Being dumb. Got to 80 on empty road, red light came up and I hit the brakes hard, not enough to lock up the tires but obviously enough to damage something, I noticed when I got to the light that my engine had actually stopped Now it won't idle at all, it will start but it's really shakey and chuggy, I was thinking that I had seriously screwed something up, but in an attempt to get it home, I kept the rpms above 3k and everything was smooth, only problem was when it dropped below that. No smoke, no overheating, just a very very crappy low end. Is there anything that is prone to comming undone during hard deceleration? It seems almost as if it's a bad ground or something. I'll look tomorrow, but I have to be at work at 8am so if anyone could quickly point me in the right direction to look, I'd greatly appreciate it.


Jerry

 

COuld be lots of things.... check your brake power booster line from the UIM? And all other air leaks... that'd be my bet!

 

Ok, I'll definitely check that first thing in the morning, it's acting like it has a MAJOR vacuum leak, I didn't notice anything right off so I looked down to check the plug wires, just to make sure ya know, and was embarrassed to discover half of a flourecent light bulb down there... Apparently my step dad broke the light we were using when we were bleeding my clutch, and he didn't grab it. It's been sitting there for a week...

 

Brake power booster hoses are all gravy, anything else I might check? (3 hours late for work and counting) I know I should search, but there are sooooo many results for "Poor idle" "rough idle" "bad idle". So many diferent situations, anybody ever experience one like I'm having? I also check other air lines, as far as I can tell there aren't any vacuum leaks, are there ground points that I should check that would be affected by the circumstances listed above?

 

Compression test?

 

no, its definitley not compression in this case. its a vaccuum leak some where old hoses are easily torn with alot of pressure going through it

 

I'm looking everywhere, I found 1 hose thats disconnected. It comes off the bottom of the charcoal canister to a T fitting, and thats where it stops... it looks as though it's been disconnected for some time though. What would hard braking put that much pressure on? So I know where to look.

 

Check that everything is still connected and plugged in. One time my TPS plug came undone when I hit a bump, so weird things can happen.

In this case, my bet is on a major vac leak, though, since that is exactly how it will act when you have a large vac leak.

 

Yea man, search again. I big "shift" in velocity could well have caused something to come un-done that you cant see, or isnt un-done enough to where you can tell. TPS being a great example from Sideways7, but another one also being if your inercooler isnt bolted down it could have shifted forward and disconnected a vac iine (random example)

 

D'oh, I forgot to specify my car, '89 gtu. Ok, so I'm out $1.69. I just coated the engine compartment in a thick layer of carb cleaner... not a single rev... So now I'm looking at electrical. Symptoms again are, Sputtering idle, shakey (Sounds like it's missing out), hesitation. These symptoms are only between 0 and 3000 rpm though, once it gets above 3 grand, it runs smooth.

 

What do you mean?

It sounds like an air leak. If it were electrical, i doubt it would run fine at higher RPM's. My car was having a severe sputtering problem at idle, as well as ANY RPM.. it was electrical (the leading coil had a bad ground or something).

But that might be a good place to start.....
Try and narrow your field. Grab a FSM and DMM and check your coils, TPS, and ECU voltages and grounds... if it all checks out, you've ruled out electrical as your problem

 

I agree with fusion-t, it sounds like unmetered air is entering the system. Check for uplugged AFM and loose clamps on the intake pipe. Basically, go over the entire intake path including the above, the hose to the BAC and the hose to the AWS solenoid.

 

Just because you spray carb cleaner everywhere and nothing happens doesn't mean you don't have a vac leak. I did the same thing to no avail, but when I pulled my UIM I found cracked hoses on the vac spider. There are several hoses that you just can't get to well with carb cleaner. In fact at the moment I have a large vac leak that carb cleaner doesn't effect. I am almost certain it is from some gouges in my LIM and the carb cleaner just doesn't get to it.

