Fuel System Problem? Please HELP!
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Start-up / Idle Problem...Fuel System?
Hi everyone. I have a '95 Ranger - 4 cyl. (2WD w/ man. trans.) with 95,000 miles.
For the past year or so, I have been having occassional problems starting the truck. Most of the time it happens after it sits for awhile or when it is humid out (from what I've observed). But it can happen even after running for awhile.
When I try to start it, the engine turns over and starts and the battery volt meter goes up to its normal position, but the engine immediately chokes out and it dies. I try again and give it some gas...sometimes that works and the engine catches and it is fine. Other times I have to keep giving it a little gas (so it won't die) for a minute or two. I then hear the engine's rpm's go up and I know it is okay.
Sometimes I can give it enough gas and warm it up so that it doesn't die, but is VERY sluggish. The volt meter is bouncing very low and the truck is shaking a bit. It will drive, but at stops it is idling dangerously low. Then it may kick in to normal...or a few times it over-compensated and seemed like there were too many rpm's and it was a very high idle.
I had a tune-up, complete with new wires and everything, last Dec. to no avail.
I cleaned my IAC to no avail.
Yesterday, I got a check engine light. Autozone said the code was P1131 (a general O2 lean code).
Not having time to do the work, I took it to Pep Boys who diagnosed it as two O2 sensors that were bad.
I had them change the O2 sensors and put in a new fuel filter.
Much to my disappointment (and frustration) the truck acted the same way this morning (FYI: It is foggy and humid out).
Any suggestions??? I am baffled... Thanks!
For the past year or so, I have been having occassional problems starting the truck. Most of the time it happens after it sits for awhile or when it is humid out (from what I've observed). But it can happen even after running for awhile.
When I try to start it, the engine turns over and starts and the battery volt meter goes up to its normal position, but the engine immediately chokes out and it dies. I try again and give it some gas...sometimes that works and the engine catches and it is fine. Other times I have to keep giving it a little gas (so it won't die) for a minute or two. I then hear the engine's rpm's go up and I know it is okay.
Sometimes I can give it enough gas and warm it up so that it doesn't die, but is VERY sluggish. The volt meter is bouncing very low and the truck is shaking a bit. It will drive, but at stops it is idling dangerously low. Then it may kick in to normal...or a few times it over-compensated and seemed like there were too many rpm's and it was a very high idle.
I had a tune-up, complete with new wires and everything, last Dec. to no avail.
I cleaned my IAC to no avail.
Yesterday, I got a check engine light. Autozone said the code was P1131 (a general O2 lean code).
Not having time to do the work, I took it to Pep Boys who diagnosed it as two O2 sensors that were bad.
I had them change the O2 sensors and put in a new fuel filter.
Much to my disappointment (and frustration) the truck acted the same way this morning (FYI: It is foggy and humid out).
Any suggestions??? I am baffled... Thanks!
Last edited by J7Bones; Oct 5, 2005 at 07:51 AM. Reason: Better description
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Junior User
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Thanks for the reply.
The fuel pump seems to be okay. When I turn the key forward, I can hear the pump start. Is this a good indicator, or is there a better way to test it?
I have no idea about where the fuel pressure regulator is or how to check it...
Did I just get hosed on having to put in new O2 sensors, or was that an unrelated event with the check engine light?
The mechanic said that the O2 sensors were likely causing the startup problem because they were bad and unable to work properly on startup until the truck got going...
The fuel pump seems to be okay. When I turn the key forward, I can hear the pump start. Is this a good indicator, or is there a better way to test it?
I have no idea about where the fuel pressure regulator is or how to check it...
Did I just get hosed on having to put in new O2 sensors, or was that an unrelated event with the check engine light?
The mechanic said that the O2 sensors were likely causing the startup problem because they were bad and unable to work properly on startup until the truck got going...
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From: Ventura ,ca. (near L.A.)
