"overboosting or rev-limiter?"

[turbo-tease]

what I have is a 89'Dodge Daytona with a 2.5 turbo 1, the cat started rattling for the first time in 18 years! (original cat)so I removed the cat & put in a staight pipe. what I have noticed is that the power seems to have increased & boost psi is stronger & more of also! now to my problem if this indeed a problem(I'm sure it is) I left work the other day & kicked it in the butt & it took off like a bullet, 60 foot out it was like it was down shifting every 60 feet or so until I got out of it & let the bov do it's job. I was up to about 90 mph at that time when let out of it! this was all in about the course of an 1/8 mile. Anyone know what is going here? Im just confused here I just don't know what happened.

Please help!! thanks in advance! mike.

[dragbaron]

i hope you have a working boost gauge and tach in the car. if so, go out and try it again. see what the boost gauge and tach are reading. if you're hitting around 14lbs of boost, then i would say your hitting overboost cutout ( i think this would also make the check engine light to come on). it sounds like you have an auto trans, so unless you're shifting it yourself it wouldn't rev that high on its own if you left it in drive. is this car stock, except for removal of the cat?

[crazymadbastard]

I would say overboost, the mitsu turbo wants to boost higher whenever you have less exhaust restriction. Send $$ for a cal and a 3 bar map to fwd, problem fixed.

[puppet]

I would say check the fault codes ... if you hit overboost cutout, the "45" will be stored there.

[turbo-tease]

Quote:

Originally Posted by puppet I would say check the fault codes ... if you hit overboost cutout, the "45" will be stored there.

ok,I just checked the fault codes & it had a stored 45 fault code!
was there a cure for this problem for good? yes, sorry this does have an automatic transmission. is the map for the stock set up a 3-bar?
car is not stock it has mild upgrades like computer & motor build ups.

[MooseMotorsport]

Same thing happened in my Neon two weeks ago. I got on it and had to brake hard to go around a turn, car coughed and threw a MAP code. I haven't figured out how to fix it either. They don't make a 3 bar MAP for my car so I'm most likely going to put in a voltage clamp.

[puppet]

Stock MAP is (2)bar.

[dragbaron]

Quote:

Originally Posted by turbo-tease ok,I just checked the fault codes & it had a stored 45 fault code! was there a cure for this problem for good?

my only guess would be that you're running a manual boost controller, and was running it just before overboost cutout. then when you removed the cat, the increase flow caused it to spike or creep higher than where you had your controller set at. if this is correct, all you need to do is reset your controller back a couple of pounds.

[turbo-tease]

Quote:

Originally Posted by dragbaron my only guess would be that you're running a manual boost controller, and was running it just before overboost cutout. then when you removed the cat, the increase flow caused it to spike or creep higher than where you had your controller set at. if this is correct, all you need to do is reset your controller back a couple of pounds.

nope, don't have a boost controller,maybe someday! I just removed the cat because I couldn't take the rattle anymore.

[IROCNOROLL]

Quote:

Originally Posted by turbo-tease nope, don't have a boost controller,maybe someday! I just removed the cat because I couldn't take the rattle anymore.

Welcome to the sensation of excess boost. Great isn't it.

There is a vacuum line coming off a nipple on the side of your turbo outlet. It runs thru an orifice(looks like an inline hose connector) to a "T". From there one line goes to your waste gate can on the turbo and the other side goes up to the front of the car to the boost control solenoid.

If the orifice is plugged there is no boost signal for the waste gate can. The solenoid is usually open and the ecu tells it when to cycle closed to build pressure to the w/g can, thus controlling boost. If one of these lines are cracked or broken there will be no signal to the w/g can. Quick test is to run a separate vacuum line to the w/g can directly from the intake manifold. This should limit boost to about 6 - 7 psi. This verifies that the w/g can is functional. If this works then find the blockage before the "t" or the damaged / broken line in the system and repair it. Happy hunting.

Might be a great time to try a manual boost controller or build your own "g" valve, once you have found and repaired the actual problem.

[turbo-tease]

ok thanks! but now I think I might even have a bigger problem,saturday I took the car out for a drive but just a normal cruise drive acrossed town. On my way back home the started running real rough,real shaky like kinda like a bad misfire. This was at a cruising speed of 40-50 mph when I pushed the throttle to go up the hill when running like this it started knocking!Whatever this is it will not clear out! I noticed before on the vac. side of my factory gauge it had 20 on it,now it has only 15 on it now since this problem started! WHATTHE HECK HAPPENED HERE? sorry for that this is just so avoying!
please help, please I need this to get back & forth to work this is my daily driver! :

if anyone can help me that would great! a.s.a.p. please. thanks again, mike.

[turbo-tease]

help please!, does anyone know why this is doing this?? HELP!!

[IROCNOROLL]

Quote:

Originally Posted by turbo-tease help please!, does anyone know why this is doing this?? HELP!!

Codes?

External conditions...Timing belt jumped(best guess with the symptom)...huge vacuum leak...fuel pump dying/filter plugged/pressure regulator off cal...hep or ignition timing moved...dead plug/wire/ injector...Map out of calibration(may not set a code).

Internal...cam/rocker/valve/valve spring/piston/piston ring/worn stub shaft drive to the distributor etc.

In other words we need more info to work with after you check the codes and possible external causes.

[crazymadbastard]

Do a compression test. I fear your overboosting killed a piston.

Also check your vacuum lines just in case one popped off.

[turbo-tease]

Quote:

Originally Posted by crazymadbastard Do a compression test. I fear your overboosting killed a piston. Also check your vacuum lines just in case one popped off.

I will be doing a compression test this weekend, I hope I didn't kill a piston!
I checked over my complete vacuum system & I found no problems with them.What I did mange to do was to pull off spark plug wires one at a time,4,3,2&1 when I got to #1 it made no difference in the way it was running,I have spark I tired another plug to check if the plug was bad but still no difference.It is not using any coolant & no oil leaking except for is leaking past the valve seals.I can smell gas in the cylinder.I haven't checked the fuel injector yet! I will do that this weekend also! It is running real rough now & am no longer driving it because i don't want to hurt anything else,it is running like dog crap!I revved it up a little bit after changing the plug & I thought I heard a pop or a knock threw the intake!? but I am not real sure on that! this thing is just driving me nuts!!