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oil pressure gauge reads on low side at idle (picks up if I shift to neutral and step up idle slightly), and also a bit rough --not irregular, but a bit of a shake--do I need to set up the idle? is this a tune-up issue? Seems fine when driving.

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Check first for vacuum leaks beyond that there is a large screw on the top of the intake where the big black hose goes in that is the idle speed adjust. Oil pressure sounds normal.

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  • 1 month later...

The rough idle seem only to happen when in gear (drive); all fine in Park or neutral position. It idles at about 1k rpm in Park, and drops to 700 and holds seady but as I say a bit rough when in drive. Does this suggest anyting more specific?

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If valves were out of adjust, would it idle rough in Park and in Drive? Again, to me, it seems like a regular idle, though just a bit low/rough under load in drive at idle. If valves needed adjustment, would it be more of an irregular rough idle? Though the mechanic mentioned a "miss"...

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Check the simple stuff first, vacuum hoses split, cracked, disconnected. PVC valve not stuck open (rare, but if its gunked up yes)

How many miles on the truck? have the valeve ever been adjusted?

I put my money on valve adjust, sounds like the way mine was, idle seemed a little rough, and would stall when I put it in gear. turned up idel speed and that took care of it for a few thousand miles. It got progressively worst and reached a point where there was no more idle adjust, and it was difficult to start as I'd have to give it gas until it warmed up, but even then it wasn't idling right.

Mine had 88,000 miles on it and the valves have never been adjusted.

John Mc

88 Dolphin 4 Auto

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John--75k miles; '8422re. I know the previous owner had it serviced regularly at a Toy dealer, but don't think either timing chain replaced of valves adjusted. Can any mechanic do this, or is it a dealer job?

It doesn't sound as bad as your s was--no stalling at idle, regular, about 700 rpms, but just rough when gear engaged.

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On the 4 banger, if you can change plugs, you can adjust valves.

Order the new valve gasket kit that has the two 1/2 moons and new rubber cover bolt bushings

GASKET KIT

Youll need a cheep set of feeler gauges

Follow the instructions

When you remove the valve cover, ods are good the four rubber bushings will NOT just pop out, the rubber will be hardened around the bolt and will need to be unscrewed.

Prefer adjusting HOT, but cool will work I setmine at .007 (IN) and .011 (EX) cold

Look at post #7 I did a basic how-to

ROUGH IDLE

set the crank at #1 TDC (Top dead center) you'll be able to adjust 1/2 the valves here, then rotate the crank 360 deg (note the cam only rotated 180 deg) and you can adjust the rest.

Before I made any adjustments, I used the feeler to see where they were adjusted now. On mine the exhaust valves there was no clearence, the valves were actually being opened just a tiny bit. Thats what the problem was.

Loosen the adjustor lock nut, then turn the adjuster screw loose a 1/4 turn, slide the feeler between the rocker and the valve, snug the screw and wiggle the feeler. It takes a little practice to get the screw snugged, then tighten the lock nut, and get the correct wiggle of the feeler. The feeler should not be loose where it slide easily, but it shouldn't be tight either. you want just a little resistance when moving the feeler.

When adjusted, it may be a little difficult to get the feeler back in there between the rocker and the valve, but you should be able to get it in there and it should move with just a little resistance.

To set your mind at ease - this isn't rocket science. if your off a little, not a big deal, i.e. if your trying for .007 cold, but you get .006 or .008 it will be OK.

Heres why your adjusting valves.

If they are too close (like mine were) then the normal expand/contract of the engine will cause the valves to open, stay open thus effecting compression and fuel charge. This will greatly effect exhaust valves, as they are designed to be cooled by two methods, thru the stem and into the guide, but just as important, they need to rest against the seat so heat can transfer from the valve and into the seat.. If the valve doesn't come into contact with the seat, this will cause "burn't valves.

If they are to far open, the rockers will slam the valves open and closed like a hammer. This will be noisy and annoying (sound like a diesel), and in the very worst case, will mushroom the valve stem and hammer the valve seat on the head. this premature wearing the valve and seat.



