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Discussion Starter #1
I've notice that my Zuki is loosing some oil, however, the spark plugs all look good and I'm not noticing any smoke out of the tail pipe and the engine really don't have any leaks. But I've also noticed that I'm getting oil pressures as high as 60 to 70 PSI. I was reading somewhere that a stuck PCV value can cause abnormally high oil pressures which result in blow back causing a loss of oil. So my question is - why should the normal oil pressures be and has anyone else seen anything like this?

Thanks,
David
 

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According to my 88 manual oil pressure should be 48-60psi @3000rpm. So your reading seems a little high but could be your guage also. High oil press is not usually going to cause loss of oil unless it blows out a seal.
The pcv can cause oil loss if it sticks open and draws oil into the intake or if it sticks closed or plugs up can blow through vent or gaskets with crankcase pressure. The pcv valve is designed to draw oil fumes from the crankcase into the intake for emmisions. the valve closes when restrictoin increases such as when oil is being pulled into the system. If it is not working right you can have problems.
That being said, check the pcv hose for oil, it should have a light film but no liquid. Regardless I would install a new pcv.:)
Here is some advise; if it is not leaking it -it is burning it:huh:
 

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Discussion Starter #3
Thank you, I'm going to pick up a new PCV valve today. I have a question about the possibility of it burning the oil. Yesturday I had a California Smog test done on it and it is allowed something like 150 PPM at idle and I forget what at 2500 RPM. At idle it failed and they said it is running rich, which makes me beleive it is the carb. However, at 2500 RPM it is only reading 15ppm which the guy said is extremely low. If it is burning it, could the readings be this low?

I'm just wondering...
 

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Assuming a 1.3 engine, the factory specification is 42.7~59.7 psi @ 3000 rpm warm. however, there is some degree of dependency on the oil you are using, heavier oils will show higher pressures, lighter oils may result in lower pressures. One perhaps important point - the upper limit is determined by the oil pressure relief valve and is not really critical.

If you're loosing oil, it can only be one of two things, you're leaking it or you're burning it - and the absence of smoke doesn't mean it's not being burned. About a year ago I did a complete rebuild on a G13 which had significant ring wear (dry compression was 90psi give or take, across all four bores), and was burning over a quart between changes every 3000 miles, and there was no smoke to speak of - you had to be driving behind me, and watching closely, and you just might see the slightest puff when I changed gear.

The PCV valve can contribute to oil consumption in some case, but I doubt that it does on these vehicles - it also has no impact on oil pressure, and oil pressure has no impact on blowby.
 

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yeah, oil pressure is the pressure that the oil pump is operating at and is affected by things like clogged oil galleys and high viscosity. Excessive crank case pressure is what causes it to blow past the gaskets, and worn rings will cause the blow by in the combustion chamber. So if it's dripping oil, then you have excess crank case pressure or worn gaskets. If it's burning it then you have worn rings, If the oil pressure is too high then a chemical flush of the engine may clear up some of the deposits blocking the galleys.

Which PPM's are too high on your smog report? HC or NOx?
 

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Discussion Starter #6
It failed with 223 PPM HC at idle - the max is 150. At 2500 RPM is was 15 and allowed 180...
 

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wow that's pretty significant. The HC is from too rich mixture that results in partially burnt fuel entering the exhaust. I'd say its either the O2 sensor or possibly a restricted intake? Sticking choke, dirty air filter? Running too rich isn't going to be a clogged or restricted jet, and it's not going to be from a float hanging up. Another thing that can cause high HC levels is the MCV (mixture control valve) not functioning or having a delayed opperation. The MCV opperates on hard decelleration to lean out the mixture and prevent high HC levels when you let off the throttle to decellerate. That would still fall under the high speed test on the dyno.

NOx ppm elevations are from a too lean or missfire where unburnt fuel enters the exhaust, or from running the combustion chamber too hot. That's most often the problem with the samurai so at least you aren't getting any issues there. Those are usually the more expensive to fix as well.
 

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Discussion Starter #8
wow that's pretty significant. The HC is from too rich mixture that results in partially burnt fuel entering the exhaust. I'd say its either the O2 sensor or possibly a restricted intake? Sticking choke, dirty air filter? Running too rich isn't going to be a clogged or restricted jet, and it's not going to be from a float hanging up. Another thing that can cause high HC levels is the MCV (mixture control valve) not functioning or having a delayed opperation. The MCV opperates on hard decelleration to lean out the mixture and prevent high HC levels when you let off the throttle to decellerate. That would still fall under the high speed test on the dyno.

NOx ppm elevations are from a too lean or missfire where unburnt fuel enters the exhaust, or from running the combustion chamber too hot. That's most often the problem with the samurai so at least you aren't getting any issues there. Those are usually the more expensive to fix as well.
Baratacus,

I changed the O2 sensor and PCV valve yesturday and I changed the oil as well, but when I went to the parts store they cannot find a replacement for the MCV, so where can I find one?

I also bought a carb kit which I'm going to try to get in this weekend and I'm hoping to check the timing. The guy where I had it tested said the timing was spot on, but I was told that on these old vehicles they have to test it with a light just like we would normally have to do - but by looking at the vehicle it is obvious that the timing mark cover hasn't been removed on this Zuki in years. I know I'm shot gunning this thing, but I really need to get it done, but I'm going to be running out of funds really quickly if these things don't work, so thanks for you input. Hopefully these things will work, but if you or anyone else knows where to get a MCV I would greatly appreciate the input.

