Please help: Car sounds like a WRX + Rumbles
- Thread starter Spetz
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I just did a compression test and it does not seem that I have a bent valve (figures below).
I also double checked and the leads are connected correctly.
What could this be?
I am about to install my original injectors and see if that changes anything.
The odd thing is when I disconnect one particular injector it makes no difference in how the engine runs. Any other injector makes the motor almost stall.
Any ideas?
Compression readings:
Can someone tell me:
1. Is 150psi dry too low?
2. Dry tests are surprisingly even, but wet tests are surprisingly uneven, what does this mean?
I also double checked and the leads are connected correctly.
What could this be?
I am about to install my original injectors and see if that changes anything.
The odd thing is when I disconnect one particular injector it makes no difference in how the engine runs. Any other injector makes the motor almost stall.
Any ideas?
Compression readings:
- Cylinder 1, 151 psi dry, 162psi wet
- Cylinder 2, 151 psi dry, 179psi wet
- Cylinder 3, 150 psi dry, 174psi wet
- Cylinder 4, 150 psi dry, 181psi wet
- Cylinder 5, 151 psi dry, 190psi wet
- Cylinder 6, 150 psi dry, 180psi wet
Can someone tell me:
1. Is 150psi dry too low?
2. Dry tests are surprisingly even, but wet tests are surprisingly uneven, what does this mean?
I suspect some installation problem when you reinstalled your rocker arms. I am not familiar with your engine but I am guessing that some rocker arm wasn't aligned in the same way you removed it and it's opening and closing the valve at incorrect timing. What I normally do is to set the crankshaft to exactly to TDC before I remove the rocker-arm assembly and then when I am done with the work, I reset the crankshaft to exactly TDC again before I reinstall the rocker-arm assembly, which ensures that the rocker-arm assembly is installed in the correct orientation.
Here are the brief instructions from the AutoZone repair guide if it helps:
3.5L Engines
Fig. Camshaft, rocker arm and shaft assemblies-3.5L engine
1. Disconnect the negative battery cable.
2. Remove the rocker arm cover.
3. Install the lash adjuster clips on the rocker arms, then loosen the bearing cap bolts. Do not remove the bolts from the bearing caps.
4. Remove the rocker arms, shafts and bearing caps as an assembly.
To install:
1. Install the bearing caps/rocker arm assemblies. Tighten the bolts to 23 ft. lbs. (31 Nm).
2. Remove the lash adjuster clips.
3. Install the rocker arm cover using a new gasket.
4. Connect the negative battery cable.
Here are the brief instructions from the AutoZone repair guide if it helps:
3.5L Engines
Fig. Camshaft, rocker arm and shaft assemblies-3.5L engine
1. Disconnect the negative battery cable.
2. Remove the rocker arm cover.
3. Install the lash adjuster clips on the rocker arms, then loosen the bearing cap bolts. Do not remove the bolts from the bearing caps.
4. Remove the rocker arms, shafts and bearing caps as an assembly.
To install:
1. Install the bearing caps/rocker arm assemblies. Tighten the bolts to 23 ft. lbs. (31 Nm).
2. Remove the lash adjuster clips.
3. Install the rocker arm cover using a new gasket.
4. Connect the negative battery cable.
The rocker arms went in as they came out. They were never taken off the rocker arm shaft, just lifters were removed, cleaned in diesel and the installed again. Everything was very clean so I did not bother disassembling.
Considering my compression test, does this not mean that the problem would be not related to the valvetrain but be somewhere else?
Considering my compression test, does this not mean that the problem would be not related to the valvetrain but be somewhere else?
Originally Posted By: Spetz
Compression readings:
Can someone tell me:
1. Is 150psi dry too low?
2. Dry tests are surprisingly even, but wet tests are surprisingly uneven, what does this mean?
They don't seem to be very good results. Since oiled readings are much higher, it looks like you have a lot of cylinder/ring wear. Also, the difference between cylinders are quite high. Differences may be caused by varying degrees of wear as well as some cylinders having valves not sealing or gasket leaking in addition to ring/cylinder wear.
