LUVTruck.com

Ok gang, I decided to swap out my points distributor with an electronic setup out of an 81 isuzu I-mark. After reading the info on the site here, and some threads I finaly figured out I just needed power to the green connector on the ignitor.. duhh! lol I wont admit how many dozen ways I hooked it up trying to make it work, before I saw the thread that says to only hook up the green plug. Anyway, now it works at least, starts right up and idles great. However I drove it to work this morning and it has a really nasty sputter now at part throttle, pops, sputters, sounds bad.

It runs fine at idle, smoothest its been, it will also smooth out and pull at full throttle or near full, but anything between idle and full throttle sputters and misses something bad, feels like chitty chitty bang bang rolling down the road at cruising speed. Does anyone have an idea what I might try checking? I am not running the ballast resistor, and the cap, rotor, plugs, coil and wires are all new. Oh and the miss wasnt there with the points, and the timing is set to 10 before tdc as it was with the points. Nothing else was changed, so im sure its the ignition. I saw that the ignitor is like 400 bucks too so if it might be that then I think ill go back to points till I can find a good ignitor. That seems like the logical place, but maybe I just hooked it up stupid. I checked ground, and im running power off the black wire with the red strip, I havnt checked it for 12v, I just hooked a test light to it. Any advice would be greatly appreciated, Thanks

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LUV Truck Desserter!
76 Daily driver (SOLD)
73 LUV (rusting away at the moment)
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63 Nova
74 Camaro

I was just reading another post by rondog, and he described this same problem, as being an EGR issue, and i remember I found that the egr hose was off the thermal valve, and i reconnected it since i figured it came off, but this may be may be my problem now that I think about it. Ill try that and update. Seems it could be the EGR is causing the miss and only comes in at part throttle, not idle, not WOT.

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LUV Truck Desserter!
76 Daily driver (SOLD)
73 LUV (rusting away at the moment)
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My problem ended up being a bad carb. that I thought was good. I bought a rebuilt one, one more time, and then it was great.

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OK, I'm over it. Where's the beer?

You could try opening the plug gap up from .9mm to 1.1mm. Electronic has a bigger gap.

What plugs do you have in it??? NGK BPR6ES (11) or similar???



Make sure the vac advance is working properly.


Is it only under load it breaks down???


Try with a direct battery hookup too. Could be the something else runs off your power wire and they dont like each other.


Did you reuse your existing coil??? Id say you might need one for the electronic ignition.





Bob.

_________________
Current project, 1979 KB Isuzu Ute.

Daily driver, '86 Rodeo Spacecab.
Chasing parts for Isuzu Impulse.

My problem turned out to be the vacuum advance unit. The stock unit from the I-mark was throwing too much lead into the motor, and made it miss like crazy. So for now I have just unhooked it. I tried to see if the stock one off my points distributor would work, but it doesnt fit the electronic dist. body. Your post made me realize the problem may be vacuum related as it went away at full throttle, so I was relieved it was something simple.

I did try to hook it back up this weekend, and even with -8 retard it still cant handle the amount of lead the vacuum advance puts in. Using my timing light I tried to see just how much, and it was up above 15 degree's when the motor just died. So i wonder how many other guys have run into this. Im guessing the i-mark must have some goofy retarded ignition setup and needs tons of vacuum advance for smog reasons.

Right now I have mine set at 10+ lead, and the mechanical advance adds another 8-10 degrees at cruise speed and it seems to be happy with that. As for plugs im running autolite 65's gapped at .044". The coil is a new Napa unit I put on it when I first got it running a couple years ago, it doesnt seem to get hot so I havent bothered with a ballast.

i was out at the bone yard, and stocked up on Ignitors (elec control module) for the hell of it, these things are worth their weight in gold, so a spare is always good!

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LUV Truck Desserter!
76 Daily driver (SOLD)
73 LUV (rusting away at the moment)
---------------------------------------------
63 Nova
74 Camaro

The plug thing doesnt mean much to me.
I swear by NGK. Bosch plugs have also treated me fairly well.
Motorcraft and Champion go in the bin. I wouldnt use them as schrapnel.

I could look up 44 thou, but being metric and all down here. Sounds like about 1.1mm

The resistor on the coil is to stop it burning out the points. You wont have that trouble now.


Bob.

_________________
Current project, 1979 KB Isuzu Ute.

Daily driver, '86 Rodeo Spacecab.
Chasing parts for Isuzu Impulse.

Thanks for your help guys. thanks Bob, I knew there was a real reason why I didnt put it back on, I just couldnt remember why they used the ballast resistor in the first place! lol

I might try a set of NGK's with a platinum tip.. Im trying to get the most fuel mileage I can now that im racking up the miles. Im proud to say (well sorta lol) that the LUV is my sole transportation now till I get one of my other trucks fixed. I sure wish I could find a set of gears in the 3.50-3.73 range for smooth quiet highway driving lol

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LUV Truck Desserter!
76 Daily driver (SOLD)
73 LUV (rusting away at the moment)
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63 Nova
74 Camaro

From what ive learned there no real benifit to the platinum tips. They are just for a longer service interval and well suited to the sort of car that you have to remove the motor to change the spark plugs.



As for fuel mileage, i would look to maybe setting the motor up to run on a higher octane fuel. The motor is designed to run on 89RON fuel. Our base fuel here is 91 RON and several people on the Ozgemini.com forum swear by running their motors (G-series) on 95 ron fuel. My dad swears by it too, he has a 94 model pickup. We also have a 98 ron and a 105 ron. The claim to fame with the higher octane is that you get better mileage, power and a cleaner running motor..
Ive tried it in my truck and i noticed no extra power gains or smoothness or increase mileage. I actually got worse economy. But then its that worn ont you check the fuel and fill it with oil.