 

Ok, so the problem may not have occured BECAUSE of the hard stop. I accelerated pretty hard too (never got about 7500 though) I was looking at it a moment ago, I gave it some gas and brought it to about 5 or 6 k, when I let it back down to idle a noticed a small amount of smoke coming from between the engine and the firewall. I sprayed some carb cleaner back there, you know, because where there is smoke it's always a good idea to spray a flammable substance, and the engine gave a small increase in speed. My question is, if I take off the dynamic chamber, is there a gasket that MUST be replaced underneath it? As of right now I can't see **** back there.

 

try to get a 2nd person to hold the rpm high for u

while u listen around for leaks...

if u have an exhaust try to silence it with an insert...


if that doesn't work.. you can pressurize the system and listen for leaks with the motor off

 

I would rip off your UIM/TB/IC. That way you can see all of the hoses and maybe even replace all you vacuum hoses if you feel so inclined. Then look up the vac hoses in the FSM.

-Ben

 

Yes, the UIM/dynamic chamber gasket. You can order it at any autoparts store for 20 bucks or so.

I agree with apexFD, it would be a great idea to do so even for the sole purpose of replacing all of your cracked and brittle VAC lines under there. Plus if you're smoking from the area, that will give you a great view of parts of the motor that need your attention.

 

So I've gone over every single air hose I could get my hands on, physically felt everything I could for any sort of crack or what have you, even gave most of the hoses a little tug to make sure they were on securely. I'm at a loss here. There are 103847230958731507 little hoses in the damn thing. Would just 1 of those being loose cause me lose my idle? I've checked larger air hoses of course, and everything there looks to be up to snuff. I took the tb/dynamic chamber off last night, i think everything was all there...

Just checked my tps, it was reading 340 ohms closed and 4800 WOT, I adjusted it to spec, it seems a little smoother and more responsive, but it still shakes HARD below 1500 rpm, I can hold it at 750 and it shakes hard and the exhaust sounds like my suburban. Any hoses that I may have overlooked, I'm really stuck here.

 

Sounds EXACTLY like what my car was doing when i had a faulty primary ignitor. Except my car would not smooth out at higher RPMS it did it all the time. THe motor shook so bad it was rocking the car, and had about a 2 second delay from when i'd hit the accelerator to when the motor would slllooooowwwlllyyyy start to climb the RPM's..

check your primary ignitor?

 

This is irritating, what the sweet caress is wrong? So far i've check all of my vac lines, replace most of them (Others didn't look too bad) check my plugs, plug wires, and coils, check my timing, looked for anything that may be unplugged and have found a but load of connectors that aren't hooked up, but they look like they've been that way forever, and this car was running terrific a week ago.

It WILL run, but as I said, very shaky at low rpm, under heavy throttle it is really shaking climbing the rpms, but once it gets up to 1.5 or 2k it smooths out a little, but still sputters every now and then. I'm going to try to get a video so you can see what it does more accurately

 

This is the car running like crap
http://www.youtube.com/watch?v=ESzznH2YZXw
Here's how I ran my vacuum lines. I have no idea if this is right, but it looked good at the time. Let me know if these are wrong please.
http://www.youtube.com/watch?v=dfXb4v1x2v8


If there are any other videos / pictures I might be able to post, let me know and I'll hop on it right away. Thanks guys for all your help.

 

btw, Just took a listen. Front rotor, "pfft..pfft..pfft..pfft..pfft..pfft" Rear rotor "pfft..pfft..pfft..pfft..pfft..pfft" Is the "pfft" supposed to be near deafening? lol I'm going to jump to conclusions here and say that I did not blow a seal. Any other clues?

 

hooray for constantly updating. So I took everything back off because I have nothing better to do, and I found the most beautiful tear through the gasket that sits between the uim and lim. I mean torn in half btw, right over the rear most hole. Terrific... Ordered a new one from mazdatrix it will be here tomorrow or tuesday. That sound like it could do it?