— Important —
Check Engine Light or MI indicator will lit up for a variety of reasons. This solution noted here specifically involves the following symptoms and is not a generic solution for all MI indicator issues.
1. Engine Hesitation/stall
2. Sudden deceleration and lack of response to accelerator pedal
3. On Scanner it reports Rail pressure error as the fault detail.
4. FLAT Priming Bulb
There could be other problems which shows same symptoms, so do detailed troubleshooting.
Bought this truck few years ago, as brand new from Tata. its a 4X4 Pickup, with Tata’s well known 3.0L Dicor (CRDI) engine. why well known? it uses the most famous TATA 407 LCV block, Push Rod, Gear timing, robust and reliable. I love this engine and its the only reason why I purchased the Safari 3.0L and Xenon 3.0L too. In short it is a 407 Engine with Delphi CRDI Kit.
My brand new Xenon got very strange problem. Intermittent hesitation. I used to live in Bangalore and drive around city. Occasionally I used to get “Check Engine” (MI) Lamp in cluster with hesitation, vehicle will slowdown and recover automatically and run smooth. The MI or Check engine lamp used to go off once I stop and start the vehicle.
It used to happen rarely until I took a long 750Km drive from Bangalore to Trivandrum, Kerala/India. On this 12 hour non stop trip, towards the end of the journey, the vehicle was literally slowing down every 15 minutes, check engine light, hesitation and what not !! Surprisingly the problem was gone after 12 hours of overnight resting.
Took it to Tata – did OBD Scan, it reported Rail Pressure Error. Usual suspects – HP Pump, Dust in Tank, Clogged Fuel Filter, Clogged Sediment Filter [ Yes in India, the Diesel vehicles have two filters to filer the fuel, due to the high quality of the fuel 🙂 ]
Tata Service Center also suggested that the Fuel Tank Design is a bit weird that It can cause issues if you run the vehicle with less than 15L of fuel, specially going on a uphill/down hill , as the fuel flows all the way down to one side of the tank and misses the pickup line.
Hmm..Brand new vehicle..Was not willing to leave it all to Tata, as this vehicle is serviced by their Commercial Vehicles Wing, even though mine is a Personal Vehicle 🙂 .Thanks to Motors Vehicles Department, not Tata.
They asked me to leave the vehicle to do complete inspection. Intermittent problem and the clueless kids at Tata Commercial Vehicle service Center ..hmm..I decided..let me take the risk, I will fix it 😀
So, step#1. Identify the problem. Started checking the scenarios where the issue was happening. To my surprise the problem was more often during long drives, or Up/Down hill with low fuel (less than 1/4th Tank). So I filled full tank fuel to iron out the issue of poor Tank Design. Drove for few days, and surprise, I see the problem even in full tank.
Very careful inspection of the fuel line showed me the first cause – the Priming Bulb goes FLAT !!!
This is usually located very next to the Fuel Filter, before Fuel Filter in the Fuel Line.
Ah..So its not the Fuel Filter which is Clogged. Who else ? The Sedimenter.This is usually located near the Fuel tank in vehicles with 3.0L Engine
Tried Draining the water out of it, it was draining real ugly black color fluid.
You need disconnect the water sensor cable and unscrew the bottom cap. let the all the bad fluid drain out and wait till you see clear diesel coming out and put back, connect the cable. The cable controls the indicator on the dash, called Sediment Filter alert. Basically it means your filter is full of crap coz you have been using crap fuel. 🙂
Anyways, I thought of replacing the whole damn thing as the content from drain was real bad. Ordered and replaced the whole filter for almost 4K INR, approx 60$.
Thought I solved it, but no..after few days, I saw the bulb flat again, and problem too of check engine and hesitation. There was nothing else left to do, than dropping the Tank. Decided to do that over a weekend !
How to remove Tank :
Basically common Sense will get you across to removing the tank Mechanically. however the trick is in removing the fuel lines from Tank. They use Quick connectors. Press on the flat side of the connector – and pull them, they will come off. Its much easy.
Another option is to remove the rear left wheel, remove the trim inside wheel arch, and get access to the top of the tank. I went under the vehicle and inserted my hand through the gap on top of the tank to remove the connectors.
Here is what I found after dropping the tank and removing fuel intake unit
what you see on top is the fuel intake unit. Remove 6 Bolts and you are in for the surprise 🙂
I still wonder what that black substance is – in a brand new vehicle’s Fuel tank. the Vehicle was at less than 6000Km ODO at this time.
Cleaned it and put it all back, have done over 15000Km and the problem never appeared again. I still wonder how can a brand new vehicle off Tata’s factory can contain something like this inside its fuel tank. Anyways one more issue – Solved 🙂