chrisbrown19067

Ok, so I have a 1986 mustang 5.0 HO 5spd. I recently pulled the engine, rebuilt it and added some bolt-ons. I started the car yesterday, and IT RUNS LIKE ****! I need help trying to get it to run ok. My setup: 306 w/ 10.5-1 compression, TFS twisted wedge heads, TFS stage 1 cam, FRPP roller rockers, TFS Street heat intake, 65mm TB, 24lb/hr injectors, 75mm Pro M MAF. I converted the car to Mass Air using an A9L computer.

The car will start and run, but it is very erratic. The idle is choppy and jumps around(barely idles). When driving, it pops out of the intake(maybe lean). I think i also hear a slight ping under partial throttle. It bucks back and forth and surges under partial throttle too. The exhaust doesn't smell rich and it pops from the intake, so i definetly think it is lean. I set the base timing at 12 degrees.

Anybody have any suggestions?? Do you think the 24lb/hr injectors are enough or should i go with 30's. Also, i have a stock fuel pump right now. I will be installing a 255lph unit on Monday

1fstlx

if it pops out of the intake its the wrong timing. first things first did u set the timing correctly? nice combo too u should make great power. 24's are plenty. 30's are power-adder / 351 territory.

92cobra

make sure when you set the timing the spout connector is out. Also, double check the maf was callibrated for 24lb injectors and not 19lbers, also double check the tps.

chrisbrown19067

I set the timing at 12 degree's with the spout disconnected. The MAF is calibrated for 24's. As for the TPS, i talked to a mustang guy and he said to set it at .7 volts with the key on. So i did this, i havent checked the voltage while running yet. Do you guys usually set it running?

gearbanger

if it pops from the intake then it has to be running lean for some reason. do you have a fuel pressure regulator?

1fstlx

ive set the tps while motor is off key on. u wanna be as close to 1 volt as possible at wot

1fstlx

sorry meant to say closed throttle. 5 volts wide open. do this with key on engine off

chrisbrown19067

Well I am gonna go set the TPS to 1 volt. I dont have an adjustable fuel pressure regulator yet, but am going to get one.

1fstlx

just remember it as close to one volt as possible at closed throttle ok?

chrisbrown19067

well i set it at 1 volt. and set my base timing at 10 degrees. I just drove it and it seems a little better. I didn't hear any intake popping. It still runs terrible though. IDK. I hope the fuel pump comes in the mail tommrow so i can install that and get that out of the way. I looked at the calibration on my MAF and it says its calibrated for a cold air with a 90 degree elbow. I have a cone filter on the maf now. How much could it really matter though?? I am going to get a cold air for it though, or make one. Also i checked the vacuum when the car is idling(very rough) and its around 15 or less.