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Ok, Here's the story. I find a 79 4wd in a nearby town. It needs some work of course. Get it home and start messing with it. Finally get it cranked, but runs like it has an extremely large cam in it. Its the 1.8 4cyl. I determined that it is only running on 2 cylinders. Swapped the plugs and wires to see if it would change, it didnt. It still ran the same way, but is confined to 4 and 2. Cylinders 1 and 3 make the engine run worse. If I have good plugs, wires and spark, what could be the issue?


Thanks,
cmont1124
79 Luv 4x4

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Luvn Life!
79 4x4 1.8, 31's, Project 4 life. Eventual swap.

How do you have the dizzy wired,clockwise or counter-clockwise?

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"You can't please everyone,so you've got to please yourself"

Are u calling the rotor "dizzy"? If so it turns counter clockwise 1342 firing order.

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Luvn Life!
79 4x4 1.8, 31's, Project 4 life. Eventual swap.

So today, I took the carb off due to the fact that gas continued to leak into the carb. Turned out the float wasnt shutting off the gas. Fixd it. I am still getting spark but will not crank. I feel as if I have a mechanical issue that is not letting spark to 4 and 2. Possibly a worn cam or something? Do I need to adjust the valves? Any help would would be appreciated.

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Luvn Life!
79 4x4 1.8, 31's, Project 4 life. Eventual swap.

Could be valve adjustment, burnt valves, bad plug wires, swapped wires from 4 and 2, bad distributor cap, flat cam lobes, extremely bad rings/piston on #4 and #2, head gasket blown to those cylinders, bad spark plugs, and probably a few other possibilities.

Don't fret. just start eliminating potential problems. I'd start by swapping plugs, wires, and cap to see if any of those help. While the plugs are out, do a compression test. If those two cylinders are really low, pull the valve cover and check the valve adjustment on them. Try not to do too much all at once, test one thing, then move on to the next.

Also it is a bit confusing when you say you "don't have spark to 4 and 2". It sounds like the more accurate way to put it is that is isn't firing on #2 and #4. If you get spark jumping from the wire to the plug or block then you have spark, even if that cylinder isn't actually firing. I was a little confused when reading your post at first. It sounds like you've already narrowed the problem down quite a bit, now just have to keep at it testing things along the way.

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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

If you unplug the wire from your #4 or #2 plug and ground it while cranking it, do you get any spark?

Yes I have spark to all 4 plugs when grounded. But now the truck won't start at all. Turns over and hits but won't start and run. I don't know.

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Luvn Life!
79 4x4 1.8, 31's, Project 4 life. Eventual swap.

I think I'd be wanting to run a compression check on it. If you don't have a tester right now then the next best thing would be to look at the cam and valve adjustment. As you turn the motor around the rocker arms should be just slightly loose when the valves are closed. If someone tightened things up too much the valves would never close and those cylinders wouldn't fire. Also line up the timing mark on the crank pulley at 0 degrees and look at the cam. There is a mark right behind the cam gear that should be either straight up or straight down, or you can also look at the pin that goes through the cam gear to line it up. If that isn't lining up that would indicate the cam timing is wrong.

Another thing to look at would be the points. Generally that won't cause just two cylinders to not fire like you're seeing, but it could be contributing to the problems. It is a common source of failure too.

Are there any signs of the prior owner working on parts of this truck? I have found in the past that is a good path to follow. Recheck whatever looks like it has been opened recently and possibly put back together wrong. Back to the cam timing I mentioned, if they had just replaced the head/headgasket, that would be an easy thing to get screwed up.

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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

Thanks 800,
The valves are a little loose at close. They all have about the same play.
I will check the cam tmrw. I took the points out, cleaned and put back in but will pick up some new soon, along with a feeler and gap gauge. Thanks again for the info. I'll be hollerin back at you.

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Luvn Life!
79 4x4 1.8, 31's, Project 4 life. Eventual swap.

Today, bought some new points and put them in. Then, when you think youre making headway....BAM!!! No power to the coil. Tracked it down and finally got spark to the distributor. Fired it up, adjusted the timing, idle screw, air/fuel mix. Taking fuel great and fires right up. Cleaned carb yesterday, probably didnt hurt. Temp gauge not working and oil light stays on. I guess I will be tracking down those bugs in the near future. Not for sure how smooth the little engines run, but still has a slight shimmy to the engine. Its not a miss, it just has a shake, almost like a lope??