Here is some good info:
http://www.gregsengine.com/cylinder-compression-testing.html
Anyway, I would first concentrate on fixing your problem with the rocker arms or something else in your valvetrain apparently improperly installed after your valve-seal replacement.
Compression readings:
- Cylinder 1, 151 psi dry, 162psi wet
- Cylinder 2, 151 psi dry, 179psi wet
- Cylinder 3, 150 psi dry, 174psi wet
- Cylinder 4, 150 psi dry, 181psi wet
- Cylinder 5, 151 psi dry, 190psi wet
- Cylinder 6, 150 psi dry, 180psi wet
Can someone tell me:
1. Is 150psi dry too low?
2. Dry tests are surprisingly even, but wet tests are surprisingly uneven, what does this mean?
They don't seem to be very good results. Since oiled readings are much higher, it looks like you have a lot of cylinder/ring wear. Also, the difference between cylinders are quite high. Differences may be caused by varying degrees of wear as well as some cylinders having valves not sealing or gasket leaking in addition to ring/cylinder wear.
Here is some good info:
http://www.gregsengine.com/cylinder-compression-testing.html
Anyway, I would first concentrate on fixing your problem with the rocker arms or something else in your valvetrain apparently improperly installed after your valve-seal replacement.
Originally Posted By: Spetz
The rocker arms went in as they came out. They were never taken off the rocker arm shaft, just lifters were removed, cleaned in diesel and the installed again. Everything was very clean so I did not bother disassembling.
Considering my compression test, does this not mean that the problem would be not related to the valvetrain but be somewhere else?
Yes, disassembling them would be a bad idea. However, did you remove and install them in exactly the same crankshaft position to ensure everything was oriented correctly? Could there be something else that went wrong during the installation of the rocker arms or valve springs?
Since this problem was absent before you replaced your seals, I suspect some installation problem with your springs, rocker arms, etc.
The rocker arms went in as they came out. They were never taken off the rocker arm shaft, just lifters were removed, cleaned in diesel and the installed again. Everything was very clean so I did not bother disassembling.
Considering my compression test, does this not mean that the problem would be not related to the valvetrain but be somewhere else?
Yes, disassembling them would be a bad idea. However, did you remove and install them in exactly the same crankshaft position to ensure everything was oriented correctly? Could there be something else that went wrong during the installation of the rocker arms or valve springs?
Since this problem was absent before you replaced your seals, I suspect some installation problem with your springs, rocker arms, etc.
Gokhan, at the same time as doing the valve seals I did the following:
Removed distributor (o-ring leaking)
New spark leads
New (second hand cleaned) injectors
New distributor rotor
New distributor cap
The engine does not make noise, and I believe I would not be able to install the rocker arms the wrong way (they would not fit).
Also, I am still not following with the crankshaft position. The rocker arms move up and down to open/close valves, what difference does it make where the stroke is?
I will remove the valve cover and have a look however to see if all seems ok
Removed distributor (o-ring leaking)
New spark leads
New (second hand cleaned) injectors
New distributor rotor
New distributor cap
The engine does not make noise, and I believe I would not be able to install the rocker arms the wrong way (they would not fit).
Also, I am still not following with the crankshaft position. The rocker arms move up and down to open/close valves, what difference does it make where the stroke is?
I will remove the valve cover and have a look however to see if all seems ok
Did you play with the ignition timing to see what happens or is it not adjustable? Incorrect ignition timing would certainly make the engine run poorly or not run at all. I am assuming the wires aren't crossed.
You're probably right that it probably wouldn't fit incorrectly. If you open the valve cover, check with a feeler gauge to see if the valves are opening at the correct positions.
You're probably right that it probably wouldn't fit incorrectly. If you open the valve cover, check with a feeler gauge to see if the valves are opening at the correct positions.
I opened the valve cover, everything was fine under there.
I double checked that the leads are in the right place and everything seems fine.
