[Chris Faulk]

The problem is a hesitation that seems temp. related. When I first start the car and give it a good run all is smooth (or so it seems). The more it runs the less throttle it takes to get this issue. At first I thought for sure the plug wires were bad because of the way it felt...as though something was holding it back and there are moments during acceleration where it clears out and really hauls along...then back to holding back....and clearing....and back and forth.

One thing I just remembered when I had the car hooked up to the scanner...the baro solenoid never changed from full vacuum even during boost. Think that has something to do with it...the car has no codes. Hmm...

Today I decided to un-screw my boost controller all the way out to minimum boost levels. The problem has seemingly gone away and the car accelerates at a smooth clip (I can still noticeably hear the swingvalve flapper fluttering away but not nearly as loud as before). So I'm thinking turbo related or exhaust....whether it be wastegate actuator, or turbo, or exhaust it's something there.

Ideas?

 

[klee]

Charge temp sensor going bad?

 

[Chris Faulk]

Don't think so...even when I had a known DEAD charge temp. sensor the car ran just fine still.

 

[mopar2ya]

The baro read sensor only reads once when the key is on to sample the barometric pressure. If the charge temp sensor dies the car will default to the coolant temp sensor and it will be low on power, so cold it will run fine, but as the car heats up the computer thinks the 180-200 degrees is the charge temp. If you have a scanner you can see if the computer sees the charge temp sensor. Im sure it looks at boost, charge temp coolant temp, etc and if one of them is out of range who knows what the computer will do.

 

[Chris Faulk]

The baro read sensor only reads once when the key is on to sample the barometric pressure. If the charge temp sensor dies the car will default to the coolant temp sensor and it will be low on power, so cold it will run fine, but as the car heats up the computer thinks the 180-200 degrees is the charge temp.

That would explain why the car is running so rich at WOT.

Good call there Wallace. I went to my bro's shop tonight and removed the muffler in preparation for the upgrades and plugged in the MT-2500 to check it all out. All sensors function as I would expect EXCEPT the charge temp. sensor which went to 3.9v when I started the car and it stayed there...never moved. With the car OFF this sensor was steady at 3.75v or so. I also looked at the charge temp. and it never really moved off of 180-degrees. That sure seems out of range in my opinion. I think a new charge temp. sensor is in order.

We went through the procedure to check the system and with a shorted sensor plug the scanner was 0v and open it was 5v so that all checked out.

Charge temp sensor going bad?

So to answer your question Kenneth...yes it sure seems so. Check on a price and I'll call you tomorrow.

 

[nemiro]

Highly doubt it's the charge air. Your problem seems much more like a broken up catalyst.

 

[Chris Faulk]

Highly doubt it's the charge air. Your problem seems much more like a broken up catalyst.

That's also coming off this coming weekend.

That would cause the charge air to read 4v all the time?

 

[nemiro]

Actually, I think there's a problem with the scan tools on 91-3 T3's in reading the charge air sensor properly. It does not have enough fuel control authority to cause the problems you are having, anyway.

 

[klee]

Fixed yet?

 

[Chris Faulk]

Fixed yet?

Well the scanner now reads properly with the new charge sensor, but there's still the hesitation.

Only things left to check are the MAP, 02, fuel pump, and cat. The new pump and cat. will likely go in this weekend sometime.

Thanks again for the super fast help Kenneth!

 

[klee]

No problem :thumb: