P0093 causing Limp mode

skjeep · **Posted:** Wed Aug 12, 2015 7:04 am

Yeti wrote:

how many psi the pump deliver ? we can try to increase the rail pressure , but I''m not sure we solve the problem , post your file

should have about 3 psi

I have temporary disabled the P0093, but the behavior is strange.
Drives normally, has power, everything ok, even the acceleration after coasting seems to work
(this is the condition where i had the P0093 before)... BUT...
it happend twice that the engine shut down completly. And even that i have manual gearbox
it won´t restart. I have to cycle the key and crank it again.
But as i have the P0093 disabled i had no codes. Anyway there must be something fuel pressure related.

here are the files:

original 813 : http://www.jeepparts.sk/tmp/2007_KJ_man ... 380813.Bin

here the modified one with temporary disable of P0093
http://www.jeepparts.sk/tmp/2007_KJ_man ... delete.MOD

Yeti · **Posted:** Wed Aug 12, 2015 10:38 am

ok , the P0093 is well deleted , I have added a 4% in rail pressure and limiter

https://www.dropbox.com/s/4sm5su8q2f8xx ... X.MOD?dl=0

let me know

strange is the kj shut down with dtc deleted

:dizzy:

skjeep · **Posted:** Wed Aug 12, 2015 11:32 am

Yeti wrote:

ok , the P0093 is well deleted , I have added a 4% in rail pressure and limiter
let me know

going to try but when i looked at thefile in ECM it gave me a wrong checksum

- and there must be also something wrong with the file, because i also get the error about file size and request for
correction

(le dimensioni dei file selezionati sono diverse. Originale=0x100000, MODI=0x2EBA4 pertanto sarrano allineate)
In italian if you wish :-)

and also all the maps are just filled with max values - for example in the pressure limiter map there is
only one value of 64500 across all of the12 maps

Yeti wrote:

strange is the kj shut down with dtc deleted

yes,it is strange. I do not understand why it does that.
And it is a sudden shut down. There is absolutely no warning before. No loss of power,
no change in engine "feeling and sound" It just shuts down
it is like somebody turns the key of and you do not know. It is frighteninig :roll:

Yeti · **Posted:** Wed Aug 12, 2015 12:22 pm

I have controlled in ECM the file and is ok .....no wrong check reported , and manually checked with Bosch edc 16 #60

I have had a similar problem but with P0088 and I have changed the solenoid back of the pump and solved the problem

but mine shut down after a WOT when the max pressure is requested , when I let of the foot from the gas and rpm drop , the engine die

and set the code , but restart immediatly at the first key on ..your is different ghost ......have you checked the low pressure line is free from obstruction ?

BTW recheck the checksum with the right driver

JXXX_813

give me no error

Yeti · **Posted:** Wed Aug 12, 2015 12:44 pm

download it again , probably the first download is corrupted , I have download it and is ok , but recheck and if is wrong again I send you the file per email

skjeep · **Posted:** Wed Aug 12, 2015 2:53 pm

yes it was corrupted. The email one is OK

will give it a try and keep you updated

MANY MANY THANKS FOR HELP

Yeti · **Posted:** Wed Aug 12, 2015 3:06 pm

I hope we solve .....fingers crossed

patracy · **Joined:** Tue Apr 07, 2009 8:50 pm **Posts:** 115

I too am having the same issues. I'm losing prime at the filter. This all started a month ago when I filled up and accelerated onto the highway.

I've gone through the following:

1. Primed the pump. That got me home and limped along for a couple of days. I parked it then. It would "vapor lock" randomly.
2. Dropped the tank and replaced the plastic feed line with 3/8" hose. Problem remains.
3. Installed upgraded fuel filter. Problem remains.
4. Installed inline lift pump at the filter. Problem remains.

I'm kinda at a loss over what it could be now. Only thing I can think of next to try is dropping the fuel tank completely and removing the sender and verify there's no internal plumbing issues. That's the only thing I can think of causing the problem. Especially with the added lift pump.

Runs fine briefly before it looses prime. Plenty of power.

Any thoughts?

skjeep · **Posted:** Thu Aug 13, 2015 3:24 am

2Yetti:
loaded the modified tune. Allmost the same as before, but now IT WILL NOT SHUT DOWN, it only goes to limp-in mode.
I do not know why it does it because i have no DTCs (maybe because some of them are deleted).
Anyway, how it can go to limp in when there is no trigger for that (DTC deleted)
Or do i miss something?
I tend to think that the DTC delete method described here only blocks an error to show in the DTC list and prevents the ECU to throw a CEL light. It does not delete the error conditions.

