Hey guys, my 94 Bronco 5.8L doesn't hold a steady idle....slowly varies from about 500-900 rpm, I didn't get it out this weekend to drive. Last weekend, it was stalling out after driving for a little bit. Sounded like maybe a ign module maybe, I'm in the middle of upgrading the ignition system (MSD). My main question is where is the tfi module located? It's not distributor mounted.
Stalling and low surging idle
- Thread starter KYbronco3
- Start date
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Rons beast
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Hey KY,
It's mounted to the driver's fender, on a heat sink about the size of a slice of bread. Look at the fender close to the firewall, kinda under where the hood hinge is mounted, but closer to the firewall.
The ign module is rarely the cause of a surging idle. Fuel/air imbalance is more likely.
Good Luck
It's mounted to the driver's fender, on a heat sink about the size of a slice of bread. Look at the fender close to the firewall, kinda under where the hood hinge is mounted, but closer to the firewall.
The ign module is rarely the cause of a surging idle. Fuel/air imbalance is more likely.
Good Luck
yo K,
try a Self Test for Codes by my pal BroncoJoe
http://broncozone.com/topic/14269-code-reader/?pid=74587&mode=threaded
Powertrain Control/Emissions Diagnosis
1994
On Board Diagnostics I-A
SECTION 9A: Fuel Delivery Systems
http://www.thedieselstop.com/faq/9497faq/maint/vra/leftside=vras9al.htm&rightside=vras9ar.htm
See Vac leak Test post #20 at
http://broncozone.com/topic/23994-90-58l-getting-continuous-code-33-and-running-code-44/
try a Self Test for Codes by my pal BroncoJoe
http://broncozone.com/topic/14269-code-reader/?pid=74587&mode=threaded
Powertrain Control/Emissions Diagnosis
1994
On Board Diagnostics I-A
SECTION 9A: Fuel Delivery Systems
http://www.thedieselstop.com/faq/9497faq/maint/vra/leftside=vras9al.htm&rightside=vras9ar.htm
See Vac leak Test post #20 at
http://broncozone.com/topic/23994-90-58l-getting-continuous-code-33-and-running-code-44/
Hey guys, got a bit of an update possibly to this issue. Not sure if it's the same sort of thing but, Upon start up seems normal, after driving for 10 mins or so....idle goes up to 2000-2400 any time I touch the gas it sputters and acts like its missing or starving for fuel. I don't have a CEL on so not sure if there would be any codes to pull koeo
Rons beast
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2 Questions:
1-Have you checked the fuel pressure?
2- Do you have a cel when the key is turned on but the engine is not started? (sure the bulb isn't out)
1-Have you checked the fuel pressure?
2- Do you have a cel when the key is turned on but the engine is not started? (sure the bulb isn't out)
Rons beast
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You could have a code stored even if the CEL is not on. Your fuel pressure (Pump) could have an intermittent fault especially when it gets hot. I have found Fuel relays and temp senders that do odd things to a fuel pump.
It is always good to know what the fuel delivery system is doing when there is a drivability/ intermittent problem. It helps eliminate what is NOT wrong.
I don't recall if you changed the plugs and what they were gapped at, but if you can please advise as of that.
Good Luck
It is always good to know what the fuel delivery system is doing when there is a drivability/ intermittent problem. It helps eliminate what is NOT wrong.
I don't recall if you changed the plugs and what they were gapped at, but if you can please advise as of that.
Good Luck
Rons beast
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I won't say that it isn't possible. However your symptoms would have one think that the engine is not running correctly when this problem/s occurs.
The result would be the ECM getting readings outside the preprogramed parameters and saving a code. ( I.E.: running too lean and causing a lean miss would have the O2 sensor reading the lean exhaust stream and setting a "pending" code that would be a hard code when the instance continues or happens often.)
This is the reason for the idea of you checking for codes...even if there is no CEL.
Knowing the fuel pressure when running correctly and when the problem occurs tells us the state of the fuel delivery.
There by eliminating or finding the fuel delivery to be the problem. This is part of cognitive diagnostic procedures.
Everything else is guessing.
The result would be the ECM getting readings outside the preprogramed parameters and saving a code. ( I.E.: running too lean and causing a lean miss would have the O2 sensor reading the lean exhaust stream and setting a "pending" code that would be a hard code when the instance continues or happens often.)
This is the reason for the idea of you checking for codes...even if there is no CEL.
Knowing the fuel pressure when running correctly and when the problem occurs tells us the state of the fuel delivery.
There by eliminating or finding the fuel delivery to be the problem. This is part of cognitive diagnostic procedures.
Everything else is guessing.
Ok, quick update KOEO test!
No current codes.
Stored Codes (assuming I read these right)
112
23
62
46
27
Where to now? I don't know if I'll be able to test fuel pressure this weekend, but I am going to change the fuel and air filters.
No current codes.
Stored Codes (assuming I read these right)
112
23
62
46
27
Where to now? I don't know if I'll be able to test fuel pressure this weekend, but I am going to change the fuel and air filters.
Rons beast
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Ok here's the rundown:
112= intake air temp. (IAT) sensor circuit below minimum voltage.
62= Convertor clutch error
46=thermactor air not bypassing during Self test.
27= no listing in my book for a #27 code
23=throttle position sensor out of self test range.
I would write these codes down. Then clear the codes by removing the neg. bat. cable and depressing the brake pedal for at least 10 seconds.
reinstall the battery cable and start the vehicle.
Try a very slight adjustment of the TPS to see if there is any improvement in the engine running.
recheck for codes and note them as you did here.
I suspect there is an issue with the IAT, and possibly the TPS, but wouldn't condemn them just yet.
