Code 13 AND 44, stutter on boost

[FunElan]

Hi all,

Just got the Elan back after having the timing belt changed, along with all new Samco silicon coolant hoses, and new fuel injectors/FPR/fuel filter. I've driven it maybe 50-75 miles since getting it back, all trouble free.

Tonight I filled it up with fuel for the first time since getting it back, and all seemed well, until I got a random CEL while on the highway after a run up to 5k around a nice sweeping bend. The CEL went away a few seconds later.

The next time I went to get on boost, the car stuttered. It seems to drive fine off boost, but will stutter as soon as boost comes into the equation.

My laptop is charging and I will get a good ElanScan tomorrow, but I pulled codes 13 and 44 from the ALDL. I'm pretty sure the o2 sensor isn't original, and the mechanic who just had the car attempted to change it but "couldn't get it off." There are too many variables at play here and my mind is racing. Any thoughts? Hoping to get some insight before my 30 minute drive to a Concours tomorrow morning...

Thanks,
Matt

[TorqueHorse]

Any luck with the elanscan? Were you able to replicate the problem?
What were the boost pressures during this?

[Simon_P]

For anyone reading
13 = O2 circuit
44 = Lean

[Simon_P]

Most likely O2 sensor hence 13 is set - check the wires where they enter the sensor, they take a beating when you try to remove the sensor.

44 is probably secondary as the O2 sensor corrects the mixture. If it isn't then you will need to fix 13 first anyway.

[FunElan]

Any luck with the elanscan? Were you able to replicate the problem?
What were the boost pressures during this?

Well funny enough....I had to solve a different problem before I got to scan. I posted the original post before heading to the hotel bar across the street. After a healthy dose of rum, I got the idea to disconnect the battery to clear the codes overnight.

Upon attempting to reconnect the battery cables to head out for a scan, I discovered that the alarm was armed. I've never messed with the alarm. I didn't even have the fob on me! So there I was at 7:30AM this morning, trying not to wake up the neighbors.

Eventually, I retrieved the fob and got the car started. Scan attached. The car was pulling like a freight train at first! But eventually started giving me stutters under boost. It drives fine when not boosting, although maybe a tiny bit more juddery, but not super noticeable.

Attaching my scan - I can see a clear point at which the O2 sensor decided to stop "playing ball," when I couldn't get the car past .5 bar.

What's strange is that this happened right after a fill up (10.2 US gallons). My immediate thought was that crud at the bottom of the fuel tank started clogging the injectors, but the fuel filter has only ~100 miles on it as of now.

Curious what you all glean from the scan. I'm thinking I'll have to try and get that O2 sensor changed anyway.

And when anyone comes to visit Los Angeles, the rum is on me!

[Simon_P]

Looks like you've had some work done. Check the ecu ground connection on the end of the plenum/inlet and the connections battery.
Your alternator output varies quite a bit - By comparison on a similar scan mine varies by +-0.15v might be a poor connection.

Your IAC was a healthy 20 and then drops to 4 at idle. It should be 20 which suggests that it has a vacuum leak or the tickover is not set correctly (see wiki).

The ECU learns settings so after doing work you need to reset the ECU. Also check the Idle and base timing - The engine relies on these being correct - you need to follow the instructions.

Which injectors do you have - are they 2.0 ohm?

I remembered when my O2 sensor failed, but I had forgotten that it was a code 44 see Geoff's analysis of my scans here: https://forum.lotuselancentral.com/view ... 38&t=28362
The last two picture tell you all you need to know!

[FunElan]

Looks like you've had some work done. Check the ecu ground connection on the end of the plenum/inlet and the connections battery.
Your alternator output varies quite a bit - By comparison on a similar scan mine varies by +-0.15v might be a poor connection.

Your IAC was a healthy 20 and then drops to 4 at idle. It should be 20 which suggests that it has a vacuum leak or the tickover is not set correctly (see wiki).

The ECU learns settings so after doing work you need to reset the ECU. Also check the Idle and base timing - The engine relies on these being correct - you need to follow the instructions.

