OK, What a bummer. My 1996 F-250 (119K miles) just got it's first CHENG light. It only comes on during hwy speed. It clears when you shut off eng and does not come on again till you get to hwy speed (50 or so). My owners manual says it has OBD2, it was man. May 1996. I bought it new (not that matters, but it's my baby). Problem: It has OBD1???? I looked for the connection and there is none. There is a EEC connector on the drivers side in the engine compartment. I believe that's OBD1. My questions are:
1. Is this OBD1?
2. Why would my owners manual state this truck has OBD2?
3. How can I read the code if the CKENG light only stays on while the engine is running?
4. Any good sites for the codes if it is in fact OBD1?
5. Can I read OBD1 codes without a reader (beeper), again, if it's OBD1?
2 ) I think there was a transition period in there from OBDI to OBDII so if the vehicle was built on the "cusp" so to speak they could have used parts from either depending on how it went down the line and also when it was actually built.
3) There are three different types of codes: KOEO (Key On Engine Off), CM(Continuos Memory) and KOER (Key On Engine Running).
4 & 5) fordfuelinjection.com. They have codes definitions and will tell you how to jumper the sti connector to read codes with the CEL (Check Engine Light) if you don't have access to a reader.
Last edited by guzzler96; 12-30-2004 at 07:45 AM.
OBD II officially started with the '96 MY, beginning with vehicles manufactured ~ August '95. Some very late '95 MY vehicles may have OBD II capabilities as parts were coming onstream for the upcoming MY. Yours was built in May '96, so it definitely is OBD II compliant.
Take your truck to any AutoZone for a free OBD II scan.
Higher gross weight vehicles (7700 lbs?) did not have to transition to OBD-II until later. A 1996 F250 could be either OBD-I or OBD-II. If it has the connector under the hood, it is OBD-I. The owner's manual is misleading probably because it was generic for F150's and lighter weight F250s, and Ford did not publish one specific to your model.
Count yourself lucky. OBD-I is easier and less expensive to diagnose in the backyard than OBD-II, which pretty much demands a >$120 scanner to even get started.
The scan tool that I have allows the user to look at PID's. One of them is an OBDII marker. On my 02 f-250 with the 5.4, it shows OBDI, the truck has no o2 sensor after the cat and it never completes some of the readiness tests. It's not OBDII.
Brown 4x4 was talking about 97 F350's, whats your point?
I'm one of those that got caught by the change from OBD I to OBD II in about 1996. My E-350 is a chasis for my Motor Home. I bought software and hardware to use my laptop to look at data on the ECU/PCM to see how the engine and emissions were operating and to make sure everything was working okay, since the 351W engine is not to good on gas mileage, like 8mpg. But, buying the equipment is now not worth much since it needs OBD II. I can buy/build sensor to check F/A and how the other devices are operating, but with OBD II it's one stop shopping. I wrote to Ford and asked since later in the year they went from OBD I to OBD II if I could just change out the ECU and they beat around the bush and then said no. I can't understand how that is not possible. It doesn't look like they would change all the wiring just to change ECU modules.
Any one got any ideas about this kind of swap? Or, is there an aftermarket ECU that I can add on and then program for best operation.
Right now I don't know if the bad mileage (what I consider as bad) is due to the ECU shooting too much fuel because of fuel/air being off or timing not changing as it should. This engine also using extra fuel to cool off the intake if the temps get to high.
As a side story, about a year ago I installed one of those belt driven water pump motors, which did not really supply enough flow for the engine need, and removed the fan and its hardware. I bootstrapped a big electric fan behind the radiator and made a test run in the middle of summer here in Phoenix, Az. I had enough air flow to keep the temps down to a reasonable level, except when I came across town. During my test run which was about 50-60 miles my mpg went up to over 14mpg and may have even been a little higher. I didn't make an absolute gas measured to the "n" degree test, but it was enough to make me decide to buy a 55 gpm electric water pump. I'm going to make a custom fan enclosure too. I'm changing the transmission fluid and filter to make sure it is working correctly and not causing drag problems. I will also be changing plugs, wiring, cap and rotor.
My first step is going to involve nothing more than airing tires up to max rating. Change the air cleaner. My route will be about 80 + miles and I will do it late at night all freeway driving in a loop that goes around the city. I plan on staying as close to 55 mph speed as drag or air resistance goes up 4 X as speed increases. I will also be taking the small tubing off of the gas filler and use clear tubing to measue the gas to the same point each time. I plan on making changes one by one (even though it will take more gas to do the test) and I know I will never recover the money I am putting into parts, but I want to test all those "facts" people always are quoting with science numbers. I also want to do some airo things with cardboard and tape to see if I can make the Motor Home go through the air a little easier.
Within the next six months I should have some good data to pass on.
Any thoughts will be helpful. If you plan on just writing to try to put me down, save your time. I'm only looking for positive feedback or info from those that have tried things and did not have any luck. Anyone can be a wet blanket and put folks down and I'll just ignore those post, but still think what a jerk the poster is.