- Thread starter
- #121
I've considered removing the PAIR. Refresh my memory, are there 3 main grounds? I've replaced the links.
No More High Idle on Cold Start
- Thread starter harrydunn
- Start date
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There's only two that run from the battery. One on the inside of the fender, just beside the battery. The large one is on the block, just behind the starter. You can see it from the battery.
The PAIR on mine needed to go. I have a cool air intake and isolating box, so I had to put a breather filter on the PAIR. My truck farted all day with that thing.
The PAIR on mine needed to go. I have a cool air intake and isolating box, so I had to put a breather filter on the PAIR. My truck farted all day with that thing.
- Thread starter
- #123
Do you have a link to the larger cables here on Mud? I'm curious to take a look at them.
Thanks.
Thanks.
Here you go. They were very well made and substantial. I got the negatives from him. I already had the positive from the now defunct ACC.
FJ80 Heavy Duty Battery Cables
Once I looked at the post, I realized I told you wrong. There are two cables that run from the battery to grounds. Then there is one other ground strap in the kit (head to firewall).
FJ80 Heavy Duty Battery Cables
Once I looked at the post, I realized I told you wrong. There are two cables that run from the battery to grounds. Then there is one other ground strap in the kit (head to firewall).
- Thread starter
- #125
Well, I'll at least remove the grounds tonight and take a look at them. I know which two you're talking about. Easy enough to get to.
My 94 starts at 38%IAC and drops down to 36% by the time the ETC is up to 87F. Fully warmed up I have yet to see it below 23-24. I would say your IAC looks low...
- Thread starter
- #127
From the beginning of this thread my money was on the IAC or ECT sensor. I’ve had 3 different known good IACs on it and no change. Quite baffling.
- Thread starter
- #128
I suppose it’s possible that I didn’t leave the swapped-in IACs in long enough but doubtful. I left the first two in for a few days each. This just screams IAC though and any low cold idle thread on any car forum you browse is typically fixed by a cleaned (or new) IAC valve or a new ECT sensor.
******* I can’t wait to read the ending to this multi-year tribulation. I don’t even have this problem and I read all 100+ posts just to see how happy you were when you resolved the problem. But alas, we all must wait. Godspeed dude, really. (Btw I also have a Tundra in addition to my 80s - and knock on wood I’ve never had any issues with it. Even so I still love my troublesome 80s more)
The reason I happen to know my IAC history is that I am chasing an occasional low idle myself. As far as answers go, I don't have any, sorry. But.
My idle was iffy (exact low idle you seem to be experiencing - the hand throttle is a sucky solution to this problem, by the way), and several years ago I replaced the headgasket, cleaned everything up, replaced a bunch of stuff - and no dice. The 'mud consensus was "let the computer learn and you'll be fine". Not *really* (or at least not always), in my case. What usually seemed to help, paradoxically, was shutting the vehicle down, unplugging the TPS, starting the vehicle up and letting it run for a bit, shutting it down again, and plugging the TPS back in (as per: Low idle after disconnected battery). The CEL doesn't stay on, but there is a record of a TPS code in the computer. Not saying it's a solution - just a different thread with different advice, in case you haven't seen it.
In my case, it is ECU related inasmuch as once it's fixed (however I manage to do that), it stays fixed until power to the ECU is lost. Currently, the vehicle is idling fine and I have the IAC values I mentioned above.
My idle was iffy (exact low idle you seem to be experiencing - the hand throttle is a sucky solution to this problem, by the way), and several years ago I replaced the headgasket, cleaned everything up, replaced a bunch of stuff - and no dice. The 'mud consensus was "let the computer learn and you'll be fine". Not *really* (or at least not always), in my case. What usually seemed to help, paradoxically, was shutting the vehicle down, unplugging the TPS, starting the vehicle up and letting it run for a bit, shutting it down again, and plugging the TPS back in (as per: Low idle after disconnected battery). The CEL doesn't stay on, but there is a record of a TPS code in the computer. Not saying it's a solution - just a different thread with different advice, in case you haven't seen it.
In my case, it is ECU related inasmuch as once it's fixed (however I manage to do that), it stays fixed until power to the ECU is lost. Currently, the vehicle is idling fine and I have the IAC values I mentioned above.
- Thread starter
- #131
Were you dealing with a cold start low idle or a low idle when warm or both?
Both. The cold start low idle specifically is what I started with. In my case, the wiring (grounds, etc), the harness, the vacuum lines, the air intake, the intake manifold, etc., etc., were all perfect after the overhaul. The starting idle would come back *every* time the ECU lost power.
The occasional low idle when warm is a new phenomenon and possibly unrelated.
The occasional low idle when warm is a new phenomenon and possibly unrelated.
- Thread starter
- #133
Poking around with the TPS a bit this afternoon. Surprisingly, when I unplugged it and started it it ran fine which wasn’t surprising but what was surprising was that it never did set a CEL. I would have thought that would have set a CEL immediately.
Another thought, if I had to sum it up, is that it’s as if my 80 starts in “learn” mode each morning but never learns. There is no difference in cold start RPMs whether I’m starting it for the 1st time or the 101st time after disconnecting the battery or pulling the EFI fuse.
Another thought, if I had to sum it up, is that it’s as if my 80 starts in “learn” mode each morning but never learns. There is no difference in cold start RPMs whether I’m starting it for the 1st time or the 101st time after disconnecting the battery or pulling the EFI fuse.
Looking at your video with the TOYOBD reader, is it normal for the timing to be that low when it's cold? -7 or -8? Seems like it should be higher. I'm asking, I don't know what the mapping is on one of these engines. Has the timing been verified, I couldn't find if it was in the thread.
I'm guessing the "A/C" flag (on the INJ screen) is inverted? You mentioned that your A/C works and affects idle as it should. Would you mind confirming that inverting the flag makes it behave appropriately (my A/C compressor needs replacing, so my A/C flag never changes).
Another video-related question: does the IDL flag on the TPS screen behave properly (goes away when you step on the gas, comes back immediately when off the gas and stays on continuously - I'm guessing that is the expected behavior)?
Another video-related question: does the IDL flag on the TPS screen behave properly (goes away when you step on the gas, comes back immediately when off the gas and stays on continuously - I'm guessing that is the expected behavior)?
Hmm. Currently, my idle is behaving and I am seeing (on my '94) -21°-18° for timing immediately after a cold start (45°F OAT, 300' AGL).
That’s why I was asking, I don’t know how it’s supposed to act. I just find it odd that the timing would be retarded at idle. Must be an emission thing.
- Thread starter
- #138
Keep in mind, mine is only revving 775 at cold start so the timing would be correct for that RPM which is essentially idle RPM. Something doesn’t know the engine is cold. Here’s a photo of mine warmed up at idle.
- Thread starter
- #139
Here is a friends ‘94 OBD1 80-Series at cold start. Functions correctly.
Except for the fact that both of these voltages look a lot higher than mine (I have a retrofit Tundra alternator - different regulator, I guess) and the fact that I don't have any VAF readings most of the time, this looks remarkably like mine. I never see a 49% IAC when off, but then again I never see the 10% IAC that you have either.
