g50 bogging / pulsing

[jonja]

i have a '94 q45. it has this problem where a little while after it warms up, usually when i'm on the freeway, it with bog and just pulse like i'm going on and off the throttle when i'm not. the pulses are just a little shorter than one second intervals. the car also will not rev higher than 2k rpm. it problem usually goes away temporarily but comes back soon. sometimes the car will just die.

[elwesso]

Check/clean the MAF. Read posts about the MAF, that should help you out. If cleaning the MAF doesnt do anything, then replace it.

Let me ask you this, have you ever replaced the fuel pump or has the fuel pump ever been replaced? Does the CEL ever come on?

I always check fuel pressure in Q's first since FP's are a known problem area for Q.

[jonja]

yes the cel comes on. i'll do both i guess.

[elwesso]

ok then i'd lean more toward it being MAF related, more specfically the connector. Pick up some electrical parts cleaner to clean the connector and element (look on Q45.org for instruction)

[goody90q45]

ok then i'd lean more toward it being MAF related, more specfically the connector. Pick up some electrical parts cleaner to clean the connector and element (look on Q45.org for instruction)

Once you've cleaned the MAF connector and MAF pins (any green corrosion?) take a look at the female pins in the connector. If the pins have opened up like the one on the left they will need to be recrimped using a pick, skinny finishing nail or equivalent by gently bending down the pair of tabs on each so it looks like the pin in the middle. When done, coat the pins with dielectric grease and plug into the MAF. It should fit tight with minimal up and down wobble.

If you found corrosion on the MAF connector chances are you have it on other connections. If this is the case, check and clean as many connectors as you can get to.

[AlabamaDan]

That must be what I read about that they did in my maintenance history back in 1995. Mike a photo speaks 1000 words! The one you had about checking the injectors too.

[goody90q45]

Thanks. I've been meaning to shoot this one for a while since I'm always preaching crimping the pins but just had other priorities. I've got a couple more in mind that I think would be helpful that I'll get to soon.

[elwesso]

FWIW normally what I do is twist the pins on the MAF a little, so theyre at a slight angle. Either way it accomplishes the same thing, good advice Goody..

[Jesda]

Mike: Nice photo! Thats a great idea.

[Magnum PI]

Had the same problem for the past month or so. First changed the fuel pump and FPCM, the O2 sensor, with no success. Then followed all the NICO advisors advice and replaced the Mass airflow sensor. So far, it seems to have done it. There was no corrosion in the connectors in the connectors so it must have been the circuit board inside the MAF.

The car runs like new again, so thanks to NICO and all the input.