James Rouse

I just checked the resistance on my afm and the resistances on pins 6and 8,8 and 9, and 6and 7 were way too high according to the porsche manual for my afm with a date stamp of 030 what does that mean ? All of the resistances were within the ranges for the afm's with the 042 date stamp is it possible that my car has the wrong afm? Would that even make a difference? My car is an 84 model I bought it sick and am trying to fix all the horrific neglect and have done very well but the car stutters at about 1800 rpm (acts as though its starving for fuel=undriveable) and I cant track that down but most everything seems to point to the afm , any help you guys could give would be greatly appreciated!

James Rouse

anybody want to chime in with opinions on whether or not i should replace this?

SteveG

Is the "afm" you refer to the same as the MAF on the '85 and up? What date does "042" refer to? Maybe posting pics. Alan in Phoenix is the source on most of these questions, maybe a PM to him. I've not seen numbers posted for the MAF pins, but he might know.

James Rouse

Thank you Steve do you know his username right off the top of your head?

MainePorsche

It's Alan.

SteveG

Right, just "alan" his sig line says "electron wrangler"

Lizard928

The higher or out of spec resistance will affect the running. The afm is the barn door for 80-84 US cars.

If you haven't done so, replace the green wire, set timing as per manual as well as confirm both fpr are not leaking as well as the damper.

James Rouse

Thanks for the suggestions and the green wire and timing are both on the to do list , but I have already pretty well ruled out electrical as the cause of my problem (aside from the barn door ) by simply squirting fuel down the intake which allows the car to rev normally (went all the way to 4500 rpm before backing off) so that made it pretty clear to me that my issue is insufficient fuel being fed to the engine . Will be checking the Fpr's and damper tomorrow when I drop the tank to repair the massive fuel leak i just found (Joy of Joys!) Also I will be contacting Alan ASAP

Lizard928

If that is your problem, rebuild the injectors and replace the filter.

qdac

James,

I believe that the Temp I sensor values that are listed in the WSM may not be correct. There is a Technical Bulletin (Model 928, Group 24, Number 83-02 date March 15, 1983) that gives a more comprehensive set of AFM testing values than is found in the WSM.

The Technical Bulletin states that the Temp I sensor values should be the SAME between the pre- and post- 042 date code modules.

In addition, the Technical Bulletin gives Temp I sensor values for two temperatures:

20C (68F): 2 to 3 k ohms
30C (83F): 1.2 to 2.4 k ohms

There is a note that the pre- 042 values for the other tests are exactly half that for the post- 042 units. The WSM values here are consistent with those stated in the Technical Bulletin. (I'll bet that the WSM editor multiplied ALL of the earlier values by two - this is correct for all but Temp I.)

I got the Technical Bulletin from the Jim Morehouse CD set.

I have never been able to locate either the mythical date code stamp *or* any photo thereof.

Note that there is an AFM re-conditioning procedure that is described at http://www.the944.com/afm.htm. This procedure *may* help with your off-idle problem.

BTW: I have read that the L-Jet is extremely sensitive to Temp II sensor. You might check that also.

Good luck!