Which injectors do you have - are they 2.0 ohm?

I remembered when my O2 sensor failed, but I had forgotten that it was a code 44 see Geoff's analysis of my scans here: https://forum.lotuselancentral.com/view ... 38&t=28362
The last two picture tell you all you need to know!

Thanks for the response Simon. I did have some work done, so I disconnected the battery to reset the ECU. That's the way to do it, yea? I set the base timing a few months ago, but not since this past weekend.

Regarding the alternator - that's interesting, I'll have to look at the connections. Last time I looked at the belt (before replacement), it was very close to a power steering hardline. I know the battery is at least 6 years old, but that shouldn't affect this, right?

The vacuum leaks I had a hunch about, as the car was lean on the emissions test. I think the vacuum lines coming out of the 'sphere' are original, so changing them out is on my list of things to do.

I found some old posts here and on facebook confirming that these injectors worked for people, so it's what I installed, apparently 2.5ohm: https://www.ebay.com/itm/Set-of-4-BRAND ... 1637275013 The car seems to run okay with them until the O2 sensor issue starts?

I found that thread very helpful when reading the scans

[chris]

My hunch is fuel starvation; seems like you’ve had some work done in that area so I’d be removing the hatch and inspecting your mechanic has fitted the correct fuel filter and NOT kinked the hoses when he fitted the new filter (a known issue). An easy check in the first instance.

[HJ2]

You did not change the spark plugs by any chance?

[RonR]

Looks to me like you have bad connections to your O2 sensor or it's faulty.
The voltage drops to zero intermittently, then at around 1009 seconds it begins the drop down to zero over the next few minutes.
Possibly the O2 sensor heater being disconnected and cooling down?

O2 sensor volts.jpg

[FunElan]

My hunch is fuel starvation; seems like you’ve had some work done in that area so I’d be removing the hatch and inspecting your mechanic has fitted the correct fuel filter and NOT kinked the hoses when he fitted the new filter (a known issue). An easy check in the first instance.

This is a good reminder - I should check there anyway. The car did drive great for about 100 miles until this all started happening though. I would imagine a kinked fuel line would show itself fairly quickly?

You did not change the spark plugs by any chance?

The previous owner did but I feel like I should now, for the hell of it. I'll also do the 2 vacuum lines from the ball. I think I read 3mm id hose would work.

Looks to me like you have bad connections to your O2 sensor or it's faulty.
The voltage drops to zero intermittently, then at around 1009 seconds it begins the drop down to zero over the next few minutes.
Possibly the O2 sensor heater being disconnected and cooling down?

O2 sensor volts.jpg

I'm going to change the o2 sensor either way. That shop attempted to change it themselves (even though I never asked) and rounded it off so I'm prepared to cut it in half and use the brand new 6 point 22mm deep socket my father just purchased

Is there a separate O2 sensor heater?? Like an air pump of sorts? I've seen that on BMWs

[RonR]

The heater is integrated into the O2 sensor. There's a 3-wire connection at a plug just by the right hand engine mount: I'd try unplugging it and checking the condition of the wiring before wrestling with the sensor itself, it could be a cheap fix!

The 3 wires are:
1. O2 sensor signal - connects back to the ECU pin D7.
2. O2 Heater +ve - connects to the Alternator output via a splice into a wire behind the dash - you should see battery voltage here with the engine running.
3. O2 Heater Gnd - Not sure where this grounds, but you should see a low-resistance path to ground on this pin.

There is a 4th connection - O2 sensor Gnd - which is via the O2 sensor casing through the exhaust manifold and cylinder head to an earthing tag on the back of the engine. It's worth checking this as well, though I'd expect more codes than just 13 & 44 if this was loose.

Code 44.gif

Edit: For the full diagnostic charts, see the "Closed Loop" electrical manual section EMJ5 Page 34 Here

[FunElan]

Thanks Ron - I'll peek at the wiring again but I looked at it this past weekend and didn't see any obvious issues.

