Problem with Closed loop

[TrueBlue95GT]

What exactly happens when you change from open loop to closed loop? I've changed almost all of the sensors, put the manifold on three times, and still can't find why my car runs like chit when it transfers into closed loop. I've changed the MAF, TPS, ECT, IAT, Computer, both O2 sensors. I've redone the manifold three times because I thought the problem was that the manifold was leaking through the gaskets. I can't find out what is wrong. It loses power when I give it any gas sometimes when it's in closed loop. If I turn the car off and back on, the problem ceases until the car goes back into close loop. The timing is at 10* and I have a tweecer so the temps are all set down. I'm outta ideas.

 

[final5-0]

In a nutshell

In CL a 14.7 af ratio is maintained by the various sensors like O2's, ACT, EGT and the like.

In OL the O2's are no longer in use and af ratio is determined by fuel tables.

I used fuel for an example but I guess I'm trying to show that the sensors don't come into play as much as the values in the various tables and the amount of load or rpm determine which of those values are used for a given moment.

A few thoughts about your problem.

You could put your stock fpr back on to see if your afpr is at fault. Now that you have the Tweecer the afpr is not needed anyway.

I have seen others say that in rare cases a cal file can become corrupt.

Do you have the maf transfer correct?

Do you see anything that looks fishy in the dl's.

Does the car run bad with the Tweecer removed?

Later
Grady

 

[mo_dingo]

Also, when you go to closed loop, your EGR is on. Once you go to WOT, it shuts off the a/c, smog pump (if running) & EGR.

What happens when you go to WOT when the car is warm?

Your EGR could be to blame. But I wouldn't just arbitrarily replace it.
Scott

 

[TrueBlue95GT]

Once I go into closed loop, even when I WOT it, it stumbles. Like I said, this problem is only sometimes.

 

[TrueBlue95GT]

Maybe it is my AFPR. The fuel pressure takes like 3 seconds to go down when I put the vacuum line back on the regulator. Is this a sure sign? The car runs the same with the Tweecer off. I can run the stock program and it will still do it. I havent changed the MAF curve because I still have the stock MAF. If I put the stock program on without my fan settings, my temp will go up to around the M, which almost never happened before.

 

[final5-0]

Maybe it is my AFPR. The fuel pressure takes like 3 seconds to go down when I put the vacuum line back on the regulator.

Then put the stocker back on.

If I put the stock program on without my fan settings, my temp will go up to around the M, which almost never happened before.

The higher temps did not hapen before WHAT

Later
Grady

 

[TrueBlue95GT]

...when I first got the car.

 

[final5-0]

Well, you are asking the car to work harder by putting all of those hot rod parts on it.

The pulleys are not helping the higher temps that is for sure.

I looked at the sig and did not see a larger radiator.

When I put heads & cam on my car the temps went up a good bit more that I expected but then again you are making more power and that is kind of a given.

The stock radiator might not be able to keep up with your mods. The stocker might be a bit plugged up also. The stocker is so small that IMHO there is not much reserve in it for anything that might cause it to have to work harder.

I put a fulidyne and stewart pump on and the temps fell back in line.

Do you still have that little flap-spoiler kind of thing under the nose of your car that directs aif flow to the radiator?

I lost mine once and that caused my temps to go up.

A Q for you about the poor performance thing. Do you see your 02's switching back and forth in your dl's when in CL?

Later
Grady