p1188 - "Element shut-off of High-pressure pump"

[TJinBCC]

I've owned my 2005 Fortwo (.8l cdi) for a couple years and have done numerous repairs (and modifications) to it -- all of which I've been able to find answers if I ran into problems. This problem has me stumped... short of just starting to replace parts (which are very expensive).

The other day my Smart wouldn't go over 3,000 rpm (limp mode) - never experienced this before. No warnings that this would happen... it took me getting home and restarting it before the engine light would come on. I tested the code with my thinkcar thinkdiag tester, and I was getting a p1188 code: "Element shut-off of High-pressure pump".  Can I trust this code to actually be a problem with the high pressure pump?

I can do tests with my thinkdiag, but the problem is that I don't know what the stats are for my car. For instance: the element shut-off of high pressure pump stays at 100% no matter the RPM. (Also: the rail pressure sensor is reading 245 bar) Is this correct, or should it vary.

The fact is that I have always worked on cars without computers/ECU/SAM and so this is relatively new. Is there someone who has knowledge of what I should be looking for, and how I can fix this problem?

Tim

Edited January 24 by TJinBCC

[MikeT]

The mechanical camshaft-driven high pressure pump has three elements as far as I can recall so I guess the third(?) one is faulty and not operating, so the engine can't get enough fuel for full load. Could be electrical though.

[TJinBCC]

I appreciate you giving me a greater understanding of the hpfp. Could it be an electrical issue if the other two elements are working?  The other thing is: the fuel rail is measuring  245 bar of pressure.  Is this the normal amount?  If it is, then really could the hpfp still be the real problem?  Where do I get the acceptable limits for the .08l sensors?  Lots of questions...

Edited January 26 by TJinBCC

[MikeT]

What I meant is that the solenoid or whatever it is that activates the third HP pump element may be malfunctioning and if so, it's no doubt an electrical component. It could also be a mechanical issue inside the pump. I don't know how to diagnose it actually. Maybe someone else can help with that. Perhaps fiddle around with the electrical connection to the HP pump, checking for corrosion as a starting point.

[Willys]

I agree, go after the electrical at the pump for corrosion, then if you haven't already take HP pump off and peek inside. The rebuild kits aren't expensive and you can get a small or larger kit, buy the larger(more "orings etc). When inside pump check the valves in the heads of the sections. They have a captured spring and disc which get dislodged over time, worm out and they do not seal correctly. You can buy these valves(the size of a domino) from dealership if i recall correctly, maybe e-bay, Amazon...?  They weren't hard to find. 
Then go after fuel rail pressure sensor, same, corrosion and then operational...? IF you are serious about the car, you really need a STAR machine if you are doing all your own repairs diagnosis, etc....YES expensive but in the end worth it, imho. 

Not sure how far you are from Edmonton, but IZZY is there and he imho is the man to talk to about anything electrical. It's what he does and he is good at it. He goes by Stickman007 here.

Hope this helps.

[stickman007]

Izzy is overrated! lol…

 

The P1188 FC is a circuit code. This indicates that either the wiring to the high pressure pump solenoid is shorted/open, or the internals of the solenoid is shorted/open.

 

If you unplug the solenoid, pay close attention to the wiring where it goes into the connector, common spot to have damages. I don’t think u can buy the solenoid on its own. Common telltale of a faulty solenoid or sensor is it leaks. Again, when u unplug the connector, is there fuel inside? It should be bone dry.

 

When t/s common rail faults, it’s not enough to just monitor the rail pressure as it will vary depending on many factors. On your scanner, compare the fuel rail pressure request (from ECM) to the measured rail pressure (from sensor) on a graph with the engine running, and the pressure should follow the general trend even when reving the engine.

 

its not common for our engines to get the P1188 FC, but I don’t think that it will cause a limp mode. I have not verify this, but overboost and EGR can cause limp modes without a code (short term).

 

Good luck. Hope this information finds you well.

[TJinBCC]

Thanks Stickman for your response

 

I've checked the wiring and connectors, but I haven't looked closely for a wet connector.  The connector nor the pump itself have any obvious leaks.

Thanks for describing in detail how I can further check the fuel rail pressure.  I will do that next time I work on the car.

So you're thinking it might be coincidence the the limp mode and the P1188 FC occurred within an hour of each other, but are separate problems.  Hmmmm.  Possible, I guess.  I'll check for overboost, but the EGR is deleted (blocked) so that shouldn't be the issue.

 

I don't think it's related... but I did change the injectors about two weeks before this happened.  I had a really leaky injector.  The new injectors made an incredible power and performance difference... I'm not sure if this may have caused the overboost or the HPFP failure... I can't imagine.

 

EDIT:  I don't know anything about the "limp mode" yet... if the limp mode was caused by overboost, then wouldn't the car start and work a while before going into limp mode.  I'm assuming limp mode will disappear after the problem is fixed?  I'm not aware of any code or reset that needs to be done.

 

Edited January 27 by TJinBCC
additional question/thought

[Willys]

Just a question, how did you block the EGR? Also did you remove about 4 feet of heater hosing? If not it clears out a nice amount of workable space in the engine compartment.  Also if you are not using an emulator, or choosing not to use one, Did you clean your EGR completely so it can operate as it should? IF it can't move it's piston it'll cause a code and thus limp mode, no?  IF, you need an emulator IZZY is your man again, that is IF he still has any left. I did hear he was stopping making them???   I have run emulators,  and also blocked off EGRs on my cars. I have also reduced one EGR down to just the electrical connector and the piston and hung it still connected to the stock wiring with great success.  It took hours to reduce it to the smallest size I could just so it also wasn't taking up much valuable space in the bay.   Just suggestions on how to delete your EGR.

[stickman007]

I think I have a few emulators laying around if I can find them - I’m not exactly organized!

