LUVTruck.com

First off I would like to thank everyone for all of the help over the past 18 months I have owned my luv. Before my luv I had never worked on autos, and thus far reading other peoples posts has saved me. But now I am stuck!!

I have a 1981 1.8 liter 4x4. Prior to my little excursion in the desert I had it running perfectly. To get there, I did the following:

New plugs and wires
new cap and rotor
replaced points with pointless electronic ignition conversion kit
rebuilt the stock hitachi carb
new radiator hoses
changed oil
new battery
new ignition switch (and keys)
installed tachometer
new air cleaner filter
bought timing light and performed timing procedure

That about covers it. So now I will describe the conditions before my luv decided to stop running. I spent two days of rough offroading in mountainous desert in 105 degree weather. I was racing through soft river bottoms and went to the top of the highest mountain. I was in a convoy of about 6 trucks (bachelor party) and was often following through plumes of thick powdery dust. I re-fueled twice at this suspicious gas station in the middle of nowhere from an above ground tank. After the second re-feuling and after a good 5 hours of hard offroading I was on my way back to camp in first gear and it died. So, i restarted it and made it back to camp. The next morning (6am) after a long night of celebration I got in my truck to drive 3 hours to a wedding and.... it started. But, every time I would come to a stop, it would die. If I let it get below 900 rpms... it would die. I stopped half way to the wedding and I cranked up the idle screw to about 1500 rpms to help keep it from dying at stoplights. I made it home. So now when I start the luv the rpms surge like crazy (around 4500). If I feather the gas a little it will drop quickly after it has warmed up a little (vacuum leak?) but it will refuse to hold an idle at first. If i baby it for about five minutes I can get it to idle around 900 rpms but it’s a rough idle and it fluctuates up and down by about 100 rpms. I drove it once and it has no power and the acceleration is hesitant.

This is what I have done trying to fix it:

Timing light showed a miss;
new plugs and wires
new Accel Super Ignition Coil for High vibration/offroading
replaced fuel filter between tank and pump (old one was full of dirt)
rebuilt stock Hitachi carb (complete rebuild with all new gaskets and chemical dip)
new air cleaner filter (old one was full of dust)
Attempted to do timing but rough idle doesn't allow for steady 6 degree alignment
Visual check of all electrical from ignition switch to fuse box to battery
Visual check of all vacuum lines (that I know of)

Any ideas? Hunting season starts in 14 days Thanks!!!

Wow, you have already done alot of work on this machine. I would start at trying to figure out which cylinder had the skip, why it is skipping and eliminate that problem first. After all, an 85 hp 4 banger can't really afford to have much of a skip. From there one problem at a time.

_________________
In life there is the "Way things should be" and then "There's the way they are".

2005 Silverado 3/4T Crew Cab
1981 Luv 2WD
1979 Luv 4x4 Currently going through Open Heart and Cosmetic surgery
1995 Roughneck JetBoat
1981 Luv parts trk

I don't think it an electronic miss anymore. The timing light isn't skipping... its just following the sporadic idle. I did a compression test last night and i got 165 psi on all four I just replace the thermostat housing gasket because it was a slimy mess, but there was no thermostat in the housing? This is separate from my main issue though. I am going to take the fuse box apart and soak it in lemon juice because its pretty dirty and then attempt to adjust the carb and timing again. Thanks for the comment!

Ok guys... still cant figure this out and hunting season starts in 1 week!!! I cleaned the hell out of the fuse block... and just as a recap my problem is,

engine surges when cold and wont hold low idle
once it heats up i can get it to idle... but it is a sporadic idle.

I read that a clogged fuel filter can cause your fuel pump to burn out? Could it be that my fuel pump is going bad? The float is perfect and the bowl always has fuel.

I am going to start changing out all of the vacuum lines today. Let me know if you guys have any ideas. Thanks!

you said you put mystery gas in it right?

take a glass jar full from your fuel line at the carb.

let it sit overnight.

see if it seperates.

sounds like the classic mexico "petrolina" decent gas, but being in an above ground container subjects it to more temprature extremes, causeing condensation and water to form in fuel.

A.j.

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Thanks for the advice. I will give it a shot. This weekend I also replace about 75% of the vacuum lines and took off the egr valve and cleaned it. The diaphram was good but whenever I pushed on the needle it would make a crunching noise.... I think the carbon buildup might have been keeping it from seating all the way. I am going to test it today and test the gas. Thanks again.

ANYBODY........I'm just curious..not trying to hijack the thread but would the EGR valve cause this problem? I have seen vehicles running great without one and with the EGR pipe busted loose from the exhaust pipe and separated by several inches. I have even thought of taking mine completely off before when I had the engine out. Would it matter? From what I gather all it does is just what it's name implies, Exhaust Gas Recirculation. Pulls hot air from the exhaust and puts it back in the engine. Am I right?