The odd thing is when I unplug injector #4 there is no difference to how it runs. I've swapped the injector but again same thing.
I double checked that the leads are in the right place and everything seems fine.
The odd thing is when I unplug injector #4 there is no difference to how it runs. I've swapped the injector but again same thing.
Are you getting spark on No 4?
Originally Posted By: Spetz
The odd thing is when I unplug injector #4 there is no difference to how it runs. I've swapped the injector but again same thing.
There's the vital clue. That cylinder #4 is suspect. Verify spark and fuel.
If you can touch the injector while engine is running, does it tick consistently?
Pull the spark plug and lead, ground the plug, and have someone crank the engine. Can you see a spark?
The odd thing is when I unplug injector #4 there is no difference to how it runs. I've swapped the injector but again same thing.
There's the vital clue. That cylinder #4 is suspect. Verify spark and fuel.
If you can touch the injector while engine is running, does it tick consistently?
Pull the spark plug and lead, ground the plug, and have someone crank the engine. Can you see a spark?
Check the plug on the injector, swap the injector with the one next to it, try another spark plug, test the new wire ohms or try an old one, make sure the firing order is correct.
You have to go through this step by step to find the culprit. It could be a defective new part, it wouldn't be the first one.
I did an engine many years ago that came in on on a hook, it was a 6 cyl something or another and the dist was 180 in it. The bugger ran, not well but it ran.
No saying thats the case on this car but you have to look for the obscure when everything else fails.
Is there a CEL on this car?
You have to go through this step by step to find the culprit. It could be a defective new part, it wouldn't be the first one.
I did an engine many years ago that came in on on a hook, it was a 6 cyl something or another and the dist was 180 in it. The bugger ran, not well but it ran.
No saying thats the case on this car but you have to look for the obscure when everything else fails.
Is there a CEL on this car?
The CEL did not go on.
My next step is to check cam timing + distributor timing.
I will check resistance on the leads as well.
Swap back my original injectors.
I no longer have my old leads, distributor cap and rotor though but I think these are really unlikely to be defective from new?
My next step is to check cam timing + distributor timing.
I will check resistance on the leads as well.
Swap back my original injectors.
I no longer have my old leads, distributor cap and rotor though but I think these are really unlikely to be defective from new?
It's probably just the ignition timing.
Valve timing wouldn't change without removing the timing belt. Also, you don't have adjustable valves; therefore, nothing could have gone wrong with that messing the valves either.
If you removed the distributor from the engine, there is a good chance that you didn't mesh the gear correctly. As I said before, set the engine to No 1 cylinder TDC and remove the distributor cap. If the rotor is not at the No 1 wire contact, your distributor gear wasn't meshed properly and you need to remove the distributor and remesh the gear.
Once you're sure that it's meshed properly, you can get a timing light and tune the ignition timing. Digital timing-advance lights are a lot easier to use.
Here are the instructions for your car from the AutoZone guide I linked above. After reinstalling the distributor, make sure that the rotor is at the No 1 contact with the No 1 cylinder at TDC.
Before removing the distributor, position No. 1 cylinder at Top Dead Center (TDC) on the compression stroke and align the timing marks.
Disconnect the negative battery cable.
Remove the ignition wire cover, if equipped.
Detach the distributor harness connector.
Remove the distributor cap with all ignition wires still connected. Remove the coil wire, if necessary.
Matchmark the rotor to the distributor housing and the distributor housing to the engine.
Remove the hold-down nut.
Carefully remove the distributor from the engine.
Install a new distributor housing O-ring and lubricate with clean oil.
Position the engine so the No. 1 piston is at Top Dead Center (TDC) of its compression stroke and the mark on the vibration damper is aligned with 0 on the timing indicator.
Align the distributor housing and gear mating marks. Install the distributor in the engine so the slot or groove of the distributor's installation flange aligns with the distributor installation stud in the engine block. Be sure the distributor is fully seated. Inspect alignment of the distributor rotor making sure the rotor is aligned with the position of the No. 1 ignition wire in the distributor cap.
