Transmission/Sensor Woes
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Member
Joined: Nov 2006
Posts: 16
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From: Montana
Transmission/Sensor Woes
Hello all,
I purchased an old 91 F150 Lariat XLT, a last summer. (You can tell that I am on strict budget by the age of the truck.) But she needs a lot of work:
So far I've done the following"
I replaced intake manifold upper and lower gaskets
All sparkplugs distributor cap, rotor and properly routed plug wires to avoid crossfire problems
Cleaned the Idle air bypass and throttle body
Set ignition timing after removing spout connector
Symptoms:
Idle speed seems a little low, 550 - 600 rpm
Check engine light not flashing, no trouble codes present.
Whenever I put 'er in gear at idle she dies when cold or almost dies when warm.
The automatic E4AOD transmission shifting is a little vague at times. It does shift into all gears but operation seems erratic, OD is fine.
When driving at a regular city speed of 25 to 35 and after coasting it can take a couple of seconds to get back in gear when I step on the gas again. Sometimes it comes back into gear with a slight shock, as if the transmission does not know what gear it was supposed to be in. About 15 years ago I used to work for a Mitsubishi Dealership, when auto trannies shifted like that we would check wiring and pulse generator sensors on the transmission to cure the problem so the VSS and probably RABS sensors and wiring are suspects, am I right?
It would be nice if all it needed was wiring and sensors maybe and avoid a very costly rebuilt transmission.
I appreciate any and all replies, thank you
dtek001
I purchased an old 91 F150 Lariat XLT, a last summer. (You can tell that I am on strict budget by the age of the truck.) But she needs a lot of work:
So far I've done the following"
I replaced intake manifold upper and lower gaskets
All sparkplugs distributor cap, rotor and properly routed plug wires to avoid crossfire problems
Cleaned the Idle air bypass and throttle body
Set ignition timing after removing spout connector
Symptoms:
Idle speed seems a little low, 550 - 600 rpm
Check engine light not flashing, no trouble codes present.
Whenever I put 'er in gear at idle she dies when cold or almost dies when warm.
The automatic E4AOD transmission shifting is a little vague at times. It does shift into all gears but operation seems erratic, OD is fine.
When driving at a regular city speed of 25 to 35 and after coasting it can take a couple of seconds to get back in gear when I step on the gas again. Sometimes it comes back into gear with a slight shock, as if the transmission does not know what gear it was supposed to be in. About 15 years ago I used to work for a Mitsubishi Dealership, when auto trannies shifted like that we would check wiring and pulse generator sensors on the transmission to cure the problem so the VSS and probably RABS sensors and wiring are suspects, am I right?
It would be nice if all it needed was wiring and sensors maybe and avoid a very costly rebuilt transmission.
I appreciate any and all replies, thank you
dtek001
Senior Member
Joined: Nov 2006
Posts: 5,495
Likes: 7
From: Memphis, TN 38135, USA, Earth
Put your truck's specifics in your profile so we can see what you're talking about. The TRANS code (#18) on the door sticker for an E4OD is "E"; for an AOD, it's "U".
The AOD is mechanically-controlled, and the '91 E4OD doesn't use the RABS sensor at all, so it's not likely a wiring/sensor issue. The AOD is VERY sensitive to TV cable adjustment, so if that's what you have, get a Haynes manual or Ford service CD & follow the instruction precisely. The pre-'95 E4OD is known to have lots of problems, and it's an expen$ive 8!+(# to rebuild/replace, so hope that's not what you have. If it is, first thing to check is fluid LEVEL & condition. If the fluid stinks (worse than regular ATF), you can try doing 2 fluid/filter changes within ~500 miles to try to salvage it (use cheap Dexron/Mercon the first time & Motorcraft Mercon GP the 2nd), but it may be a goner.
The AOD is mechanically-controlled, and the '91 E4OD doesn't use the RABS sensor at all, so it's not likely a wiring/sensor issue. The AOD is VERY sensitive to TV cable adjustment, so if that's what you have, get a Haynes manual or Ford service CD & follow the instruction precisely. The pre-'95 E4OD is known to have lots of problems, and it's an expen$ive 8!+(# to rebuild/replace, so hope that's not what you have. If it is, first thing to check is fluid LEVEL & condition. If the fluid stinks (worse than regular ATF), you can try doing 2 fluid/filter changes within ~500 miles to try to salvage it (use cheap Dexron/Mercon the first time & Motorcraft Mercon GP the 2nd), but it may be a goner.
