Jump to content

Weird and VERY odd engine prob tonight - Ideas ?


Hybrid_From_Hell
 Share

Recommended Posts

Drove the 90 home tonightr

Its was EXCEPTIONALLY cold outside, ice everywhere, and the engine seemed "Unresponsive"

Drove home 2-3500 RPM, seemed very unkeen to "Go" until "Booted"

Got home, got out, engine running smoothly, but a smell that was unusual

Lifted bonnet, Big Bore Cast 4 > 2 Manifolds glowing red :blink: WTF ?

The only thing I can think of is the exceptionally cold air runing through the snorkel, which

maybe could have caused a further chilling, but other than that stumped. ????

I'll disconnect the snorkel at Air Box tommorrow, but anyone know WTF is going on here :ph34r::lol: ????????

Puzzled of Fernhurst

Nige

Link to comment
Share on other sites

Exceptionally cold air = exceptionally dense air per cubic volume being sucked in?

If for whatever reason the ECU isn't able to determine density of the air (as a calculation of its temperature) then it might be running weak, hence glowing manifolds?

Link to comment
Share on other sites

I agree with Phil. Sounds like Timing badly retarded - or advance not operating. This would account for the inability to rev under load and the exhaust manifold temps.

Why the megasquirt isn't advancing the timing is another question. Possible crank sensor problem? - Not reading engine speed?

Good Luck Nige, Regards, Diff.

Link to comment
Share on other sites

Engine running too rich causing the excess fuel to detonate in the manifolds.

Probably due to low temperatures or incorrect ECU settings causing the engine to constantly be running with warm up enrichment (basically equivalent of running with the choke out all the time).

Jon

Link to comment
Share on other sites

Unresponsive and red hot manifolds are a classic case of retarded timing ………. Usually many degrees ATDC

Although MLV shows that the correct timing signal is being sent to the EDIS module, you don’t actually know that EDIS is doing its stuff.

Get the timing light out next time it happens.

Alternatively it could be a very, very lean mixture, but this is more unlikely ……….as cold air will call for a richer AFR from the ECU......... Check for white plugs.

Link to comment
Share on other sites

Throttle potentiometer registering ok ?

Vacuum tube connected ok ? (I'm guessing so cuz it's ticking over..)

Air temp registering ok ?

Has sensor moved in the bracket and changed where the timing is being read from ? MLV will report the angle it's working to, not where the sensor is compared to TDC....

Hand over the manifolds and I'll see if they glow on my lowly engine.. :)

Neil

Link to comment
Share on other sites

^^^

:rofl:

Go away :P

Disconnected Snorkel this morning, still same.

Low on power, but every setting on Megatune seems OK, MAT, CTS, Spark, Advance, VE advance, TPS etc etc

Only thing was the O2 looked lean, have reloaded the MSQ, difficult to tell, but O2 seems to enrichen more,

frankly I am a tad stumped, can't see it as injector(s) down as BOTH manifolds were glowing red hot :huh:

Hmmmmmmmmmmmmmm :unsure:

Nige

Link to comment
Share on other sites

could be icing in the intake trumpets (i take it you do still have some fitted). whem the air enters the trumpets, it's speed increases as it is gulped in, this makes it cool even further, and then ice forms, resulting in restricted air flow, over rich mixture (possibly) and loss of power.

mate of mine used to experience similar power loss symptoms on his zzr600 bike a few years ago (the one with the srad system) whenever he hit 150mph :blink: in cold weather, the trumpets would freeze causing power loss.

could be totally wrong, but it's possible in theis weather, especially if all readings are saying normal....

Link to comment
Share on other sites

The MS sends the timing info to the EDIS using a SAW (Spark Angle Word) pulse. The length of the pulse derives the timing and can be in the range of 57.5 BTDC to 10 ATDC. TBH running your engine at 10ADTC would give rise to hot manifolds, but I feel it would need to be more retarded than 10 degrees.

I guess if it was lean & retarded then that would have the same result..............

If SAW is disconnected then the timing will default to 10BTDC ……. It should run quite happily on that, albeit a bit sluggish.

Here is the Blurb from the EDIS technical information,

Spark Angle Word Calculation

The algebraic formula for calculating the SAW pulsewidth is:

SAW Pulsewidth (usec) = 1536 - (25.6 x (desired spark advance in degrees))

Range: 64 - 1792us (57.5° BTDC to 10° ATDC)

Resolution: 4us (5/32nd of a degree)

Example:

You want 29 degrees of advance.

PW = 1536 - (25.6 * 29)

PW = 1536 - (742.4)

PW = 793.6

You would send a pulse that is 793.6 microseconds long to the EDIS module.

The EDIS module will do all the work of timing the spark, you just send the advance pulse.

The EDIS has an advance range of 57.4 degrees BTDC to 10 degrees ATDC. These correspond to the SAW widths of 64 and 1792 microseconds respectively.

Link to comment
Share on other sites

The MS sends the timing info to the EDIS using a SAW (Spark Angle Word) pulse. The length of the pulse derives the timing and can be in the range of 57.5 BTDC to 10 ATDC. TBH running your engine at 10ADTC would give rise to hot manifolds, but I feel it would need to be more retarded than 10 degrees.

I guess if it was lean & retarded then that would have the same result..............

If SAW is disconnected then the timing will default to 10BTDC ……. It should run quite happily on that, albeit a bit sluggish.

Here is the Blurb from the EDIS technical information,

Spark Angle Word Calculation

The algebraic formula for calculating the SAW pulsewidth is:

SAW Pulsewidth (usec) = 1536 - (25.6 x (desired spark advance in degrees))

Range: 64 - 1792us (57.5° BTDC to 10° ATDC)

Resolution: 4us (5/32nd of a degree)

Example:

You want 29 degrees of advance.

PW = 1536 - (25.6 * 29)

PW = 1536 - (742.4)

PW = 793.6

You would send a pulse that is 793.6 microseconds long to the EDIS module.

The EDIS module will do all the work of timing the spark, you just send the advance pulse.

The EDIS has an advance range of 57.4 degrees BTDC to 10 degrees ATDC. These correspond to the SAW widths of 64 and 1792 microseconds respectively.

:o:blink::unsure::rolleyes:

Glad ive got a Diesel :P

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy