P1316 Misfire Help!!

[Chase6616]

Hello all, I've been chasing this issue for a long time now. My 97 Disco is misfiring and running very sluggish. I'm getting the code P1316 (misfire causing excessive emissions). This is what I've done thus far.

1. Cleaned MAF and stepper motor
2. Champion plugs and Magnecor Wires
3. Did the whole decarbon and engine flush treatments
4. Replaced cylinder heads and complete top end gasket set

I was told I had carbon buildup on my exhaust valves so instead of having a valve job done it was cheaper to buy a set of heads and I rebuilt the whole top end. I checked to see if I had a dropped sleeve but they were all good.

I also tested the coil packs by them out from a buddies 97' that runs perfect so I've eliminated that possibility. I've heard of people having the same issues so Iv'e tried all their methods with no results. Any help....DISCO MIKE I need your guidance!!!

[osiristheclown]

Try swapping out your ECU and alarm unit with his. Swap BOTH units as a set so you don't have the ECU lock you out, and try it. Just remember to clear the codes once you put everything back in his truck. I went through a similar problem and tested every sensor, traced every wire, and generally drove myself crazy until I swapped in a good ECU and alarm from a friends truck. If your truck runs right you know where you stand, if not then you need to start checking things on your truck. Start with fuel pressure to eliminate a weak pump or restricted filter and check for injector leaks. You can check most everything else with a DVOM. Then report back.

[deeb]

Originally Posted by Chase6616

Hello all, I've been chasing this issue for a long time now. My 97 Disco is misfiring and running very sluggish. I'm getting the code P1316 (misfire causing excessive emissions). This is what I've done thus far.

1. Cleaned MAF and stepper motor
2. Champion plugs and Magnecor Wires
3. Did the whole decarbon and engine flush treatments
4. Replaced cylinder heads and complete top end gasket set

I was told I had carbon buildup on my exhaust valves so instead of having a valve job done it was cheaper to buy a set of heads and I rebuilt the whole top end. I checked to see if I had a dropped sleeve but they were all good.

I also tested the coil packs by them out from a buddies 97' that runs perfect so I've eliminated that possibility. I've heard of people having the same issues so Iv'e tried all their methods with no results. Any help....DISCO MIKE I need your guidance!!!

i have some similar symptoms, wicked sluggish, lots of smoke/stinky exhaust...can you hear the misfire from anywhere in particular? mine i can hear clear as day coming from the pass side ex manifold and maybe down toward the cat.

[Chase6616]

Wow I really hope its not the ECU. I will try that and see.

As for the sounds I can clearly tell its misfiring, just how the engine vibrates and sputters. I also can't seem to figure out my idle issue. Sometimes when I start it it will idle at 2k-3k and some times it will idle at like 500-750 and feels like its going to stall. I've heard that the VSS can cause this. Can anyone tell me where that is located?

[osiristheclown]

The VSS is on the back of the transfer case. Look up between the parking brake assembly and end of transfer case and you'll see it and the 2 wire connector. You can unplug it and drive it to see if it makes a difference.

The ECU isn't the end of the world, plenty of good used ones available for reasonable cost. Swapping it out would at least eliminate it as the cause. From there you can check sensors with a DVOM to figure it out.

FWIW, I had a problem where my truck was running like it had jumped time and was dumping fuel into the engine. I checked every sensor, connection, and wire in the engine compartment. It turned out to be the ECU, and I confirmed it by swapping one from a good running truck.

[Chase6616]

ok so I bit the bullet and took it to dealership and had them run a full diagnostics and the original code P1316 was no longer showing up. Instead It's throwing P1138- O2 problem rich. So now I'm not sure where to go from there. The mechanics told me it sounded like the fuel injectors were stuck in the full open position dumping way to much fuel (which would explain the bad fuel smell from the exhaust and terrible MPG. I'm thinking though that if there was a problem with my injectors, shouldnt it throw a code for that???

Oh and the ECU swap isn't going to work the day before I called my buddy to ask about it, he had fried his....

I saw that you mentioned switching the ECU and Alarm unit. Do they need to both be from the same vehicle. I'm asking incase it comes down to buying a new one can they be from different Discos?

[osiristheclown]

If they are out of the same truck they are sync'd to work together. If you just swap the ECU you will be able to start the truck once then it will lock you out and won't work in either truck until you have it re sync'd to the alarm unit. If you take the set together you can plug and play and no harm done. If you have someone who can sync the units to work together you can replace just the ECU. I know this because I have a locked ECU that ran my truck perfectly but nobody local to sync it to my alarm.

[cplthomas]

How would one go about syncing the ecu to an alarm?

[osiristheclown]

The ECU and 10AS alarm unit can only be sync'd with a scanner like Testbook or Rovacom, etc. I actually contacted a vendor about the issue and they have a couple trucks they said they could install my ECU and alarm unit into, sync them and ship them back. The price was fair, I just happened on a complete setup at a bargain price. I still have the ECU I was going to send out, but I needed to buy an alarm unit anyway since mine is down near the pond somewhere.

I did ask about the possibility of having the alarm feature turned OFF in the ECU.
They stated that it had been tried but the setting never held.

If you need a GEMS ECU from a 96/early 97 NON AEL truck I'll sell mine cheap, but it needs to be sync'd by someone with the appropriate scanner.