In my experiance the motor doesn't even need o2 sensors untill it warms up. Basically if you have a bad o2 sensor your motor is stuck in cold start mode and leaves the mixture rich thus using more fuel.
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So the motor should start even if the O2 sensors are not there at all?!?!??!?!
What should I tell the mechanic that insisted that the O2 sensors were bad and were the cause of the general P1131 code and the start-up problem? I spent a good chunk of money yesterday, mostly because I just wanted this frustrating problem fixed. Did I waste my money?
What should I tell the mechanic that insisted that the O2 sensors were bad and were the cause of the general P1131 code and the start-up problem? I spent a good chunk of money yesterday, mostly because I just wanted this frustrating problem fixed. Did I waste my money?
Elder User
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From: Ventura ,ca. (near L.A.)
If your getting a code for you o2 sensors and replaceing them caused it to go away thats great. But i don't think you starting problem has anything to do with it. It's most likely a different problem. You can check for a vacuum leak around the throttle body that can sometime cause stalling, also check to see if theres a unhooked hose or any holes in the big rubber hose that goes between the mass air flow sensor and the throttle body.
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From: Ventura ,ca. (near L.A.)
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Thanks! Good to know... I guess my frustration was trying to get me to look for someone (i.e. Pep Boys) to blame.
As for the starting problem, if it is a vacuum leak, wouldn't the problem occur all the time instead of only occassionally?
Could the MAF sensor be dirty or bad? Hypothetically, what happens if the MAF is bad or dirty?
As always, thanks for your input.
As for the starting problem, if it is a vacuum leak, wouldn't the problem occur all the time instead of only occassionally?
Could the MAF sensor be dirty or bad? Hypothetically, what happens if the MAF is bad or dirty?
As always, thanks for your input.
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Elder User
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From: Ventura ,ca. (near L.A.)
I would definately try cleaning the Maf. I clean mine with electrical cleaner every 6 months when i clean my K&N, (i live near the beach and it corrodes quickly). I mentioned that there might be a hole that rubbed through somewhere that might be intermittenly leaking. You original post said that it was a general fault for a lean condition which is consistant with a vacuum leak. In my experiance bad 02's are a rich mixture. I would fire up the truck and let it idle and take a can of carb cleaner and spray everything that can leak vacuum, like the hoses, throttle body, intake gaskets etc. If the idle jumps up when you spray a certain spot then you found your leak.
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Would such an intermittent leak only occur in the morning? Generally, once the the problem happens in the morning, it will run good the rest of the day.
Also, is there a specific product I should use to clean the MAF? Is the process difficult?
Thanks again!
Also, is there a specific product I should use to clean the MAF? Is the process difficult?
Thanks again!
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No. The only code (P1131) appeared yesterday when the Check Engine light came on, and it is off now that Pep Boys changed the O2 sensors and fuel filter.
In trying to diagnose the problem a few months ago, it was not reading any codes... That is when I tried cleaning the IAC.
In trying to diagnose the problem a few months ago, it was not reading any codes... That is when I tried cleaning the IAC.
Post Fiend
Joined: Jan 2003
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From: Connecticut
The fuel pressure regulator looks like a small metal mushroom with a vacuum hose coming off of it. It's located on the top of the engine, attached to the fuel rail. It's job is to keep the fuel pressure at or near a constant level.
Cleaning Your MAF Sensor
If you don't have one already, go out an pick up a copy of the Haynes Repair Manual for your Ranger.
Cleaning Your MAF Sensor
If you don't have one already, go out an pick up a copy of the Haynes Repair Manual for your Ranger.
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I have the repair manual. Thanks.
If the fuel pressure regulator was bad or dirty, would it register a code? As I told JimW411, there are no codes registering at the moment now that the O2 sensors were replaced.
If the fuel pressure regulator was bad or dirty, would it register a code? As I told JimW411, there are no codes registering at the moment now that the O2 sensors were replaced.