lunyou thinks i am crazy
oh wait....carry on
oh wait....carry on
Bought the 87 4runner - help me gets it's power back!!
- Thread starter lunyou
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I time mine by ear. With ethanol, etc in fuel these days you may need to be more advanced than what fuels needed back when the vehicle was made. The timing light should get you close enough to get power back though. You may advance it slightly from there and see what feels best when you drive. If it pings, you have gone too far.
Why do you jump the wires again??? I hooked up a timing light without jumping the wires and mine was right on +5... I'm chasing a power gremlin as well...I'm leaning towards a valve issue, exhaust suction with the paper trick.
- Thread starter
- #25
Can you explain the paper trick?
Take a receipt from the store or other thin paper and cover half the exhaust holding it a little tight, watch and see if it blows out as well as sucks in at idle. It will be obvious, it creates a blur you can see it going in. It moves super fast.
Indicates sticking valves...one piston pulls air back through the open exhaust valve.
Its an easy fix...pull the head, get 16 valves, $8 each and find a good machine shop to install them and test the rockers and springs...most are around $150 in labor. You can do the HG as well as the timing chain. Total deal is $400 or less and you have a new top end.
Thats my plan at least, or just buy an engnbldr head assembled. HAHA
Thats my plan at least, or just buy an engnbldr head assembled. HAHA
use a vac guage for thatgauges have been a valuable tool to mechanics for years. Even with modern computer controlled engines a vacuum gauge is still a valuable tool for diagnosing engine and transmission problems. ]Engine/Transmission RelationsAn important part of transmission diagnosis is to make certain the engine operates properly. If the engine performance is incorrect, the transmission will receive the wrong information. Many times what is perceived as a transmission problem is in actuality an engine problem. The engine sends signals to the transmission through a vacuum line, throttle cable or both. These signals basically synchronize torque with transmission line pressure, shift feel and shift timing. Malfunctions in items like the air filter; spark plugs, EGR valves and other parts of the fuel, electrical and emission systems could result in improper transmission performance.
Vacuum Gauge Engine Performance Testing A vacuum gauge shows the difference between outside atmospheric pressure and the amount of vacuum present in the intake manifold. The pistons in the engine serve as suction pumps and the amount of vacuum they create is affected by the related actions of:
Normal Engine Operation
At idling speed, an engine at sea level should show a steady vacuum reading between 17" and 21" HG. A quick opening and closing of the throttle should cause vacuum to drop below 5" then rebound to 21" or more.
General Ignition Troubles Or Sticking Valves
With the engine idling, continued fluctuation of 1 to 2 inches may indicate an ignition problem. Check the spark plugs, spark plug gap, primary ignition circuit, high tension cables, distributor cap or ignition coil. Fluctuations of 3 to 4 inches may be sticking valves.
Intake System Leakage, Valve Timing, Or Low Compression
Vacuum readings at idle much lower than normal can indicate leakage through intake manifold gaskets, manifold-to-carburetor gaskets, vacuum brakes or the vacuum modulator. Low readings could also be very late valve timing or worn piston rings.
Exhaust Back Pressure
Starting with the engine at idle, slowly increase engine speed to 3,000 RPM, engine vacuum should be equal to or higher than idle vacuum at 3,000 RPM. If vacuum decreases at higher engine RPM's, an excessive exhaust back pressure is probably present.
Cylinder Head Gasket Leakage
With the engine Idling, the vacuum gauge pointer will drop sharply, every time the leak occurs. The drop will be from the steady reading shown by the pointer to a reading of 10" to 12" Hg or less. If the leak Is between two cylinders, the drop will be much greater. You can determine the location of the leak by compression tests.
Fuel Control System Troubles
All other systems in an engine must be functioning properly before you check the fuel control system as a cause for poor engine performance. If the pointer has a slow floating motion of 4 to 5 inches - you should check the fuel control.
Recap
Connect the vacuum gauge hose as close to the intake manifold as possible and start engine. Run engine until normal operating temperature has been reached and then allow to idle. On V type engines having two manifolds, make separate tests on each manifold. If required, set the idle adjustment on the carbuetor so that the engine idles smoothly.
NOTE: Vacuum readings will vary according to the altitude in different localities. From sea level to 2,000 feet elevation all normal engines should show a vacuum reading between 17 to 21 inches. Above 2,000 feet elevation the vacuum reading will be about one (1) inch lower per each 1,000 feet rise in elevation.
Vacuum Gauge Engine Performance Testing A vacuum gauge shows the difference between outside atmospheric pressure and the amount of vacuum present in the intake manifold. The pistons in the engine serve as suction pumps and the amount of vacuum they create is affected by the related actions of:
- Piston rings
- Valves
- Ignition system
- Fuel control system
- Other parts affecting the combustion process (emission devices, etc.).
