speed density help

1sick94hb · July 1st, 2008, 04:56 PM

Ok 88 mustang GT. car appears to be stock. I cannot get the car to run right. runs very very rich. pours black smoke and kill my eyes. idle surges all over the place and the motor stumbles pretty bad and stalls alot. I can diconnect the CTS and the car will lean out but idles very high. So far i have installed a new CTSx2,MAP(also the vacuum hose running to the map) O2 sensors, injectors,fuel pump, fuel rail and FPR, pick up in the distributor, cap, rotor, wires and a ECM. If i put a new set of plugs in the car it runs great doesnt seem like it has an aftermarket cam in it but it has alot of power for a stock 5.0. After around 30 minutes of driving the car around it will finally start to foul the plugs out and load up real bad. Should i try doing the MAF conversion on it?? I have checked everything i know to check. Ive set the TPS to 0.98V at idle and ive done the idle procedure probably 10 times. The car does have aftermarket exhaust but nothing i do to this car seems to help. I can either get the car to run really rich or really lean(bad lean pops) but i cant seem to find a medium between the 2. There are no vacuum leaks i even installed a new upper plenum gasket as well as cleaned the screen for the PCV valve.

Darrell · July 1st, 2008, 05:33 PM

Did you check for codes?

1sick94hb · July 2nd, 2008, 10:15 AM

KOER i get both o2's not switching indicating rich and for koeo i get a CTS and a MAP sensor out of range code. Which all of these have been replaced. I am going to start tracing the wiring harness today and see if something is a miss with it. When i bought the car it had sat for a few years. Put a fresh battery in it and fresh gas and it fired right up and ran great. The more i drove it though the worse it started to run.

1sick94hb · July 2nd, 2008, 01:40 PM

well i came in this morning and wiped the slate clean. i cleaned all 8 plugs and disconnected the battery and cleared any codes. before i attempted to start the car i checked for KOEO codes and got 5 codes. TPS,CTS,MAP,and 2 other one but anyway i went to the local junkyard and snatched a TPS off a thunderbird and now the car runs perfect which seems weird cuz i tried a known good TPS off another mustang. But now the car runs great and doesnt kill my eyes! Also found out the ECU that was in the car was out of a 87 t-bird which should work but just for the sake of felling better i pulled the ECU out of a 88 mustang.

Darrell · July 2nd, 2008, 03:37 PM

I could be wrong but I believe the ECU for the Mustangs is different than any other car. That could very well have been your problem all along.

badshoe · July 2nd, 2008, 09:41 PM

The TBird PCM is not correct if your engine is a Mustang GT 5.0L. The Mustang engine has 19 lb injectors (higher flow than TBird 5.0L) and I think the Bird has a different firing order. The firing order I'm sure has been changed on your engine however the injectors are still shooting out of sequence with the Bird PCM. I would say most likely it's the Mustang processor that fixed your car.

1sick94hb · July 3rd, 2008, 02:22 AM

Not sure on the ecm. i called ford this morning questioning the ecu as it was a refurbished ford unit. gave him the numbers and it came up for a t-bird which was a speed density car for that particular year. Anyway now the car runs awesome. Just need to do the base idle procedure on it in the morning and it should be good to go!!!

July 1st, 2008, 04:56 PM	#1
1sick94hb Newbie Join Date: Apr 2008 Posts: 10	speed density help Ok 88 mustang GT. car appears to be stock. I cannot get the car to run right. runs very very rich. pours black smoke and kill my eyes. idle surges all over the place and the motor stumbles pretty bad and stalls alot. I can diconnect the CTS and the car will lean out but idles very high. So far i have installed a new CTSx2,MAP(also the vacuum hose running to the map) O2 sensors, injectors,fuel pump, fuel rail and FPR, pick up in the distributor, cap, rotor, wires and a ECM. If i put a new set of plugs in the car it runs great doesnt seem like it has an aftermarket cam in it but it has alot of power for a stock 5.0. After around 30 minutes of driving the car around it will finally start to foul the plugs out and load up real bad. Should i try doing the MAF conversion on it?? I have checked everything i know to check. Ive set the TPS to 0.98V at idle and ive done the idle procedure probably 10 times. The car does have aftermarket exhaust but nothing i do to this car seems to help. I can either get the car to run really rich or really lean(bad lean pops) but i cant seem to find a medium between the 2. There are no vacuum leaks i even installed a new upper plenum gasket as well as cleaned the screen for the PCV valve.

