driving w/ no hac sensor?

Insidious Surmiser

Insidious Surmiser

Formerly 89jdm7m
May 12, 2006
2,172
0
0
Oceanfront
Just trying to verify the issue i have w/ my motor. I have a 87 n/a supra. It has a 89 turbo motor, and 87 wiring harness and ecu in it, but I don't have a hac sensor for a 87 turbo, since the donor car was a 89. The car ran fine in greensboro, NC earlier today (roughly 800ft above sea level). Today I had to drive to virginia beach (at sea level) to go to school. Half-way there from north carolina my car started running really rough, and sounds like it misses at idle. The ecu also throws code 32 only.

Cliffs: 87 turbo car w/ no hac sensor. drove fine 800 ft above sea level, drives terrible at sea level. Throws code 32 only. (HAC sensor)

Is it fair to say I need to find a HAC sensor?
 
jetjock

jetjock

creepy-ass cracka
Jul 11, 2005
9,439
0
0
Redacted per Title 18 USC Section 798
In theory the symptom should be unrelated to the missing HAC sensor because 1) 800 feet is peanuts and 2) HAC is a trim sensor. Even more noteworthy is the TCCS fail safe default for an open or shorted HAC sensor is 760 mmhg. That's sea level pressure. I could tell you how to get rid of the code but you really ought to find a sensor for when you go high.
 
Insidious Surmiser

Insidious Surmiser

Formerly 89jdm7m
May 12, 2006
2,172
0
0
Oceanfront
well, i got a sensor, and the car still runs like shit.... too bad i've no idea what i'm lookin for:dunno:

it's got a terrible miss at idle, and rough as hell :(
i'll be looking into it further here in a bit...
 
Insidious Surmiser

Insidious Surmiser

Formerly 89jdm7m
May 12, 2006
2,172
0
0
Oceanfront
GrimJack said:
At the risk of repeating myself, check your codes, plugs, and wires.
Click to expand...
I did

no codes
wires were between 13-21k ohms
coils were all at 1 ohm (toyota says .3-.5 ohms is the correct range)
plugs were normal

:dunno: let me know if any of that sounds off

i'm really clueless here, but i'm sure as hell not done investigating, because i havn't found the problem.

Also, when I had an exhaust bung put in my downpipe, it was welded crooked. I had to cut my downpipe in half so I could get it on and go back to school. I was already 2 days late. So, i'm running a bic ddp about a foot long on a stock ct-26. I tried to have a shop fix it before I left, but they wouldn't touch it because "it's in the area the catalytic converter is supposed to be".
 
3p141592654

3p141592654

90T
Oct 11, 2005
3,819
20
38
Thousand Oaks, CA
OK, but the tests you did seem to show the coils/wires were okay, and your said the plugs looked fine. I guess I am wondering what the evidence of ignition problems is? I think at this point you really need something like a scope trace of each plug to verify all is well. Also, the ECU has some diagnostics for bad spark built in to the igniter as JJ has described in his TCCS section but no codes are coming up. Of course, ignition problems can still occur that the ECU will not catch.

If it was me I would do some simple checks to confirm that it is not a mechanical or fuel issue at this point.
 
Insidious Surmiser

Insidious Surmiser

Formerly 89jdm7m
May 12, 2006
2,172
0
0
Oceanfront
I'm also running 1-2 ft. of a bic dowpipe right now, on a stock turbo. Long story short, I had to cut it in half to get it on the car. I tried to get it repaired before I went back to school, but the guy wouldn't touch it because it was where the catalytic converter was supposed to be. Let me know if the car should even run like this.
 
jetjock

jetjock

creepy-ass cracka
Jul 11, 2005
9,439
0
0
Redacted per Title 18 USC Section 798
It should run OK like that unless you have a leak near the O2 sensor. Does it run better when cold? Take a look at the O2 sensor signal. You could also put a timing light on each plug and watch for the misfire or measure the temp of each exhaust runner. Try to ID whether it's one cylinder or a global problem. Does the engine have any aftermarket electronics on it?
 
Insidious Surmiser

Insidious Surmiser

Formerly 89jdm7m
May 12, 2006
2,172
0
0
Oceanfront
jetjock said:
It should run OK like that unless you have a leak near the O2 sensor. Does it run better when cold? Take a look at the O2 sensor signal. You could also put a timing light on each plug and watch for the misfire or measure the temp of each exhaust runner. Try to ID whether it's one cylinder or a global problem. Does the engine have any aftermarket electronics on it?
Click to expand...
I'm in class right now, so i'll probably go out in the shop in a minute and see if I can investigate it further. I'll probably check the O2 signal first then put a timing light on it.
 
Insidious Surmiser

Insidious Surmiser

Formerly 89jdm7m
May 12, 2006
2,172
0
0
Oceanfront
jetjock said:
Class and shop? As is automotive school? If so you should have all the stuff and talent ever needed to quickly solve this. Am I missing something?
Click to expand...
Nope, like I said, i'm not done looking for the issue. All of my spare time has been spent looking for the issue, and I cannot find it.
 
You must log in or register to reply here.
Top Bottom