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1985 Toyota Supra running on 2 cylinders

I remember this discussion . . . . and how frustrating it was for all the guys responding to @knocksensor

Just replace the motor with a known good motor of the correct model year . . . or install a rebuilt motor of the correct model year

In all honesty, it sounds like not much has changed since the discussion started almost 3 years ago

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Is this one of those threads where someone needs to say " Put down the tools and step away from the vehicle " ?

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Since time is not of the essence I might throw out a few things.
Carbon tracking inside the distributor cap. Just because a cylinder is dead does not mean the spark is going to evaporate. It’s going to go to the closest ground and which oftentimes is the closest cap terminal.

What about the possibility of the compression on the middle cylinders being artificially inflated due to a head gasket breach (gasket and/or warped cylinder head) all the way down the row; less 1 and 6 of course.
Saw a VW 5 cylinder with something like this one time.
In other words, one cylinder huffing into another and so on due to a severely warped head.

Just some food for thought.

There are some people here who think that the compression numbers of 120-130, with one cylinder being 110 are poor, and others who say this is fine. I am really curious about this, as I have a car which is difficult to start and idles poorly but does not stall. A professional mechanic did a compression test and leak-down test, and measured compression of 130, 150, 151, 130 and felt that this was acceptable, and the problem was likely something else. The factory service manual for this vehicle does not give a “standard dimension” for the compression pressure, only a “service limit” of 100 PSI.

When one cylinder is considerably lower than the others it’s possible that adjusting the valves could improve the situation but more than likely the low cylinder will soon drop too low to operate.

Why are we still at it . . . ?!

Everything that we’re talking about now has already been talked about literally years ago in this very discussion

As far as I can tell, nothing has changed, as far as op and his car goes

The next thing we SHOULD be hearing is that op installed a known good motor of the correct model year, or that he installed a freshly rebuilt motor of the correct model year

But something tells me that’s not going to happen anytime soon . . . or ever

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no one of these years I will just change the engine that I already have. this summer may be the year. but first I want to check on these injectors closer. i just find it so interesting that it runs totally perfect at a idle and it sat for 8 months and started in a half second and ran perfect. on 2 cylinders. the fact that it can even move like that is not normal.

I’ve done enough compression tests on anything with wheels to know that 130 PSI sucks. I suspect this kind of BS is perpetrated in part by Chilton’s manuals. They all say that 130 is great. One of those manuals even states that 150 on one cylinder is fine and 110 on another is perfectly acceptable. Not.

Same Chiltons that says 6 PSI of oil pressure at 1800 RPMs on a Buick 3.8 is normal and good.

The only auto engine in which 120 is good is an air cooled VW Beetle and that’s only because of their 6 to 1 compression ratio.

The rule of thumb is 20 X compression ratio at sea level. Subtract a small amount for altitude or a barometric pressure change.

Some of the so -called domestic brand cars back in the 70s smog era would run somewhat lower than usual compression numbers (say 170-175 or so) but it wasn’t because of engine wear. They ran the camshaft timing retarded compared to the prior decade where horsepower was up.

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Swap the injectors from 1 and 6 into 5 and 2 and see if those are the cylinders that fire now. That would confirm bad injectors or not.

I think we’ve given this guy MORE than enough advice over the years

yes . . . YEARS

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Being willing to change the engine but not the injectors is not normal.

I thing after this owner dies or goes into a nursing home, this car will go to the junkyard in it’s present condition.

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Maybe the car should go to the junkyard, in its present condition . . . now :smirk:

Compression sucks. Any time or expense other than fixing that is pointless.

If the old horse is going lame a new saddle is not going to cure anything.

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Must be a terrible distraction, you made 4 posts this week on this thread.

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