mass air flow?

SES not on. I noticed the harness to my TPS is pretty deteriorated. I'm assuming due to it being next to the exhaust. There's a 97 being parted out a half hour away from me. I'm going to call them up and see if they have the harness, the MAF and the TPS. Hopefully these parts will fit with the 95 throttle body. Anyone know before I head down there?

werdstrave wrote:

Hey guys,

I'm experiencing some engine choke after I start the car when it's at idle or in park. It sounds like the car is getting ready to stall out. After I rev the engine at a stop or once accelerating from a stop is when it does this. After putting my foot way down on the gas pedal it will suddenly rev way up and take off. Seems like I need to flex the peddle a couple of times to get it to wake up. After getting it moving there is no stalling or sputtering at all.

Do you guys think this is the MAF sensor? Before I had this problem, I replaced the idle air control valve so I know it's not that. Any recommendations on how to clean the MAF?

There was another person who no longer posts regularly on this board that complained of this - turns out he was hitting the PCM's rev limiter when "rev the engine at a stop."

I'd have to see a log of the sensors to give a better answer. Alex Peper's CarCode, and the factory TechII scanner are among the devices that will record such a log.

As for the MAF save yourself a headache, just get a replacement TB gasket (rockauto.com is cheapest, they should however be available locally for short money) and remove/clean the TB. You will need a can of TB and a can of MAF cleaner. If you can get the liquid (NON aerosol) cleaner from a GM dealer. My local GM dealer actually uses the Castle spray (see http://www.castleproducts.ca/Catalog/ShopChems/cleansrite.html) which I don't like (although I used it) because it works too well, I swear this stuff would melt the dark flecks out of a piece of rose colored granite. It works VERY well but is a little tricky to use, be sure to heed the label directions or you'll take paint off all kinds of stuff and melt any plastic within 2 ft. You'll need a throwaway aluminum vessel (a pie place, bread loaf pan, steam table tray or some such, unless you ahev a parts washer and if so you've already quit reading by now).

Anyway, while the TB is off remove the MAF sensor (you will need security TORX bit for this most likely - go check) and clean it separately with MAF cleaner (IIRC basically isopropyl or methyl alcohol with additives - not sure - just use the CRC stuff)

HTH


Albertj

Thanks Albertj. Can you describe the rev limiter on the PCM?

Also, this is such a rookie question but believe it or not I've been diagnosing my car since I've owned it without any diagnostic machines at all. Can you recommend what I need to buy to read codes for my 1995? I think I recall it to be an OBDII car with an OBDI interface. The vehicle was made during the transition.

ugh, it keeps doing this. It seems to now only happen when the car first accelerates from a stop. The engine like chokes a bit and then after I depress the pedal more, it's fine. Feels almost like a miss fire.

Hit the MAF sensor with contact cleaner. Still having the same issues.

How does it run if you unplug the MAF sensor? Does it run pretty much the same way?

Haven't tried. Should I drive it around a while unplugged? Any harm in doing this?

Good call Derek. I just tried this. The choking symptom in park exists when the MAF is unplugged. However when I brought it to a stop and then tried to accelerate it didn't do the same choke I described earlier. Acceleration was smooth. Maybe I need to drive around town more with the MAF unplugged.

The acceleration choke only happens 10%, park choke only happens 1% of the time when the MAF is hooked up correctly....

Sounds like this might be my issue. Contact cleaner was already sprayed on the MAF sensors, I suspect that's all CRC MAF cleaner is. Any other other cleaning techniques?

Should I go in and try and clean out the throttle body like albertj said? I feel like that might be extreme. Just don't want to have to buy a brand new MAF.

If it runs about the same, you likely have a bad MAF sensor. I'm not sure what contact cleaner is, but anything besides specifically MAF cleaner should not be used. At any rate, another MAF sensor is worth a try.

Albertj,

I just bought the throttle body and air-intake cleaner by CRC along with there MAF cleaner. The TB cleaner says to not use on supercharged cars. I'm assuming the mean not to spray it on there when installed. I will be removing the TB to clean.

Unless there is another cleaner out there that is made of them.

The TB cleaner that says that i should not be used on supercharged vehicles can cause damage to the coating on the supercharger rotors. It will work great on the throttle body, but it just needs to be removed, which is a good idea anyways, because it is easier to clean the back side of the valve with it removed.

Yes I will be removing the TB. I think the warning was geared toward users who were keeping it in place and just spraying in there.

werdstrave wrote:

Albertj,

I just bought the throttle body and air-intake cleaner by CRC along with there MAF cleaner. The TB cleaner says to not use on supercharged cars. I'm assuming the mean not to spray it on there when installed. I will be removing the TB to clean.

If you re-read my post I said/wrote to get a TB gasket and remove/clean the TB.

Even if you could leave the TB on, don't. If you do, you'll never get the back side clean and it will still run like poopy.

Albertj

Yup. Last time I questioned you I replaced my entire front end only to find out my cradle bushings were making the noise. So, I think I'll take your advice.

On a completely unrelated topic, do you know what/where the "instrument cluster" is? I'm chasing "low coolant" light that's always on and my manual says to trouble shoot some "instrument cluster connectors". I will repost in another thread if need be.

Oh...I guess that's the speedometer and what not....ugh, taking apart the dash is such a PIMA

Alright, I got the throttle body off and have been spraying it with this cleaner....looks a little better.

Question, is it possible to spray something through the supercharger? When I look in there, there's tons of carbon build up.

If not, how would you clean that baby up? I bet it would have a lot more kick without all that build up in there.

.. just read this thread. (Don't run around with a 95sc with the MAF unplugged!! There is no MAP sensor to take over like the series 2 has!)


Regarding the TB cleaning, I hope you removed your MAF from the TB before spraying in TB cleaner or you will have killed it.


Don't spray anything at all into the SC. The carbon in there is actually good. It tightens up the tolerances between the rotors and where the rotors touch the casing. This improves effecency of the blower.


While you have things apart, provided you didn't kill the MAF, gently clean the wire in the MAF sensor with a Q tip and rubbing alchol or electronic contact cleaner/MAF cleaner. And when I say gently, i mean it.

Karma wrote:

(Don't run around with a 95sc with the MAF unplugged!! There is no MAP sensor to take over like the series 2 has!)

my bad for suggesting that - it's a standard technique troubleshooting S2 MAF sensors.