P0093 causing Limp mode

Tulmaster · **Posted:** Fri Jan 09, 2015 3:40 pm

Yes you made some good points regarding bacteria in the fuel. Perhaps slimy is not the best description but it was red and fine particles of rust form a dust and mixed with a lubricant it is slick. Since as you say bacteria is not red, and the pump was full of rust which would pass on to the fuel rail and settle there, I will, given the circumstances, continue to consider it rust (at least for the present).

gmctd · **Posted:** Fri Jan 09, 2015 5:31 pm

Tulmaster wrote:

Yes you made some good points regarding bacteria in the fuel. Perhaps slimy is not the best description but it was red and fine particles of rust form a dust and mixed with a lubricant it is slick. Since as you say bacteria is not red, and the pump was full of rust which would pass on to the fuel rail and settle there, I will, given the circumstances, continue to consider it rust (at least for the present).

Point being: if you have water-dependent bacteria infestation, rust can form and spread where the H2O touches any metallic surface in the fuel system

My KJ is in limp mode due to positive fuel deviation after sitting 4yrs with 6yr old fuel in the tank - actual fuel = demand fuel on the scantool - tho I'm not currently pursuing it intently, resolution seemed iffy till reading your post, cause the DRBIII doesn't lie

First thing I'll do now is open the fuel filter\manager to see what color and odor the 6-yr old fuel is apocalypsed.....er, unveiled.....no, revealed is the correct translation from the greek

thermorex · **Posted:** Fri Jan 09, 2015 6:03 pm

I have couple 55gal barrels with diesel from 2011, mainly as a fuel source for my diesel generator. Last summer, when I started the generator for maintenance, the rpms were raising and dropping, and I knew it's because the old diesel. I tried various additives with no success. Then I tried this, it kills algae, got it from Napa for I believe about 7 bucks a bottle:

This cured my rpm fluctuations on the generator and I added it to the barrels also. Haven't tried this old fuel in the jeep, as I prefer fresh from the pump, but every few tanks I pour couple ounces in the tank. And, as gmctd previously suggested, couple ounces of synthetic 2 cycle oil/tank. In the winter I add about 4 oz/tank of power service to prevent gelling.

gmctd · **Posted:** Fri Jan 09, 2015 8:06 pm

I may give that a try - IIRC the KJ has more than 1/2 tank left from when I filled it back in ought 9 - it was struck by lightning in ought 10, got it running in ought 11 or 12, ran it once around the block and parked it - there it sits, today, so infested fuel is likely the problem

Also found my lawn'n'garden equip survived winters better by adding 2-stroke oil to the gasoline - as the gasohol evaporates the remaining oil film protects the pewter carb'n'stuff from alcohol-induced oxidation - 2-stroke oil is formulated for combustion-chamber service, so doesn't form\leave harmful deposits in the 4-stroke cylinders

Tulmaster · **Posted:** Sat Jan 10, 2015 12:34 pm

Just FYI for those interested, Given my pump was at a shop at the time I went ahead and purchased a Bosch re-man for the price of $825 which included shipping. While searching for best price in pumps I found a re builder in England that offers the standard 1 year warranty at a price that translates to just over $600 with shipping. The core charge is minimal, about the same as shipping from the states back to England so you could get a re-man pump and keep your core for right at $650. Here is the web page.

http://www.commonraildiesels.com/produc ... 104-p-5154

www.commonraildiesels.com/product_info. ... 104-p-5154

gmctd · **Posted:** Sat Jan 10, 2015 1:49 pm

gmctd wrote:

I may give that a try - IIRC the KJ has more than 1/2 tank left from when I filled it back in ought 9 - it was struck by lightning in ought 10, got it running in ought 11 or 12, ran it once around the block and parked it - there it sits, today, so infested fuel is likely the problem

This stuff stabilizes Diesel fuel with a water dispersal component, alcohol, which is intended to precipitate any water into fuel tanks which have a bottom-drain tap
- not so good for the non-drainable KJ tank
- an emulsifier would be needed to keep the water suspended in the fuel for removal in the W-I-F section of the filter

Also found my lawn'n'garden equip survived winters better by adding 2-stroke oil to the gasoline - as the gasohol evaporates the remaining oil film protects the pewter carb'n'stuff from alcohol-induced oxidation - 2-stroke oil is formulated for combustion-chamber service, so doesn't form\leave harmful deposits in the 4-stroke cylinders

skjeep · **Posted:** Fri Aug 07, 2015 4:49 am

Hello

i have a strange problem with 2007 KJ 2,8CRD 6 gear manual shift

After months of fighting with hard start (almost no-start when hot), leaky fuel fiter head, injectors etc
i have ended with ocassional P0093 and P0088 DTCs, but they seem to occur in strange conditions

what has been done:
replaced the fuel filter assembly
replaced all 4 injectors (2new, 2 reman) all 4 show good correction, no leaks to dump, bench tested
overhauled CP3 pump with new MPROP valve
changed fuel rail with regulator and pressure sensor (not new but 100% good, tested, from a donor vehicle)
changed a broken EGR tube
fuel system tested for pressure and leaks
etc...