Thread Starter
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Member
Joined: Nov 2006
Posts: 16
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From: Montana
Originally Posted by dtek001
Hello all,
I purchased an old 91 F150 Lariat XLT, a last summer. (You can tell that I am on strict budget by the age of the truck.) But she needs a lot of work:
So far I've done the following"
I replaced intake manifold upper and lower gaskets
All sparkplugs distributor cap, rotor and properly routed plug wires to avoid crossfire problems
Cleaned the Idle air bypass and throttle body
Set ignition timing after removing spout connector
Symptoms:
Idle speed seems a little low, 550 - 600 rpm
Check engine light not flashing, no trouble codes present.
Whenever I put 'er in gear at idle she dies when cold or almost dies when warm.
The automatic E4AOD transmission shifting is a little vague at times. It does shift into all gears but operation seems erratic, OD is fine.
When driving at a regular city speed of 25 to 35 and after coasting it can take a couple of seconds to get back in gear when I step on the gas again. Sometimes it comes back into gear with a slight shock, as if the transmission does not know what gear it was supposed to be in. About 15 years ago I used to work for a Mitsubishi Dealership, when auto trannies shifted like that we would check wiring and pulse generator sensors on the transmission to cure the problem so the VSS and probably RABS sensors and wiring are suspects, am I right?
It would be nice if all it needed was wiring and sensors maybe and avoid a very costly rebuilt transmission.
I appreciate any and all replies, thank you
dtek001
I purchased an old 91 F150 Lariat XLT, a last summer. (You can tell that I am on strict budget by the age of the truck.) But she needs a lot of work:
So far I've done the following"
I replaced intake manifold upper and lower gaskets
All sparkplugs distributor cap, rotor and properly routed plug wires to avoid crossfire problems
Cleaned the Idle air bypass and throttle body
Set ignition timing after removing spout connector
Symptoms:
Idle speed seems a little low, 550 - 600 rpm
Check engine light not flashing, no trouble codes present.
Whenever I put 'er in gear at idle she dies when cold or almost dies when warm.
The automatic E4AOD transmission shifting is a little vague at times. It does shift into all gears but operation seems erratic, OD is fine.
When driving at a regular city speed of 25 to 35 and after coasting it can take a couple of seconds to get back in gear when I step on the gas again. Sometimes it comes back into gear with a slight shock, as if the transmission does not know what gear it was supposed to be in. About 15 years ago I used to work for a Mitsubishi Dealership, when auto trannies shifted like that we would check wiring and pulse generator sensors on the transmission to cure the problem so the VSS and probably RABS sensors and wiring are suspects, am I right?
It would be nice if all it needed was wiring and sensors maybe and avoid a very costly rebuilt transmission.
I appreciate any and all replies, thank you
dtek001
Adrianspeeder,
Yes I did mix up 2 transmission types: I do have the E4OD. with the (PRN(D)21 and the OD lockout button) The engine is a 5.0 L
Steve83,
I decoded the door jamb sticker as Steve83 suggested found that the Transmission Code is "E" which should stand for E4OD.(I know about the AOD TV Rod, adjustment sensitivity), my other ride is equipped with one of those and after replacing the transmission myself I had to pay a local transmission shop to make the adjustment or the rebuilt would fallen apart in short order.
I checked the ATF fluid and it looks bright red not brown, it does not stink or seem to have any particulate matter; I know there could be some stuff in the pan. I only looked at the dipstick. I will replace ATF fluid and filter a couple of times like you suggest. Seems like the transmission was flushed prior to me purchasing the truck so that does not sound so good either. I don't believe in flushing with a machine without opening the pan and removing the filter and whatever other stuff might be in the pan.
So, should I not be looking at the VSS at this point? I'm also going to try resetting the idle speed a little higher. I could mess with the idle bypass valve to reset the base curb idle.
Thank you Adrianspeeder and Steve83 for your responses and assistance. I'll let you know how things developed.
dtek001
Thread Starter
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Member
Joined: Nov 2006
Posts: 16
Likes: 0
From: Montana
Originally Posted by dtek001
Hello all,
I purchased an old 91 F150 Lariat XLT, a last summer. (You can tell that I am on strict budget by the age of the truck.) But she needs a lot of work:
So far I've done the following"
I replaced intake manifold upper and lower gaskets
All sparkplugs distributor cap, rotor and properly routed plug wires to avoid crossfire problems
Cleaned the Idle air bypass and throttle body
Set ignition timing after removing spout connector
Symptoms:
Idle speed seems a little low, 550 - 600 rpm
Check engine light not flashing, no trouble codes present.
Whenever I put 'er in gear at idle she dies when cold or almost dies when warm.
The automatic E4AOD transmission shifting is a little vague at times. It does shift into all gears but operation seems erratic, OD is fine.
