robm

1987 4Runner 22re 5speed. Just had engine rebuilt by engnbldr along with his street head and 268 cam. The engine shakes at idle. Once the rpms get above about 1500 it smooths out. I've been fighting this for weeks now. I've searched and searched, but can't come up with a solution. Idle is set, dashpot is adjusted. New oem tps adjusted properly. The engine idles steady and timing is set, but it does jump around about a half degree. I've replaced all vacuum lines and egr valve. Sprayed cans of brake clean looking for leaks, but can't find any. Also, I've noticed that when I pull the plug wire off #1 spark plug there is no change in how engine runs. New denso plugs and oem wires. Compression is good, right about 160 across the board. Any help much appreciated!

skypilot

iTrader: (1)

Read all the spark plugs. You may just have a bad wire. Or you might have an air leak were the intake manifold splits. I had one gasket fold over on installation and another one actually blow out on a really bad backfire.

Odin

Have you checked the distributor for shaft play? Take the shaft that the rotor is mounted on and remove the rotor. Now try to move the shaft from side to side, it shouldn't have any side to side movement.
If it does the bushings are shot.

That's about all I can tell you about these distributors other than checking the air gap.

Also make sure all of the spark plug wires are FULLY SEATED into the cap and on each plug.

(Once it's firing consistently and correctly on all four try the below.
Keep in mind here my experience comes from carberated first generation small block Chevys)
So you've fitted a cam with greater duration than what the stock one had. In dang near every situation that will require a slightly richer idle mixture to smooth the idle. It's probably going to be worth it to go ahead and remove the small round metal cap on the AFM and adjust the idle mixture screw under it for a little more fuel at idle. I'm not talking about the large cap that's held in place with sealant.
bswarm will probably chime in and fill you in on it.

Again make sure it's firing good on all four, the timing is set correctly, it's at operating temperature with the valve clearances set before you do this or you'll get the mixture wrong.

bswarm

If #1 plug looks ok, check #1 injector.

robm

Plug wires are good, swapped in a different set and same thing. Injectors were sent out to witchhunter and all injectors are firing. Just had upper plenum off inspecting the injectors, put new gasket on just to be safe. I bought this thing not running, but the only thing that hasn't been replaced is the iacv and vsv.

PapaChulos4U

Cam lope?

robm

One thing, I am having serious issues getting all the air out of the cooling system. Not sure if that can cause this.

robm

Talked to Tod at engnbldr and this cam is designed to be extremely quiet.

scope103

Which means #1 isn't firing. Most likely causes (already mentioned) is a bad plug wire or injector not opening. The plug wire is easy; put your timing light on the #1 wire; if the light flashes the plug is firing. (Unless it's firing at the wrong time, but that would pretty much take out all the cylinders.)

Since you say the timing is set (and we all use #1 to set timing), then you probably have an injector not opening, or at least not spraying fuel. Pull the plug wire, let it run for a second, then stop it and pull the plug. Is it wet? If not, no fuel. Use a stethoscope on the top of the injector; you should be able to hear it click as it opens. If it's opening, you could have a clog somewhere.

robm

Yes, #1 is firing. I can hear the injectors ticking with a stethoscope. Also, pulled plug and it is wet and smells like fuel.

JagerFiend

Move #1 spark plug to another hole and see if the problem switches to another cylinder.

robm

Tried that and it stays at #1 cylinder. Funny thing is it goes like a raped ape.

bswarm

Leave a rag in #1 intake runner? You have fuel, spark, and compression. All that's missing is air. I've seen it happen before.

PapaChulos4U

It could be the coolant system. When I rebuilt the motor in mine it would surge a bit until it was completely burped. Had to have a buddy tap the gas as it was on an incline to pull the coolant into the block. After that, no problems.

robm

In the upper plenum or lower?

bswarm

Wait, you said you're having problems burping the air out of the coolant? Any steam coming out of the exhaust or cyl#1 when the plug was out?

Odin

Was thinking it but didn't want to say it. Yikes

robm

No, thank god! But yes, I've spent hours trying to get all the air out.

Fundy Rider

I had the exact same issue on rebuild with eb rv head 261 cam and flamethrowers new injectors with all new parts . Was driving me bonkersand finally said to myself gonna throw original injectors back in with oh 300 000 miles on them and guess what. She purred like a kitten.

You ve narrowed it down to #1. Fuel air and spark. Don t take it all for granted it may be your harness not getting full voltage with corrosion in the harness to Injectors. This was going to be my next step. Re check what you have and make sure they are up to snuff with meters and suck.

I lucked out with a screwdriver on the injectors and had no tick in one or two. Good luck I lost alot of hair.

robm

Still having problems. Today I rented a fuel pressure tester. When I test it at the cold start port with motor not running but fp and b+ jumped I get 38 psi, but when I relieve the pressure via the gauge it only recovers back to 24 psi. With engine running and jumpers removed I get 30 psi, but again when I dump the fuel it only climbs back up to 24 psi. Seems very low. I have a fsm for a 1988, mines a 1987, it states 38-44 and 33-37 without connectors jumped. So, I took it a step further and tested fuel pressure at the inlet of the fuel filter and never got more than 30 psi. I can't for the life of me find any info on what psi the pump is supposed to put out, but that seems low. The pump and sock are brand new denso unit. I even ran compressed air through all my fuel lines, both ends disconnected of course, just to confirm none of the lines were blocked. Also, my #1 spark plug and brand new denso O2 sensor are black, wouldn't that mean it's running rich, but with low fuel pressure I would assume it would run lean. Sorry for being long winded, but this issue is literally consuming my life and not in a good way lol.