now the car starts without any problem, hot or cold on max 3 turns of a starter motor
fuel pressure buildup is quick and reliable
fuel injection pump can delliver max pressure without any problems
injector corrections are ok
cylinder ballance is ok
when idling fuel pressure slightly oscilates above/below the setpoint
- at least according to the tests with StarScan scantool

Drives well, no lack of power or hesitation, driving a steep hill i can go to the redline, i can drive it 160 km/hour on the freeway like being hi-jacked without any single problem. As soon as i let it coast down for a while and try to accelerate
(no matter if with or without downshift, no matter if i push the pedal hard or light) i get a P0093 (and sometimes and rarely also P0088) and a limp-in mode. It does not shut down (or may be does but i do not see it because of a manual shifter) When i was testing it and until i found a way how to simulate the conditions i olso got a P0302 - cylinder 2 misfire.

All this could lead to a problem with the CP3 pump, but what wonders me is that there is no power loss under heavy load.

what do you think about modifying the rail pressure limiter threshold or temporary disabling the P0093 in the ecu?

as described here:
viewtopic.php?f=98&t=78418&start=40

thx for replies

flash7210 · **Posted:** Fri Aug 07, 2015 6:52 am

skjeep wrote:

Drives well, no lack of power or hesitation, driving a steep hill i can go to the redline, i can drive it 160 km/hour on the freeway like being hi-jacked without any single problem. As soon as i let it coast down for a while and try to accelerate
(no matter if with or without downshift, no matter if i push the pedal hard or light) i get a P0093 (and sometimes and rarely also P0088) and a limp-in mode. It does not shut down (or may be does but i do not see it because of a manual shifter) When i was testing it and until i found a way how to simulate the conditions i olso got a P0302 - cylinder 2 misfire.

All this could lead to a problem with the CP3 pump, but what wonders me is that there is no power loss under heavy load.

what do you think about modifying the rail pressure limiter threshold or temporary disabling the P0093 in the ecu?

as described here:
viewtopic.php?f=98&t=78418&start=40

thx for replies

Read through this document:
http://oregonfuelinjection.com/pdf/jeep-2.8-05-06-diagnostic.pdf
It does not specifically mention the P0088 but it may be related.

It still seems to me that you have a air in fuel problem.
Do these checks:
1. check everywhere for fuel leaks
2. make sure all your injector lines a tight
3. make sure all your rubber lines from the tank to the fuel filter to the CP3 are tight

There is a possibility that one of the fuel line couplings back at the tank is leaking air into the system. You can cut out the coupling and replace with rubber line and hose clamps.
Or you can install a lift pump in the fuel tank.

skjeep · **Posted:** Fri Aug 07, 2015 9:21 am

flash7210 wrote:

Read through this document:
http://oregonfuelinjection.com/pdf/jeep-2.8-05-06-diagnostic.pdf
It does not specifically mention the P0088 but it may be related.

It still seems to me that you have a air in fuel problem.
Do these checks:
1. check everywhere for fuel leaks
2. make sure all your injector lines a tight
3. make sure all your rubber lines from the tank to the fuel filter to the CP3 are tight

There is a possibility that one of the fuel line couplings back at the tank is leaking air into the system. You can cut out the coupling and replace with rubber line and hose clamps.
Or you can install a lift pump in the fuel tank.

Hi Flash7210. Thanks for reply.

I know the documet from oregon diesel
i am sure that i do not have fuel leaks, i have tested also with external fuel tank
There are also no leaks from injectors, everything is tight, clean and dry
i have also replaced the rubber hose from filter with some clear tubing
and there are no air bubbles there when idling or revving the engine on neutral,
however i could not watch it so close while driving

I do not have lift pump but i will consider that

flash7210 · **Posted:** Fri Aug 07, 2015 10:23 am

skjeep wrote:

overhauled CP3 pump with new MPROP valve

Did the overhaul include a new cascade overflow valve?

Quote:

when idling fuel pressure slightly oscilates above/below the setpoint
- at least according to the tests with StarScan scantool

Do you have your own StarScan tool or is this what the shop told you?

If you have a Android phone or tablet there is the TorquePro app that combined with a ELM-327 OBD bluetooth adaptor can give you lots of useful sensor data.
It cant give you exact fuel rail pressure but it can display the rail pressure solenoid setpoint as demanded by the ECU.