As for the diff. You could change the back tyres. Go to something with a bigger rolling diameter. But it will put your speedometer out.

Ive also tried this. I had 31x10.5" duelers on the back for a bit. It was sorta like pushing shit up hill with a stick. Because it moved the rpm range down the motor wasnt on song enough to maintain a constant speed on anything other than level ground. A slight hill or incline and you were flat to the floor and looking for 4th gear.
I towed a trailer with these wheels on it and i just left it in 4th gear. So its a pretty fine line upping the ratios.


A car i owned years ago i swapped diffs in. It was a 3.36 and it got blown up. Then i swapped in a 3.55, the pinion bearing went. Then i got a 2.92 and it snapped an axle. Then i went back to a 3.36. It was a 202cid 6cyl with a TH200. The 3.55 was the worst economy followed very closely by the 2.92. The 3.36 was the best by a bit for economy.


Bob.

_________________
Current project, 1979 KB Isuzu Ute.

Daily driver, '86 Rodeo Spacecab.
Chasing parts for Isuzu Impulse.

Well I was reading another thread about swapping in a P'up rearend like from an 86-89 era, im just not sure what gears are available, I would like to find a 3.42 or near that, would be ideal. Im not really after power with this rig, just economy.

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LUV Truck Desserter!
76 Daily driver (SOLD)
73 LUV (rusting away at the moment)
---------------------------------------------
63 Nova
74 Camaro

But thats the thing. You need the power to get the economy.

If you dont have enough go to push the ratio economy goes backwards pretty fast.


Bob

_________________
Current project, 1979 KB Isuzu Ute.

Daily driver, '86 Rodeo Spacecab.
Chasing parts for Isuzu Impulse.

I just got a set of NGK GR4 (stk# 2635) plugs to try, they have the V tip. So what can i do to improve power? I have considered a turbo, but that is alot of work lol

_________________
LUV Truck Desserter!
76 Daily driver (SOLD)
73 LUV (rusting away at the moment)
---------------------------------------------
63 Nova
74 Camaro

djewett--Your vacuum advance problem may just be --this. The vacuum advance causes the mounting plate in the distributor to rotate when actuated. The wire coming in through the housing has to flex/bend a little every time it moves and may be broken internally. I had one do that to me one time, drove me crazy. Would cut out, backfire, etc. Repaired the wire and its connection and cured the problem. With the advance working again you will gain some mileage also.

Oh ok, you mean the wires coming from the pickup unit? I could test them with an ohm meter and see. Heck I should have grabbed a spare pickup when I was out at the yard.

_________________
LUV Truck Desserter!
76 Daily driver (SOLD)
73 LUV (rusting away at the moment)
---------------------------------------------
63 Nova
74 Camaro

djewett, i am following this one because i have the opposite problem. mine spits and stumbles at idle and as you give it gas... once up to a steady rpm it smooths out and it runs fine, however the mileage is terrible, maybe 10 mpg. so like i said, looking to get some insight on mine

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Tact is for people not funny enough to be sarcastic.

Yeah, thats the ones. Mine was the point type unit but those wires still have to flex every time the plate moves. In my case it broke internally right where it came through the gromet at the housing. Difficult to find too because it had to be just in the right place to go intermintent. Found it by carefully flexing a bit while connected to an ohmeter. In your case I would just try a different pickup and wire assembly. I would almost bet on that being the problem.

Hey Bob!! How you been? Ok carb problems? Mine did this right after I got it running, and it turned out to be some bypass jet in the carb had come loose after the rebuild. It just idled rough, sounded like it had a cam, popped and didnt like to idle. What are you running for carb and ignition?

Hey not to get off topic but have you run accross any G180 motors? Ive got a pet LUV project brewing and im looking for a spare motor.

_________________
LUV Truck Desserter!
76 Daily driver (SOLD)
73 LUV (rusting away at the moment)
---------------------------------------------
63 Nova
74 Camaro

stock carb from a 79 on my 80 and the same ignition as you


i haven't run across any spare motors but could use a rebuildable one myself

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Tact is for people not funny enough to be sarcastic.

It sound like a fuel problem just by the smoothing out at part throttle, like the idle circuit is goofy. Bad fuel mileage may also hint to fuel issue, but hard to say off hand. Have you pulled a plug to see what that tells?

Im noticing the Isuzu G series motors are not too easy to find these days. I need to make sure parts are plentiful before I begin any commited project just yet.

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LUV Truck Desserter!
76 Daily driver (SOLD)
73 LUV (rusting away at the moment)
---------------------------------------------
63 Nova
74 Camaro

i am gonna run thru the fuel system this weekend hopefully and see what i can find wrong.....

pulling wires makes it miss on that cylinder so it's firing fine

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Tact is for people not funny enough to be sarcastic.

Well are the spark plugs fouled? This might indicate a rich condition, or if they are clean and look new, you could have a lean condition, you could put a rag over the carb to see if the idle smooths out at all, if it does you have a lean idle mixture. I know the hitachi carbs can be a pain if things aren't just right.

_________________
LUV Truck Desserter!
76 Daily driver (SOLD)
73 LUV (rusting away at the moment)
---------------------------------------------
63 Nova
74 Camaro