?Startup Issues - WTF?

[wicked]

I jsut mean removing the injectors from the block physically, leave them plugged in and see if you get fuel squirting when you turn the key. You've narrowed it down to something with the MPI, correct?

........or just use a test light.

 

[Kooldino]

I jsut mean removing the injectors from the block physically, leave them plugged in and see if you get fuel squirting when you turn the key. You've narrowed it down to something with the MPI, correct?

I see what you're saying. Worth a shot.

 

[Kooldino]

........or just use a test light.

Tried that before, got nothing.

 

[Fudgie]

Probably safer going with something like this:

http://buy1.snapon.com/catalog/item...&group_ID=1452&store=snapon-store&dir=catalog

The MPI fires the coils once when the key is flipped to the on position? Sounds like an old Mazda with a bad cap and rotor that while cranking when cold would blow the airbox to bits due to crossfire. After the pop, does the car start and run ok, or is it missing?

 

[Fudgie]

Hard to tell with a testlight. Should have 12v at the injectors which is easy to check with the light, but connecting it in series at the injector connector and trying to watch and see if the circuit is grounded by the ecu can be diffcult.

........or just use a test light.

 

[Maxx Mazda]

So when you hear this pop does your boost gauge always twitch, every time?

 

[Kooldino]

Probably safer going with something like this:

http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=11238&group_ID=1452&store=snapon-store&dir=catalog

Nice find! Now to find one for our injectors.

The MPI fires the coils once when the key is flipped to the on position?

Yes, one quick fire. Apparently, the Haltech does the same.

Sounds like an old Mazda with a bad cap and rotor that while cranking when cold would blow the airbox to bits due to crossfire. After the pop, does the car start and run ok, or is it missing?

It would start and run, but it would run very rich for the first 20 seconds.

Once I changed to the 626 intake mani, it really hasn't happened nearly as frequently or intenseley as it used to.

It also used to occur more frequently in hot summer weather. I think fuel vapors play a role in this.

 

[Kooldino]

So when you hear this pop does your boost gauge always twitch, every time?

IIRC, it did.

It would often blow vac lines off of my intake manifold, and when the boost gauge twitched, it would pin the needle.

What's interesting is (if you go back and read all of the older posts) this same issue seems to happen with multiple EMSs, and multiple styles of injector setups (4 injectors in the stock place as well as 8 injector setups). However, I don't recall seeing it occur with pre-TB injector setups.

 

[Maxx Mazda]

One would think that the pre TB injectors fuel would be cut off by the TB, and thus not ignited...

 

[Fudgie]

The snap-on one that I have is adjustable so it can fit any connector. Good tool to have in the box. Interesting that the 626 manifold lessened it. Probably running rich because the afm was on fire! (flame)

Nice find! Now to find one for our injectors.




Yes, one quick fire. Apparently, the Haltech does the same.



It would start and run, but it would run very rich for the first 20 seconds.

Once I changed to the 626 intake mani, it really hasn't happened nearly as frequently or intenseley as it used to.

It also used to occur more frequently in hot summer weather. I think fuel vapors play a role in this.

 

[Kooldino]

One would think that the pre TB injectors fuel would be cut off by the TB, and thus not ignited...

Not only that, but with the car not running, they would just spray and run down the IC piping.

 

[Kooldino]

The snap-on one that I have is adjustable so it can fit any connector.

Oh, cool.

Good tool to have in the box. Interesting that the 626 manifold lessened it. Probably running rich because the afm was on fire! (flame)

lol

I have a theory that the VICS chambers would somehow trap extra vapors or something. Only hole in that is that while the car is off, the VICS butterflies are open.