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Discussion Starter · #1 ·
I've been having this problem forever it seems. p1130 and p1150 are there too but they're definitely results of the rich condition. Also it has trouble starting sometimes.
Things I've tried(not all are specifically in response to this)
  • All new and properly gapped spark plugs
  • All new COPs
  • New K&N Fuel Filter
  • New K&N Air filter(on a CAI)
  • All new fuel injectors
  • New before cat 02 sensor on driver side but made no difference so I didn't replace the other(it was a bitch)
  • New timing chain, guides and tensioners(the old guides broke and the chain was rattling just a bit)
  • I replaced the purge valve and charcoal canister with used ones from my old mustang which didn't run rich
  • I cleaned the MAF(IAT sensor is part of MAF on this car)
  • ECT sensor seems to be working fine
  • I swapped the FRPS with one from a perfectly fine mustang and no difference
After all that I really thought fixing the timing issue would fix it but the only difference it made was the engine doesn't rattle anymore lol(runs exactly the same)
The engine doesn't run terribly but I feel it cutting the fuel at 1000-1500rpms and it runs out of gas way too fast ofc
I'm out of ideas at this point somebody please help
 

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do you have a good scan tool?

first thing, you must verify that the 02 sensors are not lying

while looking at the 02 voltages with the scan tool, you can drive the 02 lean by adding unmetered air and watch

this is a 1hr diagnosis max.
 

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Discussion Starter · #3 ·
I have a pretty crappy basic scan tool but at this point I'd love to buy a new one, do you have a good recommendation?
 

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i use a auto enginuity

its okay

find one that stream live data, and fits your budget
 

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I've been having this problem forever it seems. p1130 and p1150 are there too but they're definitely results of the rich condition. Also it has trouble starting sometimes.
Things I've tried(not all are specifically in response to this)
  • All new and properly gapped spark plugs
  • All new COPs
  • New K&N Fuel Filter
  • New K&N Air filter(on a CAI)
  • All new fuel injectors
  • New before cat 02 sensor on driver side but made no difference so I didn't replace the other(it was a bitch)
  • New timing chain, guides and tensioners(the old guides broke and the chain was rattling just a bit)
  • I replaced the purge valve and charcoal canister with used ones from my old mustang which didn't run rich
  • I cleaned the MAF(IAT sensor is part of MAF on this car)
  • ECT sensor seems to be working fine
  • I swapped the FRPS with one from a perfectly fine mustang and no difference
After all that I really thought fixing the timing issue would fix it but the only difference it made was the engine doesn't rattle anymore lol(runs exactly the same)
The engine doesn't run terribly but I feel it cutting the fuel at 1000-1500rpms and it runs out of gas way too fast ofc
I'm out of ideas at this point somebody please help
Iac or tps sensors if these sensors are not ready correctly when working or accelerating then this can cause those issues with no codes saying there bad. Test these with voltmeter the how to is can b found on Google for sure try that

Sent from my SM-N975U using Tapatalk
 

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Discussion Starter · #6 ·
I'm getting the Innova carscan 1000 tool that links to ur phone in 30 min, I'll try swapping the IAC then the TPS with my other mustang gt to see if it helps the condition
 

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Discussion Starter · #7 ·
I got it and did a full scan, I'm getting some ECT and coolant temperature errors so looks like I'll replace that today and go from there!
 

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does it stream live data?

or is it a code reader?

codes does NOT mean replace parts?
 

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Discussion Starter · #9 ·
Update: i bought the ECT just in case but i think the codes i got were from me unplugging it and testing it with my multimeter last night so im not going to replace it yet. The live data on my drive to get it tho showed my short term fuel trims normal all except when idling also my fuel pressure showed maxed out the whole time at 110psi???? idk if its a false reading but i tested it with two different drives, im going to give swapping the IAC then TPS soon a go
 

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what are the long term fuel trims?, short is not important

why would you swap any parts?

do you think if fuel pressure is over double what it should be, that could be the cause of rich limits?

putting a fuel pressure gauge on the rail, to confirm would be an idea, no?

wouldnt you expect the issue to be more pronounced at idle, as puleswidths are already low, and the ecm, has hit the wall?
 

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Discussion Starter · #11 ·
the long terms max out at -25 always which is triggering the p1130 and p1150, i was looking at short to see at what conditions does it try to cut the fuel. It seems like this is idle related to swapping the IAC might help and its easy enough just to test. I think getting a fuel pressure gauge to confirm is a very good idea, i doubt the pressure is actually 110psi since 40psi is the normal which makes me think of the FRPS but i already swapped that with my other mustang and it made no difference. the short trims were normal at drive and reverse idle but park and neutral idle give the bad trims causing the long terms to go to 25%
 

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IAC? what?

do you want to diagnose or not?

I pay no attention to what you have changed and assume is good, that is not diagnosing

the PCM is seeing 110psig, and say you its not. what you say matters not

you put a gauge on it, before doing anything else

you want to change everything at once, good luck, i will just read along with some popcorn
 

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Discussion Starter · #13 ·
IAC made no difference, I'm getting the fuel pressure sensor in a half hour then I can check that, the fuel pump shouldnt be able to go that high so i think the PCM is misreading which means the FRPS is bad but as I said before I already swapped it with a good one to test and it made no difference. There are many ways to diagnose not just one, I know ur methods are best but I'm still trying anything just to at least narrow the issue or point me in the right direction. I was swapping the IAC as a suggestion made by Benni614
 

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try anything, that is good

i will enjoy, thank you
 

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99.9999% of all electrical issues, is the WIRING

not the load
 

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Discussion Starter · #17 ·
Do you think it could be a bad ground then? that would make a lot of sense I'm pretty sure i saw a ground from the engine to the frame all rusted when i was underneath and the bad ground could be messing with the data the FRPS sends to the PCM. I went to get a rental fuel pressure tester kit at autozone but their gauge was faulty so I'm going to look for another one in a different town tomorrow.
 

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if fuel pressure shows 110 then your logger is wrong as the ecu cannot measure anything above 78 psi

Also the in tank PPRV limits pressure below that.

The most likely culprit is the fuel pump ground is shorted out in the tank from either a hose clamp that wore the plastic isolator out or the FPDM has gone bad and is running the pump full.

You need to otherwise verify the maf voltage isnt going stupid high.
 

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Do you think it could be a bad ground then? that would make a lot of sense I'm pretty sure i saw a ground from the engine to the frame all rusted when i was underneath and the bad ground could be messing with the data the FRPS sends to the PCM. I went to get a rental fuel pressure tester kit at autozone but their gauge was faulty so I'm going to look for another one in a different town tomorrow.

if you think you have a faulty ground, take the meter out, and do a voltage drop to battery negative, should see near 0 volts, if good, no?
 

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Discussion Starter · #20 ·
I made a new ground from battery to engine and from engine to frame and it made no differnce, I tested the ground with the meter like you suggested and it was fine. I'm concerned about the fuel pressure reading being maxed out, i also noticed the car still starts and run(just kinda crappy) with the fuel pump fuse pulled, I'm not sure what this means I'm open to any ideas
 
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