Bad vibration and CEL. can't find answer

[femmeDSM]

Content Removed-Forum crash disrupted posts time stamps causing this reply to appear as the first post L2RTSiAWD

 

[VaB90gsx]

Hey guys. I just put in a jdm 6 bolt with poly motor mount inserts, and had my transmission completely rebuilt w/ new clutch/fw/pp, as well as a new slave cylinder. I was giving a buddy of mine a show off ride but was shifting very slow since I only have about 350 miles on the new clutch set up. When I went into third i began to accelerate and all of the sudden the car starts vibrating really bad. I turn in somewhere and let everything cool down. I start it up and it seems to idle fine and it ran fine on the way home. Didn't rev it over 2k. Well I let it sit for a couple weeks (not my daily). The other day I started it to try to see if I could troubleshoot the problem. Now it vibrates very badly at idle. I drove it around my court at very low rpm's in first and second gear and it vibrates just as much as at idle. The only time the vibration stops is while I'm in gear but decelerating (foot completely off throttle) for turning. I can't quite pinpoint where the majority of the vibration is coming from. I'm scared to keep it running longer than I need to, so if you have hot spots I could check fairly quick that would be appreciated.

Basically my question is what are things I could possibly check. All my belts are tight and they all seem to be in perfect condition. They were all replaced with the swap. All the motor mounts are intact and are holding up very strong. I doubt its the balance shafts since this is a pretty fresh motor. Is it possible that the cam angle sensor is off alignment? What else do you guys suggest I look for.

I'm also getting a check engine light but i don't want to spend 100 bucks in a tow back and forth to auto zone to pull the code. I dont know anyone around the area with a logger for me to pull it that way either. I'll tow it somewhere after I've checked everything else and decided I can't figure it out. Please just post up suggestions on things to check. Hopefully you guys can save me a few bucks! Thanks in advance.

 

[femmeDSM]

Vibration is sometimes hard to diagnose.
I'll start by asking you to clarify a few things, so we'll know where to start.

"Vibration" can mean different things to different people. Does the whole car physically SHAKE while this is going on? How is the idle? Are you hearing interior pieces vibrating? Does the vibration get better or worse at higher rpms? Have you gotten it into boost? If so, anything abnormal? (Do you have an aftermarket boost gauge?)

A few things I would check right off would include the spark plugs and plug wires, boost leak test, fuel filter, timing, visual inspection of all vacuum hoses and intercooler pipes, etc, and check for exhaust leaks (i.e. cracked exhaust manifold). Most of these can be done without starting the car.

Without knowing what that CEL is indicating, it will be hard to give an accurate diagnosis. The CEL could be from the TPS sensor, CAS (hence checking the timing), or a couple other possibilities that are escaping me at the moment.

You don't need a logger to check codes. All you need is a cheap-o analog voltmeter. You can hook the leads up to the diagnostic port and read the needle sweeps. A search should turn up the proper way to do this, but I can try to steer you in the right direction if you need help (assuming I remember how to do this, ).

 

[VaB90gsx]

Vibration is sometimes hard to diagnose.
I'll start by asking you to clarify a few things, so we'll know where to start.

"Vibration" can mean different things to different people. Does the whole car physically SHAKE while this is going on? How is the idle? Are you hearing interior pieces vibrating? Does the vibration get better or worse at higher rpms? Have you gotten it into boost? If so, anything abnormal? (Do you have an aftermarket boost gauge?)

A few things I would check right off would include the spark plugs and plug wires, boost leak test, fuel filter, timing, visual inspection of all vacuum hoses and intercooler pipes, etc, and check for exhaust leaks (i.e. cracked exhaust manifold). Most of these can be done without starting the car.

Without knowing what that CEL is indicating, it will be hard to give an accurate diagnosis. The CEL could be from the TPS sensor, CAS (hence checking the timing), or a couple other possibilities that are escaping me at the moment.

You don't need a logger to check codes. All you need is a cheap-o analog voltmeter. You can hook the leads up to the diagnostic port and read the needle sweeps. A search should turn up the proper way to do this, but I can try to steer you in the right direction if you need help (assuming I remember how to do this, ).

By vibration, the entire car shakes and rumbles. It's fairly constant, meaning not jerky vibrating. The idle is very stable, sitting around 650 rpms. I haven't revved it over 2.2k rpms in fear of jacking this new motor up. I do have an aftermarket boost gauge, but I really dont want to even try to get into boost right now. I've changed the plugs / wires, and recently rewired nearly everything inside the engine bay. I've eliminated nearly all the vacuum hoses, but the ones still in the car all still appear fresh. There is a new (2.5k miles) header and the ic pipes are all very tight. I'll check the fuel filter in the morning but if you dont mind me asking, what vibration problem would this effect? I don't have easy access to a timing light but I'll try to get that done tomorrow as well. I'll also have to get all the tools necessary for a boost leak test but I'm pretty confident that this isn't the problem. I just read the vfaq for the voltmeter diagnostic set up and I'll definately be doing that tomorrow.

Thanks for the quick reply. I'm going to the junkyard in the morning. Do you recommend picking up anything in case it is any of these parts? Like a CAS or TPS? Any other items it could possibly be that I should try to pick up "just in case"? Thanks again.

