Engine Severe Lack Of Power Under Load

Fuel sample for alcohol content? I my experience backfired are always timing issues. Either mechanical timing or ignition. I would verify cam/crank mechanical timing. Those engines were common for excessive slack in the chain at higher mileage. It’s easy enough to pull the valve cover and inspect. Look for chain cutting into the timing cover. Also check valve adjustment while you are in there.

thanks for your advised, about 5 month ago I did valve adjustment, and timimg reseat on the distributor, but sure I will check that, in the incylinder wave form the spark timing seem ok and does not move left and right , advance or retarded during changes in engine rpm.

That would cover ignition timing but not mechanical timing. As others have stated you need to prove the crank position in relation to the dampener marks as well as chain position. Don’t overlook alcohol content.

On your first file the fuel injector is firing twice per engine stroke. I would only expect one, usually about 360 opposite the compression peak. Next step for me, would be finding out what this engine is using for inputs, like crank and cam sensors and scoping them for anything odd.

yes I saw that but this is multiport not sequential fuel injection .

Yes, you are right. I haven't looked at one of these in a long time. :) Hope I didn't lead you in a wrong direction.

Thy fire in a group of injector as they are multi port.

Here is a picture of what I was referring to.

I thought the same Richard, looks to me as if the injector is being fired after tdc on the power stroke? Perhaps this would account for the glowing cat?

I see three easy clues in what you have written. #1 = the glowing cat, #2 = no throttle response & #3 the popping/backfire. The glowing cat says there is plenty of oxygen flowing through the engine, and plenty of gas, but the gas is not being burned in the combustion chamber. The popping sound comes from a misfire issue, either from a mechanical engine problem, or from the ignition timing…

thanks make sense

What is your manifold vacuum at base idle? If you have or suspect an engine breathing issue, start with your vacuum gauge. Look for a low or severely fluctuating needle. I'm not entirely confident in the backpressure test I saw in your video. Were there any wide open throttle snaps in there, or any throttle snaps under load? Remember that the engine gulps a LOT more air under load, and what…

I agree with you ,how ever on the wave form for the in cylinder does not appear to have exesive back pressure .

Clogged cat?

I tested it is on the post the video

I just looked at both of the Vids again. From the sound, and by watching the pressure gauge, when you snap the throttle, both the gauge and the sound says your vehicle is constipated. It is NOT breathing correctly.

Thanks , for your input

In looking over your data captures, This one sticks out to me. diag​.​net/msg/m301jdm2fr… When working on a problem like this, most times I find that watching scan data and looking for what happens in the data will be the quickest way to find the problem. In that capture, at WOT, why is the o2 voltage very low? The only thing that can cause that o2 voltage is a lack of fuel in the…

Alcohol content being too high would cause a lack of power and would show as very lean.

to be honest with you I have never dne that test in my are there are not i 85 gas stations, but I wanted to do it. what is normal acceptable??

10-15%

easy to do a quick test with a plain water bottle. make even marks on the side or use ribs in bottle. Add 10 parts fuel and 1 part water. shake and wait a few minutes for the water and alcohol to settle. The amount the water increase in volume is the percentage of alcohol.

thanks for the input on saturday I am going back to that vehicle, I will update the findings.

Good luck. I look forward to hearing the results.

Misfire can cause lean O2 sensor readings because the oxygen is unused and passes by the O2 sensor.

but how it works you have both unburned fuel ad oxigen. I know the 02 sensor reads oxygen but remenber on good running engine at wot they read full rich ??

good running is the key. if not misfiring there is no Oxygen left over and therefore the O2 sensor reads rich. If the engine is misfiring, Oxygen is not used and the O2 sonsor will read the Oxygen. Even with a single misfire on the lab scope you can see over activity of it going lean too quickly. That is from the wads of Oxygen for each misfire going by the O2 Sensor. For example most O2 sensors…

Did you see the 02 sensor and spark plug photo is attached to this post?? Is showing rich at idle and cruising, when wot shows lean , spark plugs are black.

Yes I did. plugs black from running rich at idle. Between WOT and idle. about half way through the waveform you see the O2 Sensor go from .1 volts and flutter up to .4 volts and back down. That kind of movement is from a misfire or in you case a couple cylinders fired a few more times using a bit more oxygen. It went up and down in voltage 5 times in a second. that is showing bursts of oxygen…

My first instinct he… it trying to rev at WOT is ignition timing or lack of ignition. Can you do a cylinder pressure test and do a WOT and zoom in to see ignition timing and pressures? The other thing to check is if all the injectors are flowing properly. On your WOT ignition pattern two cylinders have twice the KV as the other two. Why? Is it fuel related or pressure related. May need to do…

very interesting points you touched , yes I added fuel and wot not response .

The injector were missing was during decceleration

Not always on your capture. Look again and sometimes on decell still firing injector but very small pulse. Second capture shows enleanment on decel then richens back up for idle and then injector just stops firing.

Intersting I will dig deeper.

I was analyzing the waveform, I am going back to this vehicle Saturday. in repetition I see in one cyinder has god firing only .

