90CamaroTBI

Ok guys I did some searching but need a little more. The motor is a 91 lb9 and runs rough mostly at idle and a little at lower rpms and really light throttle.

The car has new msd cap, wires, and plugs. Also a new o2 sensor and tps. I looked at the IAC and it looked pretty new but I cleaned what little was there off of it. I cleaned out the throttle body and passages until they shine. The car also has a new EGR valve on it because it was throwing a code, when I took the old one off the passages were pretty clogged but I cleaned what I could out and with the new valve the code is gone. The car also has new svo injectors.

I noticed that the car runs rougher when cold and idling at about 850rpm than it does at like 650rpm when warmer SOME of the time but it still does not run smooth no matter what temperature. Running out of ideas, can anybody else throw me some more? I just ordered a new cat and a catback because the clogged EGR ports made me suspicious. Even though half of my cat is gutted, I thought maybe it is still clogged and backing the stuff up. Some has built up since I changed the valve about 7 months ago.

Also is there a way to clean up the EGR system without pulling the whole intake off. Maybe something to run through the system? How would I get it in there?

Any help would be awesome guys I really appriciate it. BTW I run 7 degrees of timing on 93 octane.

flaming-ford

iTrader: (7)

i would suspect a vaccumm leak by the sounds of it. A good way to check would be to use a propane torch and just let the propane run, while the engine is running. If the idle picks up then you have your vaccumm leak.

couple other little ideas would be a possibility of a bad map sensor, check to make sure its getting its normal 0 to 5 volt sweep, without any big dead spots.

lastly could be a plugged return line causing you to run high pressure all the time. or a leaky fuel pressure regulator but, i highly doubt it by the sounds of it.

i'd check for vaccumm leaks and go from there if it were me.

90CamaroTBI

how would i go about testing the map sensor? Could the cts be bad?
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Also at idle sometimes it has a miss which is when it is running rough, I guess its all the same/

90CamaroTBI

anyone?

90CamaroTBI

Ok I have searched for hours now and the only two details I can add is that it SOMEtimes surges when cold in park and there is a weird inconsistant growling type noise under the plenum while idling sometimes. The IAC is spotless but is there any way to know if the motor just dont work right? Any help is great because this problem has gone on for a year now.

Pat Hall

iTrader: (31)

Actually, I think he was referring to the throttle position sensor, and mistakenly said the map sensor. You can check tps voltage by hooking up a digital voltmeter between the connector and the sensor, turning the ignition key on, and rotating the throttle. If the voltage increases steadily and smoothly, the tps is fine, if the voltage is erratic/jumpy, or there's dead spots, then it's bad.

kanmudhog

iTrader: (4)

How exactly did you half gut your cat ?

90CamaroTBI

there are two chambers in my converter and I changed the tps, it was in the original post.

Lucid

iTrader: (4)

Yeah how did you half gut your cat? lol

You need to run your car and get behind the muffler and put your hands over the tail pipes and see if the exhaust is coming out more on one side than the other.

Also when the car is cold bang on the cat and see if you can hear stuff banging around inside.

When my CAT failed, it clogged and the car wouldnt even run. Eventually you could get it to run but then it would run with no power at any RPM. The stuff made its way down the exhaust pipe and clogged the muffler too.

When the exhaust shop replaced the cat, they disconnected the muffler and ran the car and black soot shot right out of the pipe.

I have seen a Camaro run poorly and start shooting gunk back out of the EGR valve because the exhaust is plugged.

90CamaroTBI

Well that sounds like a good idea because I am putting a cat and catback on today.

90CamaroTBI

Exhaust fixed nothing lol.

kanmudhog

iTrader: (4)

Did you have the exact same problem before you replaced the egr ?
Did you instal the svo injectors at the same time as the egr ?
What size injectors were they ?

Lucid

iTrader: (4)

Sounds like you should start with the basics:

Check the TPS voltage and make sure its spot on at idle.