[FunElan]

I checked out the wiring of the sensor and saw what may be very tiny cracks in the minuscule amount of copper wire that's visible, the one that's black

[Rambo]

Just a thought, but I don't suppose you got a tank of dodgy fuel did you? Water, x contamination, particulate matter....... ? Might be as well adding some fuel/injector cleaner. Nothing lost anyway.

PS over here people have been having lots of issues with the new E10 fuel (10% methanol) I only ever use E5, 97 or 99 RON

[FunElan]

Just a thought, but I don't suppose you got a tank of dodgy fuel did you? Water, x contamination, particulate matter....... ? Might be as well adding some fuel/injector cleaner. Nothing lost anyway.

PS over here people have been having lots of issues with the new E10 fuel (10% methanol) I only ever use E5, 97 or 99 RON

That was a thought I had as well...not sure how quickly (how many miles) into a tank that would have an effect, but I do have some injector cleaner I can throw in. Can't imagine that could harm brand new injectors. Thanks for the reminder Rambo

Everyone over here has to use E10. My 68 BMW responds just fine to it. It was my understanding that letting a car sit for a while will expose the true horrors of ethanol. I just use it as a good excuse to drive everything at least once a month

[Simon_P]

I found some old posts here and on facebook confirming that these injectors worked for people, so it's what I installed, apparently 2.5ohm: https://www.ebay.com/itm/Set-of-4-BRAND ... 1637275013 The car seems to run okay with them until the O2 sensor issue starts?

any injectors will appear to be ok even the completely wrong ones. Closed loop the O2 sensor will adjust for the slower injectors but as you go up in revs the difference becomes more significant. Add to that the injectors fire every stroke so double the error. Under boost excess fuel is used for cooling. So at 6500 revs and full boost do your injectors deliver to little fuel? Or to much? The correct injectors deliver the correct amount of fuel.

[FunElan]

Just an update here....spent most of the day assembling front suspension on my father's 69 Elan. Towards the end of the day, we got to the M100. I decided to do a smoke vacuum test before changing the O2 sensor to find the vacuum leaks that Simon pointed out above. My thought was that perhaps a vacuum leak is what is affecting my sensor and causing lean running.

We immediately saw smoke pouring from the back of the intake (eventually got to the intake in the LF wheel arch). I stuck my hand back behind the engine and fished around, and found a vacuum line not attached to any port. A quick look at diagrams here suggested that this line connected to the secondary throttle vacuum reservoir. I bet when my mechanic installed the heater hoses, he knocked this hose off and didn't notice. This explained why my stuttering issues were only happening when on boost (re: when the secondary throttle is activated).

If you've ever pulled one of these engines, you've seen this reservoir, but if you haven't you likely never will. Raccoon hands are necessary!! I fought with it for a while and eventually we installed a brand new vacuum hose (in an electric blue color now). I also installed a new PCV because I had one on the shelf.

Alas, we ran out of time for the O2 sensor. BUT, that will be swapped out in the next 2 days. We'll have to cut it in half. Attaching my scan after the fixed vacuum line - the car drove GREAT for a while but eventually stuttered again. I disconnected the battery for 25 minutes before this scan. The stutter wasn't terribly strong for a few pulls, and then grew in intensity. A block from my garage, the CEL came on. This time, it's just code 44, not 13.

Looks like fixing this one vacuum leak improved IAC position, but there may still be another vacuum leak. Amazed that this car passed its emissions test. Curious if y'all find anything else from this reading.

[RonR]

Looks like the same type of failure as before, O2 sensor voltage shows small periods of 0 volts, then tails off to nothing after around 10 minutes:

O2 sensor volts Sep 3.jpg

[FunElan]

Looks like the same type of failure as before, O2 sensor voltage shows small periods of 0 volts, then tails off to nothing after around 10 minutes:

O2 sensor volts Sep 3.jpg

Cut the old sensor off and installed a new one today. Very important to chase the threads before doing so, they were really rusty! Attaching new scan. O2 voltage looks much better, granted it was a short drive. IAC position looking better too. There are so many readings in here, so I always appreciate insight as I am a novice.

Very thankful for this forum!