Fuel pressure cuts out, able to restart with full pressure, but cuts out again.

[IUP99snake]

I've been running into a recurring issue where the car has been cutting out, losing power, and eventually stalling out. I am able to immediately start up the car again, get full fuel pressure (30-40psi), and then it falls off and stalls. As a strange side effect, my left turn signal indicator light turns on, but doesn't blink.

Sometimes, after a few attempts, the issue goes away and I am able to drive off like normal. Sometimes it happens after the car is warmed up completely and I've been driving for a while, and sometimes, it happens within a few minutes of starting the car. But this morning, the issue kept persisting.

It's clearly a fuel pressure issue. The question is, what's causing the fuel pressure to cut out randomly.

I just changed the fuel filter a few months ago.

I have a Walbro 255 LPH pump which was installed 5 or 6 years ago. I also have 42LB injectors. I haven't changed any wiring with the fuel system.

I'm thinking it could be perhaps a clogged fuel sock, or maybe a fuel pump driver module.

As a side note, I've been having a parasitic voltage drain, where the battery will die after the car has been sitting after a few days. It's not the GEM module, because I've pulled that fuse and the issue persists. So, I'm thinking maybe the fuel issue and the voltage issue are connected. Maybe the FPDM is what's pulling voltage.

I've also been battling the dreaded p0171 p0174 lean codes in both banks for the past few years, but that has been such an ongoing issue, I think it's a vacuum leak or something rather than a fuel pump issue.

Under normal operation, I get around 30 psi of fuel pressure, all the way up to 55-60 psi under throttle according to my Auto Meter gauge.

Is the FPDM on all 99-04 mustangs interchangeable? What about from other fords, such as Crown Vics, V8 explorers, Navigators, whatever? I could just go to the Junkyard, pick one up and see if that fixes the issue. Or, I could always just go to the parts store, pick up a new one, and return it if that doesn't fix the problem.

Is there any other electrical component or box besides the FPDM that I should be worried about?

Has anyone experienced any fuel pressure issues such as this before?

Homer

 

[clbailey]

I have the same problems with my fuel hats on my Walboro in my GSX. I normally bang on the top of the fuel tank and it clears anything up. Im assuming since the car sat with hardly any fuel in it the tank rusted inside and the pump is picking up flakes.

 

[IUP99snake]

I have the same problems with my fuel hats on my Walboro in my GSX. I normally bang on the top of the fuel tank and it clears anything up. Im assuming since the car sat with hardly any fuel in it the tank rusted inside and the pump is picking up flakes.

hmmm.. my car did sit for about 4 months over the winter, and the first time this problem ever happened was within an hour of driving the car for the first time with the old gas in it.

I found a few articles to troubleshoot the FPDM (Fuel Pump Driver Module) and the FRPS (Fuel Rail Pressure Sensor), either of which could be causing this problem.

I also have to replace the O-ring for the fuel tank filler neck, so while I've got the tank dropped, I'll pull out the fuel pump assembly and check for debris, loose wires, corroded hoses, or a dirty fuel pump sock.

We'll see.

 

[clbailey]

Post up the outcome, please.

 

[thebestdj07]

Sounds like the fprs but then it done. One guy in the club was haven the issue of it.running for a min then it would cut out. He said his fp would jump to like 100 though. Its possible for the fpdm as that would draw on the battery.

Try disconnecting it and leave the car sit and see if you still have drain.

 

[IUP99snake]

Sounds like the fprs but then it done. One guy in the club was haven the issue of it.running for a min then it would cut out. He said his fp would jump to like 100 though. Its possible for the fpdm as that would draw on the battery.

Try disconnecting it and leave the car sit and see if you still have drain.

Good idea to check for battery drain. I found a few instructions and diagrams for testing the FPDM and the fuel pump, and I'm going to give that a shot. None of them mention parasitic drain, but that's an easy enough test.

I'm also worried a little bit that it might be the fuel pump, or maybe something's clogging the fuel pump sock.

Funny story, when I first installed my Procharger back in 2003, we started it up for the first time and let it idle to make sure there were no leaks or check engine lights, etc. Within 5 minutes of idling, the new Walbro 255 pump we had just installed seized up and the car stalled out. If it had happened 10 minutes later, the car would have been on the dyno and I would have destroyed my motor. Whew. Anyway, we swapped out the Walbro for the stock pump and ran it on the dyno. It made 462 whp and the stock pump made plenty of fuel pressure. Nevertheless, I returned the Walbro and got a replacement.

