Weird LJET fuel delivery issue!
06-02-2018, 12:36 AM
#16
Okay everybody. Started the car back up today. It started hesitantly but it did start and ran. Again poorly. Stumbling around 7 to 800rpm. Fuel pump fuse in. I disconnected the AFM. No change in rpm. I disconnected the the TPS. No change in RPM. I disconnected the coolant temperature sensor. No change in RPM. Revved the engine. It went over 2k this time but at around 3 loss of power heavy stumbling and nearly stalled. Let off the gas and the idle returned to about 700 800 rpm haunting idle. I took some videos I’ll see if I can upload them or post a link. Had one VERY loud backfire
Im thinking the sensors are sending the right signals but the DME isn’t sending the right information where it needs to be when it needs to. Would the altitude sensor under the dash cause this?
If disconnecting all those sensors made no change in how the car ran is it safe to assume assume that they are functioning the way they should?
Im totally stumped.
Jake
Im thinking the sensors are sending the right signals but the DME isn’t sending the right information where it needs to be when it needs to. Would the altitude sensor under the dash cause this?
If disconnecting all those sensors made no change in how the car ran is it safe to assume assume that they are functioning the way they should?
Im totally stumped.
Jake
06-02-2018, 10:44 AM
#17
Rainman
Rennlist Member
Rennlist Member
I'm really surprised at several things in your post.
1) that it idles without the TPS connected, unless your TPS was dead or mal-adjusted in the first place.
2) that it revs up without the AFM connected, at all.
altitude sensor only leans out the mixture above 1000 meters or so. you can just disconnect it to rule it out though.
1) that it idles without the TPS connected, unless your TPS was dead or mal-adjusted in the first place.
2) that it revs up without the AFM connected, at all.
altitude sensor only leans out the mixture above 1000 meters or so. you can just disconnect it to rule it out though.
06-02-2018, 10:51 AM
#18
Yeah same here. That TPS is as old as the car to the best of my knowledge. As well as the temp sensor and AFM.
Ill give disconnecting the altitude sensor a shot thanks for the insight.
Regards
Jake
Ill give disconnecting the altitude sensor a shot thanks for the insight.
Regards
Jake
06-03-2018, 12:09 PM
#23
I gave them a call on Friday. No matter what I do it’s gonna cost me at the very least $50 to borrow parts and $150 to buy
AFM.
Honestly if unplugging all those sensors didn’t effect how the car ran, and this weird thing where it will start and run without a fuse, I’m starting to suspect the DME itself has failed in some way. I can’t see how if any one of those sensors suddenly failed that the car would somehow run without that fuse. I did pull the DME relay once and that seemed to really kill the pump it didn’t start at all then.
AFM.
Honestly if unplugging all those sensors didn’t effect how the car ran, and this weird thing where it will start and run without a fuse, I’m starting to suspect the DME itself has failed in some way. I can’t see how if any one of those sensors suddenly failed that the car would somehow run without that fuse. I did pull the DME relay once and that seemed to really kill the pump it didn’t start at all then.
06-06-2018, 05:28 AM
#26
Been a little busy. Pulled the dash to inspect the top of the fuse panel. The wiring looks in excellent shape. Also pulled up the paper work from the last dealer visit. They changed the oil, found fuel in the crankcase, adjusted the fuel mixture, and adjusted the idle. Checked the oil today and I don’t like it. It’s not as terrible as it was before but it’s contamnitated. Car needs another oil change. Will not be starting it or attemtpting to start it until after that’s done.
So it’s obvious there is way way way too much gas in my situation. How is that possible if they reported normal fuel pressure readings? Do I need to try another test? Adjusting the mixture and the Idle made no difference than when my car first started showing these symptoms.
Now, why in the hell is my car erratically, or rather, intermittently running so rich that it stalls, dilutes my oil, in turn making it run even more like trash, until eventually it will not start either from (and I’m assuming here, wet plugs, or simply just too rich of a mixture for proper combustion). The misfiring must be detonation rather than pre ignition.
Regards,
Jake.
So it’s obvious there is way way way too much gas in my situation. How is that possible if they reported normal fuel pressure readings? Do I need to try another test? Adjusting the mixture and the Idle made no difference than when my car first started showing these symptoms.
Now, why in the hell is my car erratically, or rather, intermittently running so rich that it stalls, dilutes my oil, in turn making it run even more like trash, until eventually it will not start either from (and I’m assuming here, wet plugs, or simply just too rich of a mixture for proper combustion). The misfiring must be detonation rather than pre ignition.