Why do the injector waveforms have different slopes and fully open on times & no pintle bump? It seems to repeat on every other cyl. My other post was referring to timing advance. Found cold solder joints in PCM.

Hello Joel from what you are experiencing I wonder if the crankshaft sprocket key way has worn or the key has broken, I believe it happens on this motor. I noticed in your running compression test uneven peaks, this may be due to sampling if not it's going to be a mechanical issue. Check the crankshaft pulley for loosening and possibly remove and inspect the key way, I remember getting quite a…

This one does not have ckp sensor ,the pick up sensor is inside the distributor and signal sent to igniter

I don't see a compression test. If all cylinders test low, I'd check the timing chain position. Also make sure the #1 piston is actually at TDC, the balancer ring on the crankshaft pulley could possibly slip.

Like others have said check timing chain or belt did it jump , has it been replaced? How much flow is coming out the tail pile to me with a red cat could be plugged

I removed the o2 sensor and accelerated like tgat not change , there is the small video qhen I did the test

Wow! A lot of hi-tech diag going on here. My thought is back fire with breathing issues = broken valve spring(s). Just a thought..... Davie

normally I start with the 4 basic, if I do not find some thing there I go for the fift basic , on time or enough , some other tech point me some things I have missing this is good community .

another thing I don't see mentioned is to verify that the Vane Air Meter actually works. Use a scope or a meter and move it with your hand. Do the same with the TPS. I realize you adjusted TPS months ago, but today is now, not then.

sure thanks I have to make my second trip to that trucks but I needed more weapon,

Looking at your ignition waveform it appears that two cylinders are firing normally and two have excessive resistance. Could be caused by a lean condition. Maybe a valve issue or a head gasket blown between two cylinders.

This is a capture zoomed in to show a good non misfiring spark plug spark time with a repeating cylinder with misfires. I'd like to see a capture with the coil primary and coil secondary, along with a secondary lead on the cylinder 1 plug wire, with a steady brake torque, near 1500 rpm

This is thought because is manual transmission

Hi Joel: I know that you wrote the timing and TPS issues were resolved but I have to question if that is really true. If memory serves, you can't set ignition timing with a defective/misadjusted TPS. Do the timing marks move when you jump the connector? If not, those issues probably have not been corrected. Guido

I had one of these with a camper built on back and I think dual wheels? I swear I think i finally found the timing wasn't advancing due to some cold solder joints in PCM? Also had an issue with PCM/FI relay wires under fuse/relay box. Damn it. Can't remember details.

to be honest with you I did not check the tps or timing light at this time but I will, yes you are ocorrect if the tps is not on the Idle positions the base timing is wrong

"if the tps is not on the Idle positions the base timing is wrong" That is an oldie but a goodie Joel. Learned that one through research and fixed a truck once, about five years ago. Feliz año nuevo

Joel; Good morning Sir, I hope this message finds you doing well. Zooming into your In Cylinder Waveform, during WOT the Ignition Timing is still near TDC (No Timing Advance). With a timing light hooked to the vehicle and simply revving the engine, do you see the PCM trying to "Advance the Ignition Timing"?

I am getting back to this vehicle next saturday , I will report back . Thanks for your help I will test it with the timing lamp .

Zoomed in on the WOT in-cylinder does show the ign timing at about 3*TDC. Also the exhaust valve opens at or after BDC, there is 6-8psi of backpressure, ( the backpressure test video showed the needle jumping up to that value, I wondered if was “real backpressure” or a pulse caused by the charge burning in the exhaust pipe) and the cylinder pressure starts to drop before TDC. The idling portion…

thanks for the help anlalizing, I will get back to this vehicle next saturday , I will update the result .

In the video with the timing advanced; When the throttle is snapped, the timing falls to base then recovers to full advanced. So, it’s not “stuck”. Is the problem an input or glitched ECM? Scoping the “CMP” may give a clue. If an ECM is handy for substitution that would be a fast test. Opening the ECM and looking for bad solder joints, especially on the connector terminals ? Rapping on the ECM…

I did not do any thing else from before and after on those 2 videos than exited the magnet and there was the big change, I did not remove the plugs , this vehicle does not use cmp the ckp is basically the pick up that is inside the distributor , but ipening the ecm I like that idea .

I don't know if this will help or not, maybe you already know this about the VAST system on 22RE engines. But the next to the last paragraph in the attached file says this engine will run at defaulted base timing even if the IGt signal from ECU is open or not functional. Maybe the IGt wire has a poor connection or the advance signal from the ECU isn't happening.

good info I did not know .💪🏻

I'm posting these good GIF and PSD ignition files from a 93 Corolla 1.8 to compare with your misfiring ignition files. CH A coil negative primary winding volts during a WOT snap CH B cyl 1 plug wire CH C primary coil amps CH D coil secondary voltage

thanks , I like tbe way you have good captures thanks for sharing , by the way what do you think about this vehicle I found already the spark advance is not taking place , I belive this will be ecm as the igniter should be told what to do rigth??