When driving at a regular city speed of 25 to 35 and after coasting it can take a couple of seconds to get back in gear when I step on the gas again. Sometimes it comes back into gear with a slight shock, as if the transmission does not know what gear it was supposed to be in. About 15 years ago I used to work for a Mitsubishi Dealership, when auto trannies shifted like that we would check wiring and pulse generator sensors on the transmission to cure the problem so the VSS and probably RABS sensors and wiring are suspects, am I right?
It would be nice if all it needed was wiring and sensors maybe and avoid a very costly rebuilt transmission.
I appreciate any and all replies, thank you
dtek001
I purchased an old 91 F150 Lariat XLT, a last summer. (You can tell that I am on strict budget by the age of the truck.) But she needs a lot of work:
So far I've done the following"
I replaced intake manifold upper and lower gaskets
All sparkplugs distributor cap, rotor and properly routed plug wires to avoid crossfire problems
Cleaned the Idle air bypass and throttle body
Set ignition timing after removing spout connector
Symptoms:
Idle speed seems a little low, 550 - 600 rpm
Check engine light not flashing, no trouble codes present.
Whenever I put 'er in gear at idle she dies when cold or almost dies when warm.
The automatic E4AOD transmission shifting is a little vague at times. It does shift into all gears but operation seems erratic, OD is fine.
When driving at a regular city speed of 25 to 35 and after coasting it can take a couple of seconds to get back in gear when I step on the gas again. Sometimes it comes back into gear with a slight shock, as if the transmission does not know what gear it was supposed to be in. About 15 years ago I used to work for a Mitsubishi Dealership, when auto trannies shifted like that we would check wiring and pulse generator sensors on the transmission to cure the problem so the VSS and probably RABS sensors and wiring are suspects, am I right?
It would be nice if all it needed was wiring and sensors maybe and avoid a very costly rebuilt transmission.
I appreciate any and all replies, thank you
dtek001
Adrianspeeder,
Yes I did mix up 2 transmission types: I do have the E4OD. with the (PRN(D)21 and the OD lockout button) The engine is a 5.0 L
Steve83,
I decoded the door jamb sticker as Steve83 suggested found that the Transmission Code is "E" which should stand for E4OD.(I know about the AOD TV Rod, adjustment sensitivity), my other ride is equipped with one of those and after replacing the transmission myself I had to pay a local transmission shop to make the adjustment or the rebuilt would fallen apart in short order.
I checked the ATF fluid and it looks bright red not brown, it does not stink or seem to have any particulate matter; I know there could be some stuff in the pan. I only looked at the dipstick. I will replace ATF fluid and filter a couple of times like you suggest. Seems like the transmission was flushed prior to me purchasing the truck so that does not sound so good either. I don't believe in flushing with a machine without opening the pan and removing the filter and whatever other stuff might be in the pan.
So, should I not be looking at the VSS at this point? I'm also going to try resetting the idle speed a little higher. I could mess with the idle bypass valve to reset the base curb idle.
Thank you Adrianspeeder and Steve83 for your responses and assistance. I'll let you know how things developed.
dtek001
Senior Member
Joined: Nov 2006
Posts: 5,495
Likes: 7
From: Memphis, TN 38135, USA, Earth
Don't try to mess with the idle. Maintain the engine properly & it'll idle properly. NEVER adjust the throttle stop screw. Read the instructions on the emissions sticker under the hood.
. 
The VSS is shared by the cruise & the EEC, but the style you have is notoriously relilable. It's unlikely that it's the source, but you can certainly inspect & test the wiring from it to the EEC. The Haynes manual shows the circuits.
. 
. The VSS is shared by the cruise & the EEC, but the style you have is notoriously relilable. It's unlikely that it's the source, but you can certainly inspect & test the wiring from it to the EEC. The Haynes manual shows the circuits.
.
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Member
Joined: Nov 2006
Posts: 16
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From: Montana
Transmission Sensor Woes
Steve83,
Thanks again for your insight. I will check the sensor wiring, you did not consider it a high probability so I'm going back to basics. The first thing I'll do is make sure the idle stop screw has not been messed with. There is a whole procedure that involves a feeler gauge and a 0.25" blade after running the engine 'till it is out of open loop.
dtek001
Thanks again for your insight. I will check the sensor wiring, you did not consider it a high probability so I'm going back to basics. The first thing I'll do is make sure the idle stop screw has not been messed with. There is a whole procedure that involves a feeler gauge and a 0.25" blade after running the engine 'till it is out of open loop.
