[sleepys350]

got a 1992 mustang 302 vic jr heads corbra intake custom grind comp cam. stock maf 19# injectors a9l computer. washing down #1 plug. checked all ignition. pops through intake sometimes. gas in upper intake. rough idle. tps has 5 volt in and out. changed computer to another a9l no different. runs great at times like a turd at others. any help before i go to carb?

[vristang]

Either the tps sensor is fubar, or you're checking it wrong.

What is the firing order of the 'custom cam'

Pull the diagnostic codes...

[Kryptonite92]

The car sleepy mentioned above is actually mine, we are all pulling our hair out trying to figure out what the problem is. the firing order of the cam is 13726548, the tps sensor is brand new i checked both the orange wire and the green wire both have 5 volts which i know cant be rite, im gonna have the codes pulled asap. would the o2 sensors cause this? another question is, is there any difference in the computer harness from 92 to 93? the harness and comp came off a 93 gt. also runs like crap when cold after warm up its ok but after about 2-3 min of idleing the rpms instantly drop and it struggles to idle, i can shut it off and start it and it runs fine for 2-3 min then the same thing happens. My car is in excellent condition which is rare around here which is why i dont want to put a carb on it so any help is greatly apreciated.

[mittjere85]

Posted via Mobile Device

[mittjere85]

your tps reading should be 0.98v

[hotcobra03]

Have u Tryed order 15426378 .if not sure go to step 1 pull all plugs out and follow rotor feel 4 piston

[hotcobra03]

Also direction goes counter clockwise and tdc as you already know

[hotcobra03]

Tps function has nothing to do with running rich.it does power.ck codes test say ck if 68 koeo and 58,31,41 koer if yes they must be done first.

[Black1987Stang]

kinda sounds like what mine was doing when I only had one o2 sensor or as if I had a bad one....it was basically taking the info from the bad/missing sensor and making that side of the engine run reallll lean, I had real low vacuum at idle, ran like it had a huge cam in it and it wouldn't idle on it's own. and it would be ok for a minute or two sometimes if I started I guess since it runs through the startup cycle or something. I found it out when I got my Tweecer R/t and ran it in Calcon and saw it trying to command real lean readings. I turned off the 02's by running it in open loop all the time and now it has 16.5 inches of vacuum and runs smooth like stock.

That tps reading ain't right but if it was a tps or firing order problem I don't see why it would be running fine for those 3 minutes, it would be running crappy all the time.

Does it run different for a while if you run it after leaving the battery disconnected for a while?

[FoxFiveO88]

i had a similar problem after my MAF conversion...ended up just having to clean the build up on the plugs and adjust the timing a little....

[jrichker]

Originally Posted by Kryptonite92

The car sleepy mentioned above is actually mine, we are all pulling our hair out trying to figure out what the problem is. the firing order of the cam is 13726548, the tps sensor is brand new i checked both the orange wire and the green wire both have 5 volts which i know cant be rite, im gonna have the codes pulled asap. would the o2 sensors cause this? another question is, is there any difference in the computer harness from 92 to 93? the harness and comp came off a 93 gt. also runs like crap when cold after warm up its ok but after about 2-3 min of idleing the rpms instantly drop and it struggles to idle, i can shut it off and start it and it runs fine for 2-3 min then the same thing happens. My car is in excellent condition which is rare around here which is why i dont want to put a carb on it so any help is greatly apreciated.

Try to dump the codes. My bet is you won't be able to get them to dump.

Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

See Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical





If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.



The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.



The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.


There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see EQUUS DIGITAL FORD CODE READER (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.