Rob Longson

hello everyone

apologies but i am fairly new to forums.

i have a 52plate st170

the issue i have is when starting the car, it can be abit hesitant starting but does start within a few seconds.

it then sounds like a misfire, splutter and as if it is struggling to run. the revs are at about 1300-1500 and after a few mins it then drops to normal idle speed and the engine sounds fine.

when driving sometime between 2000-3000rpm the engine can be hesitant again, splutter

i normally then drop a gear to be over 3000rpm and the thing just pulls like a train.

no problems with the car below or above when dirving but it is getting worse.

i have changed the following

spark plugs
leads
coil pack
air flow sensor
throttle body arribing this week.

could this problem be the inlet manifiold or the box of tricks that controls this?

if this is the case does anyone have a rough idea how much it would cost fit these?

really appreciate anyones help as i love my car and i know i spend a fortune on it but it is incredible to drive and puts a smile on my face.

happy to continue to spend the money as will never get tired of this beast.

thank you in advance

STeve

iTrader: (11)

my gut feeling its a fuel related issue basing it on what you have already changed as the 170 does suffer with pumps where fuel pump in tank filter and external filter have not been cleaned/changed regular and starves engine of fuel, would never call the 170 a beast though lol

Rob Longson

Ah thank you for the reply, i have a new fuel filter to fit this weekend too. i was under the impression that it could be the inlet manifold as this is what a few people from garages have told me. i will change the fuel filter and see if this helps.

the 170 may not be a beast... but it is my beast lol

has 187k on the clock and apart from this issue it is still going strong

STeve

iTrader: (11)

I own a 170 myself and it does make me chuckle when people refer to them as beasts, but when you change your filter hopefully it will give you a indication of what condition your pump is in judging by how clean the filter is

RichieST

iTrader: (2)

Glenn on here had a similar problem, there is a gauze on the pick up in the tank that gets clogged. Could be worth looking at.

Rob Longson

thank you to you both, i will atempt to try this. is it a job that someone with not alot of experience can do. i know i can do the fuel filter as i have done this before on the car. can the fuel pump etc be a job for me or is it a job for an expert.

it is so hard to get these problems resolved and so glad i joined this forum.

have read other posts on the net about similar sympotoms but this is the first time the fuel system has been mentioned.

haha, i know they are not a beast but not a bad car for what it is and does make you smile when driving.

Rob Longson

it is just weird that is it at start up for a little bit and then intermitant on a certain rev range that has got me confused

are you able to post video on here as i could do that to show the problem if that would help anyone...

RichieST

iTrader: (2)

The tank needs to come out to access the fuel pump, or you can be a bodger and cut a hole in the floor under the rear seats.

Rob Longson

i may just get a new tank off ebay with a pump and then replace the lot. i dont have any cutting equipment so taking the tank out and putting a replacement in sounds the easiest route to take

STeve

iTrader: (11)

the tank is plastic so you should not need to replace that, I break st170s and most do buy a spare complete pump just in case or to build up ready to swap over and normally the actual protective bag around the pump feed itself get clogged with crap which can put pump under strain and make it fail, burton racing sell replacement pumps for around 50 new if you go that route

Rob Longson

do you have any pumps going from any one you are breaking?

STeve

iTrader: (11)

I do have some still fitted in cars they sell for Ł50 fully complete plus Ł5 postage

Rob Longson

Rob Longson

is this the pump you were refering to?

how many do you have available and are they something you may have in a few weeks? will be off work in a few weeks when i plan to fit this part as currently moving house too.

STeve

iTrader: (11)

I always have them as Im always breaking 170s and yes thats the little pump that sits inside the tank sender module

Rob Longson

awesome - thank you

so this is a silly question but if i bought that one from burton and took it to a garage to be fitted then they should know how to fit it and i assume i wouldnt need anything else to go with this?

you help has been amazing than you. learning lots

STeve

iTrader: (11)

yes for any decent mechanic its a bread and butter job = straight forward

gazhep

ive got fuel pump bought it 2 weeks ago paid Ł100 for it made no diffrence to my car so put old one back in and your problem sounds like air idle control valve if revs are surging just a thought but loads of stuff on you tube about it i will sell this pump if anygood to anybody Ł40 i tryed to take it back shop wouldnt take it said smelt of fuel

Rob Longson

hi there,

i have heard several different theories as to why my car is acting as it is and the all seem plausable.

the car does idle fine when starting and then settling down but as it does the normal routine it sound like it is either being starved of air and struggling to run but once the idel settles to normal then the engine sounds fine.

the 2nd issue is when driving, it does feel a little sluggish sometimes however the main issue is betweek 2k and 3k revs as i am cruising it will then do what it does at start up so i increase the revs by changing gear and it is fine.

