Ran codes, where to start???

[wytstang]

Ater I dove on the high why a few days ago the CE light keep coming on/off. So I ran for codes and this is what I got KOEO
158-MAF sensor went above 4.5 volts during the last 80 warm-up cycles.
176-HO2S (sensor) system lean (bank 2) bad O2??
542-Fuel pump Secondary Circuit open (PCM/Fule pump Gnd. (fuel pump circuit fail)
543-Fuel Pump Secondary Open (PCM to battery). (When the PCM commanded the fuel pump on, voltage was not detected on FPM.) What's FPM??

Fuel pressure is "usually" at 31 vac on 40/w vac off. A few days ago I was farting around and noticed how slugish it felt past 4000rpms. Looked at the FPG it read 25 at idle and 35/w vac off. I have no idea where to start any ideas are welcomed???

 

[mo_dingo]

Ater I dove on the high why a few days ago the CE light keep coming on/off. So I ran for codes and this is what I got KOEO
158-MAF sensor went above 4.5 volts during the last 80 warm-up cycles.
176-HO2S (sensor) system lean (bank 2) bad O2??
542-Fuel pump Secondary Circuit open (PCM/Fule pump Gnd. (fuel pump circuit fail)
543-Fuel Pump Secondary Open (PCM to battery). (When the PCM commanded the fuel pump on, voltage was not detected on FPM.) What's FPM??

Fuel pressure is "usually" at 31 vac on 40/w vac off. A few days ago I was farting around and noticed how slugish it felt past 4000rpms. Looked at the FPG it read 25 at idle and 35/w vac off. I have no idea where to start any ideas are welcomed???

You might want to check your fuel pressure regulator and your fuel pump and see what's going on. Those numbers are low.
Scott

 

[HISSIN50]

Wyt - you are good. In chatting last week or so, you somehow knew fuel issues were coming around the corner for you.
Scott is better than I am with MAF stuff and if that could have an effect.

I find it strange that you did not pop two banks worth of lean codes if it is truly a fuel pressure issue. If the fuel filter is questionable, that would be a first thing to replace (that goes against what I just said, but who knows)........ (I know you know that, but sometimes I forget little things so reiteration is good).

Otherwise, I would check the FP again and see how it does. Do you have a cowl mounted gauge or anything like that? Seeing pressure at WOT at 4K in real time would be cool info.

The FPM is the Fuel Pump Monitoring system. The control path for the control side of the FP goes through a relay in the PCM and then through the CCRM. The FPM is probably simply noting that you have a loss of juice to the pump at some point (kind of like an IDM code for ignitions).

How far did water make it into the interior. Do you think any of the PCM connections got wet and now could have surface corrosion? Just seems strange that this happened relatively soon after the rain-out.

I cant really think of anything helpful bud.

Good luck.

 

[Threeotwo94]

Im getting the same codes 542 and 543 and the same symptoms.
Let me know if you get anywhere with this and ill do the same for you. Good Luck.

 

[wytstang]

You might want to check your fuel pressure regulator and your fuel pump and see what's going on. Those numbers are low.
Scott

I have a spare fule pressure regulater I'll swap them out, and see if that helps.

Wyt - you are good. In chatting last week or so, you somehow knew fuel issues were coming around the corner for you.
Scott is better than I am with MAF stuff and if that could have an effect.

Unfortunatly I six sense was right

I find it strange that you did not pop two banks worth of lean codes if it is truly a fuel pressure issue. If the fuel filter is questionable, that would be a first thing to replace (that goes against what I just said, but who knows)........ (I know you know that, but sometimes I forget little things so reiteration is good).

I'll swap it out it's due

Otherwise, I would check the FP again and see how it does.

Same reading 25 vac/on 35 vac/off

Do you have a cowl mounted gauge or anything like that? Seeing pressure at WOT at 4K in real time would be cool info.

Nope I may just pick up another one so I can veiw it.

