some engine trouble on a 97 aspire

[ldesbiens]

I recently acquired a 97 aspire with 63000 km which is in good condition overall, but I have some engine troubles :

- The car is sometimes hard to start, eventually you need to fully depress the accelerator pedal to get it going.

- The idle is ok but sometimes it dips and it actually died at idle once or twice ( but only in Park, never in Drive ??)

What I did :

- I changed the spark plugs
- The wires and distributor cap are recent
- I replaced the fuel filter ( I was surprised how little fuel pressure was remaining in the hose)

-recently I got a p0170 (fuel trim) check engine, the long term fuel trim was very low - 11 % which means the engine is running quite rich.

- I measured the manifold intake vacuum, and it's at 14 " Hg (<-- not good)

- I cleaned the EGR valve

- I adjusted the timing but was a bit puzzled by the 2 marks on the crank pulley, there is a yellow one which should be it, but also a white one, about half an inch to the right (which means really advanced) the timing was originally adjusted on this mark.....could it be that the timing belt has a jumped a tooth and someone made a new timing mark to go along with it ??

any ideas to get me going ?

thanks !

[rotinaj13]

rotate the engine to the yellow mark and look for the marks on the cam to lign up 12 o'clock and 3 o'clock there is a ridge on the valve cover and on the head it ligns up with. The timming light should light and match the white line with the pointer.

[ldesbiens]

oh, ok I get it ! thanks !

So white mark it is.

that's great info, I'll be able to check my valve timing without removing the water pump pulley !

[ldesbiens]

What I did :

I put the timing back where it should be.

What I noticed is that while in Park, the car has a lot of trouble maintaining its idle, it goes up and down, sometimes it dies. If I'm in Drive, no trouble the idle is very smooth.

and as I said, I'm puzzled by the the very low vacuum reading, 14 in of Hg, in Park and 13 in of Hg in Drive.

any ideas what is going on ?

thanks in advance.

[FB71]

sounds like valve sealing or blowby issues. are the vac readings steady or fluctuating?

[ldesbiens]

no the readings are steady.

[FB71]

not valve sealing then. remove the oil fill cap while the engine is running, and look for smoke/air coming out at 2000 rpm

[rotinaj13]

if there is a vapor comming out what does that indicate? because my readys were steady but i know mine would have preasure comming out... blowby?

[FB71]

yup, blowby. rings or cylinder walls shot. time for an engine swap!

[ldesbiens]

I found something wrong this evening :

the fuel pressure regulator is spitting fuel by its vacuum line !

so that explains the difficulty starting the car (I had to push the gas pedal to the floor as if the engine was always flooded), and the stutters at idle.

Any good sources for this part, Ford is asking 260 $ cad !

as I think of it, one of the spark plug was darker than the others.....must be coming from cylinder 4.

That still doesn't explain the low readings on the vacuum gauge, but one problem at a time.

[FB71]

actually, it does explain the low vac and blowby. Liquid fuel ingested into the cylinder will wash down any oil on the cylinder walls. That super thin coat of oil aids in ring sealing and reduces ring and cylinder wall wear. Also, the leaking fuel acts like a vacuum leak, raising the pressure slightly in the manifold. To verify this, block the vacuum line and the port on the regulator, change the plugs around (move the dark one to another cylinder), add a squirt of oil to each cylinder through the plug hole, fire it up, get it warm, and recheck your readings.

[rotinaj13]

surprising i did the smoke test with my car. It puffed at idle but when reving it didn't. Allthough it u tilted the pcv up it looped when revving... LOL

[ldesbiens]

update:

I changed the fuel pressure regulator, got one for 23 $ cad used.

The car runs great now, it starts like a charm.

Sadly the vacuum readings haven't improved.


I did not do the oil in the cylinder vacuum test as suggested by FB 71, thank you, but it is a bit too cold outside for the time being, I try to keep it to the minimum ( it's about 0º F today ).

I have the feeling the mechanical timing is not right ( maybe the belt jumped a tooth), If I remove the water pulley to check it, I might as well go all the way and change the timing belt, I'll do it in the spring.

Thanks

[yvanlavoie20]

check compression

if your belt skip a theet a piston-ring damage can be see in a compression test, you should have at least 175 psi in all 4 cylinders, normally an 1.3 should have 195-215 psi with a snap on tester (new) if under 170 psi mil light come on with fuel trim error codes. i search on a car for this and try about all an other car for parts... :? the only thing i never check...compression.