S13 Sr20det

[jarred3636]

I recently bought a 95 silvia with an s13 sr20det. The car ran perfectly fine for a few days but then all of a sudden the car was really weak and lacked power. It had no pull to it at all. The first thing I did was unplug each coil pack one by one. After unplugging each coil, every coil would cause the engine to bog except for the first one. I figured it was a bad coil. I replaced it and yet it still wouldn't bog when unplugging. During the process, I changed the spark plugs to ngk bkr6eix but nothing was different. I then unplugged the injectors one by one and each one would cause the engine to bog except for the very first one as well. Now i'm stumped. Does anyone have any ideas as to what it could be??

Edit: The engine is all stock.

[rc1honda]

Lacked power is kinda vague term. Maybe be a little more specific.

Like does it bog? If so at what RPM? Does it smoke at all? Is turbo generating boost?

Does it lose power under load, or all across the rev range even with light driving?

Are you holding vac? What boost level are you running and does it hold it?

I am not really familiar with you diagnosis method so far. I would check each coil with a multi-meter, then pull the fuel rail intact and watch the injectors fire instead of pulling them one by one. Also, check your MAF voltage and search for vac leaks.

If you have spark and fuel then do a compression test. Fast, easy and you can rent the tool from autozone or any large auto parts store.

Pull the turbo intake and check for shaft play on the turbo.

There's really so many things that can cause your symptoms that you have to narrow it down a little for us to help.

[jarred3636]

Lacked power is kinda vague term. Maybe be a little more specific.

Like does it bog? If so at what RPM? Does it smoke at all? Is turbo generating boost?

Does it lose power under load, or all across the rev range even with light driving?

Are you holding vac? What boost level are you running and does it hold it?

I am not really familiar with you diagnosis method so far. I would check each coil with a multi-meter, then pull the fuel rail intact and watch the injectors fire instead of pulling them one by one. Also, check your MAF voltage and search for vac leaks.

If you have spark and fuel then do a compression test. Fast, easy and you can rent the tool from autozone or any large auto parts store.

Pull the turbo intake and check for shaft play on the turbo.

There's really so many things that can cause your symptoms that you have to narrow it down a little for us to help.

Sorry about that. I was still working on the car and wanted to get a quick thread in. The bogging is at low RPMs and it did have white smoke but that has stopped all of a sudden. The turbo is working well and there is no leak or anything. The boost levels are all stock. I will definitely pull the fuel rail and watch them fire tomorrow!

The method was my friends method lol he's a certified mechanic so I trusted him. While the engine was on, he unplugged the coil and the engine would bog a bit up until we plugged it back in. It did this to all of them except the first one so we figured it was bad. I replaced it with a new one but it would still not bog when unplugged. He said it could be the actual wire harness but he doesn't think that'd make sense. So now I'm here asking for all options before spending more money lol.

I'll pull the fuel rail tomorrow to see if the injectors are firing.

Thanks a lot for the input!!

[Dboyizmlg]

Sounds like a mis fire on the cylinder.

If you replaced the coil pack, spark plug, and injector, and if the problem still exist.
Then you might have a bad head gasket.
Do a compression test on it. Make sure each cylinder is with in 10psi of each other.
Ex: cylinder#1: 155
#2: 150
#3: 155
#4: 155

If it looks some thing like that, then you are good.
Of not, the. You might have to take apart the head to take a close look.

[jarred3636]

Sounds like a mis fire on the cylinder.

If you replaced the coil pack, spark plug, and injector, and if the problem still exist.
Then you might have a bad head gasket.
Do a compression test on it. Make sure each cylinder is with in 10psi of each other.
Ex: cylinder#1: 155
#2: 150
#3: 155
#4: 155

If it looks some thing like that, then you are good.
Of not, the. You might have to take apart the head to take a close look.

How do I do a compression test on the cylinder? Thanks for the help.

Edit: Sorry, I did a quick youtube search and found a video. Guess I should have done that first lol.

[Dboyizmlg]

Lets just hope you have good compression!

