Inferno451

EDIT - Skip to page 2, engine blew up due to magic disappearing connecting rod nut


K, seriously, this is driving me nuts. I promise i hate new threads about power loss just as much as you guys do, but I've been searching, reading, and working for over a month with NO results. K, so here's the deal. Basically, I'm lacking some power. I understand it's a 2.4 liter engine trying to push 5,000 pounds of steel around, but it won't break 65 on flat ground (or even a slight downhill) and i don't think they're THAT gutless. The weirdest thing though, is that i have less power under more throttle. I seem to have the most power at some magical point in the throttle, around 1/4 of the way down. If i floor it, it does OK up to about 4500 RPM, then just hits a brick wall and SLOWLY gets to 6000. In second gear, it wont break 4500. If i find that magical point, it feels GREAT. Torque curve seems to kick in around 3000, then really takes off at around 4200 all the way up to redline. Just seems like i should have MORE power under MORE throttle, you know? I'm unsure if this is related, but i hear a rattle when starting the engine when it hasn't been run in a while, and i'm pretty certain it's the timing chain. It goes away after a few seconds. I also hear it when driving at certain throttle positions. It's not related to RPM, it's definitely throttle position, and it's a faint grinding (?) sound. The throttle position i hear the grinding noise at and the the magical power spot seem pretty close together. Past the power spot, it doesn't seem to really matter how far i push the throttle down, it doesn't make any more power, actually seems to make LESS. If i'm really on the throttle, if i let off until i get to that power point, it seems to stop hesitating as much and just feel better in general. I originally thought that it seemed like a fuel delivery problem (more throttle = longer injector pulse = more fuel), but the strainer in the tank looked fine, the filter was NAPA and looked fairly new, and i just ran some 93 octane and some seafoam through lines. I have NOT done a pressure test, i will do that this week. This engine was swapped into it out of an 89, not that that should matter, right? I also swapped in the upper plenum and throttle body out of a later 22re so i could have the integrated IAC. When i did that, i forgot to reconnect the ground for the injectors and it wouldn't start. I ran it on starter fluid a few times trying to figure it out, and i noticed a small amount of white smoke from the middle driver's side of the engine compartment one time. I assume this was from the starting fluid being burned and the smoke leaking out of the downpipe (which was cracked at the time), but that's more information. I noticed that when that ground was not connected the check engine light stayed on even with the key out of the ignition, is it possible everything grounded through the ECU and partially fried it? I'm really at my wit's end here, any help you guys can give me is GREATLY appreciated. I'd like to keep my truck until i die, but i REALLY need something that can at least keep 75 on flat ground. Thanks a lot, guys, i really appreciate it! Here are the specs-

1987 4runner 22re
250k miles
100% stock besides EGR delete (same problem before modification)
New timing chain/guides (not sure about tensioner, etc, that happened right before i bought it, but chain has tension with engine off)
Got rid of EGR system with LC engineering block plates
No vacuum leaks
New head gasket/bolts
New coolant temp sensor
New battery
New alternator
New plugs/wires/cap/rotor
New Throttle position sensor, adjusted to specifications
New 02 sensor
Exhaust leaks where the catalytic converter got stolen and i have pipe clamped in it's place, also muffler rusted out
Engine burns oil
Good compression
Valves adjusted per FSM
Ignition timing adjusted to 5 degrees BTDC with terminals jumped, timing advances with terminals not jumped, per spec
Almost positive valve timing is correct, i zip tied it to the sprocket when i took off the head
Late style throttle body and upper plenum conversion (nice to have a functional cold idle!)
No oil in coolant or vice versa

dubbsbetty

iTrader: (2)

If you fried the PCM nothing else would work, likely the truck wouldn't even even go into closed loop, don't think it's that. It's very possible that the motor is tired already , not too likely for these engines though, if well maintained that is, good compression, etc. In most cases, if the EGR was blocked off that would definately create some overheating issues as well as hesitation, stumbling, and throttle issues, but maybe not these motors? Never personally tried it but everything i've learned says it's there for a reason, unless the truck is strictly off-road, in most cases doesn't see much of anything past 3rd gear I hope. Did you check to see if the accelerator pedal isn't being obstructed by anything and keeping it from fully depressing? Hope this helps at all

Inferno451

The problem was there before the EGR delete, i got rid of it to rule out a faulty EGR and to reduce clutter in the engine bay. I've noticed zero change in performance with it gone as far as engine temperature (right in the middle) or power output. With the pedal down the throttle is fully open. I know the engine is worn, and there's some blow by when i take the oil cap off, but that wouldn't explain why it has power and will rev to redline under part throttle but not under heavy load, would it?

bob200587

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Inferno451

Thanks bob, that's very helpful . Translation?

bob200587

Use paragraphs. Walls of text are too hard to read.

ETA: I read it anyway, and I'm not sure I really understand... but, The 22RE's peak on HP at 4500 or so, after that it pretty much just spins faster without making anymore power.