Normal Engine Operation
At idling speed, an engine at sea level should show a steady vacuum reading between 17" and 21" HG. A quick opening and closing of the throttle should cause vacuum to drop below 5" then rebound to 21" or more.
General Ignition Troubles Or Sticking Valves
With the engine idling, continued fluctuation of 1 to 2 inches may indicate an ignition problem. Check the spark plugs, spark plug gap, primary ignition circuit, high tension cables, distributor cap or ignition coil. Fluctuations of 3 to 4 inches may be sticking valves.
Intake System Leakage, Valve Timing, Or Low Compression
Vacuum readings at idle much lower than normal can indicate leakage through intake manifold gaskets, manifold-to-carburetor gaskets, vacuum brakes or the vacuum modulator. Low readings could also be very late valve timing or worn piston rings.
Exhaust Back Pressure
Starting with the engine at idle, slowly increase engine speed to 3,000 RPM, engine vacuum should be equal to or higher than idle vacuum at 3,000 RPM. If vacuum decreases at higher engine RPM's, an excessive exhaust back pressure is probably present.
Cylinder Head Gasket Leakage
With the engine Idling, the vacuum gauge pointer will drop sharply, every time the leak occurs. The drop will be from the steady reading shown by the pointer to a reading of 10" to 12" Hg or less. If the leak Is between two cylinders, the drop will be much greater. You can determine the location of the leak by compression tests.
Fuel Control System Troubles
All other systems in an engine must be functioning properly before you check the fuel control system as a cause for poor engine performance. If the pointer has a slow floating motion of 4 to 5 inches - you should check the fuel control.
Recap
- Engine problems can affect transmission performance.
- If you suspect an engine problem, connect a vacuum gauge to the intake manifold.
- Note the location and action of the vacuum gauge needle.
- Use the information in this article to determine the engine problem.
- Correct the engine problem before doing extensive calibration work on the transmission.
Connect the vacuum gauge hose as close to the intake manifold as possible and start engine. Run engine until normal operating temperature has been reached and then allow to idle. On V type engines having two manifolds, make separate tests on each manifold. If required, set the idle adjustment on the carbuetor so that the engine idles smoothly.
NOTE: Vacuum readings will vary according to the altitude in different localities. From sea level to 2,000 feet elevation all normal engines should show a vacuum reading between 17 to 21 inches. Above 2,000 feet elevation the vacuum reading will be about one (1) inch lower per each 1,000 feet rise in elevation.
updates?
timing guns are for ......well
Haha, mine was retarded 6 degrees and my timing gun fixed that in 5 minutes. The truck really came to life. I tried so many things electrical before finding this. Now it runs perfect. Remember the jumper on the diag. port.
- Thread starter
- #33
Updates? Yeah I changed the plugs, wires, and the airfilter. It seems to have helped a little. It is comfortable to drive at least. Still needs exhaust work, timing fixed, and I need to get around to changing the fuel filter.
I also gave it a face lift. Pictures are in the other thread.
I also gave it a face lift. Pictures are in the other thread.
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Red Toyota fetish?
- Thread starter
- #36
Red Toyota fetish?
Seems we buy vehicles of the same color a lot. For a while my wife and I had matching a 4runner and pickup, both dark green and with white stripes. Then she got a red Pontiac and then the red started. Now she got a yellow Mustang and I'm dreading the yellow trend. Of course as it stands we have room for one more vehicle but we can't fill that spot because, I liken it to one of those slider puzzles where you have to have an empty space to move vehicles around.
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Do that timing asap!! It can be way way off and you will see more difference with getting that straight than anything else. Also, jumper the timing connectors while the engine is running and make sure the idle drops when you do it. If the idle doesn't drop you need to adjust your tps. Its a real pain but necessary for the truck to run right.
Agreed on the timing, the diffeence in power for me was amazing. I adjusted my TPS prior to the timing, no luck there.
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yeah tps is either right or wrong. no "range" of performance for how it's set. quite a few times i've tried to time a 22re but needed to adjust the tps first. without it set right the engine doesn't know it's idling and timing will be wrong. and when you connect the test connectors engine will only drop rpm if the ecu thinks it's idling, hence a tps adjustment may be required...
- Thread starter
- #40
Okay as an experiment I went out and started the truck and then loosened the nut on the distributor. It was originally rotated all the way clockwise. I slowly brought it counter clock wise and noticed a HUGE difference in the way the motor sounded, the smoothness, and the overall quality of the sounds was better.
Is it really that simple? I moved it a little bit and locked it in and the truck is like a new rig. Any precautions to take when doing this sans timing gun?
Is it really that simple? I moved it a little bit and locked it in and the truck is like a new rig. Any precautions to take when doing this sans timing gun?