Codes 41, 65

[Desert Patina]

It is good to drive my car again. It is a little sluggish still, and it knocks even when not in premium. But perhaps the computer has told me why...

I'm getting codes 41 and 65.

41 seems straight forward enough, somehow the engine knows the fuel is lean. I can buy that, with how long it sat I am expecting I need to change the fuel filter a few times.

But 65, "Check intermittent HO2S (signal or ground) – Fuel Control" is a mystery to me, and I'm worried about my circuitry.

Also for some reason even after locating a near impossible TurboCoupe EGR Control valve, it is still giving me 82, 83.

[MikeFleming]

Do you have an LA3 EEC installed?

41 & 65 are related. The signal from the O2/Heated O2 is having issues. Intermittent or always lean.

Which means you're really close. Keep working at it.

[Desert Patina]

Yes, its the LA3.

I've had it in a shop since last Friday. Right now they are suspicious that the cam is off, which is possible. I did the string method, and I don't know really how absolutely accurate it is.

[MikeFleming]

FYI: Cam timing will not cause code 41. Unless it's so far off that the engine will not run.

String is usually close enough for government work, assuming the sprocket, head & block decking and belt stretch are all stock. Not taking into account "old fart eye sight" or paralax.

[Desert Patina]

Good to know.

They haven't seen the 41 code return in a while, and all I can figure is that I might have pushed out a connector on the ECU since it is uncaged at the moment and a few clips broke keeping the pins down on the female side. I sourced a new female side and will swap it out soon.

meanwhile they are trying to diagnose why the engine seems to have no power at low RPM, and only mediocre power above 3k. That happens all the time, even when there is no 41 code.

Even after the re-timing we are still chasing that issue. At least at idle we have 44lb of pressure for fuel.

They are going to do a compression test next and perhaps hunt down vacuum leaks after that. Then perhaps see if timing isn't advancing enough.

Personally, I seem to remember complaining about this often (its just so infrequently ran that I don't have a working memory of the car running right). I wonder if my next move is to just get a stock or mild cam and replace what could have been a hot cam from the person I bought it from.

[Desert Patina]

Do burnouts really happen after the engine hits 4500 rpm?

Well, after an engine rebuild (I really liked the service at Bailey's in Mesa) and a new head (I happened to catch Bo himself putting a stage 3 with a 2.5 on ebay) it works much better.

Is it supposed to break traction in 1st gear, like around 4500rpm? I've driven some powerful cars, and even recently rode in an SVO that the guy did a burn out in, but nothing just roared and started skidding out in a straight line on first and second well after the clutch was engaged.

Anyway, here's the deal. The engine smells rich. Its unmistakably rich. However it is giving the 41 (lean) code again at idle. And only at idle.

It also gives 14 and 72. Both of those I think are just left overs from when we were starting the engine back up. But the engine light comes on at idle so I believe the 41 is still happening.

What could case it to burn rich, but post lean?

Many thanks.

[brsvo]

I don't have experience with a 2.5 cam but I believe it. My 2.1 will spin in 1st just letting the clutch out and stepping it down. Second too after doing 1st but just slightly. Vacuum leaks could cause these problems. What kind of car do you have because there is no check engine light in my SVO.

[Desert Patina]

Yeah, even if I make sure the clutch is engaged at 1.5k before stomping on it, the tires freely spin after 4.5k. Its just unexpected for me, it makes sense but surprising still. Like seeing a unicorn.

Also I was wrong, it is also a 2.1 cam, which I think is just a higher cam with the same overlap as the 1.5.

It could be a vacuum leak, but that would be maddening. When we put the engine back in the car we chased the vacuum lines with propane to see if the idle surged, and didn't find anything. Though, it does have a slightly hunting idle normally.

The check engine light is something I rigged up when I modified it to have an LA3 ECU. Its the old boost warning light.

[Mike S]

Did you check to see if the ECT sensor is putting out the right voltage? Also, the VAM door stuck slightly open could cause more air and fuel to be dumped at idle even though it is not needed.

[Desert Patina]

The ECT is the one on the manifold, or the one on the block below the manifold?

Could be suspect, the fan stays on all the time ( EDF circuit on LA3 )

[MikeFleming]

The ECT is the one on the manifold, or the one on the block below the manifold?

The ECT (feeds coolant temp data to the EEC for determination of fuel, ignition & idle speed calculations) uses the weatherproof 2-wire connector thingie in the top, center of the intake manifold. There is a coolant passage leaving hte cylinder head between intake side cyls 1 & 2.

At the rear, top of the engine block, under the large T-adapter for the oil pressure gauge sender, is the coolant sensor that feeds the TEMP gauge in the dash.

In the bottom of the intake manifold, also in the same coolant passage, is the coolant fan switch.


Could be suspect, the fan stays on all the time ( EDF circuit on LA3 ) Unless you have re-wired the fan output circuit on the LA3 (added lots of additional wires/pins to the EEC and a few relays) your EEC (the LA3) has nothing to do with cooling fan operation on the SVO.

[Desert Patina]

Green57 was wondering about this, and it looks like he was right. The fan is always on because the ground for the EDF is inverted from HEDF.

For HEDF, 52 pin ground means fan on. For EDF, 55 pin ground means fan off. re: http://forum.turboford.org/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=4;t=000339

Looks like I can fix with a regular BOSCH 5 pin relay rather than the Volvo relay, or wiring a little 2A normally closed relay inbetween. But I'll still use the Volvo relay for the HEDF if I ever install the Volvo two-speed fan.

But for the purpose of this thread, the ECT isn't suspect anymore.

I'm sure its either a vacuum leak, or an exhaust leak. Perhaps something popped off under boost during the WOT shakedown.

[MikeFleming]

I'm sure its either a vacuum leak, or an exhaust leak. Perhaps something popped off under boost during the WOT shakedown. Everything intake-side should have clamps to prevent hoses, etc. from "popping off" under pressure.

Similar to how we treat coolant hoses under similar pressures.

[Desert Patina]

Well, good news is it passed emissions.

I don't use all of the ports on the vacuum tree, and one of the caps blew off. I replaced it, and it passed easily ... except for NOX. It just squeaked by in NOX.

Maybe I should install urea injection for the next test.

[MikeFleming]

Maybe I should install urea injection for the next test. Gonna install a "VW" badge on the hatch??

[Desert Patina]

It would go with the on/off switch for knowing when it was in a smog station...

[MikeFleming]

^
Probably need to add some GPS equipment for that.