 

if you’ve changed to a high flow nozzle, potentially you’re altering the boost curve - more exhaust flow that your wastegate can’t dump in time. Use your scanner to monitor boost - you will need to max out load before you can get a good reading. Find a small hill that you can take a good run. 3rd/4th gear at 3.5k rpm under high load will give u a reliable reading. If you can hold 18psi for about 3-4sec, you’ll set the overboost limp mode (you may not get CEL).

[TJinBCC]

I did the work on the EGR when I replaced the intercooler fan.  All the pipes connected to the EGR and the EGR itself (as well as the intake) were cleaned before I blocked off the EGR. (I guess I should just double check the EGR solenoid to make sure it's still working -- and make sure it's not causing the limp mode)  I didn't remove any of the heater hosing.    I thought of eliminating all the extra hoses, but decided to keep every existing part in case I wanted to easily reverse the procedure.

[TJinBCC]

Stickman:

 

if you are talking about the injector nozzle... I just replaced the injectors with the stock Bosch replacement.  If they changed the boost curve (which I expect they did, even though they're stock) then I'm surprised that it took so long to go into limp mode (3 weeks).  And when it went into limp mode I wasn't putting any big load on the engine.  I will try putting a load on the engine and test the live boost values (although it being in limp mode, I can only get up to 3k RPM - and would I even be able to get the turbo to show any abnormal boost given it is in limp mode)

 

But I greatly appreciate the help and ideas you've given and the additional information you've supplied me with, which I so much need in this situation.

[Willys]

Have you played around with your waste gate rod to adjust your boost pressure to keep it close but not too close to the over boost limit???
What scan gage are you working with? Can it be plugged in while you are driving to allow you to monitor the boost pressure?  I work in psi not the metric bar system so only know the numbers in psi. I keep my boost numbers around the 16.4 psi....yes you can go higher but you risk it going over the limit for brief times and if that is longer than a few seconds it trips the limp mode again. It's a personal thing to where or not you want to drive it to be that close or you can be happy like me slightly lower and very very rarely have an over boost limp situation.
When you get the limp mode, do you shut the car off and wait for the SAM to click off before trying to drive again? If you do not allow the SAM to click the limp situation won't go away. 
Many of us own a ScangageII as our scanner as it is always attached and on the dash for us to monitor as we are driving. It isn't cheap as it once was but imho it is still worth the money spent.  Same goes for a STAR machine.   Also talk to IZZY regarding his thoughts and expertise on the STAR machines and where you possibly might get one from....remembering that they are a grey issue so to speak.  So do your research quietly.  There are many threads or there used to be on our site about how to get and use a STAR system.  The way I made it worth having was telling myself that 3 trips to a dealership or shop would equal the cost of one and everything after those first trips was gravy.  Also if you are so inclined you can help others using your STAR which will help recoup some of that cost. Other members/owners are normally happy to give you funds for this service if you want to call it that compared to going to the dealership and paying their outragous shop rates. A few years ago, I was standing at the parts counter at my local dealership and saw a key price flier advertisement....$456 for one key to be reprogramed !!!!   I asked was that for one of the high priced models in the showroom he said no that's where they start at and go up from there!!!!   It takes 20 minutes with a STAR machine to do 2 key fobs.....doing key fobs alone will pay for your STAR....!!!   That is if you offer your services to other Smart Car owners in your area.  Everyone wins and is happy to not pay the dealership prices.

Sorry went off on a rant again....back to the topic at hand....lol.

OH, just another thought about your fuel system,....do you use some sort of fuel conditioner???  I use Diesel Kleen from Canadian Tire every other tank full...I add 50 ml. And during the summer I add it when I remember.....it sounds like a mechanic in a can crap, but it does help over time( maybe 3 doses) to clean up your fuel system. It also will be a slightly noticeable improvement.I'm sure there are other manufactures which sell similar  if you don't like this one.  Worth the trial just to see.  imho.

[stickman007]

If the nozzles were OEM replacement, then no, not likely to affect the boost curve.

 

With limp mode, boost is restricted and you will not get an accurate reading. Is the P1188 FC active? Or inactive? If it’s active, then it would be pretty conclusive that it is the root cause of the limp mode. I will be working on another smart this weekend. I can unplug my pump solenoid, will let u know if I get limp mode.

 

i have seen where the wastegate was seized and as soon as the throttle is pressed, it goes straight to limp mode. Check to see if your wastegate is moving - if it is, then it is a start. Make sure the small tube/hose around the TIK is not ripped. If it is, then it acts like the wastegate is seized and you’ll go into limp mode the 1st time you hit the throttle.

 

If you are able to rev past 3k, but lacks power severely, then check the small tube on the RHS front of the intake manifold, sometimes that tube pops off or rips and the MAP sensor doesn’t see boost and limits the power severely (basically no turbo). You won’t get a CEL with that.

 

Also, just for kicks, monitor your rpm to make sure that it is limiting you to 3k. I worked on a smart car where the tach was reading wrong and the owner thought it was limp mode.

[stickman007]

As for the STAR machine, I can help guide u to setup your own, but it’s basically a clone setup from China, not exactly reputable.

 

I primarily use my Autel Mk906 Pro. It is able to code smart car keys though I’ve been running into issues lately - not sure if the aliexpress fobs are bad, I can only code OEM fobs. I previously have been able to, but lately have not had any success with aliexpress ones.

[TJinBCC]

Wow!  So many helpful thoughts and comments.  Thanks so much guys!!!

I'm very busy these days.

I still haven't had time to do the testing and diagnosis from the list of things you've given me...

Instead, the Fortwo is parked and I've pulled out my old trusty Jetta with the collectors plates.

I will get back to you with a response as soon as I can.

Thanks again.