So the error handling is still the same, when conditions for an error are met the error is set it only prevents it from showing.
Could anyone confirm that ?

What i am gonna to try is original file (with DTCs) and a bit more modified fuel pressure map. We will see what happens.

Yeti · **Posted:** Thu Aug 13, 2015 5:01 am

4 Patrcy , have you check for DTC ?

skjeep

is really strange , normally without a DTC the ecu do not know there is a problem and don't go in limp mode , I can't understand why they go , try to put original the limiter map , but leave the max value at 4% ..example 16000 leave it at 16640 and other value original

patracy · **Joined:** Tue Apr 07, 2009 8:50 pm **Posts:** 115

P0093 is the only DTC.

patracy · **Joined:** Tue Apr 07, 2009 8:50 pm **Posts:** 115

So, I must admit, I probably prolonged my issue with the hose. I didn't pay attention on how the tank mounts under the jeep. There's a valley next to how the hose likes to lay down. I had it pinched when I reinstalled the tank. It was just enough to allow a small amount of fuel to be sucked through. But under heavy load, it'd choke. I knew something was up when I unplugged the lift pump and it took 2 minutes and 45 second to fill a 20oz coke bottle. I've dropped the tank (to inspect what was going on) and zip tied the hose over. Buttoned everything back up and I have probably 5x the flow now from the lift pump. When I get a chance tonight, I'll take it for a test drive. I *hope* all of this resolves my issue. Having a pinched hose certainly doesn't help.

skjeep · **Posted:** Fri Aug 14, 2015 4:54 am

Yeti wrote:

is really strange , normally without a DTC the ecu do not know there is a problem and don't go in limp mode , I can't understand why they go , try to put original the limiter map , but leave the max value at 4% ..example 16000 leave it at 16640 and other value original

update:

Created custom map with all DTCs enabled and modified fuel and pressure limiters. in some areas 4%, in some 10% :lol:

Still have P0093 with almost the same conditions - but now it is much, much harder to simulate it.
I need to let the engine coast under 1900 rpm and then try accelerate. When i play with that for a while it throws that DTC and goes to limp-in.
What wonders me is that the DTC is set, i can read it with scan tool, car is in LIMP-IN mode but the CEL light on the dash is off.

i know that the map is not 100% (it is only a test map), sometimes and randomly (let´say every 5-10 starts) i have two more dtcs immediately after start (egr and turbo related) but if i delete it they do not show again until next start.
Under load id runs like a hell (with a bit of black smoke :SOMBRERO:

). The acceleration and rise of power is huge. So i think that if it is able to do this it can not starve for fuel. It is against all logic

but on the other side,there must be some problem with fuel system. But i do not know where and i do not want to throw even more $$$ into it just swapping parts.

Yeti · **Posted:** Fri Aug 14, 2015 8:40 am

please post your mod file ........depending where you have increase the 10 % you can do a damage on a nozzle in the injector

for patracy , let us know if you solve

Yeti · **Posted:** Fri Aug 14, 2015 9:01 am

ps , black smoke is not conductive for high rail pressure ...is the opposite , high pressure heat the fuel and increase spray and burn well and do less smoke , but you do not obtain more fuel like a chip module on the rail sensor ...is different logic , black smoke is your egr and or your intake .....inlet or outlet cac or the intercooler ...or the egr that leak turbo pressure or you do somthing wrong in the ecu

patracy · **Joined:** Tue Apr 07, 2009 8:50 pm **Posts:** 115

Yeti wrote:

for patracy , let us know if you solve

That has corrected the shutdown error. I still get some hard starts. Somehow I'm still getting air in the system. I'm going to install a check valve at the filter to prevent fuel from draining back to the tank.

But with that said, it seems to perform even better than it did before with the lift pump and things being "perfect".

Yeti · **Posted:** Fri Aug 14, 2015 9:26 am

sorry , but I do not understand if you have the lift pump or not at this time

thanks

patracy · **Joined:** Tue Apr 07, 2009 8:50 pm **Posts:** 115

Yes I added a lift pump.

patracy wrote:

4. Installed inline lift pump at the filter. Problem remains.

Yeti · **Posted:** Fri Aug 14, 2015 10:43 am

oopss sorry

patracy · **Joined:** Tue Apr 07, 2009 8:50 pm **Posts:** 115

So I ended up pulling the entire fuel system apart once more. Turns out the lift pump I added had a small air leak on the inlet side. I dissembled it and applied silicone. It worked perfectly all day yesterday, no hard starts of stalls. Parked it last night nose uphill at a good angle. Fired right up this AM no problems. *Hopefully* my troubles are over for that part. Now to chase down a random vibration at times at 60-65mph.

P0093 causing Limp mode

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