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Discussion Starter · #21 ·
Hell yeah brother!

i have a Calmini tri-Y header coupled to a 2 inch exhaust, running through a straight through muffler (glass pack?)

i don't know the brand of the muffler, so i might have to go under and have another look. It's actually not a very well made exhaust, with all the clamps holding it together and the loose bushings. Obvious home job and not a very good one at that.

Still sounds wicked, tho. 8)
 

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Discussion Starter · #23 ·
Alright. I found the plug sitting underneath the valve cover. Reinstalled it, and it did absolutely NOTHING to fix my problem.

I am so glad to see all my money and hard work is paying off. Perhaps i really do have burnt valves. I couldn't slip my .008 gauge underneath #2 and #3, so i guess that's that.

Also found that i have hardly any bloody fuel left after i put 20 litres in last time i had it out. Is that because it all leaked out that open port on my EVAP canister?

That port doesn't even draw any vacuum! Is it contributing to a leak or not?! God damn, I am at the end of my rope!

Does anyone have any ideas, if at all? All i want is for this thing to behave itself like it did 10,000 K ago. I sprayed oil down the IAC back then and that seemed to fix the issue. The hose on top of it was split at the end, so that's probably a reason why it fixed it.

The first thing i did with that stupid valve when i had the whole intake apart was test it, and it worked PERFECTLY.

Only thing i didn't replace was the injector seals, and they didn't seem to have anything wrong with them at all.
 

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Discussion Starter · #24 ·
I just tried tightening up all the bolts on the intake manifold. Did it do anything? Of course not.

Car still stalls at idle, and the extreme misfiring over 2500 RPM is back.

I am honestly just considering giving up at this point. I've spent ungodly amounts of money on this thing and absolutely none of that money or my time and effort seems to be going anywhere at all.

Everyone says 'vacuum leak' for things like this.. What bloody vacuum leak?! I have sprayed EVERYTHING with carb cleaner, NOTHING has changed. I have replaced EVERYTHING VACUUM RELATED, Nothing has changed, I have inspected each and every single hose twice over, and this stalling misfiring problem is still persisting.

Am i seriously in for thousands of dollars worth of repair work because a single exhaust valve was a little bit too tight for a few kilometers? I hate this.

I'll try checking the crank angle sensor's output with my scope tomorrow. If the o ring's leaking. perhaps it starts running bad when the engine has a bit of time to run because oil comes up into the sensor and fouls the output. That's all i have at this point.
 

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Try a vacuum gauge yet? HANG IN THERE. You'll get through this. I have seen these concerns and frustrations before and EVERY time, the problem was eventually found and NOBODY had to spend thousands of dollars. Dennis
 

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Discussion Starter · #26 ·
Yeah, i really need to get me one of those. What's the vacuum supposed to read normally?

So far it seems to run okay for the first minute, It's just when it runs long enough to kick down into low idle everything goes south and the misfire kicks in.

The oil emerging from underneath the crank angle sensor cover is what concerns me. If there's oil interfering with that optical sensor, you'd think it'd cause a misfire.

No idea why i'm not getting a check engine light for that, but this is very early OBD stuff, so perhaps they just aren't checking for that. The service manual shows 4 slots on that rotor, which makes me think all it does is tell the computer what cylinder's about to fire. Miss a step, and all sorts of things could go wrong.
I'll hook it up to my scope, see if there's anything weird in the output waveform. If i see missing 'squares' i'll know what to take apart next. (ESPECIALLY if the erratic waveform lines up with the misfire)

Is it true that this particular EFI system dates back to 1983? I've seen pictures of 1983 impulses with a very similar looking fuel injection system bolted on, so it'd explain why it's all so weird.

Sorry for my earlier attitude, BTW. I got told over the phone today that the job i interviewed for needs somebody more experienced to press buttons on a point of sale machine. Really fouled up my mood, especially with how long it's taken me.
 

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Sorry about the job thing.
It's been a long time since I had a 2.6 dizzy opened up, but I thought I remembered a LOT of slots. I could be wrong on that.
Page 43 of my build thread shows where I was having a vacuum leak problem. Includes injector stuff and before and after vacuum gauge readings. Hope it can be of help or encouragement. Dennis
 

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Yep, you're right. It's got several. This makes a lot more sense to me. guess the 4 slots are just a sync' signal of sorts?

IMG_20210506_234129[1].jpg

I took it apart last night to have a look, and saw the sensor was covered in oil. Strange, considering all the o ring does is seal the oil from leaking outside the engine, not inside the distributor.

I guess this means i need a new distributor? I haven't tested the sensor waveform yet, But this is concerning.
 

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Pulled the distributor and figured out why the oil's coming in. Distributor bearings feel very smooth, no rough spots or anything else suspicious. But..

IMG_20210507_180012[1].jpg

O ring looks to have failed from 'compression set'. the most common failure mode of o-rings. The rubber is so hard and brittle that it split in half when i tried to pick it off.

And the oil is coming in through the crank position sensor's plug socket.
distributorleak.PNG


My hypothesis is that the oil is coming in and skinning over some of the fine little slots on the trigger wheel. It'd explain why the problem comes on after it's run for a minute, or about the time it takes to start kicking down into low idle.
 

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Okay, I got a new O ring and replaced a cracked hose which was going from the middle of the intake tube into the valve cover. While i dont think that could cause a vacuum leak, i'm sure it'd definitely lean things out.

