JBeachstang11

Thank you sir!

JBeachstang11

Checked continuity from MAF wiring back to harness and doesn't appear to be any breaks at all.

Going by this test to check the resistance

http://www.myo-p.com/Ford-EEC/Main%20Frame.html

Instead of 10k ohms or better across the #50 MAF sig and #9 MAF rtn wires I was getting (on the 20k setting) 2.01

Also between the #50 MAF sig and ECU Grnd I was only getting 3.01 instead of 10k or more (on the 20k setting)

Results of this according to that test say faulty control unit. Also verified my Injector info and changed the breakpoint to 1.9182 from the 3+ that is was effectively richening it to no avail.

Same crap idle and stall or surge if I hold the gas down just a tad.

JBeachstang11

Not sure what's going here but I've known the ECU was an A9P in my 5spd car but what I just noticed was the harness plug going into the ECU say A9P on it as well...

It's had a few owners, my tag is painted over on the drivers side and running down my vin only gives me basics, no trans info.

Does that section of the harness change with different ECU's?

JBeachstang11

Really have no idea at this point. New computer, new 02 sensors (old ones were coming apart), idle reset, even capped vacuum at pipe off intake, away from vac tree and still does it. Voltage good at 02 sensor heaters. No idea

Only thing that remains a constant here is unplugging the MAF sensor and it will idle, but it is a new sensor and the curve is entered in the computer..

88 orangepeel notch

You've got me stumped, you've done everything that I would have tried. I only read the last 2 pages of this thread to get caught up, were there any codes stored on the way old ECM before you swapped them?

Also, I've seen a bad ground do some really weird things on these cars,

JBeachstang11

I now it's been a mess.

Only öld comp" codes before I swapped were
Pulled codes eng off Key on and got..

15 rom test fail or power interrupt to memory
85 ecessive fuel pressure or flow, canister purge circuit

91 (not sure since eng was off?) Oxygen sensor problem, fuel pressure out of specified range or injectors out of balance

96 Fuel pump circuit

Now the codes I pull off the new computer, eng off key on are
15
31
85
84
96
""
-1-

31
96
""

JBeachstang11

Finally got my build sheet from Ford. Turns out from what I can gather this car was an automatic car and at some point somebody swapped in the manual trans.

Now it has a manual computer and I know there is a wiring issue on pin 30 between the two with the neutral safety switch but I'm not sure how that would cause an idle issue.

Still stumped as the idle problem is almost the same as it was before I rebuilt the engine so it must be a wiring harness issue or a TB issue or maybe my vac tree is cracked but something has carried over, even though most of the sensors are new with the fresh engine build.

Still digging.

BTW Moates recommended I start with the "Cobra" strategy to begine with as it is already setup for the TB, Inj, and MAF mapping. but now the car smokes sometimes like its getting too much fuel..

88 orangepeel notch

Wish I could be more help, but your thinking on a vacuum leak is where I'd start. Good luck

Have you checked fuel pressure?

JBeachstang11

Well I appreciate all the help and tips you've given so far orangepeel.

I haven't checked the fuel pressure yet, good point. It does have a new stock type regulator and PO swapped in 190lph pump but like you said best idea is to eliminate variables.

JBeachstang11

Fuel pressure is spot on using a test guage. Right at 40psi.

Car starts and runs fantastic for a couple mins then settles into a chunky smokey idle, that's when it begins to smoke. No smoke at startup.

Ebay injectors were leaking, swapped in new ford 24# M-9593-LU24A units. Did leakdown test on 1-4 bank and engine is sealed up tight. Haven't done 5-8 bank yet. Swapped faulty MSD coil, now Accel.

Changed oil because of Injector.

So far is running fairly well other than a smokey idle and starts to "chug" while driving it now. I really feel it is too rich from the smell of the exhaust.

Finishing my wideband install.

Need help with my quarterhorse tuning. I can email my tuning file if anyone can look at it and see if there are any serious problems.

Setup is

Injectors
HS 23.3102
LS 29.0729

Brkpoint .9999

Offset
15.9375 0.7813
14.0000 0.8750
13.0000 1.0000
12.0000 1.1250
11.0000 1.3125
10.0000 1.5313
9.0000 2.0313
8.0000 2.2188
7.0000 3.5313
6.0000 4.4375
5.5000 7.5000
0.0000 7.5000

MAF transfer 75mm ProM chrome bullet

15.9998 1233.738
5.0000 1233.738
4.8000 1105.739
4.6001 986.927
4.3999 877.621
4.2000 777.185
4.1001 729.978
3.8999 642.216
3.7000 561.741
3.5000 488.553
3.3000 422.652
3.2000 392.236
3.0000 336.157
2.8000 285.781
2.6001 240.791
2.5000 220.197
2.3000 183.128
2.1001 150.811
1.8999 122.613
1.7000 98.217
1.6001 87.445
1.3999 68.752
1.2000 52.594
1.0000 39.604
0.8000 28.832
0.7000 24.396
0.5000 16.792
0.3000 11.089
0.1001 6.653
0.0000 5.069