98 3.4L - Low power, hesitation, no CEL

Killa-Cotton

Killa-Cotton

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98 T4R 3.4L - Think my timing is off a tooth - No CEL ??

I drove my wifes 98 4Runner over the weekend and noticed it has low power, it hesitates and generally runs weird. To give you a quick run down it had the Timing Belt replaced and a tune up including new factory wires, plugs, etc approx 25k ago. I've just replaced the plugs again, cleaned the MAF and TB, installed a new fuel filter and a new cat. While it does run smoother it still acts like someone is holding the truck back when you accelerate. I'm getting no CEL and it has thrown no codes according to my scanner. Any ideas?
 
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Have you ever changed the fuel filter? Could be something as easy as that. Possibly a stopped up catalytic converter also.
 
It could be really dirty injectors. I had the same thing on my 220000 mile 4runner. I replace all of the normal items, but it wasn't until I seafoamed it that I really noticed a difference. Also, I know many people aren't a fan of Lucas oils products. I will tell you that I buy the fuel injector cleaner in bulk and add it to every tank of gas on all my vehicles. I think I drove it clean because it feels like it is a totally different truck. I just runs good.

If you have the cash you could also get a motovac treatment. I hear those will transform an engine that has had bad gas through it its whole life.
 
I just checked my base timing with a paperclip jumper between TC and CG terminals on the DLC3 port. It's at 0 degrees BTDC. It should be at 8-12 degrees.
 
Are you using a timing light? Where did you get those numbers from? The FSM says to jump TE1 and E1 of the DLC1. Then you should get 8-12 deg. Not jumped is 3-19 degrees idling in neutral.
 
You're right, It was the TE1 and E1. I copied the ones I posted from the wrong FSM. Yes I used a timing light and connected the two terminals and my timing is at right at 0 degrees BTDC (8-12 spec). With the terminals disconnected It was between -2 to +2 BTDC (3-19 spec)

kball said:
Are you using a timing light? Where did you get those numbers from? The FSM says to jump TE1 and E1 of the DLC1. Then you should get 8-12 deg. Not jumped is 3-19 degrees idling in neutral.
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The ECM controls the timing so ...? Has this been the case since you got the timing belt changed? You could pull the top timing cover back a little and check the marks.
 
I don't know, I bought it about 11k after it was replaced by the dealer. I think it may have jumped a tooth or two. Can the ECM control the base timing? If so, that might be the problem.

kball said:
The ECM controls the timing so ...? Has this been the case since you got the timing belt changed? You could pull the top timing cover back a little and check the marks.
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The timing is auto adjusting so it will move between the ranges given in the FSM.

Edit to be more clear: the belt of course does not change. Valve train timing is stagnate. The ECM auto controls the ignition timing.
 
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OK, checked my timing again via a Timing light on #1 plug wire: Jumped DLC the timing is 0 deg TDC and not jumped is 4 deg ATDC. It does advance when the throttle is applied. This means It's approx 8-12 deg off of the base timing and 7 deg off the ECM controlled timing. Could this be any other than the initial timing is off. Should i get a CEL if it is?
 
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I think you should pull the top timing cover back and check the marks along with the crank pulley marks and see if they are lined up. If they are it must be an ECM issue. I guess it could be a crank or cam sensor problem but I would think you'd get a CEL.
 
Yep, that's what I thought. I was going to pull the cover tonight but I'm losing light. I'll pull it tomorrow and spin the crank around approx twice and I should get the marks to line up?
 
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Mine sounds just like the description your giving but im getting a cel PO125 last i knew. Hit the gas and it has no power, Throttle response very limited and now its starting to smell kinda like burnt eggs? Also, when i ran the history report on mine, it came back that the previous owner had a very similar situation to yours but he did have a cel on whilst yours doesn't. In the end his needed to rebuilt due to jumped timing i believe? I'll look it up tomorrow and let you know, might be something worth looking into.
 
jsukey said:
I can't believe that would warrant an engine rebuild. Considering that it's a non-interference engine.
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Whats really surprising is the milage dated on rebuild. Only had 180xxx which is kinda early for a 3.4 to go boom. Ill dig the history report out tomorrow and list what was done.
 
So the records show that the Crankshaft timing belt sprocket has slop in keyway and moving, allowing valve timing to change.Replaced crank sprocket,guide,cover,450 crank pulley bolt.
 
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