On mine when you jumped the connector nothing happened. Found terminal/wire that went to PCM was open circuit. The wiring was intact. So i opened PCM and found several cold solder joints. I would also agree about replacing the plugs. When they get fuel fouled like that they sometimes won't ever clean up. Makes you really feel dumb when the plugs are 90% of the problem. But stuff happens. Lots of…

In your last video, it looks like the ignition is firing near 35 degrees BTDC at idle and then near the maximum 44 degrees BTDC during the high rpms. I would first begin with the procedure to set the base ignition timing at idle, which I guess would be near 10* BTDC. Then scope the ECM signal to the igniter for the ignition timing advance as the rpms slowly increase from idle to about 2,500…

Maybe you have done this already, but remove cylinder 1 spark plug and turn the engine so cylinder 1 piston is at TDC. Check that the timing mark on the harmonic balancer lines up with the "0" mark on the timing cover. These ECM timing advance captures are from an 01 Malibu 3.1 CH A when the engine is cranking, before the Bypass voltage rises, the ignition fires at the rising DREF or…

put lab scope on pickup signal from the distributor to make sure it is good. if that signal is bad the computer cannot control timing properly. The igniter sends a signal to the computer and the computer sends a modified signal back to control timing. One is IGf and IG? . I cannot remember off the top of my head the 2 signal names. If the signal from the pickup coil is bad then the rest will be…

thanks I will

- Forgive me if I'm wrong but one of your scope patterns show the last two ignition events in the ignition scope pattern to be very erratic. The other two cylinders have a better pattern to them. The turbulence seen in the spark line shows either a compression leak or a lean condition in the cylinder. The pattern doesn't indicate an igniter problem as it would effect each cylinder the same. If…

I wonder if the fuel quality is part of the problem?

I have not tested the fuel quality because I road tested the vehicle when the ignition timing is peg at 25 degrees btdc, and works like known good running engine . power , aceleration response all good .

Hey Joel, after wasting a lot of time once, I told myself that I would ALWAYS check fuel quality every time I hook-up the fuel pressure gauge from then on. It is to easy not to do it. The drain hose is right there....ya know? You just fill the vile and set it aside while you move on to other checks. Certainly should be done before the scope gets involved. Contaminated and separated fuel can…

When the ignitions timing is stuck advanced, the vehicle recover the engine power and the ignition wave form gets clean .

I’m curious, what is the O2 sensor reading with the timing advanced?

normal switching and no more bck firing when was advance about 25 degres btdcin this conditions the engine runs great plenty of power , the cuatomer lives on an area where thereis a up hill , I can test it there, at one time got stuked at 50 degress btdc ad did back fire on both intake and exhaust. as when it get stucked on base timing with no advance.

Does this truck have a knock sensor?

yes it does

Is it producing a signal? Cause if it is, the timing is going to become retarded.

I have not checked it , thanks for your inputs most definitely can effect

In your video where you are measuring ac voltage from the pick up coil while cranking, your dvm is measuring an average of the signal. You would have to use a meter with a 1ms capture to see the 1.1 volt ac sine wave up and down.

Are those spec the manufacturers give us , for average or peak to peak??

Peak to Peak is the voltage. Your lowest cranking was 1.1volts AC.

The service manual doesn't give specs for that test. When I check the pick up coil on those engines I usually see around 1 volt positive max and a little less than 1 volt negative min with a 1ms capture.

This GIF is from your last PSD file. At idle, the IGT is switching the coil primary dwell off at 16.5 degrees before the NE. At WOT, there is 0 degrees timing advance. The IGF is the coil primary winding voltage.

So in this case every thing points to computer not controling the ignition timing rrigth?

It is normal for the ignition timing to be advanced 16 degrees at idle and it is normal for the ignition to retard to zero degrees at a WOT snap.

Off idle, the CH C IGT is advancing the ignition timing 20 degrees before the CH B NE Again, the CH D IGF shows the coil primary winding being pulled to ground for a dwell time, then released by the IGT, to create the spark in the secondary winding

Thank you very much for the explanation.

Looking at your pico file I think you have a bad igniter. When the engine was cranking before it went into timing control it did not fire the coil twice. It had a good signal from the distributor and the igniter put out the square wave to the computer but did not pull the coil to ground. so there was no spark. Timing will not be correct if the igniter cannot pull the coil to ground and release…

This GIF is from your capture with the distributor pick up coil on cranking to start. When cranking, the coil primary dwell time is turned off by the NE in CH B When started, the coil primary dwell is turned off early, before the NE, by the IGT in CH C, which is the ignition timing advance. CH D is the IGF, which is the coil primary voltage, which is pulled to ground for a dwell time, then…

look at the video

Any news? Tap, Tap, Tap...is this thing on?

I am waiting for the ecm to arrived. I will update when installed.

- Conclusión, computer soldering , fixed . Clean resoldering joints. Now we have control in spark advance BAZINGA!!! I finally was useful. As my dad would say..."even a blind sow picks up an acorn occassionaly"...

Thanks for your help to every body.