I had similar fuel system problems, a P0090 code, that had me chasing my tail for a couple of weeks. Turned out that the problem was a intermittent open circuit at the rail pressure sensor.
I replaced the connector to the pressure sensor and installed a rail pressure gauge (electronic) and all has been good ever since.
You may find that you have a similar problem.

skjeep · **Posted:** Fri Aug 07, 2015 2:08 pm

flash7210 wrote:

Did the overhaul include a new cascade overflow valve?

Yes, new overflow valve, new MPROP solenoid, new o-rings, gaskets etc.
I assume that the pump is ok because when cranking it builds pressure almost immediately
and the maximal fuel pressure test via StarScan is also OK - does not even need the prescribed
1500-1600 RPM, the pressure maxes even at 1300-1400

Quote:

Do you have your own StarScan tool or is this what the shop told you?

yes, i have my own StarScan so i am able to watch all the data when i need. I have also an ELM adapter and Torque app,
also some other PC-based diag apps, all of them show the same result.
The only thing is that all of them (inc. StarScan) are relatively slow in data reading.
It might be useful to use a scope or some needle gauge

Quote:

I had similar fuel system problems, a P0090 code, that had me chasing my tail for a couple of weeks. Turned out that the problem was a intermittent open circuit at the rail pressure sensor.
I replaced the connector to the pressure sensor and installed a rail pressure gauge (electronic) and all has been good ever since.

sounds good, i will check all connections to the FPS. Where did you get the rail pressure gauge from?
Where it reads data from? Did you piggybacked the FP sensor?

What do you think about the ECU flash idea to increase the fuel pressure threshold?

Yeti · **Posted:** Mon Aug 10, 2015 5:52 am

skjeep wrote:

flash7210 wrote:

Read through this document:
http://oregonfuelinjection.com/pdf/jeep-2.8-05-06-diagnostic.pdf
It does not specifically mention the P0088 but it may be related.

It still seems to me that you have a air in fuel problem.
Do these checks:
1. check everywhere for fuel leaks
2. make sure all your injector lines a tight
3. make sure all your rubber lines from the tank to the fuel filter to the CP3 are tight

There is a possibility that one of the fuel line couplings back at the tank is leaking air into the system. You can cut out the coupling and replace with rubber line and hose clamps.
Or you can install a lift pump in the fuel tank.

Hi Flash7210. Thanks for reply.

I know the documet from oregon diesel
i am sure that i do not have fuel leaks, i have tested also with external fuel tank
There are also no leaks from injectors, everything is tight, clean and dry
i have also replaced the rubber hose from filter with some clear tubing
and there are no air bubbles there when idling or revving the engine on neutral,
however i could not watch it so close while driving

I do not have lift pump but i will consider that

Hi I have read your PM , I do not suggest you to flash your ECU in this condition , rise the fuel pressure do not cure your problem if you do not reach the pressure setpoint you have the dtc and limp mode and disable the two dtc do not solve the real problem , I think is air in fuel or vacuum from the tank because the pump in Neutral do not reach high pressure , and you can't see great air bubble , you must repeat the condition that cause the limp mode and stop it and see if you have air bubble .BTW you have a strange limp mode based on ths condiction , the fuel rail pressure is at max level after 2800 rpm at full load and the dtc are set after some time if max pressure is not reached ....example 3-4 gear shift at full throttle

and I have a question for you , what value you read in cilinder balance test and injector test ?

only to compare in my KJ .......I have some trouble too :-(

skjeep · **Posted:** Mon Aug 10, 2015 9:16 am

Yeti wrote:

Hi I have read your PM , I do not suggest you to flash your ECU in this condition , rise the fuel pressure do not cure your problem if you do not reach the pressure setpoint you have the dtc and limp mode and disable the two dtc do not solve the real problem , I think is air in fuel or vacuum from the tank because the pump in Neutral do not reach high pressure , and you can't see great air bubble , you must repeat the condition that cause the limp mode and stop it and see if you have air bubble .BTW you have a strange limp mode based on ths condiction , the fuel rail pressure is at max level after 2800 rpm at full load and the dtc are set after some time if max pressure is not reached ....example 3-4 gear shift at full throttle

i will install a lift pump today and we´ll see. What wonders me is that the DTC comes only when accelerating from previous
coasting condition, for example go 100km/h at 5. or 6. gear, let her coast to 60-70, downshift to 3 or 4 and give some gas and yup- you have it

Try to rev her up until redlinine, start from 1. with full throttle and tyres spinning, take a steep (and i mean really steep) hill, take it to the highway at 160-170 km/h... do that for hour ( or for a a day if you want to) and you have no DTC, no hesitiation, no loss - runs like a champ when shifting under full throttle.

