel pump firing away.

You might be thinking electrical. All the connections look good. I pulled into AutoZone one evening and asked if they could run an electrical check. Battery, alternator and starter all passed with flying colors. I did find one bullet connector that was unplugged (fusible link?) and plugged it back in but no change. There's a few empty harnesses hanging out in the engine bay, not sure what those are. One is near the vacuum canister. Plugs, wires, cap, dizzy all seem to be working fine. Good spark off all 8 wires at the plugs and cap. Good spark to the secondary.

My power steering line leaks (needs new clamp from hose to hard line) and has spritzed alot of the lower engine bay. Possibly caused a failed electrical connection somewhere.

If the carb rebuild doesn't fix it, I might be looking for a 4WD diesel 720. Rare, I know but there's less parts to break and gas mileage is generally better. Oughta even out the higher price of diesel right now. Besides that I'm all about systems where I can manufacture the fuel. I like electric heat in my house because I can harvest solar. I like diesel engines because I can make my own bio.

I'll keep my progress posted in the hopes that it could help someone else with their issue.

Peace,

Brian

[flinterman2000]

The car I'm using now was doing the same thing. I serviced the carb and it improved a little. The main culprit was the dizzy. serviced the dizzy and voila, idles normal but the power is spongy, has good top end but has some oil leaks. Oh by the way its a Mazda Capella.

[bdag]

Thanks for that tidbit, flinterman. I might have to revisit the dizzy. Not looking forward to the price tag.

I checked the choke at hot and cold and it was full shut after pumping the pedal from cold. It was full open after a freeway drive last night. *Myth busted*

It also started right up after it died today. Not sure if the freeway drive helped or the fact that it was 4 degrees warmer than yesterday.

post6237964.html?hilit=choke#p6237964 makes me think it could be the carb. However fastboatman's vac line post post5765197.html?hilit=19%20feet#p5765197 has got me thinking to try that first being a cheaper fix. Has anybody deleted the brass beads without issue? How do you transplant those anyway?

An old guy told me to buy a new hose the length of the longest I need. Replace the longest hose, then cut the ends off that to replace the next longest, etc. The problem I can see is that if I miss one hose in the sequence, I'll be out buying some more hose. At about $0.60 a foot, I guess 30 feet shouldn't cost too much. If I do the vac line replacement I'll document all lengths and diameters. Somebody might be able to use it in the future. If that doesn't work then I'll do the carb with the peace of mind that the vac lines are golden.

I also failed to mention that half a can of Seafoam in the gas tank and the rest in the crankcase didn't help.

Oh and the LED on the ECM under the driver's seat is steady green. Most of the time. Sometimes it fails to come on. But it never blinks out any error codes.

[bdag]

Holy crap! So I just ran a quick ten minute errand, down the freeway and back. Truck had been sitting for 3 hours. Outside temp is about 41 and I didn't have to friggin feather the accelerator one bit! Could be the temperature. Anybody ever mess with the vacuum control valve? Could mine be shot?

Or maybe he knows I been talking about him online.

How'd my truck get online?

[bdag]

50 plus degrees this afternoon and the truck ran like a champ. Idles down around 600-800 or so. Died once and wouldn't restart. Acting like the battery was dead. Pushed it into a parking spot. Started fine 15 minutes later when I got it. Drove home fine.

Am I just blathering on or does anyone have suggestions about this temperature issue? Carb and that's it?

[PEZi]

Sounds like a bad ground or something if it wouldn't even crank over...

[bdag]

Tried to turn over like the battery was low. Real slow and not enough CCA to turn over. I've got a random orange wire in the engine bay with a ring adapter on the end. Maybe I'll ground it and see what happens.

My previous blathering comment wasn't meant to be rude. Just wondering if my monologue style was interesting or annoying.

[bdag]

In case anybody is interested to know, the Seafoam seems to have cured a lot of problems. It was 30 degrees this morning and the engine ran fine after a short warmup. I let off the throttle at stops without the engine dying. At a longer light the engine idled fine but then went to a lower idle (down to 4 plugs?) and almost died. I had to feather the gas a bit but after that it was fine. I still plan on rebuilding the Hitachi but I'm not in dire straits anymore. I still plan on checking to make sure the starter and fuel pump and whatever else have a solid ground.

I suppose I should check my fuel and oil filters now, eh? That crap that burned off ain't gonna just disappear.

[flinterman2000]

Hitachis' are crap. If you don't need to pass smog get a webber 32/36. Your milage, power and fuel issues will improve.

[artemoushue1]

Hitachis' are crap. If you don't need to pass smog get a webber 32/36. Your milage, power and fuel issues will improve.

AMEN!!!! God bless the 32/36 conversion. My Weber passes emisions just fine though.

[love_my_gt]

Glad you got the issues worked out without having to replace the truck lol

If the carb rebuild doesn't fix it, I might be looking for a 4WD diesel 720. Rare, I know but there's less parts to break and gas mileage is generally better.

Just a little info I picked up when I started looking for a diesel. They never released a diesel 4x4 in the states. You'll either have to have one imported, converted, or find one that has already been converted.

All the diesel 720s were rear wheel drive and 5 speed.