Update: I was able to get the car running properly after a few more tries. But before that happened, I did a simple check of the FRPS (Fuel Rail Pressure Sensor) by unplugging the electrical connector when it was idling. Immediately, the fuel pressure shot up from 30 psi to 60 psi. This happened both when the problem was occurring and after the problem went away. That eliminates the FRPS as being the problem. Usually, when the FRPS goes, it'll throw a code anyway.

This is what I'm gonna do.
1: Disconnect the FPDM and let the car sit to check for parasitic drain

2: Do some voltage tests on the FPDM. I'm also going to do some vacuum tests on the FRPS with a hand vacuum pump. I'll probably go to the pick-n-pull and get an FPDM from a wrecked car and swap it out to see what happens. Just for good measure, I'll pull off the FRPS and replace that too.

3: I'm going to let the car idle and and cut power to the pump. I want to see if there is an immediate or gradual drop in fuel pressure and see if the car immediately quits, or takes a couple seconds.

4: I'm going to make a jumper to supply full power to the fuel pump and keep it in my car in case this happens again. If the pump has full power but it's still happening, I know it's something with the pump, sock, or fuel pump hat.

5: Lastly, I'm going to drop the tank, change the fuel filler neck grommet (which needs changing anyway), pull the fuel pump hat and inspect the pump and sock for any debris or other problems.

Anyway, it's fixed for now. But it's been happening at an increasing rate. It's happened 4 times in the last 3 months and every time, I have been able to get the car running fine after a few tries and get home. But I'm worried I won't be so lucky in the future.

Homer

 

[STEEDA SNAKES]

I am having this same issue with my '98 Steeda Cobra. It sits in the garage, way more than it gets out. It is SC'd and has a T-Rex fuel pump, my fuel pressure gauge jumps around and then falls to zero, and the car stalls and dies. If I let it sit for awhile it will start again. What did you do to fix it?

 

[Black*Death]

If you haven't thought of it yet I have read of people having fuel and electrical issues

when the constant control relay module (CCRM) fails.

I have no personal experience with the CCRM though

 

[IUP99snake]

It must have fixed itself. After dealing with the symptoms for a while, I think it is an electrical gremlin that the fuel pump is also connected to. For example, the other day, it would happen when ai turned on the A/C or the headlights.
I was gonna go to the parts store to read the codes, but they went away and the check engine light went out

I honestly think its a problem with the ecu or tune. Next time it happens, the first thing I'm gonna do is check the codes.

 

[STEEDA SNAKES]

I replaced the fuel filter, but that didn't seem to change anything. The fuel that drained back out of the old filter didn't seem dirty. It may just be a failing fuel pump or dirty sock, or fuel system. The car barely gets driven, it has 26k original miles. The gas is probably a little over a year old. I put an octane boost and fuel system cleaner, along with six gallons of fresh fuel in the tank. I am driving it gingerly around the neighborhood each day, and it seems to be getter better (better fuel pressure and less lagging). I guess I will continue this for a few more days and see what happens.

 

[DuffManRHA]

It must have fixed itself. After dealing with the symptoms for a while, I think it is an electrical gremlin that the fuel pump is also connected to. For example, the other day, it would happen when ai turned on the A/C or the headlights.
I was gonna go to the parts store to read the codes, but they went away and the check engine light went out

I honestly think its a problem with the ecu or tune. Next time it happens, the first thing I'm gonna do is check the codes.

As mentioned above, and especially after reading that it happens with the A/C, it is quite possible that it is the CCRM. I don't have a writeup, although I guess I should do one up, but the CCRM is able to be taken apart and you can test all the relays, which are just regular 5-pin Bosch-style relays but with circuit board connectors instead of spade connectors that you usually see. I took mine apart by drilling out the rivets and carefully prying it open, and after testing all the relays (mine were fine, but you can test them just like any other relay) just use some bolts and nuts to bolt it together before bolting it back into place.

