I recently did the timing belt and water pump on my 4Runner. Put everything back together and it fired up the first time. The next morning it took quite a while to start it while it was cold. We got it to start and once it had warmed up it would start up fine.

Thinking it might have been the timing that was off, we pulled the plastic cover off of the top to double check timing. Turned the crankshaft pulley over to 0* ignition timing (as FSM says is the same as the CR mark pointing straight up) and both camshaft marks were spot on. The timing belt cam marks were also spot on.

When we initially start the truck it turns over and over for a long time then after several tries will fire and it "lumbers along" for a while and then it starts to sounded pretty nice. We can run it for a minute or two, shut it off, and it will start back up nicely. The key here seems to be that it will not start if it has been sitting for several hours.

Observations:
-A compression test yielded 90psi on 2 of the cylinders.
-A lot of things smell like fuel.
-The EGR intake tube (I think??) makes a very loud pulsing noise and sucks a lot of air until it has warmed up.

With the diagnostic plug bridged and the timing set correctly it has no power. It barely accelerates at low RPM and above 3k it won't even accelerate.


I've been working with my Dad and Grandpa on this and they are at a loss at this point. Any help would be greatly appreciated!

 

90psi on two cyls is what your problem is. now question is is it rings, cracked head or bad valves or a head gasket.

Was it acting like this before or after you did the timing belt/water pump? Gonna assume here 3.0 since you said timing belt and not timing chain.

 

Yup 3.0. It was driving great before the timing belt. (Other than 10mpg, but I think that might be a vacuum hose that was disconnected or the o2 sensor going out)

I suppose its possible that the compression gauge wasn't tightened all the way. Discussion with my Grandpa, he is saying that he thinks the compression is a result of another problem.

 

redo the compression test if there is any doubt it read improperly. Especially if it ran fine before the timing belt etc etc.

 

K thanks we can try that. ONCE you get it running, the engine runs smooth, as if all the compression is fine. That aside, any other ideas for this?

 

not sure how to do the timing on the 3.0's. I don't know if there is that same check connector you have to jump in order to set the ignition timing or not on the 3.0.

 

Yup got that already

 

Sounds like maybe the check valve in the fuel pump may be leaking, allowing the fuel to drain back into the tank. This usually also requires a leak either in an injector or in the fuel plumbing topside. Since you're smelling fuel, you almost certainly do have a fuel leak somewhere. Try jumping +B and FP in the check connector, then turn ignition on (but don't crank it) for at least 30 seconds, before trying to start. That will run the pump and pressurize the fuel rails. If it starts right up, then you may have leaking FP check valve. Also pressurizing the fuel rails may allow you to find the leak(s). Check the pulsation damper, back end of the passenger rail, and the rubber section of the fuel return line, attached to the side of the fuel pressure regulator, front end of the driver side rail.

There's no tube on the EGR system that's open to the atmosphere, so if something attached to the EGR IS sucking air, something is connected wrong. Post a pic if you can of what's sucking air. That doesn't sound right. It could be a huge vacuum leak that could account for your lack of power.

If you want to recheck compression, use these steps:

1. Warm up the motor to operating temp, then shut off.
2. Remove the air hose between air meter and throttle body.
3. Unplug the cold start injector.
4. Unplug the igniter.
5. Remove the plugs.
6. Attach the compression tester and have a helper crank the motor while holding gas pedal to the floor.
7. Watch the needle as it climbs with each compression stroke. Take the max reading, or the reading after a maximum of 8 compression strokes. Take the reading after the SAME number of compression strokes for all the other cyls.

 

Thanks very much for your reply sb5walker. I pressurized the fuel lines and did not see any leaks, it did however seem to make the vehicle start better from that point on.


Finally got it working again and it probably runs the best it ever has.

Not exactly sure what ended up resolving the problem but I figured I would post the process.

- Cleaned several of the plugs
- Replaced Fuel Filter
- Replaced Timing Belt Tensioner (Don't think the old one was behaving quite right)
- Cleaned TB and adjusted TPS

After all this the ignition timing was WAY off. Set it back to 10-12* and it runs great. Pulls better throughout the power band and a lot better above 4k.

I'm using someone elses pic, but I basically did the same setup. The intake tube at the very top left of this picture (The one disconnected), I put a small filter over that.

The truck is running great but every once in a while (especially idle) that tube sucks a lot of air and makes a very loud noise.

 

Congrats on getting it running smoothly. Sounds like the misadjusted timing and dirty plugs may have been responsible for loss of power. But jeez, brand new Denso K16R-U plugs are under 2 bucks apiece - why mess with cleaning when new plugs will always give better performance? Hows the cap and rotor? Plug wires?

The disconnected tube is, I think, the PAIR intake - that's an emissions system that allows fresh air to be drawn into the exhaust stream to complete combustion of any hydrocarbons that managed to sneak through the cyl unburnt. You'll hear some exhaust noise when the valve opens. Putting a filter on it should be fine. Originally, it went to a plastic resonating chamber attached to the air filter assembly.

 

I replaced the plugs a year ago or so with NGKs. Its burning a lot of oil so it doesn't help the plugs. I have no idea how long its been since the wires/cap/rotor have been replaced. (If they ever have) I've had it for 2.5 years, and about 32k miles and never done them.

I've always been a little skeptical to change them if they are working fine. As a college student, I don't have $50+ to just put into it if it runs currently, unless it made a significant performance or mileage increase.

I believe it is the PAIR valve. I've got a filter on it right now so its working just like it was when it went into the resonator box deal.

 

I do understand what it's like to be a starving college student. But the distributor cap goes bad the quickest of any ignition component on my veezy - faster even than the plugs. The inner terminals corrode where the spark jumps from the rotor. (The rotor should be replaced at the same time.)

The factory wires are Yazaki and are excellent and last a long time. But if they are original they undoubtedly need to be replaced. Check that the boots and wires are soft and rubbery, with no cracks or carbon tracks. A Denso wire set from Amazon is a decent replacement at much less cost than the dealer wires.

A corroded cap or bad wires will cause the spark to be weak, leading to poor running, less power and worse mileage - which would cost more than the price of new cap/rotor/wires.

Do you know whether the burning oil is due to rings, valve seals or both? A compression test will give a hint. I would try using Valvoline MaxLife 10W-40 - it has seal-swelling esters that would probably cut down oil consumption if due to leaking valve seals. For filter, I recommend using either the Toyota 90915-YZZD3 or Purolator PureONE PL20195 (available at Advance Auto Parts).