I cannot find the voltage specs to test each and have limited time today.
Perhaps someone else has those specs and can help out here.
I think the convertor clutch and thermactor are reactive codes and not indigenous to the problem.
Hope this get you on the right track
Good Luck
112= intake air temp. (IAT) sensor circuit below minimum voltage.
62= Convertor clutch error
46=thermactor air not bypassing during Self test.
27= no listing in my book for a #27 code
23=throttle position sensor out of self test range.
I would write these codes down. Then clear the codes by removing the neg. bat. cable and depressing the brake pedal for at least 10 seconds.
reinstall the battery cable and start the vehicle.
Try a very slight adjustment of the TPS to see if there is any improvement in the engine running.
recheck for codes and note them as you did here.
I suspect there is an issue with the IAT, and possibly the TPS, but wouldn't condemn them just yet.
I cannot find the voltage specs to test each and have limited time today.
Perhaps someone else has those specs and can help out here.
I think the convertor clutch and thermactor are reactive codes and not indigenous to the problem.
Hope this get you on the right track
Good Luck
Ok, thanks for your help. I went ahead and ordered the MSD coil, Ford racing 9mm wires and a TPS (since it gave me free shipping) so, I'm going to clear the codes and get these parts replaced. I hope the converter issue was just some funky thing it was confused about. I looked up the 27 code which shows vehicle speed sensor problem....any ideas there?
KJRbronco88
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Following this information. I have a 1988 bronco and it's will idle right a couple minutes and then starts to spit and sputter and die. I can hear the fuel pump come on when I start it and when it's spitting and sputtering until it almost dies, I hear the fuel pump making noise. I have replaced the coil, plugs, air control motor,and fuel filter. Any suggestions?
Rons beast
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Hey KJR,
Welcome,
First check for codes as directed above by M5.
It is important to know what is happening in the engine when the sputtering is happening. A fuel pressure gauge is essential for monitoring fuel delivery.
Intermittent sputtering can be from fuel delivery, power to the fuel pump, ignition module, or distributor pick up coil or related primary wiring.
This can be tricky to diagnose as I believe the injector dwell is regulated by the comp, but initiated by the distributor signal. Knowing if proper fuel pressure is being delivered is a must.
Hope this helps
Good Luck
Welcome,
First check for codes as directed above by M5.
It is important to know what is happening in the engine when the sputtering is happening. A fuel pressure gauge is essential for monitoring fuel delivery.
Intermittent sputtering can be from fuel delivery, power to the fuel pump, ignition module, or distributor pick up coil or related primary wiring.
This can be tricky to diagnose as I believe the injector dwell is regulated by the comp, but initiated by the distributor signal. Knowing if proper fuel pressure is being delivered is a must.
Hope this helps
Good Luck
yo,
DTC 112 to 114, Intake Air charge temperature sensor (ACT or IAT)Troubleshooting & Possible Causes; "...Codes 112 to 114 will set a IAT sensor code in the EEC, remove and inspect the sensor it could get contaminated by engine oil , K&N oil or dust. Clean the sensor with isopropyl alcohol. If the sensor still fails replace the unit..." Intake Air Temp (IAT); (Air Charge Temperature [ACT] prior to 1992)
IAT will have a connector with 2 wires. looks like it plugs right into the intake tube. to remove it, unplug it and pull it out'
Clean the sensor with isopropyl alcohol. If the sensor still fails replace the unit
the IAT sensor is installed in the lower intake manifold and in the air cleaner tube on SFI engines.
dirty one will look like this:
http://www.supermotors.net/getfile/104574/fullsize/iats_dirty.jpg
by Big
IAT sensor on the 94 is located on intake manifold near the #6 runner. It screws in the intake manifold itself
Now I recall giving you this info earlier @ http://broncozone.com/topic/24835-iat-sensor-and-a-coolant-line-s/?do=findComment&comment=130323
========
All the other Codes (2 DIGITs are not applicable; should be 3 DIGITs. REDO Self Test
Ford went from two-digit to three-digit EEC IV Self-Test codes in 1991 to service the increasing number of service codes required to support various government On-Board Diagnostic (OBD) regulations. The phase-in from two-digit to three-digit codes started in the 1991 model year..."
DTC 112 to 114, Intake Air charge temperature sensor (ACT or IAT)Troubleshooting & Possible Causes; "...Codes 112 to 114 will set a IAT sensor code in the EEC, remove and inspect the sensor it could get contaminated by engine oil , K&N oil or dust. Clean the sensor with isopropyl alcohol. If the sensor still fails replace the unit..." Intake Air Temp (IAT); (Air Charge Temperature [ACT] prior to 1992)
IAT will have a connector with 2 wires. looks like it plugs right into the intake tube. to remove it, unplug it and pull it out'
Clean the sensor with isopropyl alcohol. If the sensor still fails replace the unit
the IAT sensor is installed in the lower intake manifold and in the air cleaner tube on SFI engines.
dirty one will look like this:
http://www.supermotors.net/getfile/104574/fullsize/iats_dirty.jpg
by Big
IAT sensor on the 94 is located on intake manifold near the #6 runner. It screws in the intake manifold itself
Now I recall giving you this info earlier @ http://broncozone.com/topic/24835-iat-sensor-and-a-coolant-line-s/?do=findComment&comment=130323
========
All the other Codes (2 DIGITs are not applicable; should be 3 DIGITs. REDO Self Test
Ford went from two-digit to three-digit EEC IV Self-Test codes in 1991 to service the increasing number of service codes required to support various government On-Board Diagnostic (OBD) regulations. The phase-in from two-digit to three-digit codes started in the 1991 model year..."
