My 3.5 Gdi has 127 k km and loses power and almost stalls under laod either hills of quick acceleration, on flat with no load its ok until the accelerator is pressed. HJAve just had the throttle control sensor replaced but problem persists possible causes appreciated

Possible causes (from web research) have included 02 sensor, carbonation of the intake manifold, air filter sensor, throttle body, fuel pump relay - can anyone shed any light please before I take it to the garage (possibly not the dealer)

Very first thing I'd do is replace the two fuel filters. The one which is part of the injector unit is quite common to block and will cause the problems as you describe. I had the mechanic replace as mine was cutting out intermittantly. new filters and alls good.

While in there have the fuel pressure checked as another common problem on earlier models was pump seals & tank scavange filter especially if you have run injector cleaner through recently.

Jim

THanks for the reply Jim

TTHe fuel filters were on my list. Response from both the AA and the garage it is going to tomorrow (not the local dealer) was carbonation of the intake manifold, apparently there is a new cleaner that can be used. Interesting thing is that the delaer, when replacing the throttle control, didnt mention carbonation and ther were supposed to have checked filters. Just before the problem got bad had successfully comppleted on off-road fundraiser in the Wairarapa (NZ posters will no where) with no problems on very steep and rough tracks. One possibilty that some detritus in the tank also got sucked up
HAve printed ypour response to take to the garage

Thanks

Trevor

Carbonation on intake manifold??? New one on me. I'd do a bit more checking on this before handing over the $$ to repair something which is non-existant.

Jim

Afternoon Jim



I have just got my GDI Pajero back from the garage and had a trouble free run to my office. I gave your response and other details from my web searching to the garage and on reading what I gave them they decided that the filters were the problem and I gave the ok to remove the manifold to check them out. Both were quite blocked so they were removed and replaced with new filters cost $20 each. As the intake manifold was off they cleaned it and the throttle body of all deposits (some carbon build-up had occurred) as well as stripping and cleaning the fuel pump before re-assembling. All up it was an 8 hour job and it ran trouble free on the 15 km to work including one good climb. The garage doing the work also said that the Mitsi dealer they spoke to (which I believe was the dealer that had been servicing the vehicle up to now) when ordering the parts had never replaced these filters in any GDi engine before and the feeling I got relayed to me was that they were a bit bemused by it all. The garage also has special cleaning solution/kits that have been developed to deal with carbonation in GDi motors but felt this wasn’t needed.

What I need to do now is to get a few more kilometres under the belt to make sure that the problem has been sorted.

Really did appreciate your prompt response and interest



Regards

Trevor

I hope you got it all sorted now Trevor. The filters clogging is a common problem and my mechanic has seen a number like this. I had some very similiar problems as you and this completely solved that issue.

As another thought make sure all the electrical contacts under the engine bay which lead to and from the ECU are clean and making good contact. Another common problem is the miscomunication between the ECU and sensors (ie AFM, O2, injcetors, etc). By removing cleaning (with emery cloth), spray with electrical cleaner and sometime bending pins slightly will eleiminate this anoying probblem. One of the first signs canl be with the tranny changing gears at odd times. This can also be the result of not changing your fluid at approx 80k which really needs doing.

Jim

My 3.5 GDI has exactly the same problem and I notice that when I remove the fuel filler cap that there is always a rush of air as if there was a vacuum in the tank. Logic tells me that this is wrong but can anyone confirm if this is normal or if the fuel cap is blocked causing a vacuum. I'd also like to know where the two petrol filters are located and if they are easy to replace.

Any help would be appreciated...

There has to be a breather on the tank to allow air to enter as fuel is being used. I'm not exactly where this is on the Pajero but should be through a charcol cannister in the engine bay. If this is blocked it will form a vacume in the tank. Fuel cap may bypass but if the sel is very good it will hold a good vacume

Fuel filters. One is in the tank on the pick up line and the other is by the fuel injector pump. I had mine done but to be honest gave to the mechanic to do as it was winter and I needed the truck done for school runs. Maybe someone else can pipe in here on the hows and where's to replace.

Jim

Thanks for that, I tried to run the car without the fule cap for a short while but the problem was exactly the same so tank breathing can't be the problem. Is the fuel filter in the engine bay a user servicable part? If so, there's no harm in changing it out to see if it's the problem - if I don't track this down soon I'm going to go mad!!!

Yes, fuel filter in injector pump is servicable. I did not do myself but Mechanic said it was easy to replace once he gained access to it. Filter was only like $20.

Jim

Hi there Benki,
Ihave been reading up on the threads and now I have these issues too! I recently changed my old square air filter for a performance one( did the necessary connections) changed my fuel filter underneath the vehicle but as soonas this was done , I noticed that the vehicle seemed to be starved for gas as I DEVELOPED A FLAT SPOT ON accelleration causing the vehicle to stop and go.. I thought it was that I didn't fit the bonjo bolt properly causing a low fuel pressure to the engine but now afterchecking andreplacing I notice that the car gave much difficulty in idling. it does now but at a very low rev just below 1000km once i rev the engine it seems that it doesnt get enough fuel and cuts off...is the timing off or is there another filter on this 3.5 v6 GDI THAT i DON'T KNOW ABOUT and cud be dirty?
I really need some answers and help here wud appreciate it


Canvalex

There is a filter screen and settlemet tube in the tank on the pump inlet side which has been known to cause problems. I'd start there and make sure all your fuel lines are clear with no air leaks. Some are known to allow air into your system which causes a pressure loss in the system. If you want to confirm the problem before you start ripping apart you can get this all checked by monitoring the fuel pressure to see if it is up to spec with no dead spots under load.

Hope that this helps.

Jim

Following up on your reply Benki, I 'm having a little issue with my high pressure fuel pump on my 3.5 GDI (98) can this be repaired in terms of blowing it out and cleaning it as opposed to trying to get another one as they are very expensive in the real world ....
Canvalex