dtek001
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From: Montana
Transmission/Sensor Woes
Greetings,
Finally it was time to spend some money and get at least a code reader; scan tools are expensive and not all of them will readily work on OBD I without purchasing extra adapters. I have no use for OBD II. So a cheaper reader sure beats counting MIL flashes or the infamous 10 megohm Analog Multimeter needle sweeps. When the truck was just purchased I started out counting MIL light flashes to diagnose pinging sluggish take off. It ended up being an EGR problem. I cleaned everything made sure the EGR was free and working. Corrected a vacuum problem, checked the sensor and the MIL went off. I figured that was the end of it. Driveability improved and the EGR seemed to work OK. Total investment: $36.00. I will end up replacing the EGR after all, even with the MIL off I got codes 328 and 334. Next problem on the list was the engine shutting of when shifting into gear, especially reverse. I checked the TPS voltage, well within range, I cleaned the and checked the resistance for the IAC valve and adjusted the set screw to factory specs using a feeler gauge and all. Idle speed problem solved, no more shutting off in reverse! When I thought things were looking better I find something that could be bigger trouble: Creamy substance under air filter element! Time for Head resurfacing and whatever else they need + gaskets? Then I remembered that I did not change the oil after replacing upper and lower intake manifold gaskets. I used a shop vac to remove all gasket bits and pieces but oil and coolant seem to mingle when you do this anyways. I lost some coolant during the procedure and did not replace all of it before road testing the truck. There was overheating for a few minutes before I could find a gas station and repleninsh the radiator with the engine running. I have not driven the truck very much afterwards, I've been fixing other details. Presently the temp gauge reads about half way up the scale but I did not replace the thermostat after the event either. (I plan to replace it tomorrow) I would like to believe that the "cream" underneath the paper air filter is mostly the coolant that got mixed with the engine oil at the time of the repair and it is simply boiling out. It could also be a head gasket, any thoughts?
dtek001
Finally it was time to spend some money and get at least a code reader; scan tools are expensive and not all of them will readily work on OBD I without purchasing extra adapters. I have no use for OBD II. So a cheaper reader sure beats counting MIL flashes or the infamous 10 megohm Analog Multimeter needle sweeps. When the truck was just purchased I started out counting MIL light flashes to diagnose pinging sluggish take off. It ended up being an EGR problem. I cleaned everything made sure the EGR was free and working. Corrected a vacuum problem, checked the sensor and the MIL went off. I figured that was the end of it. Driveability improved and the EGR seemed to work OK. Total investment: $36.00. I will end up replacing the EGR after all, even with the MIL off I got codes 328 and 334. Next problem on the list was the engine shutting of when shifting into gear, especially reverse. I checked the TPS voltage, well within range, I cleaned the and checked the resistance for the IAC valve and adjusted the set screw to factory specs using a feeler gauge and all. Idle speed problem solved, no more shutting off in reverse! When I thought things were looking better I find something that could be bigger trouble: Creamy substance under air filter element! Time for Head resurfacing and whatever else they need + gaskets? Then I remembered that I did not change the oil after replacing upper and lower intake manifold gaskets. I used a shop vac to remove all gasket bits and pieces but oil and coolant seem to mingle when you do this anyways. I lost some coolant during the procedure and did not replace all of it before road testing the truck. There was overheating for a few minutes before I could find a gas station and repleninsh the radiator with the engine running. I have not driven the truck very much afterwards, I've been fixing other details. Presently the temp gauge reads about half way up the scale but I did not replace the thermostat after the event either. (I plan to replace it tomorrow) I would like to believe that the "cream" underneath the paper air filter is mostly the coolant that got mixed with the engine oil at the time of the repair and it is simply boiling out. It could also be a head gasket, any thoughts?
dtek001
Senior Member
Joined: Nov 2006
Posts: 5,495
Likes: 7
From: Memphis, TN 38135, USA, Earth
Originally Posted by dtek001
I will end up replacing the EGR after all, even with the MIL off I got codes 328 and 334.
Originally Posted by dtek001
Creamy substance under air filter element! Time for Head resurfacing and whatever else they need + gaskets?
Thread Starter
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Member
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From: Montana
Jumping to Conclusions
Thanks Steve83,
I guess I am jumping to conclusions here. I did check the EVP sensor and vacuums but it was a cursory check at best. There's never time to do things right the first time but always enough to go over and over the same problem adding the cost of unneeded parts. Thanks for setting me straight. The next task is an oil & filter change + PCV and following the proper EGR troubleshooting process.
dtek001
I guess I am jumping to conclusions here. I did check the EVP sensor and vacuums but it was a cursory check at best. There's never time to do things right the first time but always enough to go over and over the same problem adding the cost of unneeded parts. Thanks for setting me straight. The next task is an oil & filter change + PCV and following the proper EGR troubleshooting process.
dtek001