Open/Closed Loop Question

[russgill]

Car starts fine but if you just let it run it will die, I need to keep the accelerator down and run at 1500 rpm or there abouts for about 3 and 1/2 minutes until the temperature gauge hits 140, it then drops into closed loop (solid dot on Scanmaster). When this happens I am good to go.

Is this normal?

We have had some very cold weather here in Florida


Thanks

 

[Smokin-6]

Are yout TPS and IAC numbers where thay should be? (Mine warm at idle- TPS .42 and IAC 20-30, this is a normal range) What chip do you have?

 

[russgill]

TPS 42 and IAC 55. Chip is Turbo Teak 5.6

Thanks

 

[TurboBuRick]

I would remove the iac and clean out the passage.

Also check for vac leaks.

Like already mentioned 20-30 is a ideal range for a warm motor @ idle.

HTH

 

[pacecarta]

tt runs open lop until temp reaches 140

you can go before then and all should be ok as the blms will control the fueling based on how you.'ve been driving
but doesnt hurt to let the oil come to temp before womping on it


when you get to operating temp if iac is still at a little high (or over 30) you could turn the iac set screw near the throttle blade in to open the throttle blade slightly , that will drop the iac count # , you may find the tps over .44, if so reset that

www.vortexbuick-etc.com has te procedure for setting tps and iac

 

[russgill]

I'll run her around this morning and double check the readings. I'll be back

Thanks

 

[Timbuick]

I have a 5.6 chip and my car will idle right off the button even at freezing air temps (like today!), so something sounds like it may be out a little on adjustment.

 

[russgill]

Drove it around and then when good and warm came up with TPS 42 IAC 44. It idles at a BLM of 142, which I know is high, we've replaced vac lines, had a cracked manifold (drivers side)we replaced. Just a bunch of stuff. I am going down on Wednesday to my buddies garage and we'll get the IAC and TPS in line and see what that does for us.

I'll report back then.

Thanks

 

[Timbuick]

Let me know what you find! My car has idle BLM at 43 as well, although i;ve found vac leaks at the PCV valve grommet and injector O rings which I have ordered. My IAC is around 36 at idle in Park. Seems very similar to your car at present.

 

[russgill]

Tim,
You said your BLM at idle was 43, did you mean that?


Russ

 

[pacecarta]

cold weather will also drive the blm up
bumping fuel pressure up a pound or two would bring it back down but theres really no need as the blms are well within range for the ecm to adjust and it has

 

[Timbuick]

Sorry, meant to say idle BLM at 42 which is only at hot idle. Slightest touch of throttle and it goes back to 128. Eric told me that his chips will max out at 42 which prevents over fuelling in this situation. Like you, I need to find the vac leak that is causing high BLMs.
I removed the vac pod and sealed the TB and the BLM dropped to around 35.
I belive this indicates a vac leak. I then reconnected and sprayed carb cleaner at the PCV valve grommet and a few of the injector bases. The idle increased by 500rpm when the cleaner hit the PVC connection and slightly less when aimed at the injector bases.
I have ordered the replacement O rings/grommet.
Might be worth you trying the same tip.

 

[russgill]

Thanks. Will give it a try on Wednesday.

 

[russgill]

I am back. Did not get to everything we had planned, full pay customers, the discount guys like me get what's left over. Did not get to all the vac stuff (Next Wednesday) but we put a new fuel pressure regulator on we then took his computer on and compared the readings to the Scanmaster and the master was dead on. Was always concerned that reading might be off on the master. We dialed the car in on the TPS to 42 and the IAC to 25 (all full warm 180 degrees), I then took her out and she really fell on her face. Almost died and backfired. We plugged off one hose on the regulator to see if that was the problem had went out again, still the same deal. We put the TPS up to 54 and put the IAC at 48. Went again and everything cleared up and it idles smoother than ever before (when we had it close to or in spec, it always idled like it had a cam) We decided to leave it that way and see how it goes and make adjustments next time. Here is where we are now at warm idle

AF now 8 was 5 (I guess this make sense as the RPM's are up)
L8 now 48 was 42
BL now 142 was 142 (thought maybe a new pressure regulator might help)
TPS now 54 was 42
IAC now 48 was 44
RPM now 900 was 750

What do you guys make out of this?


Tim,
Still cannot understand your BLM's at 42 and mine at 142 at warm idle.

Here is what I think I read/saw some where:
Raise fuel pressure brings the BLM down (how the heck do you raise the fuel pressure anyway?)

When BLM's are down put the TPS and IAC back in spec and you should be ok

Have I over simplifed this?

Thanks