this does not happen all the time but alot of the time.

i have been told on this thread to do the fuel pump and filter and i know the filter needs changing and the pump sounds like a good idea

i have also been told it could be the inlet manifold or the box of trick that sits behind it.

this is why i started this thread as from my research i found posts on various sites from years ago describing similar issues but no real answer.

just want it to run like a normal car for a while rather then fix one issue then get another hahahaha

but thank for your input it is appreciated.

problem is i dont know a decent mechanic who can help diagnose the issue

Rob Longson

just found and read this article and it does seem to match the symptoms i am experiencing

The Electronic Fuel Pump

Although the mechanical fuel pumping system was always sufficient for carburetor-based fuel systems, eventually vehicle manufacturers moved past the use of carburetors in favor of a more advanced fuel injection system. Although the fuel pump itself is still necessary, the mechanical pump cannot generate the level of pressure needed to work with fuel injection engines. Therefore, a new system that delivers gas or diesel under high pressure, such as between 40 and 60 psi, was created. This system is what is known as an electronic fuel pump.
Nowadays, most vehicles use an electronic fuel pump, which is located within the gas tank itself, to deliver gas or diesel. There are far more inherent issues with electronic fuel pumps. The electronic system works by spraying a fine mist of fuel inside the engine's chambers and is operated through a computer control system rather than a mechanical one. As a result, both issues with the pump itself as well as the computer used to operate it can lead to malfunction and breakdown.
Remember, the purpose of a fuel pump is twofold:

1. It pushes or pumps fuel from the gas tank to the fuel injector or carburetor.
2. It creates the proper amount of pressure to ensure that the right amount of fuel will be delivered to the engine, regardless of external conditions.

Therefore, malfunctions in the fuel pump can result from an issue in either one of these processes. Let's take a look at the common signs of these problems.
1. The Engine Sputters at High Speed

The most common early sign of a problem comes when driving a vehicle at a consistently high speed. While traveling down the road, the car will run well for about 10 miles and then begin to jerk or sputter before returning to normal.
What This Means

Many members of the driving community at times will mistakenly diagnose a sputtering vehicle as one with "dirty" gas, an almost empty tank or some other fuel-related issue. While that can be the case, it is not uncommon for a fatigued fuel pump to create this same symptom as it struggles to supply a constant stream of fuel to the engine at the proper pressure. The loss of pressure causes the engine to sputter.
2. Vehicle Loses Power While Accelerating

With a similar symptom to the previous, vehicles will jerk during acceleration from a stop. The car may produce a stalling sound and then accelerate smoothly.
What This Means

Once you take your foot off the brake and hit the gas pedal, a working pump increases the flow of gas or diesel to fuel acceleration. Because a malfunction starves your car of that increased flow, it doesn't have the power it needs to respond to commands. Once pressure is restored, the engine is able to run smoothly, and the car takes off.
3. Sudden Loss of Power When the Vehicle is Under Stress

A car or truck is put under stress when the work needed to complete an ordinary task, such as forward movement, is somehow hindered by external forces. Generally, this occurs when climbing a hill or when hauling a load. If, when completing these tasks, the vehicle loses power, cannot accelerate, or begins to sputter, the fuel pump is a possible culprit.
What This Means

Generally, even an aging pump can maintain a steady stream of fuel and pressure when operating under normal conditions. These devices create resistance or fail when under stress, leading to power loss.
4. Surging

If your vehicle doesn't lose power while driving, you may find it surges - accelerating suddenly with no drive input.
What This Means

Some may mistakenly blame this on the fuel filter, reasoning that it is not properly trapping dirt and rust. More likely, this surge is created because, as a result of age and normal wear and tear, the fuel pump has irregular resistance within its motor. This creates a situation where the pump cannot draw enough electricity to maintain the pressure needed for steady speeds and may "surge" with a sudden ratcheting up in pressure.
5. The Engine Will Not Start

The final symptom of a malfunctioning pump is also the most severe. Drivers who ignore the signs eventually will end up here, with a car or truck that won't start.
What This Means

When a pump has malfunctioned to the point that the car will no longer start, this means that there is no fuel reaching the engine upon ignition. For that reason, drivers will hear the sparks try to ignite, but there will be no fuel to burn. To diagnose such a malfunction, check for a blown fuse and pressure in the fuel line, as the gauge should read 0.

mcst

Out of curiosity what fuel are you using and what driving do you do? Frequent short runs/traffic or 60mph+ 25miles or more?

Glenn_

iTrader: (1)

The problem i had was that the car wouldnt go over 3.5,4k. I cleaned the in tank fuel pump filters and adter this the car pulled like a train.