So, my SPFI wagon has this horrible hesitation under load....like almost undriveable. Can't find the info in any of my manuals on how the advance works (electronic, yes....but is there some vacuum sensor involved? how does it compensate for load?). Anywho, I was thinking of plopping in a distributor from an '85 that has the vacuum advance. Good idea? Bad idea? Should I be focusing my attention on something else?

Thanks!

Chris

I moved you post for better coverage

 

The distributor in your SPFI car is a

CAS - Crank Angle Sensor

insides shown here

The 85 has a more or less conventional electronic

dist.

completely different.

 

Have you changed your fuel filter lately?

Another possibility is the air mass sensor located by your air filter.

OK, got out today in the currently tolerable weather and played with this thing some more. Tested every aspect of the FI system to rule that stuff out of the euqation. Air mass meter is within specs, fuel pressure is correct while running and sitting for 10 minutes (fuel filter is new), throttle switch is adjusted correctly. So, the symptoms that I am dealing with- car starts and idles fine, acceleration is a bit sluggish when rolling gently into the throttle. Falls flat on it's face and backfires under hard acceleration and under load. Ignition timing is set to factory spec and appears to advance when using a timing light in the driveway. I am still totally unclear how the timing advance is controlled (ECU???) and how load is sensed (normally manifold or ported vacuum on most cars, but apparently not this one). Any insight??? The ol' Haynes book is maginal at best.

 

Chris

Sorry, should be "equation" and "marginal"

 

ALSO- Is my notion of putting an earlier vacuum-advance distributor (from an '85) in my car ill-advised?

 

Thanks.

Chris

 

 

 

 

OK, got out today in the currently tolerable weather and played with this thing some more. Tested every aspect of the FI system to rule that stuff out of the euqation. Air mass meter is within specs, fuel pressure is correct while running and sitting for 10 minutes (fuel filter is new), throttle switch is adjusted correctly. So, the symptoms that I am dealing with- car starts and idles fine, acceleration is a bit sluggish when rolling gently into the throttle. Falls flat on it's face and backfires under hard acceleration and under load. Ignition timing is set to factory spec and appears to advance when using a timing light in the driveway. I am still totally unclear how the timing advance is controlled (ECU???) and how load is sensed (normally manifold or ported vacuum on most cars, but apparently not this one). Any insight??? The ol' Haynes book is maginal at best.

 

Chris

Your other disty won`t work.

 

ECU calculates required advance from TPS and airflow meter inputs.

 

Suggest you measure fuel pressure under load when the problem occurs.

Your other disty won`t work.

 

ECU calculates required advance from TPS and airflow meter inputs.

 

Suggest you measure fuel pressure under load when the problem occurs.

 

OK, will give that a go.

Thanks.

Chris

Maybe a clogged cat?

Chris

 

you should check out the thread --- EA82 looses all power ---. You just might find a similarity/solution to your situation

 

Bill

What about vacume hoses fellas

Probably a bad TPS. Check it through the sweep with a DMM - might have bad spots in it.

 

GD

Problem solved!!! It was a crappy fuel pump. This was certainly a good exercise in getting familiar with the injection system, however. Now on to more mundane things- timing belts, oil pump seal, exhaust studs...the usual suspects!

 

Chris