Hello,
Been a while since I posted. I finished I build and plan to put the whole write up with pictures up sometime soon. Anyhow, I have an issue and can't figure it out.
Engine timing set to factory specifications via FSM. Engine idles like a dream around 800 rpm... When I go to take off, it bogs down and has no power. I have advanced the distributor and it idles rough, but has plenty of power... Seems like it's running rich as well, the exhaust is pretty heavy smelling and the new pipes have turn black inside. I tested the TPS, ohm-ed, and all readings were right in the middle of spec. I just did a leak-down test on all four cylinders and the needle barely moved and stayed in the "set" area. Didn't sound like anything was leaking as well when performing the test. The block is .040 over with the correct 1.0 pistons from LCE. The block was also decked approximately 20/1000. I did a compression test and all cylinders are right around 130 psi. The FSM reads the engine should be at 170 stock rebuilt.... with the extra boring and decking, the compression SHOULD be higher... around 180-200 right? So, if the cylinders are not leaking, via a leak down test... why is the compression so low? Also, I made many marks on my timing pulley to measure what it's advancing to. Set to factory and idling at 12', when I rev it to 3k, it advances to 19'.... should be more like 28-32 I think. Perhaps it's not getting power because it's not advancing correctly? What controls the advance and how much it gets? Do I have some hoses hooked up wrong or something? It seems the rebuild worked well, but something else is causing the engine to bog down/not accelerate correctly. Any insights would be greatly appreciated. Thanks in advance.

 

Did you use a .51 head gasket after decking?

 

I used the one that came in the LCE master rebuild kit for the 22RE. I think it's to replace the stock gasket, so likely the same size as stock. I think I've got the problem narrowed down though... cam is 39' retarded, LCE has a 43' which is pretty close and they say you need the computer reprogrammed/swapped out so it will run right... which I don't have. Also, my timing is not advancing correctly... not enough. Not sure where to start looking for the timing not advancing while rev-ing up the engine..

 

The only question mark above pertains to your compression..

Did you hold the throttle plate wide open?

What altitude are you at?

These both play a big role in your compression guage reading. Throttle wide open and you'll find some charts to convert from standard atmosphere to your elevation on Google..

You didn't give your engine type, but I'll assume by your use of the terms it's not a 22r series. Surely someone makes a degree wheel for the 3vze(?)..

Decking the block and or head will have an effect on your timing advance as well as the valve timing (they are locked together..)

 

Co_94_PU, thanks for the input... here's the info. Throttle was held in the wide open position when conducting compression test. Altitude is 900 ft and approximately 14 psi atmospheric pressure at said elevation. Altitude plays a very SMALL role in compression readings. from 0 to 5000 ft above sea level, atmospheric pressure changes from 14.x to 12.x psi. Valve timing, compression ratio and temperature are the significant factors in compression measurements. My profile picture/info section reads what the truck is, has a picture, etc, but you're right, I didn't put it in the original post... it is a 22RE 1st gen 4runner. Has a custom head. Ported, polished, 3 angle valve seats and a 39' retarded cam called a "street RV cam". Valve timing is MECHANICAL controlled by the camshaft. IGNITION advance is electronic and controlled by the CPU... which relies on several inputs from other electronic components and sensors... they are not "locked" together as you say. You can clearly adjust your distributor to advance or retard IGNITION timing and at the same time the valve timing will remain exactly the same. Hope this clears things up =]

