Trouble Starting

[Luna93]

my 93 explorer Eddie Bauer has been running fine, until I started it a few weeks ago and she’s struggling to stay at 1000RPM. She’s up and down and the check engine light goes on.

suddenly she will act normal and the light Will go off

This will continue for about 2 minutes until she completely shuts off.

mechanic said it was loose battery cables and the starter was old. He fixed both.
2 Weeks later, I’m having the same issues

anyone seen this before? Help would be greatly appreciated

 

[Travisfab]

There are a lot of possibilities. I'd pull your codes and start from there. No special tools or equipment are needed, and there are quite a few threads on how to make it happen.

 

[Roadrunner777]

I'm going to throw some general stuff out. It would be great to get actual step by step symptoms. I'm confused by 'suddenly will act normal' followed by eventually shutting off. Also, did you have starter problems? It's unclear to me how an idle problem would lead a mechanic to replace the starter and cables. Those oddities aside, here are some thoughts:

1) I think codes would be interesting, if they point to a particular component. But you may get codes, like lean mixture codes from an O2 sensor, and you would have to take that kind of thing as a symptom of a root problem.

2) Some of your symptoms are classic vacuum leak. Check the vacuum tree, back left side of engine, for disconnected lines. If you don't find any disconnected lines, then disconnect all the lines and plug the tree nipples to test. If the idle gets better, you have to track where your vacuum leak is... brake booster, trans modulator, etc...

3) Some of your symptoms could be a crack that has developed in the plastic duct from the MAF to the throttle body. That is easy to remove and inspect. Flex the corrugations, look for cracks, particularly the underside, which gets more heat.

4) Some of this could be a dirty/bad Mass Airflow Sensor (MAF). Great website on MAF: Part 1 -How to Test the Ford Mass Air Flow (MAF) Sensor

5) Possibly a bad Idle Air Control.

6) Possibly a fuel delivery problem, would need to do fuel pressure and volume tests, would possibly lead to a bad pump, filter, regulator. Some auto parts stores will borrow you a test gauge for a deposit.

7) Thinking about what the mechanic did, I wonder if he saw something that made him think the systems were getting low voltage.

I would like a better understanding of how the idle is over time because 'it suddenly gets better' and eventually shuts off doesn't make sense to me. Ok, you start it, it has bad idle, then describe it as it changes in as much detail as you can. Minor details could point directly to problems.

But, if I walked out to your truck right now and opened the hood, I would check the vacuum lines. If I had a fuel pressure gauge, I would do that test next. Then I would check that duct and also the MAF because they go together physically and it makes sense to do both at the same time.

This is not going to be a serious problem. It could be something as simple as a fuel pump relay. Need more details.

 

[410Fortune]

check the mechanics work, are the battery cables still holding and clean?
First thing to do when this happens is check fuel rail pressure
Second thing to do is retrieve the trouble code from the computers memory.... check engine light = code

 

[Luna93]

I'm going to throw some general stuff out. It would be great to get actual step by step symptoms. I'm confused by 'suddenly will act normal' followed by eventually shutting off. Also, did you have starter problems? It's unclear to me how an idle problem would lead a mechanic to replace the starter and cables. Those oddities aside, here are some thoughts:

1) I think codes would be interesting, if they point to a particular component. But you may get codes, like lean mixture codes from an O2 sensor, and you would have to take that kind of thing as a symptom of a root problem.

2) Some of your symptoms are classic vacuum leak. Check the vacuum tree, back left side of engine, for disconnected lines. If you don't find any disconnected lines, then disconnect all the lines and plug the tree nipples to test. If the idle gets better, you have to track where your vacuum leak is... brake booster, trans modulator, etc...

3) Some of your symptoms could be a crack that has developed in the plastic duct from the MAF to the throttle body. That is easy to remove and inspect. Flex the corrugations, look for cracks, particularly the underside, which gets more heat.

4) Some of this could be a dirty/bad Mass Airflow Sensor (MAF). Great website on MAF: Part 1 -How to Test the Ford Mass Air Flow (MAF) Sensor

5) Possibly a bad Idle Air Control.

6) Possibly a fuel delivery problem, would need to do fuel pressure and volume tests, would possibly lead to a bad pump, filter, regulator. Some auto parts stores will borrow you a test gauge for a deposit.

7) Thinking about what the mechanic did, I wonder if he saw something that made him think the systems were getting low voltage.

I would like a better understanding of how the idle is over time because 'it suddenly gets better' and eventually shuts off doesn't make sense to me. Ok, you start it, it has bad idle, then describe it as it changes in as much detail as you can. Minor details could point directly to problems.

But, if I walked out to your truck right now and opened the hood, I would check the vacuum lines. If I had a fuel pressure gauge, I would do that test next. Then I would check that duct and also the MAF because they go together physically and it makes sense to do both at the same time.

This is not going to be a serious problem. It could be something as simple as a fuel pump relay. Need more details.

I wish I could send you a video - but the site won’t let me.

he replaced the started and the idle valve and I’m still having problems! $500 later and I’m still going through all this crap.

he also told me when I turned it in that he didn’t have any problems at all. Now when he gives it back, it’s all messed up.

 

[Roadrunner777]

He changed the Idle Control Valve and then you started getting bad idle? This is too obvious, what am I missing?