DLO5.0HHH

ok so i have a 89 mustang 5.0 with an e303 cam bbk cold air intake bbk underdrive pullies full exhaust and thats about it when it comes to engine modifications it is also an automatic and has 3.73 gears in it and i recently got a check engine light come on but im not able to pull the code and it is running unbearably rich o actually calculated the mileage and im getting about 4 mpg and i really cant think of at could be wrong with it if anyone can give me help or a point in the right direction i would greatly appriciate it thanks guys

67mustang302

What thermostat is in it?

And you need to get that code.

Five0hFox

If the check engine light comes on and it starts running extremely rich, I would guess if you get the code, it will tell you your problem. You can check the code yourself with just a jumper wire and a 12v test light.

DLO5.0HHH

yea i kno i need the code ive tried connecting the solous up to it on many occasions but its seems like there is no power to the connecter

stanks347

Just had that problem. Replaced the ECU. All Better.

DLO5.0HHH

thats wat i was thinking the ecu but didnt try replacing it it also smokes its *** off under half or more throttle and sometimes surges at stops and bucks at certain speeds.

stanks347

Could be a fuel press problem. When I first put my S/C on I had the bucking and surging problem. I turned the fuel reg up and it helped. But with the ECU not communicating to the scanner I would try a friends ecu or a new one. My brothers solous could not read codes on my old ecu. I replaced the computer and the CEL went away and the hard starting went away. I know that a ton of people on this forum recomend not changing the ECU but when it is not talking to the scanner what else you gonna do?

DLO5.0HHH

yea i ordered one from work bout 4 days ago so it should be in any day now and i did replace the fpr and it help with the surging at stop lights and after checking everything but ripping the motor apart the ecu was the las thing i could think of i posted this just to see if anyone else has had the same problem cause a cause my buddies dad which is a mustang nut and knows everything there really is to kno said even him hasnt seen a mustang run as rich as mine lol