The FPM is the Fuel Pump Monitoring system. The control path for the control side of the FP goes through a relay in the PCM and then through the CCRM. The FPM is probably simply noting that you have a loss of juice to the pump at some point (kind of like an IDM code for ignitions).

Thanks wasn't sure what it was.

How far did water make it into the interior. Do you think any of the PCM connections got wet and now could have surface corrosion? Just seems strange that this happened relatively soon after the rain-out
I cant really think of anything helpful bud.

That's a good question never even crossed my mind, it may have reached it. That would help explain code 543 (Fuel Pump Secondary Open (PCM to battery). (When the PCM commanded the fuel pump on, voltage was not detected on FPM.)

If any one has any suggestion please feel free to add your .02.

 

[HISSIN50]

One can carefully crimp the fuel-return line (some guys are staunchly against this, but there are special 'stats' out there for doing this crimp. Parts stores sell them).
Anyhow, when the return line is crimped or impeded, if pressure goes up, that suggests the pump is pumping enough volume but the FPR is passing too much gas back to the tank.

If pressure stays low with the crimp on the return line, the pump is likely weak.

But it sounds like you wanna do a pump anyhow (me too), and you have a spare FPR, so you can play musical parts instead of doing the diagnostics.

Pressure at any time below 30 PSI just aint quite good enough........

Good luck bud.

 

[wytstang]

Another 20% sale code from yearone showed up soooooo chances are a FP will be on order (if funds allow). I'll swap out the spare and hopefully that was is good. If you need the sale code let me know....

 

[HISSIN50]

Another 20% sale code from yearone showed up soooooo chances are a FP will be on order (if funds allow). I'll swap out the spare and hopefully that was is good. If you need the sale code let me know....

Hmmmmm. Let me get back to ya on that.
I checked ebay for new pumps a while back and there were some for pretty cheap (I wanna say 100 bucks shipped for a 190 LPH from one vendor. I did not compare prices, but just noted that this seemed decent to me in an absolute sense of what a pump is worth to me). Just thought I would share so you can compare too..............

(I do need a new one - my pump might not hold out too much longer. And it would work on the 88 if need be).

 

[wytstang]

Im getting the same codes 542 and 543 and the same symptoms.
Let me know if you get anywhere with this and ill do the same for you. Good Luck.

Sounds like a plan

Hmmmmm. Let me get back to ya on that.
I checked ebay for new pumps a while back and there were some for pretty cheap (I wanna say 100 bucks shipped for a 190 LPH from one vendor. I did not compare prices, but just noted that this seemed decent to me in an absolute sense of what a pump is worth to me). Just thought I would share so you can compare too..............

(I do need a new one - my pump might not hold out too much longer. And it would work on the 88 if need be).

Let the hunt begine (at least for me) for the best priced fuel pump. I'll post it for you and other to see.

What get's me is when I first saw the FPG and noticed the low pressure later on that same day it read normal 31 vac on and 40 vac off and was running like a champ. Now it's back to low and not as peppy(sp?) past 4g's, that's what's leaning toward the fpr and not the pump being weak.

 

[wytstang]

Also does anybody know what would trigger this code 158-MAF sensor went above 4.5 volts during the last 80 warm-up cycles.

 

[mo_dingo]

Also does anybody know what would trigger this code 158-MAF sensor went above 4.5 volts during the last 80 warm-up cycles.

That would indicate that you either pegged the maf w/ too much air, which I doubt. Or, your MAF shorted out.......The sig rtn should takes the incoming 5V ref signal and used it to heat the wire on the maf. If there is no resistance, then the sig rtn will put out 5V and trip that code. Maybe the MAF is dirty, or the connectors are?
Scott

 

[wytstang]

That would indicate that you either pegged the maf w/ too much air, which I doubt.

+1 100% on that

Or, your MAF shorted out.......The sig rtn should takes the incoming 5V ref signal and used it to heat the wire on the maf. If there is no resistance, then the sig rtn will put out 5V and trip that code. Maybe the MAF is dirty, or the connectors are?
Scott

It probably needs to be cleaned, what exactly is sig rtn???

