3.9 flatspot any ideas

[UrbanRedneck]

my 3.9 has a flat spot that is there most of the time but not all of the time it still revs but is very flat in the power delivery.

I was thinking it may be the airflow meter are they comen to shit themselves and also is there an easy and better replacement.

Any ideas would be great as im not sure Thanx.

[peter r]

G`day

If it`s a flapper on the 3.9 as in the 3.9 replaced a 3.5 , could be but it can be checked with an OHM meter .

Cheers

[UrbanRedneck]

ye it is the flapper type i was thinking of changing it to a hot wire type but was unsure of what would be better and what was involved in change over.
Where might i be able to find info on checking the flapper type with ohm meter.
Cheers

[peter r]

www.gomog.com/allmorgan/plus8.html

Go to....

EFI Specific

Then .....

3.5 Injection System ( checking procedure )

This is a Pommy Morgan site , the main thing is that Pommy Flapper EFI has differences to what our Flapper EFI is but the basic stuff is the same as far as checking .

It won`t tell you how to check the flap with ohms but if you look at the way they use volts in the flap test .

Use the same pin 9 and 7 on the flapper with the plug disconected from the flapper .

Only use an ohm meter .

Move the flap through its arc using something like a chopstick better to be non metalic .

The meter should read smoothly and steadily through the range .

It should not read zero or infinity at any time .

Because the cars not doing it all the time you may need to do it a few times to find anything .

Also do the same type of check on the Throttle Potentiometer because it can give flat spots also .

The site explains how to check the TP using volts but this is similar to the AFM . They work in a similar manner . ( in this area) edit = ( )
Cheers

[UrbanRedneck]

thanx very much for that info will have a look at it today hopefuly i can find what is going on