34 replies to this topic

[Lplus]

 

Two points - I was under the impression that the fast idle should begin to operate before the enrichening begins.

 

Secondly my AEM wideband A/F meter instructions state that running the engine without the sensor connected and powered may lead to failure.  I don't think it matters if it has to be turned on and off each time it starts.

Kind of. The sensor usually goes through a heating cycle, but this should be after the engine starts as it lets the exhaust gas blow condensation off the bulb prior to the heating cycle starting. If it heats up then the engine starts, this can cause thermal shock to the bulb and break it.

 

On my haltech WB1 set up, the ecu won't read or warm the sensor up until the engine has started for a few seconds.

 

I just wired it into the ignition whilst it was fitted, so it wasn't likely to be left on without the engine running.

[babsbrown]

Cheers guys, this morning a swapped the needle over to an AAU it struggles to start even on full choke so it will need to enrichen the mix. I also double checked my wideband to make sure it still works. Luckily it does

[Kevybmini]

I would have this nice new engine setup on a rolling road before driving it, otherwise you could be doing some serious damage to it. 

[babsbrown]

Thanks Kev, the thing is cash flow at the minute and trying to trailer it to a nearby rolling road.

L

[babsbrown]

After changing to an AAU needle the engine was spitting out of the carb. Indicating to me a lean mixture. Once I turned the carb adjustment screw a little this stopped. Confirming my suspicions.

Pulling the plugs shows 2 of the plugs dark and the other 2 light grey.
I'll clean the plugs tomorrow and I have a little stretch of road I van drive it up and down tomorrow just to get it under load.

Wideband gauge is pretty much useless at idle as it sits at 19. Which is highly inaccurate. I'd probably get more of a better picture using the colour tune for fast idle, but anything after that when the cars under load the wideband should hold its own.

I'll see what tomorrow brings.

[timmy850]

Is the wideband at the tip of the exhaust?

[babsbrown]

Hi @timmy850,

No it's located just after the maniflow free flow manifold. I'm going to see how it behaves once I get it driving today. Cheers

[timmy850]

If it's sitting at 19 at idle then it sounds very lean? As long as there is no air leaks between the head and the sensor

[babsbrown]

If it's sitting at 19 at idle then it sounds very lean? As long as there is no air leaks between the head and the sensor

Yes I'm beginning to think it's a faulty sensor. I'll have a look with the colour tune tomorrow and check out the colour of the mixture. Then if the Widebands sitting at 19 still then time for a new sensor I think

[timmy850]

Did you do the calibration on the sensor prior to install?

Why don’t you trust the 19:1 reading?

[sonscar]

Listen to the exhaust at idle,throb throb throb is rich,wobble splash wobble splash is lean.try it and it will make sense.Steve..

[babsbrown]

Did you do the calibration on the sensor prior to install?

Why don’t you trust the 19:1 reading?

Thanks gents,

I actually got the car fast idling at 2.5k at 14.6-14.8 . Oil pressure 60psi steady and water temperature was good.......until...


Disaster....

Water core plug shot out of the engine and steam covered everything.
I'm hoping there's no damage to the engine internals. I removed the spark plugs and cranked it over. Oil pressure regained quickly. So I'm hopeful it's an easy fix

Edited by babsbrown, 10 April 2025 - 10:25 AM.

[amsgw]

Oh gosh, fingers crossed for you!!! How did you put your plugs in, did you use hylomar or similar?

[babsbrown]

Oh gosh, fingers crossed for you!!! How did you put your plugs in, did you use hylomar or similar?

Aye hopefully it's fine. Can't imagine much if any damage. Yes I put them in with silicoln gasket sealer. I will try blue hylomar next time. To be honest I don't think I gave them a good enough "whack" to seat them.

[babsbrown]

Update* to the post above

Ran the car for 2x 20 min periods between 2200-2500 rpm.
Torquing head nuts in between.
It fluctuated on the ARF
Between 14.6 to 15 ish.
However, after about 20 mins it's started to go really lean.
To about 17 AFR.
It was also misfiring, so knocked it off. Timing is 8 deg BTDC. Plugs don't look
Like they've been really run that much with a slight brown tinge.
Before I start spraying everything and checking for air leaks

Is there anything obvious I've overlooked? Thanks