The other thing mentioned, the fuel rail pressure sensor (FPRS) could also be bad but you can test that similar to testing a MAF sensor; disconnect the electrical connection but leave the vaccuum connection in place, and see if the problem goes away or improves, but do that and test the CCRM as well and post back with the results. It would be a shame to have the problem spring up again at 2am in the middle of nowhere so better to fix it now instead of hoping for the best.... and I saw that from personal experience unfortunately :fm:

 

[IUP99snake]

As mentioned above, and especially after reading that it happens with the A/C, it is quite possible that it is the CCRM. I don't have a writeup, although I guess I should do one up, but the CCRM is able to be taken apart and you can test all the relays, which are just regular 5-pin Bosch-style relays but with circuit board connectors instead of spade connectors that you usually see. I took mine apart by drilling out the rivets and carefully prying it open, and after testing all the relays (mine were fine, but you can test them just like any other relay) just use some bolts and nuts to bolt it together before bolting it back into place.

The other thing mentioned, the fuel rail pressure sensor (FPRS) could also be bad but you can test that similar to testing a MAF sensor; disconnect the electrical connection but leave the vaccuum connection in place, and see if the problem goes away or improves, but do that and test the CCRM as well and post back with the results. It would be a shame to have the problem spring up again at 2am in the middle of nowhere so better to fix it now instead of hoping for the best.... and I saw that from personal experience unfortunately :fm:

Wow! Rock on! That's awesome advice!

I did test the FRPS by unplugging it, both when the car was running fine and when it was having these episodes. In both cases when I unplugged the FRPS electrical connector (leaving the vacuum connected), and the fuel pressure immediately shot up from 30 to 60 psi at idle. The only difference is that during an episode, the car would still die out the same way, just a little slower because theres a little more fuel pressure. I've had a bad FRPS before, and I know exactly what the symptoms are. It throws a code that says the FRPS is bad. And you can find one off of any modular motor with a returnless fuel system. Mine went bad about 6 years ago and I pulled one off a Crown Vic at the Junkyard for 5 bucks.

It's a real intermittent issue... Let's call it a "manic episode". One day, it'll happen 5 or 10 times when I'm trying to drive home from work or something. When it first happened, I didn't know what to do, I'd pull over, let the engine stop completely, restart it, let it stall, and repeat until it wouldn't stall anymore. It always restarts very quickly, but just dies out again. I was worried I'd burn out my starter from cranking it so often. It got to the point where I started to smell my starter motor.. (Remember when you were a kid and you hooked up a 9V battery to a little motor that was supposed to run on AA's? It made that smell.)

But now that I've become more familiar with the problem, I don't even have to stop, or even let the motor stop spinning to get it restarted. I'll be going down the road at cruising rpm and it'll have an episode, and all I have to do is just leave it in gear, cycle the ignition back ONE click (not going back so far as to lock the steering wheel), and then forward to the on position, and the car will fire right back up. And by cycling the ignition off and on in gear without letting it stop spinning and having to restart it completely, I don't lose the power steering or brakes when I'm going down the road..It's almost as if I just let off the gas and was coasting in gear, followed by a slight surge as the car fires back up as soon as the ignition is cycled off and on.

It got real bad on Saturday when I had to cycle the ignition off and on during most of the drive back from work. Then all the sudden, it's fine and I was able to drive the rest of the way home with no problem. Even if I turn on the A/C or the headlights. I was going to get the codes scanned yesterday to see what it would lead me to, but the check engine light went out all by itself! That was a first!

It's not like the A/C or headlights trigger the episode every time. It'll have an episode without the A/C or headlights. But when it's happening and I turn on the A/C or headlights, that'll immediately trigger it to stall sooner than it normally would during an episode. It's like the A/C or headlights exacerbate the problem, but only during an episode. The A/C and lights don't "cause it", but they make it worse when it's happening. But when it's not having an episode, I can turn on the A/C and headlights and it'll run fine. I've never been able to induce the problem with the A/C or headlights when the car is running normally.

But as a side note with the A/C, a few weeks ago, the A/C wouldn't work for a good 15-20 minutes a couple times without any other issues. Both times, the A/C came back on eventually. I thought it might have been low on coolant, maybe when the engine got warmer, it raised the refrigerant pressure just enough to pass the threshold of the pressure switch and allow the A/C to function. So, I topped it off with a just a smidge of refrigerant one day, careful not to overfill it. Since the A/C was working when I topped it off, I have no idea if it was low refrigerant or an intermittent electrical issue causing the A/C to malfunction those two times. The A/C has always worked since then, however.

