4.0 Just cranks until I put my foot to the floor
#1
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Year: 1993
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4.0 Just cranks until I put my foot to the floor
Hey guys,
Curious is anyone has a definitive answer for this one. Tried some searches but most of the ones I found had more running issues like stalling and rough idle.
Mine just cranks and cranks until the tb is opened (anywhere from barely to wot and it will fire off immediately and run fine all day. It will do this hot or cold and is a new symptom.
was kind of leaning toward fuel pump until I read that the ecu actually stops the injectors when the tb is at wot like that during cranking suspecting flooding?
could the iac or temp sensor cause this? Like I said, it's running great otherwise.
Curious is anyone has a definitive answer for this one. Tried some searches but most of the ones I found had more running issues like stalling and rough idle.
Mine just cranks and cranks until the tb is opened (anywhere from barely to wot and it will fire off immediately and run fine all day. It will do this hot or cold and is a new symptom.
was kind of leaning toward fuel pump until I read that the ecu actually stops the injectors when the tb is at wot like that during cranking suspecting flooding?
could the iac or temp sensor cause this? Like I said, it's running great otherwise.
Last edited by dac612; 06-21-2016 at 10:28 AM.
#2
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Year: 1999
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I have the same issue, but I have not researched it yet. It happens either on first start up, or if its been sitting in a parking lot for a while (several hours or more). I did notice though that first thing in the morning if I turn the key for about 5 seconds, but don't start it (let the fuel pump build pressure), then turn key off, then back on and actually crank it, it will usually start.
#3
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I have the same issue, but I have not researched it yet. It happens either on first start up, or if its been sitting in a parking lot for a while (several hours or more). I did notice though that first thing in the morning if I turn the key for about 5 seconds, but don't start it (let the fuel pump build pressure), then turn key off, then back on and actually crank it, it will usually start.
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#6
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I would check that the IAC is working. If that part is defective it will cause the motor to choke out and not start till there was an air flow going into the throttle body. You can pull out the IAC and turn the key to run and see if it moves. if it does not move turn off the key it try moving it by hand then repeat to see if it moves. Those motors have a tendency to get caked up with carbon and stop working.
#7
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I would check that the IAC is working. If that part is defective it will cause the motor to choke out and not start till there was an air flow going into the throttle body. You can pull out the IAC and turn the key to run and see if it moves. if it does not move turn off the key it try moving it by hand then repeat to see if it moves. Those motors have a tendency to get caked up with carbon and stop working.
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#8
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Check you coolant temp sensor. Have seen it a few times where it will read -40. If it reads that cold, it will dump fuel on startup until you open the throttle body all the way(clear flood mode). You will need to be able to see live data to see what it is reading.
Also, simple way to test wiring is, when the temp sensor is disconnected, use a paper clip between the 2 wires while watching the live data and if the wiring ia good, it will shoot up to the max reading.
Also, simple way to test wiring is, when the temp sensor is disconnected, use a paper clip between the 2 wires while watching the live data and if the wiring ia good, it will shoot up to the max reading.
#9
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Checking the coolant temp sensor is great and all, good idea, but cleaning the IAC is free... look up a you tube video by a hottie country chick jeeper that's called "how to clean an IAC. " free... eliminate that first. Either way, it won't hurt to clean it. Did I mention it's free yet?
Then... if not fixxed, go after the temp sensor.
Then... if not fixxed, go after the temp sensor.
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Holding it on the floor cuts off injector pulse, to recover from being flooded. (Max air with no gas). The MAP or it's tube would be a first thing to check. Post 94 or so it's just a little elbow under the MAP on the TB. Earlier the MAP is up on the firewall. Very important that, the MAP and it's tube.
Overriding everything, it will tell the puter to dump gas with less/no vacuum to it. (intake manifold vacuum drops as you put your foot into it). It needs intake manifold vacuum, or your not having a good day!
Overriding everything, it will tell the puter to dump gas with less/no vacuum to it. (intake manifold vacuum drops as you put your foot into it). It needs intake manifold vacuum, or your not having a good day!
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#13
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Hey fellas. Little update.
Before I did anything I actually checked to see if it only worked when floored or if it would work if i just barely opened the tb. ANd sure enough I just barely cracked the throttle body and she fired right up.
I decided to check/clean the TB and iac. Definitely lots of crud in there but wasn't horrendous which may explain why it just started happening and was fine a few days ago.
I cleaned out the passage in the tb for the iac and the iac itself and threw it back together. Had a slightly long crank but fired up the rest of the day yesterday without havign to mess with the throttle so that's a plus.
Noticed i have a pin hole leak in the fuel feed line near the fuel rail. I'll get to replacing that next.
TLDR:
Cleaning my tb+iac fixed my no start without gas (air) pedal problem.
Before I did anything I actually checked to see if it only worked when floored or if it would work if i just barely opened the tb. ANd sure enough I just barely cracked the throttle body and she fired right up.
I decided to check/clean the TB and iac. Definitely lots of crud in there but wasn't horrendous which may explain why it just started happening and was fine a few days ago.
I cleaned out the passage in the tb for the iac and the iac itself and threw it back together. Had a slightly long crank but fired up the rest of the day yesterday without havign to mess with the throttle so that's a plus.
Noticed i have a pin hole leak in the fuel feed line near the fuel rail. I'll get to replacing that next.
TLDR:
Cleaning my tb+iac fixed my no start without gas (air) pedal problem.
#14
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Checking the coolant temp sensor is great and all, good idea, but cleaning the IAC is free... look up a you tube video by a hottie country chick jeeper that's called "how to clean an IAC. " free... eliminate that first. Either way, it won't hurt to clean it. Did I mention it's free yet?
Then... if not fixxed, go after the temp sensor.
Then... if not fixxed, go after the temp sensor.
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