Reading codes through CHL, hot start problem

[gt347mustang]

Ok, I am having a weird problem with my car and I will try my best to explain.

After about 4 months with the new motor and no problems what so ever my car started acting up, it’s a 94 5 speed with a 347 and a procharger

When I first start it in the morning it will start fine and run for about 2 minutes, then the rpm’s jump to 1500 and the check engine light flashes 3 times. The rpm’s stay at 1500 for about 15-20 seconds and then they fall to 600-700(normal idle for me), and then the CHL flashes very quick for a split second. This is where it gets weird, the CHL flashes and I can read codes form it! I have gotten codes saying lean o2’s and MAF voltage low canister purge and so on. So far I have replaced the TPS, IAB, MAF, cap, rotor, and wires, canister purge valve, both o2’s, distributor(PIP), AIT and ECT. I cannot find any vacuum leaks, all grounds are good and fuel pressure is constant at all times. I cannot get rid of the problem and I am out if ideas to try and just about out of money.

Has anybody else heard of this? I am also having trouble with hot starts, I can only start the car with the petal at the floor and sometimes I cannot start at all, I checked fuel pressure and spark during cranking and both seem to be working.

Does this sound like a short in the wiring? A bad Sensor? Bad Compression?

I have done numerous searches and haven’t found anything to solve my problem; any suggestions are welcome and appreciated.

Thanks!

 

[HISSIN50]

Is it a factory high-altitude vehicle? The BAP sensor is integral to the computer on SN95's (it was external on foxes).

Flooring the gas pedal while cranking shuts down the injectors. It reallly sounds like a tune issue (issues with hot starts like you have, can be too much cranking fuel). I mean no offense about the tune - but it does sound like it could stand to be tweaked some.

I have never known the CEL to flash the actual codes in real time (other than while retrieving them specifically). I would still run them the old way to double check, as well as gather underlying codes that might also be stored.

Good luck.

 

[VibrantRedGT]

Because you get lean codes from the O2's or low/high voltage codes from the MAF doesn't mean they need to be replaced. Bumping the fuel pressure up a few psi will get rid of the lean code. The MAF just needs to clocked (turned) in the right position to clear the voltage code. Cold and hot starts are due to big injectors. I'm not sure what size but with your mods hopefully its 36 or 42lb injectors. This is a tune issue. A custom chip , Tweecer or PMS is the answer to this. I am experiencing the same issue. With the PMS I'm able to add or remove fuel during start up's. I would take your vehicle to reputable tuning shop and have it put on dyno.

 

[gt347mustang]

thanks for the help guy's
But why would this start doing acting up like this after months of running like a champ? i used to have zero problems, the car ran like stock until one day it crapped out on me. By the way i am running on stock computer right now and i think the car is out of flordia(so probably no on the high elevation ecu) i do live in colorado(5000+ feet). but any more ideas on the flashing CEL?

 

[VibrantRedGT]

Ok, we still need more info on you combo. The stock computer is very finicky. Your car can run like a raped ape one day and Hyundai the next. There are plenty of factors that will cause this like temps, humidity, elevation, road conditions, fuel types, the list can go on and on. Bottom line is this. With the motor you have plus a blower your lucky the car even starts. My car with 42# injectors would shoot 10 foot streams of fuel out the tailpipes. Your car needs a dyno session and some tuning. What your experiencing is driveability issues, not broken parts.