What size tires and what gears are you running?

Inferno451

Sorry about the layout, it was early in the morning. I'm aware of the torque curve of the 22re motors, dropping off a bit after 4500 due to the long stroke. To sum up the problem in a nutshell, imagine the torque curve is maybe 3/4 of what it should be, but when it gets to 4500 it drops to ZERO and won't spin any faster. This doesn't happen with the throttle at that magic point. Obviously the engine is making less power over the entire range, but the torque curve is what it should be. It bogs noticeably at any throttle position past that certain point, then if i let off until that point, it takes off and does great, obviously with the loss of power inherent to the minimal throttle. Due to this fact, top speed on flat ground is around 62 MPH. My truck is 100% stock (Besides the EGR blockoff), stock gearing and stock 28 inch tires. I'm turning around 3000 RPM at freeway speed. I'm kind of at my wit's end with this thing. Thanks, i really appreciate any feedback.

T_F_E

subscribing, I have the same problem to a lesser extent. Full throttle definitely has less power than 1/4 or so.

dubbsbetty

iTrader: (2)

A buddy of mine had a 3rd gen pickup with the 2.4 and had a similar problem as well, he found that the chain was the issue, I know yours was just replaced but do you know for a fact that it was done correctly, you did mention a rattle and possibly a worn tension spring?

Inferno451

Well, i know the timing chain job wasn't professional, just some guy the previous owner knew. I did the head gasket because when he put the timing cover back on, he just forced it in, crushing the head gasket and causing an oil leak. I guess it's possible the chain was never replaced and only the guides were and the chain is stretched. There's very little slack in the chain with the engine off. How would the throttle position affect the valve timing if the guides were broken or the chain stretched?

Inferno451

Anybody ever had a problem like this with the fuel pressure regulator? I know it's vacuum regulated. AFM Seemed to check out, but i don't have an analog multimeter, just digital, which makes it hard to check for dead spots.

TNRabbit

I had a similar problem with my 3vze & replaced the distributor, fuel pump, fuel pressure regulator & TPS to solve it completely.

I imagine part of the problem was a well-worn fuel pump not delivering proper pressure, & a worn distributor not advancing properly, in addition to TPS not knowing where the throttle was exactly.

Runs GREAT now; ESPECIALLY under 2500 rpm. It's like a different engine at low rpms~

Inferno451

I'd like to avoid just throwing parts at this thing if possible as i'm a poor college student. Anybody know where i can rent a vacuum/ fuel pressure tester?

Inferno451

Could a bad timing chain tensioner cause this? Although the tension is on the driver's side while under load, i'm wondering if the chain is loose on the passenger side the cam could be rotating too far, advancing the valve timing. Thoughts? I went out and checked the valve timing by turning the motor over by hand, the shiny link and sprocket dimple line up perfectly at around 11 o clock while at top dead center, valves adjusted to spec.

andykrow

Hmm do you really mean 11 o'clock or just to the left of "12"? It's really supposed to be at roughly "11:45", and the tooth directly to the right of the simple (when looking from the front of the engine" should basically be pointing straight up.

About two thirds of the way down this page is a pic of the cam gear at TDC.

http://www.4crawler.com/4x4/CheapTri...ingChain.shtml

If your dimple isn't in this spot with the crank at TDC I think you found your problem.

FYI, the bright link is only really for initial setup, after one rotation it won't line up with the dimple very often.

Inferno451

Snapped a picture of my timing marks, seem pretty spot on to me. If i advance the timing one tooth, the dimple will be straight up or JUST past 12:00. This is at TDC for cylinder 1, bright link does line up with dimple every few revolutions.


Starting to think maybe AFM?

andykrow

Yeah that looks right. I don't think the tensioner could cause this, since when the engine runs the crank pulls all the slack out between it and the cam.

So you said new TPS did you test it's operation completely? Adjusted it with the multimeter?

AFM moves freely?

Inferno451

TPS correctly adjusted with multimeter and feeler gauges. No dead spots as far a i can tell with a digital multimeter. AFM flap moves freely. Just for curiosity's sake, i swapped in an old VAFM with 250k miles on it and fulled the efi fuse for about half an hour, and it feels better. Still not much power, but no brick wall at high rpm. I'm still feeling some bogging and flat spots. Top speed jumped from about 64 to around 74 on the same stretch of road (slightly downhill).

andykrow

was your newer AFM tweaked for mixture?

And you're right they aren't nearly that gutless. Mine hits 90 on flat ground, and I'm a mile above sea level. Wondering if your dizzy is advancing enough?

You say new o2 did you use a denso? I've heard of every other type having problems straight off the bat. How do your plugs look?

fork

interesting, I think my 89 22re has the same noise at startup that you mention. The sound goes away after a couple seconds. I'm thinking maybe the tensioner I used was crap. It doesn't seem to have any lack of power other than the normal 22re gutless feeling