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[borticus]

Hi folks,
Was pointed at this forum by the jeepforum.com states folks and wondered if you could help...

I have a ZJ(G) 2.5 tdi grand cherokee laredo 1997 and it's a gutless lump.  Occasionally I get acceleration that I consider ok, but mostly, it seems to have a limiter kick in so 0-60 is about half a day..........

revs ok when drop the clutch (it's a manual), had a look a MAF sensor - looked ok ( well nothing looked broken)  unplugged it - and no performance change.

slight drip to turbo oil return pipe (gasket seal not working right, but really really hard to get to those 2 allen key screws!)  can't see any problems with vacuum lines.  got 108 ohms across 1st injector so looks like it's working ok.  flushed with redex for diesel a few times.

EGR diaphragm moves when poked - no idea if it moves when loaded - vacuum line to it doesn't seem to have a big 'sook' though.

I love the lump, just wish it would be a bit more 'sprightly'.  I know it's not an F1 car, but it really feels like it's not giving it's all.

Any other obvious things I should look for/test?

cheers
Bort

[daggie]

welcome 

turbo hoses ok ? intercooler blocked or restricted ?
but it does look like no 1 injector to me with those symptoms
can you get it scaned ?

[demonicwillow]

  unplug the no1 injector sensor, drive it n see if there is any significant difference, if not then its fubar, have you jetwashed the engine bay at all ?? if so then thats a common cause of failure.

[borticus]

'have you jetwashed the engine bay' 

not got round to the outside first!!

Good ideas though - will unplug no. 1 and see if there's any difference in (non) performance.

I'd read on the USA forum that resistance across the #1 injector should be 98 ohm, so thought my 107 reading inferred it was ok and operational........

following that will look more closely at lines around the turbo..........

got me stumped though - not too many folk seem to have the same problem (which is good for everyone else!) - most have idling/limp mode - but mine's definately not limp mode - as it revs quite happily above 3k when clutch is dropped.........

will let you know how i get on.

PS  looking at members avatars .....some of you guys have great looking jeeps!

[bigjeepzj]

Hi welcome
My two pence

have you changed the fuel filter recently as the the primer pumps can get leaky and let air in after you change the fuel filter.
could have air in you fuel

they are crap try bypassing it

Dave

[demonicwillow]

just because it will rev high out of gear dont mean that it isnt in limp home mode, LHM cuts power delivery n not revs so when being driven if its power is being withheld and its restricting the amount of fuel being delivered, you wont get it to rev very high with a lot of load on, drive it down a long hill and it will rev, try going back up and it wont.

[borticus]

ok folks,
disconnected injector #1 and absolutely no noticeable difference to performance...so could be injector #1 that's died.....?
but........i have also changed the fuel filter fairly recently (as I thought lack of acceleration when i got the zg might have been due to blockage).  I notice that if i prime the filter, then loosen the big pastic 'screw' i get air bubbles....so maybe this is leaking air in from dodgy seal.......

Not quite got this one bottomed out one way or t'other... maybe i should pay £45 and get the codes read (cant seem to get it to show on odometer with the 5 ignition turn on/off - and if I count the engine light flashes, i get different codes every time i do it!)

cheers   

bort

[daggie]

where abouts are you ?

[borticus]

Hi Daggie,
Inverness - perhaps not the easiest place to get help - and the only Jeep stealership in town has been taken over by Merc...

Cheers Bort

[borticus]

Well......
I persevered with the 5 on-off cycles with the ignition (£45 for a reading?.......did I mention I was scottish!?!?) and lo and behold - I worked out how to get the odometer to give me the codes...and they were........


55, then ......................55!

As far as I'm aware 55 is the start code code and 55 is the finish code code  i.e....according to my jeep, there's nothing wrong with it!!!!

aaaargh!

[Dave The Sparky]

Does it drive a lot better when the engine is cold?

[borticus]

Hi dave,
Unfortunately we get plenty of cold up here, so I can confidently say it's sluggish in the cold, as well as the two weeks per year when it's not quite so cold.....


bort

[borticus]

ok folks, more clues for my conundrum, and wondered if anyone can help a wee bit more please....

Took the lump out for a run today - still no guts, with 0-60 in minutes rather than seconds.....into wind, uphill etc....


but..............and here's my glimmer of hope........

If and when it got to 60, and i put it into cruise, if a hill came up, it would made a valiant attempt to try and stay at that speed (albeit without much success, but I could feel the engine and 'throttle' trying......)  In fact, it made a much better effort than when it wasn't in cruise and I was trying to maintain momentum using the throttle pedal.......so.....

Do you think this would indicate a problem with the Throttle Position Sensor...? and if so.....WTF is it on the 2.5 tdi?  I can't see it anywhere - and all the online stuff I've found doesn't have air box going into turbo, - they just have a lovely obvious throttle body with air going into it on the right of a petrol engine block.....easy for them..... not for me though!...........

I feel like I'm so close, if anyone out there could offer the benefit of their jeep experience, I'd be so very very grateful......
cheers

bort

[isle of man]

Bort!! Take your balls in your hands and go to the maindealer, this will takeout the guess work.

[borticus]

Bort!! Take your balls in your hands and go to the maindealer, this will takeout the guess work.

   

less balls in hands, more short arms in deep pockets..............(it's the jock in me....)

and having had some business with stealerships, was hoping to avoid being the main contributor to them putting their third son through public school this term!

ah well, they might just have won, if no-one else has any thoughts.........

[isle of man]

Indeed, but you will still have your balls!!!

[borticus]

Indeed, but you will still have your balls!!!

  You have no idea what we use for currency up here, do you??


Oh, I just got a '27' code this evening - 'injector control circuit signal not responding correctly'.......so looks like the folks on here know their stuff and were right about injector problem....

ah well, looks like the gc is going the way of the warrior........I just seen how much those #1 injectors are.......

bort

[demonicwillow]

You dont have a throttle position sensor, being a 97 there maybe two choices here, 1st the throttle is controlled by a good old fashioned cable which attaches to the pedal and goes to the fuel regulator on the injector pump but as your getting a code 27 you probably have fly by wire, attached to the accelerator pedal is a little black box (throttle sender) which sends info to the injector pump which in turn operates an electro mechanical valve within the fuel pump, if your not getting much response with the pedal but its good on cruise then thats probably your problem (the throttle sender) the cruise control takes over the pedal function whilst engaged, but I still wouldnt rule out no1 injector. If it is the throttle sender then I believe the whole pedal assembly has to be changed.

[The Smiths]

the ZJ 2.5td does have fly by wire, and I happen to have a spare accelerator sensor & pedal in my stores.....

not saying it is this problem - just that I have one for sale