Hello everyone. I just recently bought a 1988 toyota pickup (2wd) from a guy in California (I live in cali too). Since I got it I could tell not only is the truck partially screwed but that whoever was working on it tried to fix some problems too. The major issue is that it ran rich with both the blinked AAP, and the float being a bit off. Since I bought it I have fixed both of those issues and even got the High-idle working. The only problem is that the truck runs awfully still. The truck will miss fire on both high idle and normal idle. Carb idle speed and a/f are all set to specs for the year, and I have cleaned the egr and got new plugs. When the truck is revved it will spit black smoke out the end after a engine misfire and I don’t think that will help when smogging. I was wondering if any of you guys knew what was up with the misfire or popping/backfire because I need to get to is running by the time I get my license. Thanks all!

 

Bump!

 

Bump! Bump!

 

Check compression. Check valve adjustment. .008" intake, .012" exhaust. Best when engine is warm.

 

really? bumping a thread twice in a few hours? on a late sunday evening. this might not be the right place for you.

 

I saw some other guys do it. It’s not my fault this ˟˟˟˟ty truck has kept me up late recently.

 

You mentioned changing spark plugs. Put a new rotor and distributor cap on it too, and check resistance of spark plug wires.

Also, check for vacuum leaks.

 

I saw some rust on the wire coming from the coil. Would that cause problems like this?

 

If you have rust on the coil wire, you might want to think about buying a new set of wires too.

 

What brand were the plugs?

 

came with the truck I’m pretty sure

 

Came with the truck is not a brand. Are they NGK, DENSO, AUTO LITE, CHAMPION, ETC???
the reason he asked is it can make a BIG difference.
misfires are generally timing or valves.

 

My bad lol NGK

 

NGK are good, same with NipponDenso(ND)
assuming you’ve checked and set timing(if not, please do) where does the distributer adjusting bolt sit in the slot? Fairly centered, or close to maxed out to one side? The distributer adjusted all the way to one side is a good indicator something is mis installed/adjusted somewhere else, and they tried to compensate at the distributer. Timing chain or the distributer off a tooth could cause this.
The fact that the p.o. Tried to fix the issue gives you some extra work. If they threw inexpensive cap,rotor, wire set you may have to get rid of them and get better quality, just to remove them from the equation. Denso is best.
its’s laborious, but get a decent vacuum schematic and make sure the tubing is routed properly. I see that done incorrectly quite often, especially to the EGR

Update what you find, good and bad.

 

no prob. ngk are good plugs for the 22re, so your alright then.

 

listen and learn from Jimkola
He knows what he's talking about and will be a great asset to you.

 

I replaced every vacuum line I could and checked for leaks with a little carb cleaner but nothing came up. The distributor is adjusted all the way to fully advanced and sits on the lower side. The engine surges a bit with the timing like this but other than that actually runs a bit well. I’m taking it to be presmogged Friday so I’ll see what happens then.

 

NGK plugs and wires

 

If it were a slipped chain how would I check? How would I also check the valves.

Could a misfire be an A/F mixture issue? I rebuilt the carb but my limited 16 yo knowledge might have screwed it up along the way.

 

When the distributor is all the way to one end of the slot or the other, something's off a ways. Did you set the timing with a timing light, according to the FSM, or just guesstimating?
As far as the surging goes, is the idle set right? It should be about 800 or so. If it's much above 1000, you can get surging when the brake pedal is pressed.
The valves are set with with the # 1 piston at TDC, compression. Then # 4 at TDC, compression.
Just turn the crank until the #1 piston tops out, determined by a straw in the through the spark plug hole. The timing mark on the crank should be at the 0 mark. Both rockers of the #1 valve, intake of #2, and exhaust of #3, will be off the cams on the camshaft. You'll be able to feel them move up and down off the cam. .008" intake, .012" exhaust, checked with a feeler gauge. If the valve lifters are NOT off the cams, with the pistons topped out, give the crank one full turn, again using the straw to check TDC, and check them again. Then turn the crank 1 full turn, and set the rest of the valves. Same method. Since it's much easier to turn the crank with the plugs out anyway, the straw method is a handy, quick, easy, way to see TDC, that won't damage anything is it jams up somehow.
If the #1 cylinder is at TDC, compression, as seen with the straw and the valve lifters, but the timing marks are NOT lined up at 0, the chain or the cam shaft are not aligned correctly. OR the harmonic balancer has slipped. The rubber in it can get old, and brittle, and break, so the two halves separate, and rotate in relation to one another. If the distributor rotor is not pointed to 10 o'clock with the #1 lifters off the cam, the distributor is off a tooth, or more.

The 22R timing should be set to 0°, with both vacuum lines off the distributor.

Does that rambling help at all?
Pat☺