I was driving down 405 going to Fairlady today. Before i got onto the interchange going south towards Tacoma i pushed my car for a tiny bit. I saw the rpms, but not my boost. Right on 5,000 rpm my car began to sputter. Basically at that point i lost power and couldnt go any faster. My car began to run really rough, so i went to the side of the road. I took a look and saw that my engine was shaking. Took a look around for vac hoses and found one off. I quickly put that back on, but my car still ran rough, but not as rough as before. I couldnt see anything else, so i went back inside the car. The idle was a tad lower around 750, but steady. I would have thought if it was a vac leak the rpms might jump or the car would die. I'm really not sure what is up. My guess is that there is another vac leak somwhere else, probably a gasket or somthing.

 

vac leak or tps it sounds like to me.

 

Would the TPS mess up under boost though? I just got that thing replaced twice.

 

Compression check homie....

Worst case scenario, but check it. Ive run into similar issues with more than a couple engines where the engine will shake violently, cause is that lost compression on a rotor (usually a small chip off an apex seal). That causes an imballance in firing and will make the engine idle very low, wanting to die, shaking, etc...

Then again, if compression is good (check first) then it could be a host of other things. I would start with vac sources, then check your fuel system. Standard stuff...

But chances are something bad happend with the engine.

 

Mine car has some shaking at low rpm (idle) especially when cold. No smoking though and I am pretty sure it is fuel supply issues. I am now pre-mixing it and I have been making the stock fuel pump supply my holley setup the whole time. The pump now pushing through pre-mix, along with probably not running the proper volume or psi (runs, drives, and has worked pretty damn well for the 6 months I have been using the Holley setup). I could/should run a higher volume, regulated pump. Any recommendations of brand/model that would stay quiet for the ost part? I have been eyeing a Facet pump for a couple months, but do not know of anyone running one. Well, to get back onto thread topic...
Definately check compression (quick and easy), and get a vacuum guage on it to see what your vacuum is like and start searching for leaks. Check TPS (should be easy enough if you have already had to replace it a couple times). Also I would check your intercooler connections/welds. I really hope your engine is fine. Fingers crossed.
I know that on my van I have a faulty TPS that decides when it wants to work right. I get low idle, stumble, and runnability issues when it starts acting up because it is sticking open or closed and not accurately telling the ECU the throttle position (really sucks when it happens while I am driving and the car dies, have to pull over, start pounding on the pedal to get it to start working again!).
Well... Anyways... Good Luck! Keep us informed!

 

Does anyone have an available compression tester? Hrm. if someone could direct me to one i will look into purchasing it. Untill then i'll check for vac leaks.

 

How long is just a little bit? Remember you've got no air flow though your heat box aka "intercooler without an outlet."

Were there any wierd sounds?

 

Nope, no weird sounds, besides the car running rough. I didnt hear anything like a backfire. I just took it up to 5 grand and it started sputtering and then no more power.

Well you have to think about how cold it gets on the freeway. Doug said those fans simulate like 30 to 35mph. On the freeway im going twice that speed just about. I know there is really no great way for the air to travel out, but i checked the intercooler once i stop and it was cool.

 

the fans we had were pointed up through the intercooler and the hood was open. Was it at 12psi still?

 

I didnt get a chance to take a look at my PSI when it happened. Though yesterday the boost controller wasnt holding 12psi. It was overboosting to 14.

 

Check for leaks... take some brake clean (flammable kind) and spray her down. If the idle changes, take a look and see if there are holes near where you sprayed. Maybe an intercooler coupler or something?

 

You mean non flammable kind, but that was my original plan for tomorrow morning.

 

He means flammable kind, it will get sucked into the engine through any vac. leaks and will increase the revs because of more fuel. This way you can find the general location of a vac leak.

 

I see now, never would have thought of that. As always thanks Quin.

 

no i mean the flammable kind. Non flammable kind won't burn when it get sucked in through the leak. you need the flammable kind to burn. It will increase your idle when it does. Or decrease your idle... depending on how rich/lean you are.

 

Quin are you back in WA? Where you been?

 

Oh BTW wally, I set the TPS spot on for you before you left, so there shouldn't be any issues with it.

 

Ah sweet, thanks for letting me know. I just hope its nothing internal. I'll take a look of course under the uim. I know the lim gasket has been replaced, I've had no problems with that. I dont hear anything exhaust wise, so thats good.

I think i rem. having this problem before. The cause was a huge vac leak.

 

Just my .02, I would use starter fluid or carb cleaner. Both are flammable and are made to be ingested by the engine. I've used brake cleaner before, but after some thought, I figured I'd go with what I know won't hurt anything. Not that brake cleaner is bad, it may be just fine, but I'm a wuss. lol

Oh, and how much of your vac system is still intact? I can't remember from the last time seeing your car at the NWN meet. The carb cleaner/starter fluid should be able to narrow down any vac leak quickly in any case.

 

how does your boost guage look at idle?? , if the guage is bouncy, back and forth violently then its a sign of a compression issue, where as a vac leak will make your vacume consistantly low, or make the gauge kind of "numb", like u blip the throttle and it wont react very fast...

ive got a compression tester that ive used to test several engines and its pretty accurate but i live down in milton which is slightly south of federal way

 

I highly doubt your problem is a vacuum leak
You can pick up a compression tester from harbor freight for pretty cheap

what kind of mods to the car?

 

I hada similar prob with my previous n/a engine. Came around a corner and goosed it a little...and bam the sputtering began. It turned out that I had some seal that was stuck on the inside. I don't know if that helps. Is everything running fine now?

 

I'm in the Redmond area with a compression tester in my car right now.

Where You At?

 

that sounds like a boost mobile commercial.

 

Sounds like a stuck/chipped seal to me.

Sudden loss of power and rough running seems to indicate low compression all of a sudden. I know it's a worst case scenario but with no air flow to your I/C with that hood closed you're looking at some serious intake charge temps.

Get a sawzall and put a hole in that hood!!!!