5.3l swap dies at intersections after engine is warm
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Launching!
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5.3l swap dies at intersections after engine is warm Put a 5.3L/4L60e in my 64 Chevelle. This problem keeps coming and going. It always runs great on cold start but after it warms up it will die if I come to a sudden stop. I can keep it running if I stop slowly and keep foot on gas and brake at the same time to keep the revs above about 600 rpm. I am running a external pump with corvette FPR. When I hook up the laptop everything I can trend is looking normal.
It runs great except for this issue. I have put a guage on the fuel rail to check pressure next time this happens. Anything else I might need to look at??
It runs great except for this issue. I have put a guage on the fuel rail to check pressure next time this happens. Anything else I might need to look at??
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Launching!
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Forgot to mention that this is a DBW motor. My software is fairly simple and I can only trend data, not program.
Can anyone recommend a tuner in the Russellville AR area?
I have verified fuel pressure is constant, MAF readout is normal, throttle position readout looks normal, O2 trims look normal.
Can anyone recommend a tuner in the Russellville AR area?
I have verified fuel pressure is constant, MAF readout is normal, throttle position readout looks normal, O2 trims look normal.
I'm going to suggest something simple only because it happened to me. Is your VSS (Vehicle Speed Sensor) hooked up correctly? It will stall when you come to a stop if this sensor is not hooked up or hooked up correctly.
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Launching!
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how do i properly hook up my VSS signal? What pin is this on which PCM connector?
I do have one unconnected wire that I have labeled as VSS but I thought it was just a spare VSS signal.
I do have one unconnected wire that I have labeled as VSS but I thought it was just a spare VSS signal.
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Do you have a VSS plugged into your transmission? If not, I bet that's your problem. If your harness doesn't have the proper plug....just a wire, you're going to need to purchase the plug and solder it in. I would be shocked if the plug wasn't provided for you....already installed on the VSS wire. That's pretty basic stuff for a harness manufacturer given the importance of the VSS to the overall function of the engine.
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Launching!
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It's probably not a spare. My harness had the proper VSS connection to plug into my T56. I didn't hook it up because I didn't really know what the VSS function was and the engine ran great...until I took it for a drive. Almost every stop I would make, it would stumble and then die. The motor would fire right back up and run great at a stand still but once I got moving and stopped, it would die again. It wasn't until the good membership on this site put me in the right direction did I realize that VSS serves a very important function and can't be ignored. Plugged in the VSS into the T56 and the problem ended.
Do you have a VSS plugged into your transmission? If not, I bet that's your problem. If your harness doesn't have the proper plug....just a wire, you're going to need to purchase the plug and solder it in. I would be shocked if the plug wasn't provided for you....already installed on the VSS wire. That's pretty basic stuff for a harness manufacturer given the importance of the VSS to the overall function of the engine.
Do you have a VSS plugged into your transmission? If not, I bet that's your problem. If your harness doesn't have the proper plug....just a wire, you're going to need to purchase the plug and solder it in. I would be shocked if the plug wasn't provided for you....already installed on the VSS wire. That's pretty basic stuff for a harness manufacturer given the importance of the VSS to the overall function of the engine.
Let me try to clarify this. Not saying this is your problem but it sures sounds like it. The confusion is the use of the term VSS or Vehicle Speed Sensor. A better term would be Transmission Input Speed Sensor. This sensor measures transmission output or wheel speed. The ECM uses this information to modify engine functions such as ignition
timing, AF ratio, transmission shift points, and to initiate diagnostic routines. So there should be a connection from your ECM to your transmission...independent of the one to your speedometer which is I believe is connected to the output signal. Again...just checking. It isn't clear that you have this Transmission Input Speed Sensor connected. This maybe why you are stalling at a stop. Because your ECM has no idea what timing or air fuel mixture to give you because there is no input to it concerning your wheel speed.
timing, AF ratio, transmission shift points, and to initiate diagnostic routines. So there should be a connection from your ECM to your transmission...independent of the one to your speedometer which is I believe is connected to the output signal. Again...just checking. It isn't clear that you have this Transmission Input Speed Sensor connected. This maybe why you are stalling at a stop. Because your ECM has no idea what timing or air fuel mixture to give you because there is no input to it concerning your wheel speed.
Last edited by Bilster; Oct 3, 2013 at 05:57 PM.
So the attached photo makes my point. Here is a Bowler T56 output housing modified for a mechanical speedometer. Even though you now have a mechanical speedometer, the VSS sensor is still necessary to run the engine properly.
Warped/leaking intakes are very common on the truck engines, but I don't think its your issue. If your scanner reads short term fuel trims, spray the intake flanges with brake cleaner or something similar and watch for a negative trim.
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Launching!
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Let me try to clarify this. Not saying this is your problem but it sures sounds like it. The confusion is the use of the term VSS or Vehicle Speed Sensor. A better term would be Transmission Input Speed Sensor. This sensor measures transmission output or wheel speed. The ECM uses this information to modify engine functions such as ignition
timing, AF ratio, transmission shift points, and to initiate diagnostic routines. So there should be a connection from your ECM to your transmission...independent of the one to your speedometer which is I believe is connected to the output signal. Again...just checking. It isn't clear that you have this Transmission Input Speed Sensor connected. This maybe why you are stalling at a stop. Because your ECM has no idea what timing or air fuel mixture to give you because there is no input to it concerning your wheel speed.
timing, AF ratio, transmission shift points, and to initiate diagnostic routines. So there should be a connection from your ECM to your transmission...independent of the one to your speedometer which is I believe is connected to the output signal. Again...just checking. It isn't clear that you have this Transmission Input Speed Sensor connected. This maybe why you are stalling at a stop. Because your ECM has no idea what timing or air fuel mixture to give you because there is no input to it concerning your wheel speed.
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Launching!
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The fuel trims all show as expected which has me puzzeled. I tried the brake cleaner thing before and did not detect any leak.
Quite frankly, I'm not sure. You would think so but just for grins, tell me if the sensor location I have circled in the photo is occupied and wired to your ECM. If so, end of story. If not, it's part of, if not all of, your problem.
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Launching!
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yes, there is a sensor in that location and it is properly wired to the PCM.
Sound like the lock up isn't unlocking when you come to a stop. My Monte did this with the old 200r4 easy way to test that was slightly press the brake pedal while in over drive, if the RPM jump up a little, your brake switch is working and your torque converter is unlocking properly. Not sure if it works the same way on the newer transmissions though.
Does it stall at EVERY stop once warm? Or will it stay running if you avoid overdrive? Try leaving the shifter out of OD and see if it still does it as a possible way to diagnose the lock-up function...
Does it stall at EVERY stop once warm? Or will it stay running if you avoid overdrive? Try leaving the shifter out of OD and see if it still does it as a possible way to diagnose the lock-up function...