But in every case when this happens, the right turn signal indicator illuminates without flashing, and the check engine light comes on.

Speaking of the right turn signal indicator being illuminated during it's "manic episodes", I have had other problems with the right turn signal that I thought were unrelated. First, when I signaled right, it would flash faster during a right signal as if one of the bulbs were blown. But I checked and both front and rear bulbs were fine. So, I thought I'd need a new turn signal relay. But a few days after that, I was still getting the same faster flash rate and the front right signal bulb wouldn't blink at all (but the parking light worked), which led me to believe that one of the filaments in the bulb was blown. But before I had a chance to change the bulb or the flasher relay, it all started working. It blinked the same speed as the left side, and the bulb was working. WTF???? But I still get the constant right side signal illumination if the car is in the middle of an episode.

So, about the CCRM. I did some research on it from other forums and I was able to find other people with similar issues, whether it be a V6, GT, or Cobra. It could be a loose soldered connection or maybe a rusty or worn relay in the CCRM. I used to work at a car audio shop installing stereos and remote starters and I've seen tons of bad relays and loose connections. I'm really good at soldering, so if I can find a defective connection, I have no problems fixing it.

I found a couple forum posts that had diagnostic procedures for the CCRM, but mostly it had to do with the radiator fan.
Here: Cooling Fan/Constant Control Relay Module (CCRM) - Ford Mustang Forums
Here: 1999 mustang 3.8 possbile CCRM problem - Ford Mustang Forums
Here's a description and product listing for a CCRM for V8 mustangs: CCRM (Constant Control Relay Module) fits 1999-2004 V8 Mustangs, Speed Concepts

Even though the CCRM may be different for V6 and V8 mustangs, they still control the same functions and could still malfunction in the same way.

I just had an "ah hah moment!" Being that the radiator fan comes on when the A/C is on and/or when the engine is hot, the whole problem could be boiling back to the radiator fan circuit causing a malfunction on the CCRM..which is causing either the fuel pressure to cut out. The only reason why I suspected it to be a direct issue with the fuel system is because that's the only thing I can precisely monitor since I have a fuel pressure gauge.

It always happens randomly, except for once when it was running perfectly fine on a very empty tank of gas, but when I put a half tank in it, it stalled the first time I started it back up at the gas station. Next time I put gas in it, I'll leave it running and see what happens. But now that I think about it.... it has been raining... A LOT.. here... for the past 2 weeks. It doesn't necessarily happen in the rain, but since the CCRM is in the fenderwell, it could be getting exposed to moisture, which can linger and cause problems days after it has been driven in the rain.

Now that I've seen a picture of the CCRM, where it's located, and what it controls, I'm fairly confident that this is the problem. I'm going to do a bunch of these diagnostic tests on it, but since the problem is intermittent, I won't be able to detect the problem unless I test it when the car is having an episode.

One thing I could use some more clarification with regard to the CCRM: I've also heard it being called the BCM or "Body Control Module", which is often mentioned interchangeably and mistaken for the GEM or "Generic Electronic Module". I know it's definitely not the GEM because the GEM controls a completely different set of functions, such as the dome light, chime, the single touch drivers side power window, etc.... rather than the fan, A/C, and fuel system. Is the CCRM the same as the BCM, or are they two different pieces?

The CCRM is in the passenger side fenderwell near the headlight, I believe, Since I have all that area cleared out for easy access to my blow-thru MAF and power pipe, I should be able to access the CCRM fairly easily. I'll disconnect it and let the car sit for a few days to see if the battery still drains. I'll pull it apart and inspect it. So, you're saying that the CCRM just has relays that are soldered onto a PCB instead of plugging in? Are there any microchips, resistors, or capacitors inside it, or is it only relays? If it's only relays, I could even bypass the CCRM entirely by wiring up my own relays. Or, I could solder in relay wiring harnesses to the PCB so I could remote mount the relays in a more accessible and environmentally friendly location under the hood. Or, I could just go to the junkyard and replace it for $20 bucks from any other 99+ modular V8 Ford vehicle.

Anyway, thanks for the breakthrough advice. I think this is gonna be it.

Next time the car has an episode, I'm gonna try to take some video of it. And if I need to repair the CCRM, I'll post pics and steps. I'll keep you posted.

Sorry again for the long post. Back to work!