Good luck fixing your Luv. Having it down for the opener of hunting season is damn near reason to take time off work and spend all day on it wrenchin.

_________________
In life there is the "Way things should be" and then "There's the way they are".

2005 Silverado 3/4T Crew Cab
1981 Luv 2WD
1979 Luv 4x4 Currently going through Open Heart and Cosmetic surgery
1995 Roughneck JetBoat
1981 Luv parts trk

first thing I disable. as long as you can properly tune out what the EGR did, then it doesent do anything but suck at power.

A.j.

_________________
http://www.youtube.com/watch?v=ykgDNjeTa0g

Thanks for all the input. I took off my air injectors today to clean them out and paint them and I notice two large cracks going through the exhaust manifold. Could this be what is causing my problem??? It could have happened when I was offroading.

I would guess your carb is junk.

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Certified pilots, looking down on people since 1903.

When you remove the EGR, does it make the mixture richer or leaner. I will be removing mine, (And also installing Offy intake!) but I think I already have a problem with the Hitachi running lean and it getting hot. Plugs look OK right now, not obviously too lean, but I would prefer to err on the side of rich, and I don't know how to adjust the mixture on the Hitachi. I'm better at Quadrajets.

It generally doesnt do either, since its purpose is as an inert gas to cool the chamber and displace some of the A/F mixture to lower NOx emissions. As a performance minded individual, I dont like the idea of "displacing" any of my A/F mixture with already burnt gases... sounds a little counter productive.

It tends to make the carb run towards the lean side, as now your getting a full cylinders charge at all times. but usually the problem is more with the amount of timing you have. When EGR is introduced into the cylinder, timing is raised to compensate for a slooow burning charge, this is where the problems are. If the EGR is removed and spark not looked into, during cruise mode ( when typical EGR is used) the engine can have excessivly high timing causing detonation. which to most... looks like a lean carb issue.

what I generally do for a EGR remove, is begin by pulling the timing back a few degrees and tune the carb slightly fat. the I simply plug the EGR line and test the operation of the vehicle. If it bucks or acts like something is wrong, simply plug the line back in and go back to the drawing boards. after I have gained confidence that the tune is close to what I want, I remove the EGR all together and begin tuning for max performance.

Now for the hitachi....... i cant say anything, I attempted to try and "tune" the misrable carb and got no where.... so I decided it wasnt worth my time and went with the weber. (before the buick swap). Im not much of a quadra-junk guy either... as a holley has always been my cup of tea, but man the quadra-junk made way more sense then the poor hitachi unit. I would imagine for your setup, simply pulling the timing back a degree or 2 would probably be OK as the increase in total fuel pull from the bowls should increase by several percent- but please please please use alot of caution! the G180 is like a sheet of glass, chip one corner and the whole thing breaks. That should be OK for the stock motor, stock intake etc etc.... But will require some real carb tuning for the new intake and I imagine a better flowing exhaust. as those 2 items alone will send the carb way lean with the engine improved airflow. Im sure one of our Expert G180 pros can comment on the Hitachi tuning.

just remember, this is not a SMOG legal thing to do... so if yer in cali you might want to make sure your in the clear. trust me... they get mad about that stuff.

A.j.

_________________
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Thanks for the detailed reply AJ!

I have to sit down with my shop manual and get a handle on all the emissions stuff I plan to 'remove.' I am in CA, but it's a '72 and right now there's no inspections. Since the convention is no inspections for '75 year and before, I would expect that if they ever did require them any vehicle purchased before the regulations would be grandfathered, or you'd have a Southern California full of pissed hot rodders that can't find smog parts for their '70 Chevelles.

Now back to the issue at hand...I'll definitely check into the timing, I have mine set at 12 degrees before because it's a '75 distributor. '72 spec was 8 degrees. I don't have degree tape on my balancer, but eyeballs said that there's approx. 30? degrees or so total at 2500 or so RPM (which I think is correct...)

I have already disconnected the vacuum line for some kind of fuel mixture modulator because I thought it was giving me a lean sag. You know, I also disconnected the coasting richer solenoid, maybe I could play with that again to get more fuel in. Like I said I have to sit down with the book. I may pop for a wide band O2 sensor so I know what the hell I'm doing, you're right that I better be careful since I don't plan to lunch this engine anytime soon. I don't have a line on a header yet, I was hoping to not run one at the outset. I'm not trying to get performance per se as much as I am trying to have a glass smooth, strong running engine (yes I know, just get rid of the Hitachi. But it just kills me not to be able to tune the thing!) And an engine that runs cool enough with the stock radiator before I replace the radiator for the A/C swap. Maybe it's timing like you said, most guys on here have temp problems when the timing's off.

