Hello all, Bought a truck a couple weeks ago, and its having a frustrating running issue. Once it gets to higher RPMs, usually between 2500-3000, the truck bogs hard and backfires. Checked the timing, was 36 degrees advanced set it down to 10, and it made it much much worse. I heard this could be because the cam timing is out a tooth, but checked it and its good. has new plugs, wires, cap, rotor, thermostat. Tried swapping the ignition coil since i had one laying around, but it worked just the same. Also swapped the TPS, which seemed to fix the problem, but it was back the next day.

any ideas anyone??

 

If the timming was off that much, then i would guess that the timming chain needs to be replaced. If its never been done and is the original timming chain then the guides are probably broken or worn down and the chain is stretched out.

 

You reminded me, timing chain got done about 1000 km ago, new chain and guides

 

also, I would not rule out the timing chain being done incorrectly, the PO did it right before I bought it

 

You checked the timing with the jumper on the diag port? You have to look really good for vacuum leaks in an unfamiliar truck also. Could be starving for fuel due to bad filter or pump or clogged injectors.

bako88

 

Hmm ok, i'll look for vacuum leaks, i do have a fuel filter to go on, when i have the time, also when i fill up im going to try some of that fuel system cleaner

edit: being starved for fuel doesn't make much sense to me, since right now I am only getting 330 km per tank with 29 inch tires..

 

Vacuum leak problems show up at idle and go away at higher rpms. If your idle is good I wouldn't bother with them. Just my 2 cents.

 

Have you checked your TPS?

did you jump the connectors when you set the timing?

 

did you do the timing chain your self? ive heard of timing chain issues because, they have installed it incorrectly

 

this kinda sounds like my truck in a way. im gettin crap milage and like 350 to my tank and i dont beat on her at all. but my engine runs good only thing it idles at 2000rpm for about 4 mins then 1500rpm for 5 mins when warming up?? anyways thread jack over.

 

He said the PO did it before he bought it.

You're getting 350 miles to a tank? Heck I'm getting 240 at best. Wait, how big of a tank do you have. The most fuel I've ever put in mine was a little over 12 gallons but the gauge wasn't on empty (don't want to roast a fuel pump).

Oh and that crazy idle thing is your Idle Air Control Valve (IACV) located under your throttle boby. Mine does the same thing and I need to fix it but those darn things are expensive.

 

crazy double post

 

I think he means 350 Kilometers, hes from Canadia.

 

yah sorry 350km haha but i could get 450-480 about 2 months back.

IACV ok i will look into that thanks junkers i was wondering how to fix it and i was thinking thermostat?

 

No worries. There was a thread on here a while back about it and it mentioned some adjustments. I actually went to a junk yard and pulled a TB off of a 4runner that has the IACV on it. I was going to pull it and clean it then swap it onto my TB. I just can't get the damn thing off. I might have to swap over the entire TB but then I"ll have to swap over my TPS.... I don't know if I want to get too involved in that.

 

I swapped in a used TPS, It was throwing codes that pointed to t he TPS before, but i have not checked the codes since. I will next time i can bring my truck into my girlfriends dads shop haha. Hes a pro mechanic, and I took off the valve cover and he said the timing chain was fine. I did jump the connectors when i set the timing as well.

I also forgot to mention that it gets worse as the engine gets hot.

And it got really bad today, so its parked and im borrowing my moms car for the time being

 

BUMP!!
I can only bring my truck into the shop on sundays and mondays, so I need as much possiblities as i can get so I can do em all at once before waiting another week to work on it again

 

Use carb cleaner and spray around all the vacuum hoses, injectors, intake manifold gasket, etc... If your idle raises (and the motor will usually smooth out), you've found your leak.

I doubt it's your timing, judging by the fact that you said it ran fine when you got it. Unless the belt/chain jumped, the timing should still be good. You could check the distributor to make sure it hasn't slipped.

Also, did you jump the diagnostic block and have the motor at operating temperature when you checked the timing? My guess is that you didn't. With the diagnostic block jumped, and the motor at operating temperature, timing should be 10* BTDC.

Without the diagnostic block jumped, you CANNOT properly read timing.

 

For a 22re, it's 5 BTDC.

 

When you did the timing, (I'm assuming you used the jumper on the diagnostic check plug) did the idle speed change?
If it didn't, your TPS probably needs tending to (again). An improperly adjusted or malufunctioning TPS can cause the ECU to not enter the proper mode to set timing even with the jumper installed.