Ohm the injectors, they should be very close to each other.

Check the timing, and make sure you know how to set the static AND dynamic timing.

If you have access to a scanner, run the voltages on all the sensors. Look for trouble codes.

Pull the fuse and relearn the ECM to start fresh.

90CamaroTBI

I changed the egr then the injectors, had same problem before and after both.

I changed the tps sensor because the stock one was reading .74 and even the new ac delco one reads .85 and there is no adjustment on either of the sensors, so somebody told me on here it doesnt matter because the computer will take care of it. It has an even sweep.

Kawtipping

Has the car ever run right since you bought it? Did you do the engine swap or did you buy it that way? Have you checked your coolant temp sensor(s)? Checked fuel pressure both with and without a load? There are so many things it could be. Don't throw parts at it, that gets expensive. With all the money you have thrown at it so far you could have taken it to someone who knows what they are doing, and it could have been fixed.

02 camaro

Try some sea foam. I used it on my car. My car would start right up then die instantly. So i just ran some sea foam thrugh the gas tank a now my car runs great.

Lucid

iTrader: (4)

You try this?

That might not be a bad idea, probably good idea to run some seafoam in the gas and in the crankcase through a vacuum hose. That would eliminate a lot of deposits.

To be honest, it really sounds ignition related....

How did you do the timing? Not to sound condescending but i noticed a lot of people do not know how to time their car with a computer controlled setup and a timing light.

90CamaroTBI

I have ran seafoam through every system in the car. I do not think that it is ignition related because at full throttle it does not miss or anything. To check my timing I unplug the est connector and use the light to put it at 7 degrees advanced, turn it off and plug the connector back in.
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Everything i have changed was because of the tests that i did pointing to them being the problem, the injectors would ohm low, it needed a tune up, and the tps voltage showed up crazy but then crazier with a new one.

90CamaroTBI

I got rid of two vacuum leaks yesterday, a small one from the plenum and one from the brake booster vacuum line, I also cleaned out the gunked up breather from the valve cover. Still runs the same. Can somebody tell me if my 91-92 tps sensor is fine reading at .85 volts at idle. It is a new sensor and it is non adjustable so there is really nothing you can do to it. It still has the factory idle adjustment cap on it so the screw is not turned up.

I pulled the plugs on cylinder 1 and 3. Cylinder 1 looked normal, and the cylinder 3 spark plug was pretty white and lean looking. Any help from all of this?

pandin

Check the little torq screws on top of throttle of body that plate is open to engine vac. I had some screws loose just enough to cause idle unstable worse when hot. Also note some where corroded tight but not holding gasket sealed. Idle is real smooth after fix. Something to check. Good luck!

Lucid

iTrader: (4)

You might want to call your local Autozone and see if they have a diagnostic scanner there. We have been going to AZ for so long that the manager let us borrow his scanner (because we asked him about buying one), it was an Actron unit that shows you all the sensor data.

This might be the way to go to try to figure out if one of the sensors is going south but just within parameters and just not throwing a code. Such as a coolant temp sensor thats starting to go bad, or the ECM energizing the EGR solenoid at idle when its not supposed to.

Sometimes a fresh set of eyes can find a problem that we have been missing because we get snowblinded.

How is the voltage output on the alternator?

90CamaroTBI

I have underdrive pulleys on it so at idle it doesnt charge unless it is freshly started and still idling up. When under throttle the gauge shows it charging a little over half but at idle in closed loop I know it does not charge, but it idles rough either way.

Brandon2350

A failing CTS will cause all sorts of problems. I see that you mentioned cylinder #3 looked lean which leads me to believe it's not a cts.

Typically when you have a bad CTS the motor won't run because it's so rich ...or it will run terribly rich blowing black smoke ect.

Maybe i overlooked it, but have you checked your FP?

90CamaroTBI

fp is the next thing I am going to check, but sometimes it does blow black smoke at full throttle.