up and down

[blackbird]

hi, i have a problem and i hope someone has some light to shed.
my car has that up and down idle when i start it up, i changed the cat out but not the o2 sensor, also i tend to shut off when its not warmed up well. how long do i have to warm up for?? the previous owner put a ford heated o2 sensor in it, should i just put it back to stock?? thanks for any help

 

[BlackBuick84]

I'm not sure how bad the idle is, but these engines dont idle very well. How long have u had it? If you got it recently, it may be that you're not used to it yet. Otherwise, i have no idea.

What part of chicago are you from? My GN is in the northwest suburbs.

 

[Rollin]

Moving to tech....

 

[blackbird]

great lakes, illinois

ive had it for a year n a half, i havent spent too much dough on mods cause ive been puttin my money into just keepin it running. if its not the brakes its the tranny or the engine.

 

[crs]

Up/down idle

I have been dealing with that same annoying up/ down idle for about 5 months. I've tried cleaning my IAC, but it didn't help at all. I thinking of getting a brand new one. Does your car die sometimes when you put it into gear after start up or is it fine?

 

[Danster]

I've read before on this board that surge up and down can be attributed to oil pressure rising up and down. Check your oil pressure to make it's stable.

Dannyo

 

[Tow Man]

That up and down idle is just a characteristic of the stock chip and some aftermarket ones as well!

If you have stock injectors, go with the thrasher chip! It's the best $25.00 you'll spend on your car Jim Testa's chips also idle very well! These are the only chips I have used so far and both are very good. Oh yes, there was that Red Armstrong chip that went in the garbage can

Replace whatever chip you have in it, then adjust your TPS and IAC and enjoy the smooth idle and no stalling

 

[blackbird]

small world

my car does die sometimes when i put it in drive, i found that letting it warm up till it stops up and downing helps avoid that. according to postons catalogue a heated o2 sensor will stop the up and down. i ordered one but could not install it cause the previous owner jury rigged a heated ford sensor. also i do notice the oil pressure changing, how would i adjust that?? when i get my mitts on some cash ill go with the thrasher chip, hopefully soon. i was racing a 944 the other day and i felt the car lurch and made a loud banging sound, its running good now but i dont dare kick it up until i find what it is...any ideas?? thanks guys

 

[scottyb]

Originally posted by Tow Man
That up and down idle is just a characteristic of the stock chip and some aftermarket ones as well!

If you have stock injectors, go with the thrasher chip! It's the best $25.00 you'll spend on your car Jim Testa's chips also idle very well! These are the only chips I have used so far and both are very good. Oh yes, there was that Red Armstrong chip that went in the garbage can

Replace whatever chip you have in it, then adjust your TPS and IAC and enjoy the smooth idle and no stalling

Ditto that.

I never had the hunt idle problem, but always had the tip-in stumble, sometimes stall on cold start. The Red Armstrong was better than the stocker, but still stumbled bad when cold. I installed a Thrasher 92 last week. All stumbles are completely gone. It's like a different car, much smoother all around driving, no knock at 18 lbs on 93, and faster spool.

 

[striker_29]

Do you have a scantool? Are the Iac counts and tps in range?? Thats where I would start, good luck.

 

[crs]

oil pressure change

Blackbird, How is your oil pressure changing? Is it working like a RPM gauge, or is it fluctuating when driving? About the heated O2 Sensor, that might be a good idea if Postons recommends it. I just ordered my thrasher 92, so i will give that a shot and see what happens. Keep us updated about your problem!

 

[Tow Man]

I think your oil pressure fluctuation is caused by the up and down idle speed, not the other way around!

Oil pressure increases with higher RPM and decreases with lower RPM. It's your irratic idle that's causing your oil pressure fluctuation.

Trust me, the Thrasher chip will smooth it right out! Make sure you have an adjustable FPR set to 45 PSI line off, and make sure your IAC and TPS are set to spec.

Not sure about the banging sound Describe the sound and exactly what happened and when.

 

[blackbird]

more questions

where can i purchase a thrasher??
no scantool yet, what does iac mean?? and how do you adjust the tps??
my oil guage fluctuates, im under the impression that the guage might have a short in it.
tow man, i cant describe the sound too well but it felt like a thump when i hit the gas, i hope i never get to hear it...again

 

[crs]

Thrasher Chip

You can buy a Thrasher Chip from Scott231@gnttype.org. Go to Gnttype.org to find out about the Idle Air Control Valve, which is located under your throttle body pipe, and TPS adjustment. It should be under maintenance topics.

 

[blackbird]

more probs

just got done changin the oil, accessory belt and o2 sensor, so far so good with the sensor, starts right up with no up and down! i emailed scott for a thrasher. when i changer out my belt i found that the tension pulley moved around a bit and made a clicking noise, so i guess i just found another expensive problem. i bought a fuel pump relay but i couldnt find it on the car. thanks for all your advice guys, im glad for your help.