John Mc

88 Dolphin 4 Auto

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  • 3 weeks later...

let me see if I have this right when I did valve adjusts many yrs ago to my VW, I had to follow the firing order and, if I recall, could only do one exhaust and one intake at a time i.e., when #1 was TDC, I could adjust the intake on #1, since at top of cycle and ready to draw in, and exhaust on next in firing order, or last I dont recall exactly, but seemed to be something like that.... or is the intake full open for all when one is TDC since they would also be in partial downstroke excet maybe last in firing order

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4 of the valves are closed with #1 at TDC. It will be a mix of intakes and exhaust. Turn the crank 360 deg and the other 4 will be closed. Its just the normal way for 4 cylinder inline engines.

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OK I guess that makes sense but how will I know when #1 is TDC peer through spark lug hole (sorry Q mark not working...

so loosen the lock nut, then turn the second nut to either open or close the valve to spec, then just retighten the lock nut do I have to keep wrenches on both nuts while tightening the lock to keep the adjust nut from moving or will it hold

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here's a chart. adjust 1/2 the valves in one position, turn the crank 360 deg (one complete rotation of the crank is 1/2 rotation of the cam) and adjust the rest.

I bet if you looked carefully, the same was true for the VW

You'll need to play with the screw and the lock nut to get a feel for it. When your adjusted, the feeler should have a tiny bit of drag, and you should be able to get the feeler in there.

If you do it cold, use .007 and .011

John Mc

88 Dolphin 4 Auto

post-4544-0-16773100-1377004243_thumb.jp

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When a cylinder has finished it's exhaust cycle and is starting on an intake cycle both valves are slightly open one is closing one is opening (this is valve over lap) so if you watch # 4 and see both valves moving at the same time adjust #1 valve set turn the crank and watch #2 adjust #3 cylinder then #1 adjust #4 then #3 adjust #2..This ensures that both valves you are adjusting are completely slack.(max clearance) As you can see that is the firing order of your engine 1,3,4,2. A little tip remove the spark plugs first that way you can turn your engine with a wrench on the power steering pump pulley nut much easier then trying to get some thing on the crank bolt.

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OK I guess that makes sense but how will I know when #1 is TDC peer through spark lug hole (sorry Q mark not working...

so loosen the lock nut, then turn the second nut to either open or close the valve to spec, then just retighten the lock nut do I have to keep wrenches on both nuts while tightening the lock to keep the adjust nut from moving or will it hold

Use the timing marks on the front there will be marks at TDC. With the spark plugs out you should be able to turn the engine with a wrench on the alternator pulley nut.

Your making this into a big deal, it isn't... just do it :)

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Hmm..I have a similar problem. Mine does the same thing, but it gets even worse when its rainy or real humid. Sometimes I have to crank her three or four times before she will fire and stay running. She kinda fires real hard then stops, then does it again, then starts up running on what feels like three cylinders until she warms.

I just changed the cap, rotor, wires and plugs, thinking that moisture in one of those components was the likely culprit. But its been dry the last week or so so I don't know if the problem is going to come back or not. She still idles rough, but I fiddled around with the idle screw and there doesn't seem to be a change. I'm actually wondering if that idle screw is broken or stuck, since a couple of full turns both ways did nothing.

I can't do a valve adjustment until I get back home in October, so i guess I'll just have to live with it for now.

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Dude get a manual! :) I mean people will answer all these questions here, but you'd save yourself a lot of time.

Of course the valve cover needs to come off to adjust the valves, and between that and looking at the timing mark, you'll know where tdc is. No peering through spark plug holes necessary...

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I "heard" that it doesn't live up to the original VW version so I never bought it, but ill bet its good. But since I'm used to actual shop manuals, and didnt hear great stuff about that book...figured it wasn't with my money.

I always just searched out the Factory Service Manual for whatever year truck I have. If nothing else it allowed me to do my research before I post questions, just to show I was doing some of the work.