 

[HISSIN50]

+1 100% on that

It probably needs to be cleaned, what exactly is sig rtn???

I knew Scott would be able to help out.

Sig ret is the signal that the meter sends back to the puter (it is a percentage of the Ref voltage). The .98 volt [e.g] reading on your TPS at idle, is an example of another return.

 

[wytstang]

O.K I let the car sit over night to achieve zero fuel pressure. I swapped out my fpr with my spare and started her up viola 31 psi's w/vac on with vac off 40 psi. So it looks like my fpr was going south, I'm just going to monitor it for a few days to be 100%. For my wallets sakes I hope that cures my low fp problem. For every one else ebay does have some cheap 255 lph pump, but they were all for "high pressure" not sure if there a big difference between the standard 255 and the 255 high pressure in a car not asking for it. If you want the standard 255 lph the cheapest belongs to http://www.jdsperformance.com/index.asp?initemuid=436&fcmd=item&inmake=ford they have it for 89.00 plus $6 for shipping.

 

[wytstang]

As for now I'm pretty much sure it's the mass air is either just dirty and or shorted out. That would explain the left bank reading lean and not the right being triggered and the mass air 4.5 v during the last 80 warm up cycle. Sitting all night then turning her on trying to take off, it will hesitate like it's going to shut off (late for work only). Heres a pic for any body who needs the diagram for the main harness

 

[HISSIN50]

Thanks for the FP info - great price if you ask me.

Glad to hear the FPR seems to have gotten you back into spec.

 

[mo_dingo]

As for now I'm pretty much sure it's the mass air is either just dirty and or shorted out. That would explain the left bank reading lean and not the right being triggered and the mass air 4.5 v during the last 80 warm up cycle. Sitting all night then turning her on trying to take off, it will hesitate like it's going to shut off (late for work only). Heres a pic for any body who needs the diagram for the main harness

Wow, nice pic. Thanks, that is very helpful. See the wire coming in that also ties into the o2 sensors. THat is your ref signal, otherwise knows as your reference voltage, 5V all the time. The sig rtn is the return signal, which varies 0 - 5V. But at 0, that means an open, and 5, that means a short. it's usually in between .5 - 4.7V. If you seeing higher or lower than that range, you have a dirty or bad MAF sensor. If you are seeing 0V, your ref sig could be missing, or the ground wire is missing. A simple probe w/ a DVM will tell you that. But you will have to backprobe the sig rtn to see it in action (while car is running of course.

But remember the KISS method. Keep it simple stupid Try cleaning your maf first....
Scott

 

[wytstang]

Damn it my low fp seems to be intermittent it was reading 31 vac on 40 vac off. After I left to go to work thinking all is well I take it past 4g's and it starts to break up. I get to work check it right away 25 vac on 35 vac off *DAMMIT*. O.K. I just got home and check it because it felt good 31/40. Could a pump going south give an intermittent low fp reading?

 

[mo_dingo]

Damn it my low fp seems to be intermittent it was reading 31 vac on 40 vac off. After I left to go to work thinking all is well I take it past 4g's and it starts to break up. I get to work check it right away 25 vac on 35 vac off *DAMMIT*. O.K. I just got home and check it because it felt good 31/40. Could a pump going south give an intermittent low fp reading?

Most definately......Have you check the voltage at the fuel pump to see if it's getting a full 12V. You might have a loose ground somewhere causing this.

but likeluy, your pump is going south...sorry dude.
Scott

 

[wytstang]

Most definately......Have you check the voltage at the fuel pump to see if it's getting a full 12V. You might have a loose ground somewhere causing this.

I haven't had time to probe anything, been busy working and can't afford to have the car down long enough go though the tidius(sp?) steps. I'm thinking the fp is taking a poop too . I'm going to try and check the voltage on the pump tommorow and see what I get. Thanks for you help thus far scott & Hiss very helpfull I can fell the love lol