at a loss - she won't run past idle

[thumper]

While on my way home from work Friday, I was in some stop and go traffic. I had the Mach in 1st gear and simply winding it up and using compression to slow down. Then she stalled. I attempted to restart and nothing. It would turn over, but I was dead in the middle of a bridge, and had it not been for a deputy sheriff who pulled in behind me, I'm sure I would have been the target of many nasty comments. I finally got her home and did some research and decided to clean IAC, but it did not help. All I get is that it will idle, but as soon as I give it throttle it dies. Also, upon startup, I noticed a lot of black smoke that eventually went away, but it definitely was something that she never does. Once it's warmed up and eventually dies, It won't restart. Any suggestions? Forgot to mention that I also changed the fuel filter and put in a new battery since it needed those things anyway.

[NastyNate]

Check the Fuel rail pressure sensor.

[thumper]

Thanks for the suggestion. It there a way to test it without just replacing it?

[NastyNate]

I believe you can pull off the vacuum line that goes to it and if there is gas is in then the diaphram ruptured.

[thumper]

I'll give it a go and see if that's it. Thanks again.

[DSG2003Mach1]

Originally Posted by NastyNate

I believe you can pull off the vacuum line that goes to it and if there is gas is in then the diaphram ruptured.

correct, if thats the case you also need to change oil and filter asap as well.

Check your MAF sensor connection and be sure its firmly snapped in place and the harness isnt somehow damaged. Id also check for any massive vacuum leaks (something in the intake post maf came off/loose or somehow rubbed through). If you have a K&N filter or similar that requires oiling it may have been over done and contaminated the MAF, use MAF cleaner or electrical sensor cleaner that does NOT leave a protective residue.

[thumper]

Most of that was checked today when I cleaned the iac but I do have a k&n so I will clean the MAF when I check the fuel rail pressure sensor tomorrow. Thanks for the suggestion.

[thumper]

Ok, so I cleaned the MAF sensor and although it helped, she still isn't normal. I checked the fuel pressure sensor and pulled the vacuum line and it seemed normal (no fuel in line). She idles around 900 (somewhat normal) and if I blip the throttle she cuts out and almost dies. If I ease into the throttle, I can get revs up with no problem. After warmup she was hard to start back up. Don't want to attempt to drive because I don't want to get stuck somewhere. From reading some of the other posts on the IAC valve, it does sound similar to some of those issues, but cleaning that didn't help. I wonder if it is just bad. Any other suggestions? Anything helps.

[TKat13]

If you have an ODBII reader (20 bucks on amazon) you can pull the codes but you can also check other readings like the fuel pressure sensor; etc.

Is your check engine light on? Or, was it on prior to you putting in a new battery?

[DSG2003Mach1]

trying to clean the IAC wont always help depending on whats failed but typically with a bad IAC the car will not idle, itll do everything else but it wont idle. You appear to be the other way around.

If you dont have a handheld it may be worth picking up one of those ~$20 OBD blue tooth readers with a cell phone app to see if fuel pressure drops when you give it throttle and also see how the O2 sensors are switching. Maybe an a bad O2 issue?

[TKat13]

Any mods on the car? If you had an ODBII reading you could also check the TPS readings and see if they are jumping around erratically as you press the throttle, just a thought.

[TKat13]

as usual, DSG and I are on the same page.

BTW, a decent software for your phone is the Palmer Performance DashCommand; I even have the PC version (it came out first).

[thumper]

The check engine light has never come on. I don't have any handhelds or anything along that line, but I may have access to one. Could this be a bad gas issue? I doubt it, since I have run about 3/4 of a tank since the issue started, but I don't know what a bad gas issue is like.

[DSG2003Mach1]

I doubt it based on your description

[thumper]

I've had two people today suggest that it is likely a fuel pump. One is another car guy who does a lot of his own work, but not on EFI cars. The other is a mechanic at a local import repair shop. When I described the symptoms, they both immediately said "fuel pump". I guess that's my next shot.

[DSG2003Mach1]

I would seriously grab one of those usb readers if its not your DD and see if fuel pressure drops before you go just replacing parts. Ive also read about several people lately having issues with their FPDM when its hot outside (not sure if youre talking exterior temps or just that the motor was warm at operating temp).

[01yellerCobra]

That's why you need a way to datalog. So you can see what everything is doing before you spend money you don't need to spend.

FWIW, when my FRPS blew it didn't much if any gas in the vacuum line. But it sat for a couple days before I messed with it. I pulled the sensor off the rail and was able to blow through it. You're not supposed to be able to do that.

[thumper]

I'm going to have my friend do a diagnostic on it tomorrow. He has his own shop and I'm sure he won't soak me. I'll be sure to make him aware of all your suggestions so that he can check them off the list as he looks for the issue. I'll let you know the results in a couple of days. Thanks again for all of the input.

[03Shadow Grey]

Originally Posted by TKat13

as usual, DSG and I are on the same page.

BTW, a decent software for your phone is the Palmer Performance DashCommand; I even have the PC version (it came out first).

Torque Pro is also A good one. The stereo I plan on getting will have the apps , so I can stop watching from my phone.

[VA-Mach1]

She? Pretty sure it's a it. Just rattling your cage lol. I hope you figure it out soon and let us know what you find out about it incase anyone runs into the same problem..

[thumper]

First off, if "it" costs me money and doesn't do as "it's" told, then it's definitely a "she." Ha ha. Just talked with mechanic and it is the fuel pump. New fuel pump and labor - $460.00. She better be good to me tonight.

[DSG2003Mach1]

lol, hope that takes care of it!

[thumper]

Picked her up yesterday and she's running great! On an interesting note: when I got to the shop and my car was unloaded from the tow truck, my buddy asked me to start it. I told him that it wouldn't start, it would just turn over unless I primed it a few times. He said, "if it's the fuel pump, it'll start right up." I thought that sounded strange, but I jumped in and turned the key and it started right up. Just like old times. I got out and said, "wtf" and "how did you know?" He told me that when cars with bad fuel pumps take a ride on the tow truck, they get jostled around just enough to make them fire right up. He then said, "let it idle and in a couple of minutes it will die." It did. At that point I was glad I took it to him. I didn't really want to take the tank out of the car anyway. Worth the money to not lose a weekend. Thanks again for all of you responses. As most of you can probably tell, I've been a member on this sight for a long time, but don't post much. It's nice to know that I can always come here for help.

[DSG2003Mach1]

glad that fixed it. The combination of jostling around and cooling down can make it run again for a minute.

[thumper]

I'm also glad. I've never had an issue with my car since new (45,000mi now) except for a dead battery. Having it die on me right in the middle of rush hour traffic was depressing. I plan to go home that same way today and teach that spot a lesson.