Cold Idle & Off Idle stumble

1fastGN

New Member
Joined
Oct 20, 2003
Hello All,
I am a new GN owner and need some advice!

I recently purchased an 86 GN w/ TE 44, V4 IC, .030, 206 cam, etc, etc...and I notice that when the car is cold, it idles really rough, and seems to want to die. Also, when driving the car (at any temp), when I step on the gas, it seems to hesitate a bit, stumble, then runs okay.

I have a scanmaster and Directscan, but I am not sure what values to look at in order to troubleshoot my problem (O2 volts, IAC, BLM, INT, etc).

I guess what I'm saying is I have the tools, just don't know how to use them. Any advice is greatly appreciated.
 
When I first bought my national my idle would change dramitically, bounce from 600 to 1300 rpm's but i changed my chip from the one the guy i bought the car from put in there to a correct 93 street chip well correct for what i have done to the car, you might also want to check out your tps sensor...
 
Set your TPS to 0.42v, set your IAC to less than 20 counts. Is the throttle passage and IAC passage clean? Sometimes debris or oil will keep the throttle blade from closing all the way to the correct setting. Who's chip are you running? What injectors are you running. Is the O2 switching once the engine is in closed loop? What are the BLMs and INTs readings at idle (in closed loop)?
 
Originally posted by 1fastGN
Hello All,
I am a new GN owner and need some advice!

I recently purchased an 86 GN w/ TE 44, V4 IC, .030, 206 cam, etc, etc...and I notice that when the car is cold, it idles really rough, and seems to want to die. Also, when driving the car (at any temp), when I step on the gas, it seems to hesitate a bit, stumble, then runs okay.

I have a scanmaster and Directscan, but I am not sure what values to look at in order to troubleshoot my problem (O2 volts, IAC, BLM, INT, etc).

I guess what I'm saying is I have the tools, just don't know how to use them. Any advice is greatly appreciated.


Couple of other important missing bits of info that would help us.
What injectors and what chip.
 
The injectors are 55# and the chip is a street chip, created by Neal Steward (who was located in the Southern California Area).


--Ryan
 
Hmmm, I know Neal's reputation for chips so your problem probably isn't in the chip. As others have said, check/verify your TPS and IAC settings.
 
Thanks TurboDave.

Two questions:
1. The previous owner changed the FPR from stock to adj, while I was there. He said there was a trick to getting it to seat properly. If it was not installed properly, could this cause idle probs?

2. He also swapped the stock MAF for an Imp. SS MAF w/Translator while I was there. If there was a leak around the MAF, could this cause the prob?

I just got my DS to work with WIN XP, so I'll post more info in a few days (ie TPS, IAC, etc).

--Ryan
86 GN
 
Originally posted by 1fastGN
Thanks TurboDave.

Two questions:
1. The previous owner changed the FPR from stock to adj, while I was there. He said there was a trick to getting it to seat properly. If it was not installed properly, could this cause idle probs?

That likely wouldn't have an impact on your problem. More likely would cause a fuel leak.

2. He also swapped the stock MAF for an Imp. SS MAF w/Translator while I was there. If there was a leak around the MAF, could this cause the prob?

It could ver well have an impact.

I just got my DS to work with WIN XP, so I'll post more info in a few days (ie TPS, IAC, etc).

--Ryan
86 GN
 
http://www.gnttype.org/techarea/faq/IACresetscan.html

Try this site out. Also seeing that you are new to the turbos, the tech area offers a lot of specific material.

Adjusting the IAC helped my car tremendously. Start there first, then look else where.


The above link may be to reset. There is also a page to adjust using a scan tool, now that you have yours working.
 
Ryan,

It sounds like you might be the fella that bought Larry's GN. Give me a call and I'll see if I can help you out. My # is (858) 495-0145 and it's best to try and catch me between 10a.m. and 2p.m. M-F.

Neal
 
Hello Neal. You are correct. I bought Larry's car a couple of months ago. I am located in Northern CA.

I will definitely give you a call. I don't think there is anything 'wrong' with the car...maybe just some tuning that I am unaware of.

--Ryan
86 GN
 
The Translator settings are as follows:

Base (0)
WOT (0)
Switch 1 and 2 - ON
Switch 3 and 4 - OFF
 
I would check your vacuum lines before I did anything. These cars are ALWAYS spitting them off here or there. Check for age and zip tie all your connections....it probably won't help but it will make you feel like you accomplished something. :D
 
I would check your vacuum lines before I did anything. These cars are ALWAYS spitting them off here or there. Check for age and zip tie all your connections....it probably won't help but it will make you feel like you accomplished something. :D
 
I think the number 3 switch should be set to on, unless you are using the extender chip.

The other thing I would do is while the car is running try changing the first knob setting to see which setting the car responds well to. I had the same problem as you until I did this and it fixed my problem. Maybe when I made the change on the settings the key was not on?? I can't remember anymore.

Dannyo
 
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