hi all im having awful problems with my sierra glsi
its a 1990 2.0 dohc efi
the car wont idle it just cuts out
it wont start unless i use easy start or push it on a hill
its overfueling and the spark plugs are fully black and putting out a load of black smoke
it also dies a bit between 4 and 5 thousand rpm when im driving it not reving it
but other wise it has good power.
i have changed the fuel rail changed the injectors got new injectors seals from ford and changed the fuel regulator
i washed out the fuel tank and fited seconed hand working fuel pump
i changed the ecu map sencer idle sencer crank case pip breather. spark plugs plug leads distributer cap and a new battery
i did notice one time it idled very high but it stoped and cut out agen and i had to get the easy start to start it agen as every time
the only thing i didnt change is the fuel filter behind the petrol tank
but i dont think its blocked because there is fuel geting to the fuel rail
i cant find any vacuum leaks anywhere i tryed about 150 times used carb clearer
i just cant fix it ive tryed everything
if anybody here can help me i would appreciate very much thanks

 

ECU coolant temperature sensor is a favourite for screwing things up. Its the multi-pin plugged one on the inlet manifold, behind the thermostat.

 

hi jhb tech i changed it
thanks anyways

 

change the fuel filter as its cheap anyway

 

Sounds like an air leak. Have you changed the O2 sensor ?

 

there are lots of things to check

but the main culprits are as follows:

the crankcase breather pipes that run under the exhaust, rubber, and the hard pipe that connects to the inlet

the tps

the crank sensor or loom gets covered in oil as the oil filter leaks and they live next door to each other

try them first

 

So it just started doing this at random, after driving perfectly for how many miles ?

 

hi everybody thats for getting on to me about it
i have changed the tps aswel and the crack case pipe
the car had been stood for 21 years undercover inside with out been started
so i changed the fuel pump and washed out the fuel tank
new plugs and new injectors fuel rail and fuel regulator
one oil and filter and
could it be a timing problem??

i did run perfect but the next day i want to start it it wouldnt start
so i had to get the easy start and then all the problems started
i dont like easy start also id say its very bad for it

 

They are chain driven so it won't be a timing problem

 

im going to keep at it until its fixed
if i find out the problem ill report it here

 

 

this is the car im having the problem with!!

 

basics...

fuel..

air

spark

in absence of those test why. Starting with crank trigger ( and assuming no silly immobilisers on the car )

 

hi stevie turbo
there is an alarm box that keeps clicking mad under the dash
but it has stoped im getting spark and fuel and air
im starting to think that maybe the fuel pump is to week

 

How can you be getting fuel, if the fuel pump is weak ?

You're either getting fuel injected into the engine or you are not.

Have you verified both fuel pressure and had direct confirmation fuel is being injected into the engine during cranking ?

No guesses.

You are getting good spark at all 4 cylinders, and at a time that would allow starting ?

Again...no guessing. Test and confirm.

Throwing parts at this, swapping stuff is a surefire way to make getting it running more difficult.

 

thanks for reply
its getting spark that should start it on all 4 plugs for sure
its getting air for sure
i did take the fuel pipe of the fuel rail and there is only very little fuel coming out of it drips just and there is fuel in the tank
blocked fuel filter bad fuel pump?

 

Is there power going to the pump ? Can you hear the pump prime when you key on ?

 

he's been driving it around so i'd assume the pump was ok

 

He says it wont idle and wont start ?

Something is not ok, hence he needs to do some very easy and basic checks.

Se says he has good spark on all 4 cylinders and at a time that would allow starting ( although has he really tested this correctly ? mmmm )
But it the above statement is correct, then it implies the ecu, crank triggers and ignition system are at least working correctly, certainly enough to start and run.

Hence next obvious thing to check is fuel.

Although he did first claim he had fuel...then now says he doesnt.

Testing is important...guessing is not.

 

hi guys thanks all very much of helping me out
the problem was the tps now its running 100%