Regards,
Jake.
06-06-2018, 06:10 AM
#27
This really sounds like a misaligned AFM. The reason unplugging it now has no change is because there is too much fuel already I suspect.
Here’s what I would do in this situation.
1) Pull hose off FPR...is there fuel? Using a hand vacuum pump check the diaphragm
2) Open the AFM and push the wipers to a new position so that they have a clean surface to go on.
3) Test the fuel pressure myself and leak down.
Here’s what I would do in this situation.
1) Pull hose off FPR...is there fuel? Using a hand vacuum pump check the diaphragm
2) Open the AFM and push the wipers to a new position so that they have a clean surface to go on.
3) Test the fuel pressure myself and leak down.
06-06-2018, 07:12 AM
#28
This really sounds like a misaligned AFM. The reason unplugging it now has no change is because there is too much fuel already I suspect.
Here’s what I would do in this situation.
1) Pull hose off FPR...is there fuel? Using a hand vacuum pump check the diaphragm
2) Open the AFM and push the wipers to a new position so that they have a clean surface to go on.
3) Test the fuel pressure myself and leak down.
Here’s what I would do in this situation.
1) Pull hose off FPR...is there fuel? Using a hand vacuum pump check the diaphragm
2) Open the AFM and push the wipers to a new position so that they have a clean surface to go on.
3) Test the fuel pressure myself and leak down.
there is no fuel with the vacuum line disconnected from FPR.
How would I go about checking vacuum pressure on FPR?
Again disconnecting the other sensors has also previously helped stablilize the idle for some odd reason.
The best way I can describe it is this,
When the car decides to run normally, it runs and performs exactly the way it’s supposed to, there is no misfire, no idle variations, no black smoke. It doesn’t matter if I’m driving and in gear, decelerating or accelerating, or idling when it decides to randomly sputter and stumble and eventually die. Majority of the time disconnecting the AFM keeps the car running, but even then the car will still at some point die even with it disconnected. AFIK the car should idle no matter what with the AFM disconnected, but as soon as the throttle is opened the car runs more and more lean until it stalls. When I disconnected the AFM I can still rev up to about 2k rpm before it chokes out. Regardless that still doesn’t explain how it starts without that pump fuse. Again it only does that when it’s having a fit. For example when the car is behaving normally if I try to start it without the pump fuse, the car won’t start.
I won’t know about the AFM for sure until I rule it out. I’ll have to keep looking for anyone local that’s got a spare laying around. Gotta add a starter to that list.
just for peace of mind, if there were something catastrophically wrong, such as something warranting a full head rebuild, would the car act this way? Or is it safe to say this has to be some sort of electrical issue such as the AFM as suggested or the DME control unit...or fuel pump, injectors , filter, relay, damper, regulator, cap, rotor, coil, plug wires, etc. I’m trying to avoid throwing parts at this thing Incase it does need a top end freshen up.
How would I go about checking vacuum pressure on FPR?
Again disconnecting the other sensors has also previously helped stablilize the idle for some odd reason.
The best way I can describe it is this,
When the car decides to run normally, it runs and performs exactly the way it’s supposed to, there is no misfire, no idle variations, no black smoke. It doesn’t matter if I’m driving and in gear, decelerating or accelerating, or idling when it decides to randomly sputter and stumble and eventually die. Majority of the time disconnecting the AFM keeps the car running, but even then the car will still at some point die even with it disconnected. AFIK the car should idle no matter what with the AFM disconnected, but as soon as the throttle is opened the car runs more and more lean until it stalls. When I disconnected the AFM I can still rev up to about 2k rpm before it chokes out. Regardless that still doesn’t explain how it starts without that pump fuse. Again it only does that when it’s having a fit. For example when the car is behaving normally if I try to start it without the pump fuse, the car won’t start.
I won’t know about the AFM for sure until I rule it out. I’ll have to keep looking for anyone local that’s got a spare laying around. Gotta add a starter to that list.
just for peace of mind, if there were something catastrophically wrong, such as something warranting a full head rebuild, would the car act this way? Or is it safe to say this has to be some sort of electrical issue such as the AFM as suggested or the DME control unit...or fuel pump, injectors , filter, relay, damper, regulator, cap, rotor, coil, plug wires, etc. I’m trying to avoid throwing parts at this thing Incase it does need a top end freshen up.