The compression is "low" because the cam is retarded 39' which means the intake valve closes LATE (or stays open longer is another way to say it) I found out... which will produce less compression. The ignition advance, again, works with many components to produce an end result via a final CPU output to the igniter, then to coil, then to distributor and on to the plugs. My engine... stock cam or not is NOT advancing correctly. I'm trying to figure out which part of the ignition advance system is failing to operate correctly. at idle, 780 rpm, ignition advance should be at 12'. When the engine is rev-ed up to 3k rpm the ignition SHOULD advance to around 28-32'... it is only advancing to around 18-19' @ 3k rpm which makes the engine bog down and produce little power when trying to accelerate. The distributor, igniter, coils, wires, cap, plugs are all brand new and tested to be functioning normally and correctly. The air flow meter ohm tested correctly and is a used part. The throttle position sensor ohm tested all but 1 setting which read infinite when it needs to be around 2k... new TPS has been ordered from Japan and is still not here yet \o/ CPU is throwing no faults and ohm tested correctly for function. I also used a second, known good CPU from a friends 85' 4runner and produced the same ignition timing results so it seems it not the CPU. I'm looking into what else affects the ignition timing... was hoping someone on here had a similar issue and/or knows what to look/check for. Thanks again for the input.

 

This is the chart from the TCCS manual that tells you what sensors are used in which stage of correction. Hope it helps.

 

Beautiful. Thanks bud... exactly what I was looking for.

 

Did you figure out the issue?

 

Thanks for the follow up PNW22re. I'm still working on it. I ordered a TPS from Japan, the OEM part. Just got it last week but have been busy with the holiday and all. Going to install the new one this weekend/coming week and see if it makes a difference. The one that is currently on the truck, I found out, is a cheap Taiwanese part which tells me they had issues with it before and it's not stock settings.... who knows how it was set up. The truck was running before the rebuild but I could tell it was tired and something was off. I'll post the results soon. I've definitely narrowed it down to O2 sensor, engine speed (the speedometer is not reading correctly and needs to be replaced) and/or the TPS. Everything else checks out in the green (from the list above provided by Co_94_PU). I also still need to contact LCE about possible CPU changes. They say their 43' retarded cam (mine is 39', fairly close to theirs) needs a computer reprogramming to to run correctly, so that's also a possibility. We'll see what they say...

 

PNW22re and everyone else... Thanks to PNW22re, I felt compelled to get it done right away. New TPS installed and it corrected the issue. And for the HOW it fixed it: The old TPS was sticking and not spinning freely in the housing, like it was gummed up. It also would stick once it turned about 20' or more then when I throttled down it wouldn't return to 0', it would stay around 20'. This was also the area where it wasn't Ohm-ing correctly and why I bought the new one. I think if it was cleaned up it would work properly, so I might do that to have a back-up. I set the timing to the factory 12' and idle at 800... it's purring. Then manually rev'ed it to 3k RPM and watched the advance go way out to 31'. Also no little backfires or burps...... IT'S FIXED!!! \o/ Drove it up and down the street and it performed better than when I had it advanced with the distributor... because now it's not firing at the beginning-ish of the compression stroke, but actually firing on time. I was spinning the back tires... can't believe how much power the engine has. It's on 35" tires with 4:56 gears. I believe this is due to the cam... seems to give it a LOT of torque. I think I'm going to Dyno it since it's running so well now.

 

nice! I’m having the same issue. Where did you order the TPS from?

 

I got it off Amazon. It comes from Toyota in Japan. Took a while to get here but here is the link below, just copy and paste into the browser NOT Amazon search. If the link doesn't work, just type in the Amazon search bar, this phrase, to find it:

"Genuine Toyota 89452-20050 Throttle Position Sensor"

https://www.amazon.com/Genuine-Toyota-89452-20050-Throttle-Position/dp/B00FSDN2EA/ref=sr_1_2?keywords=Genuine+Toyota+89452-20050+Throttle+Position+Sensor&qid=1575178950&sr=8-2

If you think it's the TPS, you should do a couple things BEFORE buying a part though. Go to this web page and read through the instructions AND TEST your TPS according to this document. ALSO, you can just REMOVE yours and INSPECT to see if it's not turning and snapping back correctly. If it's not smooth and spins back to 0' at the same rate... it's wasted. Here's the TPS document link: https://www.4crawler.com/4x4/CheapTr...PS/index.shtml

Let me know how it goes. The engine running poorly can be a BUNCH of stuff as I found out.... glad to help you trouble shoot before spending money on parts that may not fix the issue.