Hello all i am new to your forum and really need some help. I have a 93 5.0 with kenne bell supercharger tfs heads 70 mm tb headers etc the problem is i have several codes 15 67 in the KOEO and 33 and 66 in the cm modes . What the car is doing part throttle stumble but not all the time and will not rev with power past 5200 . Power is way down and i am really frustrated Please help i have a chilton but its so vague i replaces the egr but the new one had a different pintle so i leak checked the old one which was good

 

Do you have the code descriptions or just the numbers?

 

lets go through the codes.

Code 15 is your keep alive memory or KAM. The problem is the voltage to the KAM is missing ie: wiring problem or the KAM is bad ie: bad computer. The KAM holds all the settings the computer learns has it operates and all the codes it stores while the engine is running.

Get yourself a voltmeter, check for constant 12volts at pin 1 on computer. If there isn't 12volts then you have bad wiring and need to trace it. If you have 12volts then teh KAM is bad = faulty computer.

Remember if teh computer needs to relearn all of it settings after it powers up then you can get surging idle, poor low speed performance like you noted and rough idle!

ALSO if you have a chip, some will cause code 15. remove the chip, clear teh codes and retest.


Code 67 clutch not depressed for a 5spd car or car not in neutral for an auto. Also of teh car has a/c it wants it off due to teh added load. possible neutral saftey switch issue, this code does not effect performance.


Code 33 EGR code. The 33 is an Engine Running code, it means the EGR valve opening was not detected by the computer. This could be due to a failing EVP or a fault in the wiring (or even loose harness) or poor vacuum.


Code 66 maf below minimum voltage . Before testing the MAf make sure the MAF is clean, there are no air leaks before and after teh MAF and that all plu conection are tight and clean. these can effect the MAF and casue a code.

Testing the MAF:
MAF sensor connector:

(OVAL)
A = VPWR (vehicle power supplied by ECM)
B = PWR GND (vehicle power ground)
C = MAF RTN (signal return)
D = MAF SIG (signal to ECM)

OR

[RECTAGULAR]
A = VPWR (vehicle power supplied by the ECM)
C = PWR GND (vehicle power ground)
D = MAF RTN (signal return)
E = MAF SIG (signal to ECM)

VPWR and PWR GND test:

Turn key to OFF position. Disconnect MAF sensor from harness connector. Set VOM to volts and connect VOM between VPWR and PWR GND at harness connector. Turn key to ON/RUN position (DO NOT start engine). VOM should display +10.5v or greater. If not, connector or VPWR circuit or GND circuit to battery may be faulty.

MAF circuit short-to-ground test:

Turn key to OFF position. Disconnect MAF sensor from harness connector. Set VOM to Ohms and connect VOM between MAF SIG and MAF RTN, and between MAF SIG and GND (two separate tests) at harness connector. VOM should display 10,000 Ohms or greater. If not, connector, wiring to ECA, or ECA may be faulty.

MAF sensor voltage test:

Connect MAF sensor to harness connector. Backprobe MAF sensor connector harness with VOM between MAF SIG and GND. Start engine. VOM should display +0.2 - +1.5v DC at idle. If not, MAF connector or sensor may be faulty.




Best of luck

 

so the first test i got 11.5 v so thats ok on the next i got .1 and 100.4 not sure where the ohm setting should of been

 

MAF sensor voltage test: i got .87

 

MAF circuit short-to-ground test: with the ohm meter on the second setting ie 200k i got 100.4 and 129.7 i believe so it seems to the connector i am good what else can i test also the Maf seems to be stock there is no aftermarket writting on it etc could it be the meter itself ? . And if so can i put a bigger one on like a 90mm

 

On test one you got voltage to pin 1. so next is to rule out the KAM, after you work on the other stuff reset the memory and do a full drive cycle and retest for codes. If code 15 comes again then suspect faulty computer like I stated. For teh MAF I would get some maf cleaner and clean it 1st before junking it, also get some electrical parts cleaner to clean the plug. I have had codes before and they checked out voltage wise so I suspected the plug connection. I use a electrical parts cleaner ( I use crc electronic parts cleaner) and sprayed the male/female connector to clean them and the code cleared.

 

i am sorry to ask but whats kam and how do i test please

 

and i did clean all maf connectors and the mass air thanks so much for your help

 

See post #3 in this thread regarding KAM.

skunk21, as a moderator here I wanted to say "thanks" for all of your input in this forum. Members that contribute like you do is what makes this site great.

 

Thanks i am a total newbie to this fuel injection stuff lol man what a learning curve i will test the computer tmmw and will let you know what i get skunk21 you rock thanks for all your help .....

 

Thanks very much. Being a car guy and huge fox guy I believe in giving back. I pretty much have called this place home and hoping to make our fox section a quality place.


Okay I got a little confused when you posted your voltage test. I thought it was voltage you got at pin "1. reread my 1st post on Code 15. you need to check for voltage at pin #1 to test the computer. The "KAM" is keep alive memory like I stated in the post. If you have the required voltage then I would clear the codes, this may also clear the maf code since you cleaned everything and go througha drive cycle. If you have a chip pull ot out. just reread the post and follow the steps.
let me know how you are making out.

 

Well that's good, I have a fox that I bought new and have had it ever since. It will turn 20 in September and I'm slowly deciding to put some money into it..... I'll look you up for advice LOL.

 

Sounds nice. yeah look me up here in the 'ole fox section I'll be happy to help

 

Hello so a lil update i had too do a waterpump yesterday and finished it today i checked codes again i got 15 on the first test then a passcode 11 on the second confusing so did the key on engine running test and i got 33 44 94 lol does it ever end is there a faulty part making all this happen tmmw i will check the ecu

 

Did you verify voltage at pin #1, 2nd do you have a chip, 3rd to you work on the egr and check the vauum supply for the egr. then clear the codes and go thru a drive cycle. don't recheck or clear and recheck w/o a drive cycle. you can geta passcode then other codes w/o prper clearing and driving or there is an ecu issue wether it be voltage or the ecu itself. connaot really procede until you verify testing on code 15, test and work on the egr code. yes some of teh codes still may pop up again after but we need to get rid of 15 and then work on teh others, teh maf code may clear and the egr may clear after a drive cycle. If you keep getting a bunch of codes and odd codes and 15, etc, etc. we need to look at the ecu and do some testing there. It's hard to pin point w/o going step by step.

 

Will do today and update when done man i owe you a beer lol

 

You may need this to help:

To test your Keep alive memory at pin #1 you need to test the plug at the computer. the KAM should be a black/orange wire.

The location of pin 1

 

Ok i had a kb chip so i disconnected it tested number 1 pin i had 12 volts so i left the chip out and cleaned maf and sensor again drove it checked it and no codes sweet . however this whole endeavor started when it out of the blue started to run like crap . So first i pulled my crane ignition and went back to stock but that did not fix it . So i did the cylinder test and i have cylinder 6 not powering so i retested cause it said to do it three times and i did not read far enough so i retested again and this time no 6 but i got 1 2 4 5 cylinders not happy lol . So i am thinking injectors i also cleaned the plug to the distributor i have not drove it again but when i did drive it with the chip out it was not as happy as when it was in so i am gonna put it back . So know what to do i have a fuel pressure gauge to test for that to rule out the pump and regulator . Am i missing anything .What do you think

 

fuel pressure is at 32 whether the line to reg is on or off i am thinking bad injectors or could it be a blown head gasket i did change my water pump and have noticed i have to keep adding coolant there is water on the ground where the exhaust dumps but it could just be oregon's wetness lol or its just burping the system