July 1st, 2008, 05:33 PM	#2
Darrell MM Ninjas! 1990 Mustang LX 9.36@143 mph Join Date: Jan 2006 Location: Fond du Lac, Wisconsin Posts: 6,574	Did you check for codes? __________________ Racing in memory of Dave Bandt 11/19/69 - 3/23/08 "he's traded his wheels for wings" Professor of Natural Aspiration Thanks to: Artie at Trick Flow, Dave at Team Z Motorsports, Brian at Total Engine Airflow and Harold at Furo Racecraft

July 2nd, 2008, 03:37 PM	#5
Darrell MM Ninjas! 1990 Mustang LX 9.36@143 mph Join Date: Jan 2006 Location: Fond du Lac, Wisconsin Posts: 6,574	I could be wrong but I believe the ECU for the Mustangs is different than any other car. That could very well have been your problem all along. __________________ Racing in memory of Dave Bandt 11/19/69 - 3/23/08 "he's traded his wheels for wings" Professor of Natural Aspiration Thanks to: Artie at Trick Flow, Dave at Team Z Motorsports, Brian at Total Engine Airflow and Harold at Furo Racecraft

July 2nd, 2008, 09:41 PM	#6
badshoe Newbie Join Date: Dec 2007 Posts: 16	The TBird PCM is not correct if your engine is a Mustang GT 5.0L. The Mustang engine has 19 lb injectors (higher flow than TBird 5.0L) and I think the Bird has a different firing order. The firing order I'm sure has been changed on your engine however the injectors are still shooting out of sequence with the Bird PCM. I would say most likely it's the Mustang processor that fixed your car. __________________ BadShoe Productions, How-To-DVD's specializing in Ford drivetrains www.BadShoeProductions.com

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July 2nd, 2008, 10:15 AM	#3
1sick94hb Newbie Join Date: Apr 2008 Posts: 10	KOER i get both o2's not switching indicating rich and for koeo i get a CTS and a MAP sensor out of range code. Which all of these have been replaced. I am going to start tracing the wiring harness today and see if something is a miss with it. When i bought the car it had sat for a few years. Put a fresh battery in it and fresh gas and it fired right up and ran great. The more i drove it though the worse it started to run.

July 2nd, 2008, 01:40 PM	#4
1sick94hb Newbie Join Date: Apr 2008 Posts: 10	well i came in this morning and wiped the slate clean. i cleaned all 8 plugs and disconnected the battery and cleared any codes. before i attempted to start the car i checked for KOEO codes and got 5 codes. TPS,CTS,MAP,and 2 other one but anyway i went to the local junkyard and snatched a TPS off a thunderbird and now the car runs perfect which seems weird cuz i tried a known good TPS off another mustang. But now the car runs great and doesnt kill my eyes! Also found out the ECU that was in the car was out of a 87 t-bird which should work but just for the sake of felling better i pulled the ECU out of a 88 mustang.

July 3rd, 2008, 02:22 AM	#7
1sick94hb Newbie Join Date: Apr 2008 Posts: 10	Not sure on the ecm. i called ford this morning questioning the ecu as it was a refurbished ford unit. gave him the numbers and it came up for a t-bird which was a speed density car for that particular year. Anyway now the car runs awesome. Just need to do the base idle procedure on it in the morning and it should be good to go!!!

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