Homer

 

[Black*Death]

I think the CCRM is located near the front passenger wheel well, I believe?

 

[01yellercobra]

Off topic: How many phones do you go through by wearing out the keyboards while texting?

 

[IUP99snake]

Haha that was on my computer... I only do short posts on my phone. I was slow at work this morning, so I had to occupy my time somehow. I teach finance, so occasionally I can get carried away explaining things.

Anyway, found the CCRM, removed it, shook it around while the car was running, drilled out the rivets to access the relays inside and cleaned it out with MAF cleaner. Regardless, I couldn't duplicate the problem.

My next step is to let the car sit for a few days with the CCRM unplugged and see if I get a battery drain.

One person suggested it might be the alternator, because of how the turn signal was acting. But the battery is always strong enough to start the car up, even 20 times in a matter of 5 minutes.... Unless its been sitting for a few days.

I might take it out in the rain and put some gas in it to see if I can duplicate the results. Then I will be able to go to the parts store and get the codes scanned. But since the codes went away on their own even without disconnecting the battery, I have to wait until the problem comes back to know exactly what the computer thinks is wrong with the car.

It's running fine right now. But it was extremely low on air conditioning refrigerant. I topped that off. And now the AC is much colder.

 

[DuffManRHA]

You mentioned that the CEL came on, does the car have any codes stored?

Since you also mentioned the right turn signal, it got me thinking about the factory alarm system that most Cobras came with (or at least every one that I've seen). I know that the alarm control box is also hooked up to the turn signals to flash when the alarm goes off, so it may be indicating a fault there and maybe the alarm control box has an intermitten short in there and that is what is killing the car as well. Or, similarly, the connection could be just on the fringe to where some voltage gets through but not enough, ergo the fuel pressure problem.

The CCRM uses basic relays inside that I've sure you saw when you opened yours up, so you can and should test the relays to make sure they are operating correctly, if only to rule them out as a possible cause. You can find online how to test relays, but basically you test to make sure certain terminals have power once the relay is energized, and you can energize it with 12 volts. If it completes the circuit once the relay is energized, and you can hear a faint click inside the relay, than you can safely rule that out.

Did you test the FPDM and if not, did you not test it because you don't have the schematic for it? I have a subscription to AllDataDIY.com (which EVERYONE should have, IMO) that I can check for schematics for it if you can't find anything online but you should consider buying one if you are going to keep the car for a long time. I got my 3 year subscription for less than $20 by using a code on a coupon site. Anyway, let me know if you need the info.

On the subject of testing, did you test that the fuel pump is getting the correct voltage? You can do this test in connection (haha) with testing the FPDM to make sure the voltage correctly increases and therefore pressure correctly increases.

Finally, check to make sure that the inertia switch is not tripped. Get a flathead screwdriver and fully reset the inertia switch and then press it down again to make sure that it isn't stuck in a half-way position at all. This switch can fail and make a loose connection that can cause the symptoms you are having, except for the turn signal anyway.

 

[harricanfloyd]

I remember bringing my F450 work truck back to the dealer 3 times for the same problem. I "do"know that I ran the tank almost dry lol. After that, she was sputtering......then it would run fine. Whenever the dealer took the truck itwould run fine....when i had it, it would run fine then sputter or stall. after a week of back and forth, the dealer finally replaced the fuel pump assembly itself. She ran and continues to run like a champ.

 

[IUP99snake]

Solved!!!

I was able to solve the problem. It was pretty simple!

There are two connectors on the passenger side of the engine compartment underneath where the factory air box would be located. One is black and one is grey. Apparently, the contacts can get loose or corroded. That was the problem.

I unplugged both of these, sprayed a little bit of WD40 on the contacts, then made sure they snapped back together properly.

The car was right in the middle of an episode when I took them apart, and when I put them back together it ran like it never even happened.

It's been 4 months since I did this fix and the problem has never happened since.

And that is that!!!!

Lesson: If you have any sort of electrical issue that affects the engine or underhood functions, check all the connectors to make sure they are latched together properly, there are no loose pins, and the connectors aren't corroded. It might be good practice to lube up all the underhood connectors with some dielectric grease if your car has more than 50K miles or so.

 

[Sulli99van]

Slim line dual fan setup to replace stock fan.

 

[IUP99snake]

Slim line dual fan setup to replace stock fan.

Random, but duly noted....