Is there any way I can get my engine into closed loop faster?
Its very cold now in MI and my car takes forever to get into closed loop mode. My idle is horrible in open loop and it stalls occasionally in open loop.

Thanks

Matt

 

You'll need a heated oxygen sensor, and a
custom PROM with all the CL settings changed
to enable at a lower coolant temp..

mike

 

I thought about the prom but my car is a '85. My engine is a '89 305 TPI but I still have the '85 ECM and harness. I can't find anything on custom chips for the '85 ECM's.

Thanks,

Matt

 

Your going to have a hard time Finding any info on burning PROM's for the 85 ECM.

Your best bet would be to upgrade to a 86-89 165 or even *gasp* Speed Density

 

Just try the heated O2, if you do a search you should find the part number fairly easily.

nick

 

Bort62--I have a '86 harness and ECM off a 350TPI but I was told the harness is not interchangable, the connectors are different, it won't work with my trans and my guages(speedo mostly). I can get a '86 speedo but it won't work because of the VSS(or my lack of). Is this right or was I told wrong?

89BlueTA--Where do the 2 extra wires hook up to? The 3 wire works the same as a single wire only its heated, right? Would there be any problems once my temp gets to normal or when its 90+ in the summer(o2 sensors can't overheat can they?)

Thanks,

Matt

 

The heated O2 will get it swinging faster,
but the PROM has minimum coolant temps and
minium delays that must be met (or changed)
before CL is enabled.

The '85 TPI system can be programmed, but
most chip companies are abandoning it because
it was a one-year-only system and the
upgrade to the '86-'86 system is well
documented... 8-)

mike

 

Do you know who still programs '85 chips? Do you know how to program '85 chips? I don't have the equipment but I'm pretty good at programming, I'm kicking @$$ in my AP C++ class at school. Chip burning probably has nothing to do with C++ though.

Thanks,

Matt

 

I think a heated O2 will solve most of his problems, or atleast is worth a try. The other two wires are just 12V keyed power and ground. And will have no negative side effects.

The coolant is going to come up to temp. no matter what, unless the thermostat is stuck, and if it is not then he could cover some of the radiator.

nick

 

Ummmm - NO it won't ... or, did you clearly not read the info that Mike put forth about the PROM parameters?

Tim

 

Wrong. Pay attention:

The ECM in his case samples engine coolant temp and goes closed-loop when temp meets the configured value. The ECM has no way to sample O2 sensor temp.

Going to a heated O2 sensor is not going to do squat to get the engine to closed loop quicker, unless somehow the O2 sensor heats coolant (it doesn't). A heated O2 sensor will not solve the problem he posted.

A block heater will do the trick. These replace a freeze plug with a 120VAC heating element...plug it into the wall and it will warm the coolant, bringing the engine up to temp quicker in the driveway.

 

THere is no reason you cannot use the 86 harness in an 85 car.

Furthermore, there is no reason to use the 86 harness as you can easily repinn the 85 harness to the 86 ECM w/o any problems.

You car does have a VSS, and your speedo Is cable driven so it will not effect it.

AS far as the Closed Loop thing, A heated O2 is only useful because going into closed Loop before the O2 reaches operating temperature would give improper readings.

The Heated O2 is nessicary to make the earlier closed Loop function properly, but has no effect on how fast the car goes into closed Loop.

Programming in C++ or any other language will help you on some leve just because you know how the processes work. However, wont have much practical application as the tuning aids at our disposal are all very user friendly and very Point and Click.

 

Thanks for the advice. I do have a '86 ECm so I will probably update. I need to know how though. It needs to be quick, cheap, and easy.

Thanks again,

Matt

 

idling the car will still reach operating temperature in no time. a car can still overheat in freezing weather idling with no fan (saw it happen a few weeks ago to a friends car) the current non heated o2 sensor takes a while to be ready for open loop, so thats probably what you are "waiting" on for it to go into closed loop. you need to get into the prom to change what temp your car goes into closed loop, but the o2 has to be "ready" and the heated one will get it there faster.

 

I know idling will work but right now my car won't idle for more than 5 minutes. It is very low(600-700) and it sorta dies out. I got a new IAC or idle speed control motor as autolab calls it and now it won't idle very well in closed loop. Granted, the reason I took it in was it would die right after starting. They have my stop screw out so far I can see the threads and when the engine is warm it idles around 1000-1100 rpm in park, a bit much don't you think?

Thanks

matt

 

Wrong again. Adding a heated O2 will not change how quickly it goes into closed loop. As Mike already indicated - there is more to it than coolant temp and getting the actual signal swinging. There are minimum delays set in the PROM.

Tim

 

ROFLMAO at people who don't burn chips and have no idea how the ECM code works trying to theorize on what can help his situation when the ONLY correct (and complete) answer was given in the first response.

 

Hehehe

 

When the computer is in open loop do any of the sensors get checked by it or do any of them send signals to the ECM. Or does the ECM run the entire show until closed loop comes?
Also, any danger in running the car at 1500-2000 rpms while in neutral to get the engine warm?

Matt

 

In open loop the ECM is still looking at everything, even the knock sensor. The only thing the ECM doesn't do in open loop is use the O2 sensor for feedback. The ECM injects fuel based strictly on the MAF / MAP tables and other sensors.

As for running the engine at 1500-2000rpms to warm up, no thats not necessarily bad, as i'm sure you know that's what the fast idle cam in a carbed car does when on the choke. I wouldn't rev it straight to 2k immediatley on start-up, but after a few seconds to let oil get to everything you'd be OK