LA1 3400 permament LTFT -10...Injectors??

[Zebe9]

Hi,

As in the subject- pontiac trans sport '96
Think i filled up all the check list:
- vacuum lines
- egr
- exhaust
- fuel pressure reg.
- o2 sensors etc.

What I DID NOT do is checking the injectors, have permanent -10 long term fuel trim.
How could i check fuel injectors- the car is 165000 M-maybe they're just worn and leaking slightly??

[86FieroSEv6]

Is the STFT hanging out at +/- 4? How old is your oil? What kind of shape is your PCV valve in? Is your throttle clean?

[Azrael]

Make sure the temperature sensors are showing logical values. Also check the manifold pressure sensor. Should be reading near 100kpa with the engine off and 30-40kpa at idle.

You can check your injectors for internal shorts by using an ohmmeter on the 10-wire connector near the alternator. They should be very close to 12 ohms. If you suspect that some of them are sticking you can try this trick with the engine running: http://www.youtube.com/watch?v=cUIIn32nlvA

[Zebe9]

Is the STFT hanging out at +/- 4? How old is your oil? What kind of shape is your PCV valve in? Is your throttle clean?

Thanx for any advice.

- STFT oscillates around 0
- PCV 3 years, not sticking (clicks)
- i change oil on regular basis (n.b. its 500km just after replacement)
- throttle: cleaned 5 years ago, i dont expect any extra dirt but will check anyway
- MAP shows 37-38 kPa on hot, idle
I also sprayed all around u-intake and vacuum hoses w/flammable - does not show any change in RPMs.

Please also advice (just review my basket on Rockauto.com.. -what else got to be replaced except injectors themselves and their o-rings, which make for the injectors would you recommend? incl. reman. also ??

[Zebe9]

Make sure the temperature sensors are showing logical values. Also check the manifold pressure sensor. Should be reading near 100kpa with the engine off and 30-40kpa at idle.

You can check your injectors for internal shorts by using an ohmmeter on the 10-wire connector near the alternator. They should be very close to 12 ohms. If you suspect that some of them are sticking you can try this trick with the engine running: http://www.youtube.com/watch?v=cUIIn32nlvA

well, thanks for the suggetions.
As foe the injectors-i ll do this but -countrary ,i suspect they may be worn thus leaking.
PCM tries to de-lean the mixture by 10%..

[86FieroSEv6]

What's your altitude?

[Zebe9]

What's your altitude?

??

you mean excatly what...??

[86FieroSEv6]

I mean, what's your altitude? 100 feet? 1,000 feet? 5,000 feet? Altitude is a key factor in determining fuel mixture as air is less dense at higher altitudes and therefore without correction the engine will suffer a rich mixture. So, an error in this area may be causing your system to force adapt. Try this. Disconnect your negative battery cable for a minute. Then, key on engine off, take note of your Baro reading, if your scanner can display this PID. Also, when you start it, take note of what happens with LT and STFT as it warms up.

[Zebe9]

I mean, what's your altitude? 100 feet? 1,000 feet? 5,000 feet? Altitude is a key factor in determining fuel mixture as air is less dense at higher altitudes and therefore without correction the engine will suffer a rich mixture. So, an error in this area may be causing your system to force adapt. Try this. Disconnect your negative battery cable for a minute. Then, key on engine off, take note of your Baro reading, if your scanner can display this PID. Also, when you start it, take note of what happens with LT and STFT as it warms up.

ok, clear.
i am not gonna run into space w/my pontiac anyway....
100m=ca.300 ft above sea level, dont think it playes any key part...

[86FieroSEv6]

Then your Baro should be at or near 102kpa depending on the weather.

[SappySE107]

How old is your O2 sensor? It might be time to have the injectors cleaned, which might be a local task for you instead of buying new injectors.

[Zebe9]

How old is your O2 sensor? It might be time to have the injectors cleaned, which might be a local task for you instead of buying new injectors.

Yeah, i just think about that.
On hot:
Sens.1(on exhaust) 1xx - 8xx (mV) -replaced 6 years ago ( ca.35 000 miles)
sens.2(on catalytic conv.) 1xx - 7xx -not replaced

Baro: ignition 100 kPa, idle 37-38, run 44-45 kPa, AND todays correction: STFT 1 to -3, LTFT -12 to -14 (!)
AND (today news): P0420 DTC appeared.

A month ago tried to install Airtex EGR from Rockauto but looks its a cheap sht -could not make 30 Nm/22 lbs torque to install -base plate of EGR broke, i got a used one and put it w/same gasket - now i have no more ideas...

[SappySE107]

The O2 sensor reads lean/rich constantly, so a static number doesn't mean anything. If its not moving around quickly or at all, then it needs to be replaced.

[Zebe9]

The O2 sensor reads lean/rich constantly, so a static number doesn't mean anything. If its not moving around quickly or at all, then it needs to be replaced.

Yep. aint no magic.
But range it reads within - matters..

[SappySE107]

It can only be within 0-1 volt so I am not sure what range you are talking about. It can read a range, just very slowly and still give you this type of result.