David
 

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first test it to see if it's working or not. There is a one way valve between the MCV and the manifold. Blow into the grey side of the valve and air should pass through it. If it's clogged you can replace it with another one way valve from the autoparts store. I got a generic one for about 2 dollars. If the one way valve is ok, put it back on with the grey side facing the MCV. Once you know if the one way valve is working you can check the MCV itself. To check the MCV unit, hold a piece of paper right beneath it with the engine warmed up and running. Disconnect the small hose to the MCV and then reconnect it. The paper should be drawn up to the bottom of the unit. If air is not being drawn in when you do this proceedure, then you need to replace the MCV.

I don't know any parts stores that you can get one of these new. You may be able to order one from Hawks or from Suzuki John, but it's going to be really spendy. I'd check the scrap yards. This part isn't one that commonly goes bad, and a used one is most likely going to be just fine.
 

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Discussion Starter #10
first test it to see if it's working or not. There is a one way valve between the MCV and the manifold. Blow into the grey side of the valve and air should pass through it. If it's clogged you can replace it with another one way valve from the autoparts store. I got a generic one for about 2 dollars. If the one way valve is ok, put it back on with the grey side facing the MCV. Once you know if the one way valve is working you can check the MCV itself. To check the MCV unit, hold a piece of paper right beneath it with the engine warmed up and running. Disconnect the small hose to the MCV and then reconnect it. The paper should be drawn up to the bottom of the unit. If air is not being drawn in when you do this proceedure, then you need to replace the MCV.

I don't know any parts stores that you can get one of these new. You may be able to order one from Hawks or from Suzuki John, but it's going to be really spendy. I'd check the scrap yards. This part isn't one that commonly goes bad, and a used one is most likely going to be just fine.
Boy, no joke about the MCV! :eek:

Suzuki John => MIXTURE CONTROL VALVE...$300.00

Ouch - and I though a CAT would be bad news!!!

Well, I'll be testing the MCV tomorrow...
 

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Boy, no joke about the MCV! :eek:

Suzuki John => MIXTURE CONTROL VALVE...$300.00

Ouch - and I though a CAT would be bad news!!!

Well, I'll be testing the MCV tomorrow...
I'm thinking you were quoted the price for the mixture control solenoid valve, which is a whole different animal and lives in your Hitachi carburetor. The MCV is an external vacuum actuated valve near the front of the engine, by the upper radiator hose/thermostat housing.

You'll find info on it here -

http://zukioffroad.com/Tech_Library/pdf_documents/1986-1988_SuzukiSamurai_emissions_manual.pdf

See section 5-9
 

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no, that was the price for the MCV. You can get an entire rebuilt carb (including the mixture solenoid) for 300 bucks. Those silly little plasic parts are what kills the wallet though. Example: The one way valve between the MCV and the intake manifold.... the one I replaced for a couple bucks.... they want $80 for the samurai one way valve.

Just remember that your local scrap yard owner is your friend.
 

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OK. Outrageous! I thought it was for the MCSV, as I had priced them while rebuilding my Hitachi and decided to go with Webber, instead. I am lucky to have a spare Zuki that I can steal parts from, so I don't keep up on the prices of the little bits. Last dealer price I got was $13 for an instrument panel light! At that price, my spare Zuki must be worth $20K.
 

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Discussion Starter #14
Thanks Guys,

I check the MCV today as well as the little valve going to it and the little one seemed to be plugged up so I found a generic and replaced it, but he MCV seems to be working perfectly via the test procedure. Today, since I had replaced the O2 Sensor, PCV valve and replaced the little value I filled it up with Premium Gas and add some octane booster and drove it for a while and took it back for a retest. They guy told me it is now worse and that it would idle at the right RMP, however, upon getting it home I noticed that one of the plug wires and been pulled slightly off the distributor cap and when I replaced it the idle settled back down and the engine smoothed out – so I’ll be trying it again next week. However, I had another Zuki guy look at it today and he told me not to get my hopes up until I replace the CAT, which I can't do until next month, so I’ll let you guys know what happens in the end….
 

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cat used for smog only

replacing the cat is easy so when the smog inspection is due I install the new cat and after the inspection I remove it and put the old cat back on.
A new cat is more efficent than the old one and I pass the smog inspection easly. I seal the ends of the cat pipes and store in my garage
squid
 

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I had nothing but trouble with the m.c.v. on a 86 mazda these mid 80s vehicles w carbs seem to be trouble with ca smog check mine ran good Ill admit it was a bit rich and it never passed smog Id spend 2 or 3 hundred every time.
But back to your oil problem you finding anything out? One guy suggested his burned a qt in 3000 miles I know cars now aday dont use much oil. used to be 500 miles was barely acceptable and 1000 miles or more was just fine. How much oil are you using?
 

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replacing the cat is easy so when the smog inspection is due I install the new cat and after the inspection I remove it and put the old cat back on.
A new cat is more efficent than the old one and I pass the smog inspection easly. I seal the ends of the cat pipes and store in my garage
squid
Just wondering I hear some people relace the cat w astraight piece of pipe Does that help it run better?
 

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Discussion Starter #19
To be honest - I'm not sure how much oil it is using. I got it on the last month and I've had to add 1 qt to it, however, I've now replaced the oil so I'm starting over and I have also been using it mainly for off road driving so I've haven't been covering a lot of miles but just puting around. So, I'll have to go back to monitoring it once I get it placed SMOG, because right now I've pretty much stop focusing on anything until that it done since I can't even get the Title transferred until the SMOG passes!
 

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pulling the cat won't help it run better, but it will keep you from fouling your new cat that you had to spend $350 dollars on because CARB regulations require that you now have a CARB certified cat installed by a licenced mechanic. Maybe the older cats aren't efficient enough to get the little zukes through CARB smog tests anymore. I just spent $500 on my rig a couple months ago. They have a 7 year warantee on the cats now, probably to keep people from puting them in cold storage like squid. If my little zuke is still kicking in 7 years I hope I'll have converted to electric or hydrogen by then.
 
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