Topic: cherokee 2.5td vm engine lack of boost help (Read 32889 times)

GREGBLACK · « **on:** March 26, 2010, 02:16:01 PM »

Hi I have a 1998 Jeep Cherokee 2.5TD LTD with the VM engine , It loses power at 2,000 rpm, I have checked the intercooler hoses for splits and found none I have cleaned maf sensor and terminals (this is located in the air filter housing), I have fitted a new air filter. It has had 3 tanks of diesel through it now with injector cleaner added this has made it missfire a bit above 2000 rpm but it has increased the rpm to about 2250 before it runs out of power. I have tried it with the vaccum line to the EGR disconnected this made no noticeable difference so I have reconnected it. I have disconnected the battery to reset the computer again this made no difference. The jeep accelerates strongly to 2250 revs then loses power. I bought the car cheaply like this and have no previous history as to what has been done.It is not showing any error codes on the digital display.
Have you any suggestions as what to do with it next.
cheers greg

Mike Pavelin · « **Reply #1 on:** March 26, 2010, 02:35:50 PM »

Is the turbo siezed?

The Smiths · « **Reply #2 on:** March 26, 2010, 03:03:09 PM »

May be in limp home mode - No1 injector sensor??

tim_aka_tim · « **Reply #3 on:** March 26, 2010, 04:15:50 PM »

Sounds turboey. Seized, or waste gate stuck open.

Dave69 · « **Reply #4 on:** March 26, 2010, 05:23:35 PM »

have you revved the engine by manually operating the injector pump with the bonnet open and looked to see what is happening ?

I had a problem similar where as the engine starts and runs fine but as soon as the turbo starts spinning there is power loss. This was traced to the intercooler pipe to the turbo collapsing and restricting the airflow significantly. A quick fix is to get a used silicone sealant tube, clean up and cut length to suit and slide into the pipe. This is a tight fit but stops the hose collapsing while a new hose is sourced.
while you have the hose off the turbo try and turn it by hand and also feel for any rocking as this will indicate a worn impellar which might need replacing soon

GREGBLACK · « **Reply #5 on:** March 26, 2010, 05:24:57 PM »

hi I can Hear the turbo spooling down when I switch off I don't think that is the problem, how do I check to see if the needle is stuck in No. 1 injector I think it probably is this this as it has picked up a few revs since I started adding injector cleaner. The jeep drove up to 75mph on the level yesterday previously I could only get 65mph.
Finally how do I check the waste gate do I have to dismantle it to do this, if so would it be better to block it off with a plate.
Cheers Greg

GREGBLACK · « **Reply #6 on:** March 26, 2010, 05:33:27 PM »

Hi again first my apologies for not thanking those that have replied to me,.
Dave I haven't yet tried that as I am on my own but I will get some help and try it as soon as it stops raining(I am in Scotland it rains all the time) I have checked the pipes for splits and found none I took the pipes off and the woven protective cover but found nothing in the pipes but the cover had a few though. I still suspect No1. injector or the waste gate.
Thanks all
cheers Greg

tim_aka_tim · « **Reply #7 on:** March 26, 2010, 05:45:50 PM »

Forget the injector cleaner, it'll take forever. Tip 100ml of pure acetone in the tank.

GREGBLACK · « **Reply #8 on:** March 26, 2010, 05:53:24 PM »

Forget the injector cleaner, it'll take forever. Tip 100ml of pure acetone in the tank.
Hi I will try that Tim I seem to remember doing that to a carb about 20 years a go
cheers Greg

tim_aka_tim · « **Reply #9 on:** March 26, 2010, 05:56:16 PM »

Quote from: GREGBLACK on March 26, 2010, 05:53:24 PM

Forget the injector cleaner, it'll take forever. Tip 100ml of pure acetone in the tank.
Hi I will try that Tim I seem to remember doing that to a carb about 20 years a go
cheers Greg

Yep, the old tricks are the best.

Dave69 · « **Reply #10 on:** March 26, 2010, 06:02:30 PM »

the number 1 injector measures the resistance through the injector. too high or too low and its limp home setting or wont run. A visible check is to run the engine in neutral with the handbrake on (obvious) then pull on the throttle cable connect to the injector pump to increase the engine speed. You don't have to pull on the cable fast just at a slow rate and watch the hose. Sit in the drivers seat with the window open to hear what the engine is doing at 2-3k rpm so when you rev the engine you have an idea of where your at. If there is a hose collapse it will be quiet obvious. The mk1's had a reinforcing metal coil inserted into the intercooler hose to stop this, not sure about the mk2's

The Smiths · « **Reply #11 on:** March 26, 2010, 07:53:17 PM »

If you managed to get it over 2000rpm it is not likely to be the sensor on No.1 injector - it is the ECU that limits it so cleaner will make no difference

GREGBLACK · « **Reply #12 on:** March 26, 2010, 08:44:15 PM »

"If you managed to get it over 2000rpm it is not likely to be the sensor on No.1 injector - it is the ECU that limits it so cleaner will make no difference"

Hi could that also indicate that theneedle is sticking as it seems to misfire or perhaps it the turbo boost trying to kick in? This is the first diesel I have had so my knowledge of them is pretty thin.
Adding 100mil of acetone to clean the injectors I gather will not do any damage?
Some people claim to add 20-30mm per tank full and report increased performance and economy claims for economy anywhere from 2.5% to 20%(I don't believe the higher figure but 2.5% would be good) I have had a look at various arguments, I followed one thread that was spread over 7 years but there was nothing to substantiate these claims.
cheers Greg

