Please Help!!!!!!!!

LS WHAT · 09-09-2002, 06:47 PM

Hello all. I This is my first post and I've come to get help on a serious problem. I just got done doing a H/C/I swap on my 88 lx. I ran it for a couple days on speed density then converted over to mass air using ITS harness, A9P used from MPS, and a 75mm bullet. The car breaks up and stutters anything after half throttle. Also the power is way down. Here is some food for thought: new coil, O2 sensors, ACT & ECT sensors, checked MAP sensor, HEGO ground is connected to block as is the other ground strap to the back of the head, 17 degrees of timing, 12 in of HG at idle, 35 lbs of fuel pressure( tried other settings but really didn't affect it), clocked MAF, swapped MAF with a buddies cal'd for 30#'s, got .68 volts between C&D and 12.5 between A&B on MAF. MAF wiring is OK, got code 66(low MAF signal voltage) KOEO, I have a different computer coming to see if it's that. the plugs sre rich but not on top. I'm completely stumped here.

Any ideas would be greatly appreciated.

Thanks, Matt

Bad89stang · 09-10-2002, 04:11 AM

I would do a more thorough check of your fuel pump. Make sure that the fuel filter is clean. The only other thing I can think of is the TFI module on the distributor. Good luck.

bigblockcoupe · 09-10-2002, 10:03 AM

the mass air meter needs to be calibrated to your injector size otherwise it won't run right it's either trouble with the maf meter or your maf wiring double check everything and make sure your meter is the correct calibration for your injectors.

09-10-2002, 10:16 AM

So are you running the stock 19lb. injectors?

"...swapped MAF with a buddies cal'd for 30#'s, got .68 volts between C&D and 12.5 between A&B on MAF."

So the MAF you are running right now is calibrated for 30lb. injectors? Unless you are running 30lb. injectors to go along with that MAF, you will run into some problems.

Also, 35lbs. of fuel pressure might be a little lean. The stock Ford setting is 38-42psi. So you might want to bump it up a little. But I'm not sure if that would be your problem. The only other thing I can think of is your timing. Some motors love lots of timing and run great. Is this a stock motor? If so, 17 degrees of timing may be a little too much. But if it's not pinging, then I guess you are ok.

Check that fuel filter too, like -Bad89stang- said.

09-09-2002, 06:47 PM	#1
LS WHAT Registered Member Join Date: Sep 2002 Posts: 4	Please Help!!!!!!!! Hello all. I This is my first post and I've come to get help on a serious problem. I just got done doing a H/C/I swap on my 88 lx. I ran it for a couple days on speed density then converted over to mass air using ITS harness, A9P used from MPS, and a 75mm bullet. The car breaks up and stutters anything after half throttle. Also the power is way down. Here is some food for thought: new coil, O2 sensors, ACT & ECT sensors, checked MAP sensor, HEGO ground is connected to block as is the other ground strap to the back of the head, 17 degrees of timing, 12 in of HG at idle, 35 lbs of fuel pressure( tried other settings but really didn't affect it), clocked MAF, swapped MAF with a buddies cal'd for 30#'s, got .68 volts between C&D and 12.5 between A&B on MAF. MAF wiring is OK, got code 66(low MAF signal voltage) KOEO, I have a different computer coming to see if it's that. the plugs sre rich but not on top. I'm completely stumped here. Any ideas would be greatly appreciated. Thanks, Matt __________________ 1988 mustang lx 5.0 Trick Flow Twisted Wedge Heads, Trick Flow Street Intake, Crower 15511 Cam, Pro-M 75mm bullet, Mass Air Conversion, Mac 70 mm t-body, 30 # injectors, 255lph fuel pump, NOS stage 1, 1.72 Scorpion Rockers, BBK shorties, Mac offroad h-pipe, 2 chamber Flows, AOD w/Transgo shift kit, 3.73's

09-10-2002, 04:11 AM	#2
Bad89stang Registered Member Join Date: Aug 2001 Location: Ft. Worth, TX Posts: 456	I would do a more thorough check of your fuel pump. Make sure that the fuel filter is clean. The only other thing I can think of is the TFI module on the distributor. Good luck. __________________ You're gonna need your seatbelt

09-10-2002, 10:03 AM	#3
bigblockcoupe Registered Member Join Date: Aug 2002 Location: broken arrow Posts: 212	the mass air meter needs to be calibrated to your injector size otherwise it won't run right it's either trouble with the maf meter or your maf wiring double check everything and make sure your meter is the correct calibration for your injectors. __________________ Rice Haters Club member #68 '93 Cobra 10.20@135 '89 Gt Coupe 12.20@115

09-10-2002, 10:16 AM	#4
Simi Stang Guest Posts: n/a	please help So are you running the stock 19lb. injectors? "...swapped MAF with a buddies cal'd for 30#'s, got .68 volts between C&D and 12.5 between A&B on MAF." So the MAF you are running right now is calibrated for 30lb. injectors? Unless you are running 30lb. injectors to go along with that MAF, you will run into some problems. Also, 35lbs. of fuel pressure might be a little lean. The stock Ford setting is 38-42psi. So you might want to bump it up a little. But I'm not sure if that would be your problem. The only other thing I can think of is your timing. Some motors love lots of timing and run great. Is this a stock motor? If so, 17 degrees of timing may be a little too much. But if it's not pinging, then I guess you are ok. Check that fuel filter too, like -Bad89stang- said.