Install the hold-down nut.
Attach the distributor harness connectors.
Install the distributor cap.
Connect the negative battery cable.
Adjust the ignition timing and tighten the hold-down nut to 8 ft. lbs. (11 Nm).
Valve timing wouldn't change without removing the timing belt. Also, you don't have adjustable valves; therefore, nothing could have gone wrong with that messing the valves either.
If you removed the distributor from the engine, there is a good chance that you didn't mesh the gear correctly. As I said before, set the engine to No 1 cylinder TDC and remove the distributor cap. If the rotor is not at the No 1 wire contact, your distributor gear wasn't meshed properly and you need to remove the distributor and remesh the gear.
Once you're sure that it's meshed properly, you can get a timing light and tune the ignition timing. Digital timing-advance lights are a lot easier to use.
Here are the instructions for your car from the AutoZone guide I linked above. After reinstalling the distributor, make sure that the rotor is at the No 1 contact with the No 1 cylinder at TDC.
Before removing the distributor, position No. 1 cylinder at Top Dead Center (TDC) on the compression stroke and align the timing marks.
Disconnect the negative battery cable.
Remove the ignition wire cover, if equipped.
Detach the distributor harness connector.
Remove the distributor cap with all ignition wires still connected. Remove the coil wire, if necessary.
Matchmark the rotor to the distributor housing and the distributor housing to the engine.
Remove the hold-down nut.
Carefully remove the distributor from the engine.
Install a new distributor housing O-ring and lubricate with clean oil.
Position the engine so the No. 1 piston is at Top Dead Center (TDC) of its compression stroke and the mark on the vibration damper is aligned with 0 on the timing indicator.
Align the distributor housing and gear mating marks. Install the distributor in the engine so the slot or groove of the distributor's installation flange aligns with the distributor installation stud in the engine block. Be sure the distributor is fully seated. Inspect alignment of the distributor rotor making sure the rotor is aligned with the position of the No. 1 ignition wire in the distributor cap.
Install the hold-down nut.
Attach the distributor harness connectors.
Install the distributor cap.
Connect the negative battery cable.
Adjust the ignition timing and tighten the hold-down nut to 8 ft. lbs. (11 Nm).
I will do that today, and initially I thought this may have been the problem but from research it seems that the distributor cannot go in the wrong way + the rotor can only go in wrong 120 degrees at a time which would I think mean the car wouldn't run at all?
Originally Posted By: Spetz
I will do that today, and initially I thought this may have been the problem but from research it seems that the distributor cannot go in the wrong way + the rotor can only go in wrong 120 degrees at a time which would I think mean the car wouldn't run at all?
If this is your distributor then you have about a 10 tooth gear, meaning the distributor shaft can mesh any of about 10 ways. The orientation of the housing in the engine block is not the issue here.
I will do that today, and initially I thought this may have been the problem but from research it seems that the distributor cannot go in the wrong way + the rotor can only go in wrong 120 degrees at a time which would I think mean the car wouldn't run at all?
If this is your distributor then you have about a 10 tooth gear, meaning the distributor shaft can mesh any of about 10 ways. The orientation of the housing in the engine block is not the issue here.
Last edited:
If the slot is off-set then yes. If your mounting ears are slotted like in the pic, you will need to set ignition timing.
Quote:
Maintenance carried out:
That's the dead giveaway right there! A WRX always sounds like it's firing order off by having it's spark plug leads out of sequence! I'm surprised nobody else caught that! Check your leads and make sure they're in the correct firing order! Can you hear me shouting?
Maintenance carried out:
- Replaced distributor o-ring (was leaking)
- New distributor cap + rotor
- New spark plug leads
- Ultrasonically cleaned injectors
- Replaced valve stem seals
- Lifters cleaned out
That's the dead giveaway right there! A WRX always sounds like it's firing order off by having it's spark plug leads out of sequence! I'm surprised nobody else caught that! Check your leads and make sure they're in the correct firing order! Can you hear me shouting?
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