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Luvn Life!
79 4x4 1.8, 31's, Project 4 life. Eventual swap.

So you're running mostly smooth on all 4 cylinders now? Sounds like good progress.

I'd be a little worried about that oil pressure light. If the sending unit wasn't hooked up it would stay dark, so it either has low pressure or a bad sender. Low pressure would be bad obviously, and I haven't had too many bad senders. If it was running badly quite a while it might just be that it washed unburnt gas past the rings and thinned out the oil. My most worn out LUV motor would flicker the oil light at low idle when warmed up and the oil at its thinnest.

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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

Yeah I'm going to dig a little deeper into the oil light on Monday. I dont know why it stays on. Its just bright red all the time. Seems to be oiling the motor ok? I hope its just the sending unit. The temp gauge, I dont know either. Probably not even hooked up. So maybe if I change the oil it would go off?

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Luvn Life!
79 4x4 1.8, 31's, Project 4 life. Eventual swap.

Oil sending units are cheap, I would just replace it. First pull of the wire and make sure the light is off, then ground the wire and make sure the light is on. That test will test the complete circuit from the sending unit wire to the bulb.

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Certified pilots, looking down on people since 1903.

Yep, cheap and easy to swap, and easy to check. If your light stays on even disconnected you might just have a short or some other wiring problem.

The temp sender unit is on the bottom side of the intake. It is near the thermostat, but I believe a little towards the outside of the truck. It feels a lot like the end of a bolt so it can be hard to find. Feel around for something that is shaped like the head of a nail. The wire is a single wire (Black with yellow stripe I think) that slides onto the nail like connector from the side

_________________
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

One more day of 12 hr shifts. Then playtime with the Luv. 3 days off to try to track down some of this stuff. Thanks for all of the info!!

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Luvn Life!
79 4x4 1.8, 31's, Project 4 life. Eventual swap.

The connector to the temp sender was ALWAYS falling off on mine. It just slides over the tip on the sender, and not securely, apparently, when old. So that issue may be a simple fix. Best bet would be to replace temp and oil pressure lights with gauges anyway.

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1980 4x4, 3" body lift, G180/G180 head, Pacesetter header, Offenhauser Dual Port Intake, Weber 32/36, Electronic Ignition, Glasspack & a Smokestack.

Well............I thought that it was running good, but it still has a problem on 4 and 2. Pull the plug wire off of these two cylinders and it has no effect on the way it runs. If you pull off 1 and 3 and the truck dies, so 1 and 3 are definitely firing. 4 and 2 do not. Gonna dig into it tmrw again. any help would be appreciated.

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Luvn Life!
79 4x4 1.8, 31's, Project 4 life. Eventual swap.

Today I drained all of the gas and pulled the two fuel filters so they could be replaced. Going to pick upi some filters tomorrow and put fresh gas in. I checked the alignment of the cam timing it all looked good and the valves felt good when I checked them. I'm going to see about a compression tester tomorrow. I am getting spark to the plugs, but the spark is yellow not blue? Could my ballast resistor be causing the two dead cylinders with not having a hot enough spark to the plugs? I read that the brake master cylinder uses vacuum from the intake, is this correct? Is there an easy way to check to see if it is leaking?

Thanks

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Luvn Life!
79 4x4 1.8, 31's, Project 4 life. Eventual swap.

You can cap off the port on the intake to the brake booster. It comes off of the runner to #4 cylinder as a rubber hose, then across the firewall as metal for a bit and back to rubber at the booster. I have had a lot of trouble getting them loose at times though, the rubber wants to fuse to the metal. You'd need a vac gauge and pump to test the booster though.

Vacuum could be part of your problem, but if its bad enough to kill two cylinders then the usual test of spraying carb cleaner around the intake runners likely won't tell you much. Hard to say.

Best test will probably be the compression check. If you have burnt valves or serious piston/ring problems then the mystery will be solved and show as low compression. If the compression is good then you know to keep looking for the gremlin.

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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

Without reading all the posts again have you swapped the plug wires of the two that are not running at the cap?

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Certified pilots, looking down on people since 1903.