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Yes lining up rotor to #1 firing That is what I forgot yrs since the 67 VW v adj thanks for that video reminder!

Waiter--thanks for diagram; missed that first time--v. helpful.

thanks for link to parts site. Several choices for water pump, though--not sure which is best...apparently I can get gasket separately, and would be cheaper than buying the Beck/Arnsley, which includes a gasket--so eliminates on choice, unless the B/A is worthe the extra...

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I usually rub some oil on the engine side of a gasket. That way it will come off clean next time.

DO NOT glue a gasket to the engine.

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Since the rough idle I'm experiencing only happens when under load, and esp with brake on, I wonder if it could be related to the large brake booster diaphram connected to the brake resevoir (the lines themselves look OK). I had a similar problem with my Chevy van, and that was the culprit--as I recall there is a way to test that by disconnecting something to bypass the booster (can't remember what exactly)...but it really effects the braking efficiency.. any exp with this?

Also, I have a cylindrical cruise control device (at least that is what it appears to be) in the way of removing the valve cover--it looks like I could remove the cable where it enters the device (there is a sleeve, but a couple small screws on the cylinder itself), though don't know if this will mess something up--any exp with these?

Also wondering if, when I check the valves, only to worry about them if they are too tight--i.e., of open wider than spec, but not making noise, should I bother adjusting? If the valves were loose (too loose), I'd hear it, right?

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Its possible the brake booster could have a ruptured diaphragm. but I would say, rare.

Take 6 or 8 photos of the your engine compartment before you start, also take a couple photos of stuff you need to disconnect or remove. My memory sucks, the Digital Camera is excellent for showing me what bolts or wire runs go where.


Valve adjustment should be part of preventative / routine maintenance. I suspect most of these toyhouse have had neither., especially regarding valve adjustments.

If you get to the point that you can "check" the valves by sliding a feeler gauge between the valve stem and the rocker, then your at the point where you should be "adjusting" the valves. If you adjust them to either the cold or hot specification, they will work and make minimum noise.

John Mc

88 Dolphin 4 Auto

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Valves that are tight advances the valve timing too loose and it's retarded. Too tight is bad too loose is noisy. A properly tuned engine has properly adjusted valves.You are saying idle but under load? moving or standing still? Also what did you turn that had no effect. The idle adjust is a large screw in the top of the throttle body. You want TDC close enough? Remove the #1 spark plug remove the dip stick, stick it in #1 cylinder turn engine till it no longer move up that's more then close enough to adjust to valves.

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OK--I added pics of engine

I tried disconnecting the vacuum hose to the brake booster, but that made things really bad--engine idled really rough with the hose disconnected, then just died--so I guess that is not a way to test a prob with the boseter, but didn't see anything else to disconnect there, except brake lines.

Valve clearences are noted on the hood--they are .008 (IN) and .012 (EX) at "normal operating temperature"--so if I'm basically adjusting to those spece when cold (.007 and .011), could that be a prob? also would they be eaiser to adjust hot since nuts should be eaiser to loosen?

pics of all attached. I included a pic of vacuum hose routings

could egr issues caus a sligtly rough idle?

I did remove the pvc valve and flush it with a bit of gas to clean it, but no effect there, except it had a cleaner rattle!

post-3356-0-90680900-1377963313_thumb.jp

post-3356-0-73153000-1377963354_thumb.jp

post-3356-0-35384900-1377963387_thumb.jp

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Pretty much the same as mine,

just start removing stuff that keeps you from getting the cover off. Note that the rubber bushings under the valve cover nuts are probably de-formed and won't pop off, simply unscrew them.

John Mc

88 Dolphin 4 auto

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The EGR can give you issues. Usually it will stumble/miss as you pull off slightly above an idle in the 1500-2000 rpm range. Remove the vacuum line from the egr and try it. Don't sweat the .001 difference you'll never get them that close any way it is just feel. I prefer to adjust them hot because it does not stay cold for very long.

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