Yeti wrote:

and I have a question for you , what value you read in cilinder balance test and injector test ?
only to compare in my KJ .......I have some trouble too :-(

cylinder ballance - i have about 6-9 RPM variations between cylinders
and each cyllinder oscillates 2 to 5 RPM from average.
Let´s say if average is 830 then i have 831 -829 -832 -828 ond so on.

fuel corrections when idling
1. plus 0,45
2. minus 0,15
3. plus 0,89
4. minus 0,22

at 1200 rpm
1. plus 0,22
2. minus 0,25
3. plus 0,49
4. plus 0,17

injectors 2 and 4 are new, 1 and 3 are remanned ones

Yeti · **Posted:** Mon Aug 10, 2015 10:04 am

yes is really strange the way in which it occurs , if you are sure that the component you have changed have the proper code , the only thing for me is air in fuel ,

many thanks for the data

skjeep · **Posted:** Mon Aug 10, 2015 10:28 am

Yeti wrote:

yes is really strange the way in which it occurs

The same is for me. I can not see any single faulty component in the whole system. That is why i came to the idea to modify the pressure threshold in the ECU.
Do you have an idea where it is located (eg. which adress) in the ecu memory?
I have MPPS cable and app, can grab titanium somewhere, but if you know the location it saves a lot of time

Yeti wrote:

if you are sure that the component you have changed have the proper code , the only thing for me is air in fuel

if you mean the variant codes for the injectors, yes they are correct. Verified 3 times. Right now i am installing the lift pump, hope i will finish today so i will post the result tomorrow.

Yeti wrote:

many thanks for the data

you´re welcome, no problem
if you want to i can take some screenshots from star and post somewhere

Yeti · **Posted:** Mon Aug 10, 2015 12:32 pm

skjeep wrote:

Yeti wrote:

yes is really strange the way in which it occurs

The same is for me. I can not see any single faulty component in the whole system. That is why i came to the idea to modify the pressure threshold in the ECU.
Do you have an idea where it is located (eg. which adress) in the ecu memory?
I have MPPS cable and app, can grab titanium somewhere, but if you know the location it saves a lot of time

Yeti wrote:

if you are sure that the component you have changed have the proper code , the only thing for me is air in fuel

if you mean the variant codes for the injectors, yes they are correct. Verified 3 times. Right now i am installing the lift pump, hope i will finish today so i will post the result tomorrow.

Yeti wrote:

many thanks for the data

you´re welcome, no problem
if you want to i can take some screenshots from star and post somewhere

if you really want to delete the dtc , read the latest page in DIY ecu flash , there is a description and the address for the dtc table in base of the software version and if you want we can watch it , but we can only delete the dtc , and if it happen again , no dtc is set and no mil status is requested , but if happen again for another component failure you do not know

skjeep · **Posted:** Tue Aug 11, 2015 3:26 am

Yeti wrote:

if you really want to delete the dtc , read the latest page in DIY ecu flash , there is a description and the address for the dtc table in base of the software version and if you want we can watch it , but we can only delete the dtc , and if it happen again , no dtc is set and no mil status is requested , but if happen again for another component failure you do not know

Actually i do not want to delete a DTC completly, the idea was to increase/modify the fuel pressure threshold window to make it more tolerrant to pressure deviations or something like that. If i increase the acceptabe pressure range and also increase
the time it waits to built up the pressure it should help. If it throws DTC also after that modification i know that there is another problem and i really have some pressure leaks.

Yeti · **Posted:** Tue Aug 11, 2015 4:40 am

Unfortunately you can only change the threshold working pressure, which is both a point of reference, that is, if you do not reach that value the DTC is set , so if you raise the threshold but do not achieve it, the DTC is set yet

sorry but the programming can't help in this case , You can only hide the DTC

skjeep · **Posted:** Tue Aug 11, 2015 4:04 pm

So i have in-tank lift pump installed but now i am getting p1202 code - fuel overpressure.
It could be a sticky MPROP valve or sticky regulator on the rail, but both are new so it seems
that the pump is giving too much pressure

Pump is from opel or ford or something like that what also uses a cp3 pump so i thought it could be fine.
Fitted easily into the original location, i had to trim only about 3 mm of plastics at the bottom to make
some room for snap-in strainer on the pump inlet -also almost bolt-on install

This fault occurs only when idling for a while or when revving the engine and leaving it to come back
to idle.

Next i will install a resistor in series with the pump and we´ll see

but still no luck with this weird occurence of P0093 :shock:

Yeti · **Posted:** Tue Aug 11, 2015 5:15 pm

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

P0093 causing Limp mode

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