Dave69 · « **Reply #13 on:** March 27, 2010, 12:13:04 PM »

no point trying to add addatives or change ecu chips etc to gain more power for this make of engine. keep it std for reliability. If you think the No.1 injector has a problem it should thorw up a check engine light. the other thing is to measure the resistance across the connector pins (ohms), I can't fully remember but if the resistance is higher than 110ohms then it will flag an error. I fooled mine by putting a resistor in line but be aware that the wires do go brittle over time. Another option is to take the injectors out and get them cleaned. A diesel specialist should charge too much plus they will check the "pop" pressure so that they can see if they are all operating the same. The No.1 has the flying lead so the socket needs to have a hole in the side (make your own) but be careful not to allow the socket to slip as it will cut the wire in two

GREGBLACK · « **Reply #14 on:** March 27, 2010, 06:13:59 PM »

Hi well I added some acetone 10cc to my diesel and went on a run, It was pulling up to 2,250 with a slight missfire, at the end of a 40mile run it is now pulling up to 2,750 before it starts to die. I will add more acetone at my next refill as it seems to be clearing it. I have seen the argument's about acetone as a power additive but that is not why I have added it and frankly I am sceptical about it but it does seem to work as a cleaner.
Cheerio Greg

GREGBLACK · « **Reply #15 on:** March 27, 2010, 07:43:12 PM »

"have you revved the engine by manually operating the injector pump with the bonnet open and looked to see what is happening ?"

Hi Dave I managed to do this today, the hoses are fine no sign of collapse, I had them off the other day to physically check them for splits but thy are OK, The one leading to the inlet manifold was coated in black oil I wiped most of this out, it had been over filled by the previous owner a good 1.5" over the full mark this also cured my oil leak from the intercooler hose. Anyway I did a oil and filter change when I got it home from Kendal and then started to sort the problems. This seems to be getting better with the injector cleaner (acetone).
I only have two issues left with it one is the heater resistors this seems to be disintegrating with rust and the other is the oil pressure switch, I keep putting off doing the oil pressure switch as it is so in accessable.
I guess paying £500 for a Nov 1997 I was always going to get a few problems mainly caused by neglect.
Cheers Greg

Dave69 · « **Reply #16 on:** March 28, 2010, 12:13:41 PM »

if you have oil in the inlet hose from the intercooler check the play in the turbo impeller. the turbo has an oil feed which goes in the top and out the bottom straight to the sump. if the turbo seals are worn then they will leak oil into the intake and coat the hoses. Oil pressure switch is a case of them working or not. They are well know for failure. PTP has a thread about taking one apart in the technical section.

GREGBLACK · « **Reply #17 on:** March 30, 2010, 04:40:33 PM »

Hi again, the acetone has done the job it will now rev, I have had it above 3500 and it has a bit more go and I am not embarrassing my self by trying to overtake 16 wheelers and having to drop back behind them. Now I have just the oil switch to sort and may blank the EGR off at the same time.
Thanks for all your help and suggestions regarding the lack of power.
cheers Greg

The Smiths · « **Reply #18 on:** March 30, 2010, 08:51:33 PM »

I might shove some through - they recommend the use of it with veg oil - say it helps spray formation and gives increase in MPG - which would be very good

GREGBLACK · « **Reply #19 on:** March 30, 2010, 09:09:42 PM »

Hi I don't know about increasing mpg but it does make a good cleaner and is supposed to help remove the water that gets in to the diesel, I only put it in to clean the injectors but it does seem to run smoother. Here's a link you might want to follow http://forums.tdiclub.com/showthread.php?t=121640
Cheers Greg

tim_aka_tim · « **Reply #20 on:** March 30, 2010, 09:29:38 PM »

I wouldn't advocate acetone as an MPG increaser. I've tried it as such on many vehicles, with the one positive,
funnily enough a 3.1 VM (450 per tank with and 400 without). Given that your 425OHV and my old 531OHV are
pretty much the same, maybe it will increase your MPG, but maybe not. YMMV. Literally.

It does make an excellent fuel system cleaner though. It's cheap and powerful, unlike that injector cleaner crap.

The Smiths · « **Reply #21 on:** March 30, 2010, 10:15:12 PM »

Think I will try it (just a case of getting some and doing it

)

Sounds promsing - the 3.1 is just extra cylider.

I would be happy getting it over 23 MPG (at around 20MPG)

and as for the mention of lubrication on the other thread - I'm running high percentages of veg oil

By the way same economy if just on diesel

- its the mods and tyres that are screwing it

ivanidea · « **Reply #22 on:** March 31, 2010, 09:18:32 AM »

Can acetone be used in the crd engines?

Is it worth adding as part of the annual service?

Panic mechanic! · « **Reply #23 on:** March 31, 2010, 09:40:34 AM »

I am not sure about this but you have to be careful how much you use as it can burn out lambda sensors and bugger your cat on later engines.

GREGBLACK · « **Reply #24 on:** March 31, 2010, 10:39:23 AM »

Hi I think this was done to death by the TDI club http://forums.tdiclub.com/showthread.php?t=121640 If I remember rightly this thread spanned 7 years,all the information you need is there but it is inconclusive. Having said that I am also going to add it every tank full 10cc to a tank, but if I were you I would read some of the posts on the TDI link and make your own mind up.
cheers Greg

Author Topic: cherokee 2.5td vm engine lack of boost help (Read 32889 times)

GREGBLACK

Mike Pavelin

GREGBLACK

GREGBLACK

GREGBLACK

GREGBLACK

GREGBLACK

GREGBLACK

GREGBLACK

GREGBLACK

Panic mechanic!

GREGBLACK