Danno

"Key on, engine not running - .25v"

That's good.

"Idle 900 rpm - 1.0 - 1.2 v"

That's not good, your AFM is sending out a signal that indicates you've got 20-25% more air-flowing than actual. Your DME will then use a look-up point on the chips that delivers 20-25% more fuel than needed as well. I suspect the spring-preload screw has been adjusted. This will lead to even higher mis-matched signal as flow increases. I think this is the problem here.

But, check out your air-temp sensor as well. Measure the resistance of the air-temp sensor between DME harness-connector pins #22 and 6:

32F: 4.4-6.8 K-ohms
59-86F: 1.4-3.6 K-ohms
104F: 1.0-1.3 K-ohms

Also measure the air-temp sensor directly at the AFM across pins #1 & 4 (#5 is empty pin). A difference between measurements at the DME-connector and at the AFM itself will indicate a wiring problem in the harness.

Luke

650cc @3bar

duty cycles must be like 2% <img border="0" title="" alt="[Wink]" src="wink.gif" /> maybe you should swap injectors w/ me for my 440cc's.

i dont think your injectors can close fast enough

LMAO <img border="0" alt="[hiha]" title="" src="graemlins/roflmao.gif" />

Magown

Ok did more testing, looks like multiple probs. POS car.

AFM Voltage

Key on engine off full sweep .25v - 4.58 volts no spikes.
Crusing steady 3rd gear 3k rpm around 2.0 volts.
WOT 16psi in 3rd max voltage 4.4volts

Air Temp sensor

Pin #1 & #4 AFM on 88F outside 1.3k ohms
Pin #22 & #6 DME 88F outside .66k ohms

Coolent temp

yellow brown wire at sensor plug 1.34k ohms
Pin # 13 DME nadda

School is out and I need to drive this sucker home back to the shop tomorrow so I can work on it. How about I reinstall the 2.5 bar FPR for a 9% decrease? Maybe also adjust the spring tension on the flapper door?

fast951

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Luke:
<strong>650cc @3bar

duty cycles must be like 2% <img border="0" title="" alt="[Wink]" src="wink.gif" /> maybe you should swap injectors w/ me for my 440cc's.

i dont think your injectors can close fast enough

LMAO <img border="0" alt="[hiha]" title="" src="graemlins/roflmao.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Yes they can. I got the 75# injectors idling like stock.

Magown

My car with all it's flaws idles better now then it did with the stock stuff. Can't wait to get all these little bugs worked out.

Luke

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by fast951:
<strong> </font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Luke:
<strong>650cc @3bar

duty cycles must be like 2% <img border="0" title="" alt="[Wink]" src="wink.gif" /> maybe you should swap injectors w/ me for my 440cc's.

i dont think your injectors can close fast enough

LMAO <img border="0" alt="[hiha]" title="" src="graemlins/roflmao.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Yes they can. I got the 75# injectors idling like stock.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">SHHHHH! , i'm trying to deal here. <img border="0" title="" alt="[Wink]" src="wink.gif" />

fast951

Steven,

Unplug your O2 sensor and see if it makes a difference. Under Idle and PT a bad O2 sensor (sending a lean signal) could cause the DME to compensate so it'll be richer.

Your AFM seems ok!

Danno

Ok, looks like your AFM is working alright in non-idle conditions. But it's still opening too far at idle. I think there's an air-bypass screw on the AFM to send air around the back of the flapper-door. Open that up to send more air around without hitting the door. This will close the door a little and have it register the proper voltage of 0.79-0.85v for a 900rpm idle.

The testing of the air-temp sensor seems odd in that measuring it at the AFM gives a different result than at the DME connector. I forgot to mention that you should have the DME disconnected from the harness so that you're measuring resistance only through the sensor and not the DME circuits as well. It appears to be reading a little on the hot side, which is OK because you'll just get less cold-start fuel-enrichment.

On the engine-temp sensor, when you're measuring resistance on pin #13, you need to use a ground as well. So pick any of the pins# 16,17,19,28 and the resistance should be the same regardless of which one you use.

I think we're getting close here. Yes, the 2.5-bar FPR will lower pressure and send less fuel out, but this is introducing another error to compensate in the opposite direction for the AFM error at idle.

I still think there's something goofy with the AFM. If it's indicating 20% more air-flow (higher-voltage than normal) than actual at idle, you'll be rich. But then you said it runs better off idle with the 55-lb/hr injector setting. Which would seem to indicate a lean condition because you'll have a higher duty-cycle than needed for 65-lb/hr injectors. This would indicate that the AFM is sending out a lower voltage than normal under off-idle conditions... Maybe you can swap with someone with a known good AFM?

Magown

Ok I just retested with the connector off the DME,

Pin #22 & #6 DME 75F outside 1.27k ohms

Pin #13 & #19 1.02k ohms (was last run about 6 hours ago)

I don't have an O2 at the moment, it was fouled, so I decided to plug the hole until I figured out why it was running so bad instead of ruining another $140 02 sensor.

fast951

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Stephen Magown:
<strong>
I don't have an O2 at the moment, it was fouled, so I decided to plug the hole until I figured out why it was running so bad instead of ruining another $140 02 sensor.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">$140 for an O2 sensor? Why not use one for 1/3 price that works just as well. Contact Paragon Products and get their O2 sensor. You might need to use the connector from your original sensor.

Using a good O2 sensor will help smooth your idle some. However you still need to adjust/fix the AFM signal..

Magown

The old one got lost in all my moving around, I don't have a pig tail that will work. <img border="0" alt="[crying]" title="" src="graemlins/crying.gif" />

I have no problem using a generic 3 wire for $30. I noticed the other day that the head lights use the came kind of connector. Let me find a wrecked 944 and I'll have what I need.

dmoffitt

now i'm pissed, my friend's dad threw out my old MAF when we were cleaning his garage (where the top-end rebuild occured for my car). it worked perfectly, i'd have sent it to you free for comparison *GRRRRR* -- of course, you _could_ just go with a Digital MAF kit from lindsey or a MAP setup from GURU, that'd certainly fix any problems the stock air-meter was causing

Magown

Sure that's the plan, but it would be stupid and irresponsible for me to buy one right now , I've got other financial obligations I've tend to first. Trust me, I'm dieing to have 400wrhp. I know what it feels like for someone to toss out your stuff. I lost my spare 951 intake manifold that way.

dmoffitt

ya, i was just chiding you... it's best to fix what you have than just throw money at it (god knows these cars are EASY to do that with hehe).