 

[femmeDSM]

By vibration, the entire car shakes and rumbles. It's fairly constant, meaning not jerky vibrating. The idle is very stable, sitting around 650 rpms. I haven't revved it over 2.2k rpms in fear of jacking this new motor up. I do have an aftermarket boost gauge, but I really dont want to even try to get into boost right now. I've changed the plugs / wires, and recently rewired nearly everything inside the engine bay. I've eliminated nearly all the vacuum hoses, but the ones still in the car all still appear fresh. There is a new (2.5k miles) header and the ic pipes are all very tight. I'll check the fuel filter in the morning but if you dont mind me asking, what vibration problem would this effect? I don't have easy access to a timing light but I'll try to get that done tomorrow as well. I'll also have to get all the tools necessary for a boost leak test but I'm pretty confident that this isn't the problem. I just read the vfaq for the voltmeter diagnostic set up and I'll definately be doing that tomorrow.

Thanks for the quick reply. I'm going to the junkyard in the morning. Do you recommend picking up anything in case it is any of these parts? Like a CAS or TPS? Any other items it could possibly be that I should try to pick up "just in case"? Thanks again.

Honestly, I would hate to tell you what parts to pick up at a junkyard until you get those codes read from your ECU.

The things I was mentioning earlier were just the basics to verify that your car is 'healthy' (timing is the most important, and the most likely to be what is throwing that CEL; when the CAS starts going, the timing goes nuts).

I asked about the fuel filter because it is an often-overlooked "simple" solution to seemingly complex problems. I've seen old fuel filters cause everything from rough idle, to shaking, to stalling, to no-starts. When it goes bad, it pretty much gets a mind of its own.

After hearing a more thorough description of your problem, I *doubt* it is your fuel filter. But if you were going to check/replace it anyway, go ahead and take a look.

How is the vacuum reading on your car at idle? Should be betw 17-22 inHg. IIRC. If it's low, that could be a clue to check a few more things (cam timing, vac leaks, etc).

I'm sure you knew what you were doing when you disconnected the vac lines - but double (triple) check to make sure all fittings are tight, and no necessary hoses have been disconnected by mistake.

 

[TimG]

Pull the code. It will give you your answer. A $50 logger and a cheap palm is effective this way. Beats a $100 tow AND you can use the thing to log runs and such.

If it's only bucking under throttle (acceleration), it's a fuel/spark problem. At decelleration, your car uses zero gas. Something is broken and I'm betting the CEL will tell you what is.

 

[VaB90gsx]

Thanks for the responses. I couldn't get anything done today because of weather. Femme, i have good vacuum at idle (-20) and i'll probably replace the fuel filter regardless, seeing how it hasn't been done in a couple years. Timg, great response. I was unaware that all fuel is cut during deceleration. My only retort to this is it all happened suddenly. If something in the fuel set up has messed up wouldn't it be a problem that would gradually get worse? Unless of course the wiring was messed up. I do agree with you about buying the logging material. Sorry for asking this but I'm all searched out over the last couple days, but could someone please post up some quick / inexpensive places to order the parts necesary for a logger? I also forgot that I have an extra CAS and when the weather improves I'll try swapping those back again. Hopefully these fix the problems as my buddies and I have been planning a trip to the track on the 25th. Again much appreciated guys.

P.S. I've never known what IIRC means if someone would like to inform me that'd be great..

Edit - Is there any loggers that I could just use with my laptop so I could avoid buying a palm pilot? If so I would definately be more interested in those set-ups.

 

[femmeDSM]

If something in the fuel set up has messed up wouldn't it be a problem that would gradually get worse?

You'd think so, but that's not always the case. I've seen weird problems spring up literally overnight, with no warning. The fuel system especially is just weird like that sometimes.....

Sorry for asking this but I'm all searched out over the last couple days, but could someone please post up some quick / inexpensive places to order the parts necesary for a logger?

You can buy cheap logger cables on Ebay. And yes, you can log with a laptop (a tad more touchy to set up and get working right, but it does work). Technomotive is the software you would be using, and it is free (OpenSource). Something to keep in mind, since you have a '90...SOME (not all) 1990 cars have problems using the "regular" logger cables, and need to use the powered cable instead (www.pocketlogger.com sells these, but they are a bit pricey). I hope yours isn't one of them...Mine isn't, but I know a few others who have had problems. So just a heads-up.

P.S. I've never known what IIRC means if someone would like to inform me that'd be great..

.
IIRC = "If I Remember Correctly"

 

[VaB90gsx]

. Thanks for all the responses and help guys. It surely was a fuel problem and I feel like a jackass. The number 2 piston injector's wiring connector was loose. I clicked it in about 1/4 inch and now it runs like a champ. I did find out that the piece that holds the connector on somehow snapped. Appreciate all the information regardless guys, and have a great day.

 

[femmeDSM]

Glad to hear you're back up and running.

As far as feeling like a jackass....Don't...As long as I've been working on cars, I've made some pretty "jackass" moves in my time. Case in point: Just the other day, I was fiddling around with my shifter linkage. Hooked everything back up and went to start the car.....Nothing. Fired up, "puffed' a little, and died immediately. After literally 30 minutes of troubleshooting, and several bouts of cursing and throwing things, my boyfriend (who knows about as much about cars as I know about rocket science) came down and said "hey what's this plug?".....I had forgotten to plug my MAS back in.

So don't beat yourself up too bad. Haha.

 

[Old Mitsu Tech]

I don't believe I would have told that, Claire

 

[femmeDSM]

I don't believe I would have told that, Claire

Haha, my guilty conscience was weighing on me. I had to tell SOMEONE before I exploded.
Lol.

That was a sad, sad day, so say the least.