early 85 944 with a 87 motor?

[mcguiver7]

so when i bought my early 85 944 i was told it had a motor from an 86. i was doing the timing belt on it the other day and some how magically i have a spring tensioner which i thought only came on 87+. my dme and afm are for the early 85. could this explain my consistent idle stumble at start up?

[924Sman]

Nope...Someone put the spring tensioner on in place of the eccentric roller. No it does not affect the DME/AFM. Now if it is an 87 engine and think it is early then yes the early DME would not function properly on it. Check the engine numbers on the block near the sensors/oil cap. Post them and we can look up what engine it is for certain.

The DME and AFM must be of the same engine model. You can run a late DME/AFM on an early engine. They both work together meaning you cannot just use the DME late with an early AFM visa versa.

Dal

[carsontc]

Originally posted by mcguiver7
my dme and afm are for the early 85

since Socal Driver is gone...I will oblige…


but what about the idle control valve ?

it should match the same DME & AFM series being used as well

[mcguiver7]

block code:
m44 /01 or /07
43H 10049

afm # 0280 202 028

dme # 944 618 111 01

it has the aux air valve along with idle control valve.

[924Sman]

You are good to go. The 07 is no different than the 01. Late engine design. 85/2 body with a 87 engine according to the 43H 10069....A 43F 00001-60000 is the 85/2 engine. You have an "H" which is the 87 924S/944 na engine....G is 86...E is 84. Now I need to dig up the parts #'s to match the engine....Hang tight....

Back to the DME......

Idle stabilization valve will cause a poor idle if stuck, high or low usually high.

Dal

[924Sman]

Ok the DME is an early one on a late engine....944.618.111.01^ if this is the number you have. AFM should be 944.606.121.01^....I cannot find the 028# you gave. Not a Porsche OE number.

Check that afm # once again for me.....Nevermind I found it.....You also have the early afm. The late should end in 064 not 01. The 0280202028# is a discontinued Bosch part number. It is now 0280202064.

Dal

[mcguiver7]

just double checked it, engine code is m44 /07.

so i have a late engine with a early dme/afm?

if i switch to the late afm/dme i need to swap vac systems to accomidate the single idle control valve?

[924Sman]

The ISV is the same on the late engine. If it were a 85/1 w/AC an auxillery valve is used. You are OK.

Dal

[924Sman]

Clean the ISV 1st then buy one if needed.

To clean it.....Get 2-3 wires for jumpers. Remove the ISV and place one wire on one of the 3 posts on the ISV, one to power 12v one to ground(iirc). The valve should open/close, reverse the wires polarity and by the use of the 12v work the valve back and forth to free the valve up. Use brakekleen to spray clean it and WD40 to lube it. Play with the connections until you get the ISV to open/close in regards to the wires.

Do not use carb cleaner as this stuff leaves a residue behind. Worse if used on the throttle body/afm. This I am sure is debateable but a master tech told me this bit of info on the carb cleaner.

Dal

[mcguiver7]

aux air regulator has been cleaned and replaced already while trying to trouble shoot this problem.

like you said before i have a late motor with a early dme/afm. wouldnt this cause a problem? considering it's a higher compression motor running on a dme that is mapped for lower compression.

[924Sman]

That could be but I have never seen this before just the opposite, early engine/late dme,afm and it works. According to the manual I have it reads your way works but I cannot attest to it. But i think you may have it, perhaps the setup you have now is the issue. Only way to tell is by getting a late dme and afm and give them a go.

Shoot mine are idle(head under repair) I would lend them to you but mine is altered(dme) so they may not be a good comparison.

Dal

[mcguiver7]

so in my case most likely it's running lean. maybe i can richen it up via the co setting and run higher octane.