classicauto

iTrader: (3)

Hey guys,

Had some big problems coming home last night

OK:

Im driving along at a good boot on the highway, running about 3,500rp in 5th. I start to feel VERY slight misses, I figured it was the 3800rpm hesitation showing its face so I keep driving. Continues to do it. I get off the highway, idiling fine, but makes a funny sound during idle,an almost baffled/fluttering noise, continue down the road but now if I put my foot in the pedal ANYWHERE past maybe 2% throttle the car bucks and jerks soooo bad its not even funny and with anymore then 2% throttle it won't rev past 3500 due to the bucking.

BUT

I can get it to rev up past 3500 if I use only a tad of throttle, but still has about 50hp at this point.

Still trying to limp home Im cruising in 2nd - 5,500rpm - all of a sudden a bunch of red molten junk flips either out from under the car or out the tailpipe - this has ZERO effect on the driveability. Still all the same problems.

Get home and the car will start and idle (the funny noise is still there) but all problems still exist.

Car ran flawlessly until now. Rebuild with 46,000kms. 86 N/A GX. Bone stock.

Im thinking its fuel related but the funny noise at idle has me guessing....Air control valve? Bypass air control?

I have no idea and this is my DD, the TII won't be done for a bit yet so I need some suggestions. Thanks guys.

P.S. Before all the respones saying that I have a blown engine, I have compression on all faces and it sounds even and strong. Don't have any ACTUAL numbers yet, but I DO have compression and it will start and run as is.

edit:
Coolant temps never moved - rock solid.
Oil pressure was always there.

My5ABaby

iTrader: (7)

Red molten junk... do you still have an exhaust?

J-Rat

iTrader: (2)

Red molten junk is probably your cats or mufflers peacing out, and the other symptoms you described sound like a loose secondary injector or a malfunctioning pressure sensor.

I think what you can do (per HAILERS) is unplug the pressure sensor and see if you can transition with more then a slight throttle input.

Goofy

Would the cats melting out be a symptom or a cause of the problem?

My line of thinking is:
Running lean = Hot exhaust = cats melt = symptom OR
Cats melt = low back pressure = no 5th/6th ports = cause.

My5ABaby

iTrader: (7)

Having the 5/6th ports not opening wouldn't cause his problems.

classicauto

iTrader: (3)

Ill try that tonite, thanks

I figured that the red molten stuff must've been cat, but then again you never know.



Ill try unplugging the pressor sensor and see what I get and update from there.

Edit: Just curious on the actual workings of this procedure. Meaning when I unplug the presor sensor, if the revs smooth out a bit - despite whateer else is wrong - what is actually happening? Is the ECU not seeing the pressure signal causing it to go into a certain mode or something?

Boostmaniac

You need to find out for sure what came out of the back of your car. Under normal circumstances, any form of molten metal spewing from my car would alarm me and I'd want to know what it was immediately. Why don't you check under the car when you pull the pressure sensor.

classicauto

iTrader: (3)

Yeah Im curious, but really not worried. If the car seized when the chunk came out - yeah I'd be freakin' - but it kept going along completely fine(as fine as it could be at the time) once it happened. I checked under the car this morning for something, but no huge tell tale sign of something disastrous.

classicauto

iTrader: (3)

OK:

Unplugging the presure sensor does nothing that I can see or hear...no change in revability (haha, is that a word?) and no change in the funny sound.

Im stumped, no visible leaks on the secondaries, but I can't see the primaries without doing some wrench turning. I think I'll get another set of injectors and try them.........

If the pressure sensor being unplugged makes zero change, does that mean the sensor is good or no?

CSM RX7

if the performance doesn't change when you unplug the pressure sensor, it simply means that the pressure sensor is not causing the problem. The computer should detect that it is not connected, and run based on the default fuel maps stored in the computer. If the problem had gone away when you had unplugged the sensor, it would mean that the sensor is sending some erratic signal to the computer.

Edit: This is the case with most sensors, actually.

spot_skater

Check resistances at your MAF sensor. When mine **** the bed i couldn't go over like 20% throttle, but it would rev as high as she wanted, but with only 20% throttle all the way up. As soon as i stomped on it, she'd stumbled and fall flat on her face.

How's your fuel filter and fuel pressure, too?

classicauto

iTrader: (3)

hey, great tip, Ill check out my MAFS....I havea spare here too so that would be fuzuckin sweet if thats the problem...

Haven't checked pressure at the rail - filter is recent.