A/F Fluxuation

[supraguy31]

Ok all, Its been a While so help me out here.

Out driving the car and A/F are great, All of a Sudden they will drop to 12, 11.5 and stay there for a little and then Jump all the way over to 16.5 - 17 and then back. This has started the past 2 weeks so I thought I would ask here. Car becomes really crappy to drive as it seems like someone is behind me with a rope slowing me down at times.

I do notice also at time if I sitting at a light and start to pull off, I give it gas to move and the A/F will drop to 11.5 and slowly work itself back up to 15+-

Running a N/B and a W/B if that matters.

Any help would be greatly Appreciated...... IC Leak Maybe????

Robert

 

[jdub]

Any ECU codes?

Is this happening at ~25-30% throttle at cruise?

 

[supraguy31]

Any ECU codes?

Is this happening at ~25-30% throttle at cruise?

Yes Sir, That would be absolutely correct, Cruise is when it does it, Idle is fine and Full throttle is fine, Its either Initial gas or as your Stated Small Consistant throttle when cruising.

Dam it... Code 11

I keep clearing it and It keeps coming back. Drive for a few days and It doesnt come up then all of a Sudden it comes back. Might be the cause.

 

[jdub]

Need to fix the code 11...it masks all other codes when it is present. Start by cleaning the ECU grounds at the intake manifold.

If this is an old TPS, they develop a "flat spot" right at that RPM range. The TB will open on acceleration, but the ECU doesn't know to add fuel or it adds fuel and doesn't take it out during a gradual deceleration. The solution is to test the voltage output at the ECU:

http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=FI&P=50

Read pages 50-51 and pages 55-56. VTA Voltage should vary between 0.1 and 4.2 volts...it should be linear from closed to full open. If you have a flat spot, voltage will be constant over a small turn range about 1/3 of the way from closed.

 

[supraguy31]

Ive Put one of Ron R. FFIM on the car and Im using the Q45 Throttle body TPS. I will go out and check the grounds to make sure they are clean.

Robert

 

[jdub]

That TPS is similar to stock...wouldn't surprise me if it has the same type issue. Test at the ECU like I said above and you'll know.

 

[supraguy31]

Will do, I went out and looked at the ground wires under the intake manifold, The couple white wires are good, 1 of the Brown wires on the other connector was loose as a couple strands of wire looked to be broken.

Im working on fixing that now and then put it back to the intake manifold.

Old stuff wears out after time I suppose
Robert

 

[supraguy31]

So far no Luck, thought that I had it fixed but after I went out for a drive it ran fine, all of a Sudden it started it again.

Got back to the house, Didnt turn the car off and did a Code check. Code 11 Again, Turn the car off, immediately turned it back on and code 11 is gone. No codes after that. Only thing that I see that MIGHT cause this Problem is the 6 Pin connector at the ECU lost the piece that holds it into the ECU, Im sourcing another end clip out now and Im going to replace it.

Robert