[jarred3636]

Lets just hope you have good compression!

Is it that bad?! :eek3: my friends said the same thing lol I canceled my order of coils to put towards this damn problem.

[Mikester]

You mentioned that the first injector had no effect as well... Switch the #1 injector with another & see if the problem follows. If it follows, you'll know you have a bad injector.

Also check the coilpack sub-harness... Ensure it is grounded properly to boot. Being where they are coilpack sub-harnesses break down over time due to heat. A new subharness is about $50.

However, if switching the #1 injector's position doesn't change the problem & all the wiring/grounds are good, a compression check would be a good step before throwing parts at it.

Hopefully the head gasket is stock.

[jarred3636]

You mentioned that the first injector had no effect as well... Switch the #1 injector with another & see if the problem follows. If it follows, you'll know you have a bad injector.

Also check the coilpack sub-harness... Ensure it is grounded properly to boot. Being where they are coilpack sub-harnesses break down over time due to heat. A new subharness is about $50.

However, if switching the #1 injector's position doesn't change the problem & all the wiring/grounds are good, a compression check would be a good step before throwing parts at it.

Hopefully the head gasket is stock.

rc1honda mentioned taking the fuel line out and see if the injectors are firing, do you think it'd be easier or recommended to do that or just switch the potentially bad injector with another one?

[Mikester]

^^Just switch the #1 to a new spot. Removing the fuel feed line with injectors firing may not be good if you're not doing it in a controlled environment (like on a test bench)... The only thing I would ever recommend disconnecting the fuel line for is to verify fuel flow to the rail or fix a leak. Even then, you'd only need to turn the key on to see flow; and not crank it to where the injectors try to fire.

Injectors aren't made to dry-fire. Good way to create more problems.

[jarred3636]

^^Just switch the #1 to a new spot. Removing the fuel feed line with injectors firing may not be good if you're not doing it in a controlled environment (like on a test bench)... The only thing I would ever recommend disconnecting the fuel line for is to verify fuel flow to the rail or fix a leak. Even then, you'd only need to turn the key on to see flow; and not crank it to where the injectors try to fire.

Injectors aren't made to dry-fire. Good way to create more problems.

:faint: well it's a good thing I asked! lol I'll give that a try when I'm off work. Thanks a lot!

[Mikester]

^^Actually, what he suggested was pulling the rail out intact and watching the injectors spray- which seems to be extremely messy, but would definitely tell you if there is an injector not working. Again, there are test stations for this sort of thing.

Swap #1 with #2 and see if the problem follows... If it does- boom. If it doesn't- look elsewhere.

[jarred3636]

^^Actually, what he suggested was pulling the rail out intact and watching the injectors spray- which seems to be extremely messy, but would definitely tell you if there is an injector not working. Again, there are test stations for this sort of thing.

Swap #1 with #2 and see if the problem follows... If it does- boom. If it doesn't- look elsewhere.

Okay then sounds good! I'll check the ground as well cause I read that on another thread here. I don't know if this is related, I doubt it is but I'll ask anyway, my cluster is also bad. It's weird though cause it's just the rpm and mph gauges. Everything else works. Would this be an electrical problem or just a cluster problem?

[jarred3636]

So I did a compression test and it went 151 150 150 and 151. I'm guessing it's the injector. I haven't been able to swap them because I almost broke one while trying to take it out and I can't find a thread that states how to correctly take one out

[Dboyizmlg]

I got some thing for you

[Dboyizmlg]

SR20 Setup Tips (http://plmsdevelopments.com/sr_setup_tips.shtml#12.wb_afr)

Be patient with the injector as you start to pull it up slowly.

[jarred3636]

SR20 Setup Tips (http://plmsdevelopments.com/sr_setup_tips.shtml#12.wb_afr)

Be patient with the injector as you start to pull it up slowly.

That's extremely helpful! Thanks a lot!

[Dboyizmlg]

You're welcome

[steve shadows]

Check your timing!!! Always check timing. Especially with some of these CAS 20-25 years old.