All I know is I am having a hell of a time getting the timing right. Once I fixed the cracked exhaust manifold, plugged a vacuum leak on the carb that I have had since I bought the truck and fixed a vacuum leak at the egr adapter plate, the carb has been giving me hell. I have a timing light but I just can't seem to get the mixture right at the carb in order to time at the distributor. If I start with the mixture screw 3 turns out.... the luv wont start!!! The local shop wants $200 to time it. Screw that, I didn't come this far on my own to give up when I'm so close to having a smooth running machine. Any pointers on adjusting carb and timing from scratch on a stock hitachi???

Since I practically hijacked your thread, I feel obligated to help you out.

Before you deal with the rest of what I have to say -- does it start with the mixture screw out more than 3 turns? If yes, then it's likely and idle mixture/idle speed misadjustment. Otherwise --

First off, I've found that the idle mixture screw doesn't do too much. I've turned mine out a full 10 turns and it doesn't go rich and bog like the manual says it's supposed to. So I suggest you go with three turns and leave it. That setting is independent of timing. The next adjustment of course is idle speed. This little screw adjusts how far the throttle plate is open for idling, and if you have it open too far you can compensate by changing idle mixture, but don't. I'd say a zero adjustment is starting with the screw out (throttle closed) then screw in about 2 turns. See if it starts and idles. If it doesn't you can systematically open and close the throttle blade with the screw to change the speed. Idle speed is dependent on timing, meaning if you change the timing the idle speed will change. Keep that in mind.

So-for the Hitachi,

Mixture screw out three turns is a general rule for me. Then--

If it runs, set the timing with the timing light. Get timing correct before anything else.

Then set idle speed with screw. I like 850-900 RPM, mine is spec'd for 700 but I think that's too low and the later trucks were like 900 RPM.

Don't worry about hijacking the thread; it is all good and interesting information. Thanks for the info. I can get the truck to start with the idle mixture screw out 3 turns (360 degrees x 3 right?) It wont hold idle until it has heated up. Then I get my timing light out, hook it up to #1 and my indicator mark that I added to line up at 6 degrees only shows up sporadically or if give it a little throttle. No matter how I adjust the mixture and speed I can't get my mark to coincide with the timing of the timing light. I am showing a miss, but it seems to smooth out at certain adjustments. Also, with the mixture screw out 3 turns I can't get smooth acceleration. It seems to choke when I throttle just a little and then it catches up and the rpms surge. I don't know if its an electronic miss or the carb. I can't imagine its electronic with everything I have replaced. I will try again tomorrow. I will leave the mixture screw three turns out, try to time it and then adjust the idle.

That sounds like fuel delivery. I know you have already replaced your fuel filter but it might pay off to pull it off and see what it looks like...dump out what you can in a glass and look for sediment. Maybe Cut it in half and see what the inside looks like. I know it's new but if you have bad gas it won't take long to plug it up again. If the fuel you bought was that bad you might have to pull your gas tank and clean it. Did any of the other guys in your party buy gas from the same station and if so are they having problems of any kind?

_________________
In life there is the "Way things should be" and then "There's the way they are".

2005 Silverado 3/4T Crew Cab
1981 Luv 2WD
1979 Luv 4x4 Currently going through Open Heart and Cosmetic surgery
1995 Roughneck JetBoat
1981 Luv parts trk

The other guys didn't have any problems.... plus I burned the full tank of what could have been bad fuel and filled up with what I know is good gas. Can I simply run my fuel line to a 2 gallon container of good gas to test it? I will check the new filter. I also read some info about clogged catalytic converters causing similar symptoms. Just one more thing to check. Thanks for the advice...... and patience.

I am going to pull the gas tank and the catalytic convterter tomorrow. When I shut it off today I had white smoke back up through the carb and out the air cleaner.... clogged exhaust system/cat? Which could have led to the manifold overheating and cracking. I really hope its not a bad cat... will cost me more than I paid for the truck to fix it. I guess I will find out tomorrow.

Where are you located...somewhere that requires emissions? If so than maybe you can find a used one. If you can get by with it take the Catalytic converter off and replace it with a "test pipe". You can also cut the top open, rip out all the guts (comb I believe it is) and then weld it back together and reinstall it. If you can get by with it that way that is.

_________________
In life there is the "Way things should be" and then "There's the way they are".

2005 Silverado 3/4T Crew Cab
1981 Luv 2WD
1979 Luv 4x4 Currently going through Open Heart and Cosmetic surgery
1995 Roughneck JetBoat
1981 Luv parts trk