14CUX running rich

discostew

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Sep 14, 2010
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I wonder if you need to set the closed throttle position, then minimum idle, then reset adaptions. I remember needing to do both. Resetting adaptions does not reset closed throttle.
 

p m

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I adjusted the TPS a while back - the voltage reads okay, about 0.32V with throttle closed, and it reads 0% in Rovergauge.
Other than Rovergauge and battery disconnect, I don't have any tools to force the ECU to relearn anything.
Need to do some reading... And probably pull and reseal the intake plenum - the manifold vacuum (from the port that feeds the fuel pressure regulator) is about 9-11 psi.
BTW, I am curious about using vacuum advance off the ported vacuum. Many Buick V8 use either manifold or switchable from manifold to ported; my jeep's Buick V8 does not like full vacuum advance and it would ping under load, so I used manifold vacuum.
 

discostew

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Sep 14, 2010
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Northern Illinois
It's more about telling your ECU what the new closed throttle position is. I believe it has to be ported vac at the vacuum advance. Yeah I think I have a T4 up and running but not sure. I'll be trying it on a BMW Range sometime tomorrow. But I've been waiting almost 4 months just for an old rover to try it on. It probably gets used on 3 or 4 cars a year. We never see this shit anymore.
 

robertf

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Jan 22, 2006
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do you know what version of eprom is on there? I haven't used the android version of rovergauge but the desktop will tell you.

You shouldn't have to ever mechanically adjust the TPS on the 14cux, it dynamically sets its own min and max within a range and throws a code if its out of range.

Vac leak sounds reasonable. Lots of places in the flame trap for air to leak in, or a bad booster if your RRC has vacuum brakes.

Maybe do a compressoin check and leak down check just to rule out the low hanging fruit, but I'd kind of expect the trims to be opposite if there was a problem with valve train
 

p m

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I did a leakdown test before I tore the front cover off, and compression test after the new timing chain and gears. Compression numbers were stellar.
RRC doesn't have vacuum brakes, and I replaced the O-ring on the flame trap. The TPS is one of those with slots instead of single round holes, and it can be adjusted way outside of where ECU can learn the throttle stop.

I should have a desktop version of Rovergauge, will give it a shot.
 

Flyfish

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Need to do some reading... And probably pull and reseal the intake plenum - the manifold vacuum (from the port that feeds the fuel pressure regulator) is about 9-11 psi.
Vacuum should be reading 15-20 in. mercury. 9-11 is very low. And I probably wouldn’t unplug the fuel pressure regulator to test vacuum.... because then you’re probably pushing gas about 50psi to the injectors.
 
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robertf

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Jan 22, 2006
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Vacuum should be reading 15-20 in. mercury. 9-11 is very low. And I probably wouldn’t unplug the fuel pressure regulator to test vacuum.... because then you’re probably pushing gas about 50psi to the injectors.

Im pretty sure he’s measuring in PSIA. 9-11psia is around 15-20inmg if he is not too far from sea level
 
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Flyfish

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My gauge is indeed in inHg, but I took a liberty of converting them to psi.
Then you probably don’t need to reseal the plenum. But always good to test for leaks with a smoke machine. A Halloween smoker/fogger is a cheap way to do it if you don’t have access to one.
 

p m

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Update... Resealed the intake - no changes.
Hooked up PC version of RoverGauge, here's the log (from running in front of my house to parked in front of my office):
1620060119243.png

Check this: everything seems to work while driving. But when I stop, in gear or not, I have to open up the idle bypass screw - otherwise the idle becomes unstable and the engine will eventually stall. The graph represents the drivable settings - the idle still oscillates a bit (see below), but the IAC solenoid would quickly close, and short-term trims would go up to the max.
1620060463399.png
 

Blueboy

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Apr 20, 2004
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Update... Resealed the intake - no changes.
Hooked up PC version of RoverGauge, here's the log (from running in front of my house to parked in front of my office):
View attachment 61058

Check this: everything seems to work while driving. But when I stop, in gear or not, I have to open up the idle bypass screw - otherwise the idle becomes unstable and the engine will eventually stall. The graph represents the drivable settings - the idle still oscillates a bit (see below), but the IAC solenoid would quickly close, and short-term trims would go up to the max.
View attachment 61059
So what’s the next step?
 

p m

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So what’s the next step?
Probably, scope the O2 sensors. BTW, they are not switched side-to-side, checked this morning just in case.
Something is making the ECU to richen up the mixture.
I may also try running a resistor in parallel with coolant temperature sensor - maybe it cannot fully lean out the engine running at 70-75C.
 

p m

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Pulled the port on the intake plenum housing the IAC solenoid, cleaned it up, put it back in. No changes.
Did something I can't remember - now the hot idle in gear is around 600 rpm, pretty stable. WTF...
 

Flyfish

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Oct 29, 2004
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Update... Resealed the intake - no changes.


Check this: everything seems to work while driving. But when I stop, in gear or not, I have to open up the idle bypass screw - otherwise the idle becomes unstable and the engine will eventually stall. The graph represents the drivable settings - the idle still oscillates a bit (see below), but the IAC solenoid would quickly close, and short-term trims would go up to the max
Still might be worth putting a smoke machine on it. Plenty of other places it can have a vacuum leak.
 

p m

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do you know what version of eprom is on there?
RG tells me the tune is 3361
Still might be worth putting a smoke machine on it. Plenty of other places it can have a vacuum leak.
Not really. There are four manifold vacuum connections: to IAC solenoid (doesn't leak), to oil separator/PCV (doesn't leak), to fuel pressure regulator (doesn't leak), and to charcoal canister (haven't checked). Not sure if smoke machine would show anything with the charcoal canister, but... it might.