timing on the money, but engine sounds AWFUL????

ochizon · Post by **ochizon** » Fri Aug 18, 2006 5:51 am

With much thanks to Jsmcortina, I was able to get my engine started with the spark, but it is just very weird. When the timing on the megaquirt and the timing light match, the engine sounds like it is going to bog and die. you pull 30 degrees off of the trigger angle, however, and the engine sounds as healthy as can be. The problem here is that the timing light shows 40 degrees BTDC while the fixed angle is set at 10.

Also, when you use the timing map, as you get into higher RPMS and more advanced timing, the advance runs off course by several degrees.

I dont know what I am doing wrong here, but its driving me nuts!!!! We checked all of the mechanical timing, and it all checks out. Could it be the board?

MSNS-E V26
PCB v3.0
Tacoma 4 cyl 2.4 L w/ Dizzy
vb921

ares650 · Post by **ares650** » Fri Aug 18, 2006 7:22 am

On a 36 - 2 wheel, running a dizzy, We came up with

trigger 1- tooth 7

trigger 2- tooth 25

trigger angle - 70 degrees

At least this is what it will start with

jsmcortina · Post by **jsmcortina** » Fri Aug 18, 2006 7:29 am

Are you using a clever "dial back" strobe? These can get very confused by wasted spark ignition and show the wrong timing.
It sounds like you know what you are aiming for and have the timing close by ear but not by strobe. I believe your ears, but you need to strobe it to within a degree.

James

ochizon · Post by **ochizon** » Fri Aug 18, 2006 7:31 am

Here is a pic of the wheel, for reference.

So far we have managed very stable rpm from it.

ochizon · Post by **ochizon** » Fri Aug 18, 2006 7:44 am

jsmcortina wrote:Are you using a clever "dial back" strobe? These can get very confused by wasted spark ignition and show the wrong timing.
It sounds like you know what you are aiming for and have the timing close by ear but not by strobe. I believe your ears, but you need to strobe it to within a degree.

James

We are indeed using the clever "dial back" strobe, which I am sure could be an issue, but we are not running wasted spark, we are running a distributor (which makes this all the more frustrating - it cant get easier than a distributor!).

jsmcortina · Post by **jsmcortina** » Fri Aug 18, 2006 7:47 am

Ah yes, you already said you were using a dizzy. Please post your settings (File->SaveAs in Megatune.)

James

ochizon · Post by **ochizon** » Fri Aug 18, 2006 7:47 am

one last post to show off my snazzy new sig

I will post those as soon as I can...
Unfortuately I am going to catch a plane in 2 hours, and cant get to the laptop.

Ares, a little help later???

MustangSix · Post by **MustangSix** » Fri Aug 18, 2006 9:21 am

Is your distributor itself in phase? You could be firing the ignition perfectly timed, but the rotor will not be pointed at the cylinder. That could account for why it runs better when the trigger angle is changed.

You can verify by getting a spare cap, making a hole in it so that you can see the rotor as it approaches #1, and shining the timing light on it. It should be visible as the ignition fires. If it is too far out of phase, the spark has to bridge a considerable gap in order to fire the plug, hence the poor running.

The fix is to turn the distributor so that the rotor lines up with the plug wire on ignition, then verify your trigger angle and timing.

jsmcortina · Post by **jsmcortina** » Fri Aug 18, 2006 11:24 am

Excellent response from MustangSix. With really bad phasing the spark can jump to the wrong tower.

James

ares650 · Post by **ares650** » Sat Aug 19, 2006 6:29 am

here is the file that we are using.