Now all that's troubling me is the distributor timing. I have done it exactly as the manual has told me to twice, and both times it simply refused to turn over, occasionally trying to fire on one cylinder only.
I know for a fact that cylinder #4 is at TDC. Both valves closed, Cam timing mark on the cam belt pulley is lined up. (pulley mark isn't but thats because the balancer's slipped 20 or 30 degrees :evil:)

I tried pointing the rotor at the stud that locks the distributor down like JLEMOND recommends, and that did make it fire up, but only for a short while before it dies again. Backfired a bunch, too. (perhaps i was a tooth off? i can't really get a true line of sight.)

manualdistributor.PNG

settingmarks.PNG


Is the workshop manual wrong? :?
 

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Discussion Starter · #31 ·
Guess it is wrong. I turned the distributor a tooth clockwise from that mark, and it fired right up. Is it any better? Absolutely not.

It still has a serious misfire at 2500 RPM that stops it from going any higher, even though i have a brand new cap and rotor, and have cleaned all the carbon off the plugs.

I got a vacuum gauge the other day, and it fluctuates around 17-18. DSUZU's truck got around 22, so I'm hoping this is because he's at sea level, and i'm a kilometer above.

if i somehow STILL have a vacuum leak, i have absolutely no idea where it is or how on earth i can have one. I have sprayed oil over EVERY gasket, EVERY seal, EVERY hose, and none of what i did changed a damn thing in the vacuum reading. Looks like i'm due to spend even more money..

I have replaced everything seal related on the intake side except for the injector seals, and i didn't replace them because they didn't look bad.

I am getting so fed up with this. I'm going to take the intake off again, inspect the injectors and the seals especially well, and perhaps even shell out ANOTHER 120 bucks to get the stupid things tested.

EDIT: Went over to the injector shop today and handed them in, they'll be phoning me tomorrow to tell me how it went. Least it'll be 100 bucks. not 120.
 

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I got a vacuum gauge the other day, and it fluctuates around 17-18. DSUZU's truck got around 22, so I'm hoping this is because he's at sea level, and i'm a kilometer above.

I have a vacuum gauge hooked up and mounted in my dash. My engine has the carb conversion but I'm thinking the readings should mean the same. The barametric pressure changes about 1 inch per 1000 feet, so yea, at 3000 feet (1 kilometer) your reading is going to be lower. Shouldn't fluctuate, at least not much. Mine reads 22 to 23 at idle, engine warmed up. And it's steady. Just pulling out the manual choke will cause the reading to drop and the more air I take away the lower the reading goes. I'd be curious to know just how much the vacuum reading would change for every 1000 feet above sea level. I'm at 500 feet so that's basically sea level.
 

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I really hope you can get this figured out. I can feel your pain reading all your entries. Stay on the path and see if you can get out of the woods with this thing!
 

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Discussion Starter · #34 ·
Thanks for the words of encouragement, guys. I think the vacuum's just fluctuating due to the misfire.

Now, I wonder.. Since the misfire's at its worst at 2500 RPM, it makes me think this might perhaps be a fuel pressure issue? I've already had a couple of fuel filters get blocked up, one time while i was on the road, and both times it completely killed all my power if i tried to give it any reasonable throttle. My tank might be getting rusty.

The tan tops on the injectors also lead me to believe they are the originals. 30 years and 251,000 miles are LONG past when the automotive grim reaper starts calling, so i'm hoping the fuel injector people come back to me with some bad news! :D
 

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Discussion Starter · #35 ·
Just got my fuel injectors back last night. The man told me they were within 10% of eachother, and that he got them within 1. He demagnetized them, ran chemicals through them, replaced the screens, replaced the bottom seals, even cleaned the dirt off the casings, Did a very good job of it.

Did it fix the problem? No. The misfire seems to have moved up to 3000 and seems a little less nasty, but it is still there. I haven't tested the idle yet, but i'm sure it'll be just the same.

132 bucks, and for what? Either there's something strange going on with my fuel system, I have a vacuum leak in some unfathomable place, or i have a burnt valve 20 something thousand kilometers into a rebuilt engine.

I have NO idea how the vacuum hoses are supposed to be routed. I only have one vacuum switching valve on the starboard side of the engine bay for some odd reason. does that mean somebody's been fiddling with it before me and routed everything wrong? I get vacuum at the regulator on a cold start, The line coming from the bottom of the throttle body goes into a T plug. one end goes to the canister line (???), and the other end goes into this mystery VSV.

Anyone have a picture of what the vacuum switching valve's supposed to look like on a 90? This is weird!
 

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Is there a vacuum accumulator on the frame like the 2nd gen Troopers?
 

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Discussion Starter · #37 ·
I don't think so. I'm sure i would've seen it when i was working around the frame a few months ago.

Never seen vacuum lines go down there at all.
 

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Dang, worth a thought I guess.
When I discovered mine, and came here to ask what it was, there was a single hard line running to it.
 

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Discussion Starter · #39 ·
I just went out and tested it out. Good news is the injector cleaning really brought the ticking noise down. it's nice and quiet now, only ticking now is from the valvetrain itself.

Bad news is it still constantly tries to die at idle. The high speed misfire seems to clear up when the engine starts coming up to temp, but no matter how high i turn the idle screw, it'll still misfire a bunch and start to stall.

Still hear popping out the exhaust when it does it. I guess if the vacuum lines are misrouted, that could lean out my idle too much. That's all i have at this point.

I'll be going to my dad's place in a few days, and i'll be staying for quite a while. So if this topic goes dead, i haven't given up on it. I'll update if i find anything wrong.
 

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Here's a picture of the valve. None of vacuum hoses line up at all with what i see on the diagram, and i get vacuum at the FPR on a cold start. Clearly something is amiss.

IMG_20210516_123920[1].jpg

I sent JLEMOND himself an email asking about this mystery VSV. Hope to hear back from him soon.
 

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