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does the computer need to clear after an IAC cleaning and remount?
That's what I'm wondering since reinstalling my old one had the same symptoms as the new one.
That RPM cycle I posted sure looks like learning, but I'm not pulling it to find out. It shouldn't go on for long if it is a learning cycle.
That RPM cycle I posted sure looks like learning, but I'm not pulling it to find out. It shouldn't go on for long if it is a learning cycle.
mine still does the 2000 drop to 1800 cycle. I have a FPR inbound tomorrow. see if that fixes it. it is running rich after a run and then park
I got the new FPR today and that made a huge difference with idle stabilized and in performance in the low RPM range until it got HOT. Then the same symptoms as previous. We had checked out ohms on the IAC/ISP and a through cleaning yesterday. Maybe the resistance changes when it gets HOT? I'll try the IAC off the 91 FJ80 mañana.
what does the IAC do exactly? I can't quite deduce it from the hoses.
what does the IAC do exactly? I can't quite deduce it from the hoses.
anyone know why there is coolant flowing through and below the IAC/ISC? mine starts to fail once the 80 gets HOT. So maybe that IAC motor gets hot and starts to fail even though the OHMs are correct when cold????? I'm thinking of bypassing the coolant flow through it. Those clamps are a bitch to get on and off anyway. any thoughts out there?????
and what is this thing telling to what when it gets hot? PN 89422-35010 Water Temperature Sensor
and what is this thing telling to what when it gets hot? PN 89422-35010 Water Temperature Sensor
Sounds like you're on the right track.
ppc
M Go Blue
Coolant is routed through the throttle body is for cold weather performance and initial warmup. When the engine gets up to temp that coolant flow has little impact as there is significant heat transfer from the engine up through the intake that could effect the IAC and TPS. Rerouting the coolant flow would at best be a temporary bandaid.
replaced the ICV/IAC today after the FPR yesterday. The idle in Neutral lolling down the hill would still drop from 2000 to 1800 repeatedly. It runs a lot better at low RPM and I was able to pass a Prius coming back up the hill from the creek starting at 30 MPH which it wouldn't do previous to the FPR install. Pulled into the driveway idle dropped to 650 and she stalled and didn't want to start up. BTW, i bypassed the coolant hose that runs through the ISC/ IAC. I think that made a difference once it got hot.
There has to be a temp sensor that is controlling the fuel flow or something to make it keep doing this in spite of everything else we replace.
Anyone know which temp sensor that might be? I'm at the insure it to the hilt and drive it into the creek stage. This has been a nightmare since i bought it.
There has to be a temp sensor that is controlling the fuel flow or something to make it keep doing this in spite of everything else we replace.
Anyone know which temp sensor that might be? I'm at the insure it to the hilt and drive it into the creek stage. This has been a nightmare since i bought it.
Well...I have dropped to rough low idle when cold, like 400, and then yesterday it dropped and stalled out on cold start. So I'm not out of the woods, either, although once hot mine started holding idle, albeit still a little low. It was also a warm day last week when everything righted itself after the IAC install/fuel system cleaner/fresh tank of gas.
For now I'm going to keep driving it through another tank and see if I can pick up any other common elements before I replace anything else. I'm tempted to go ahead and replace the TPS, but with it testing out I'm wary that this is just doing PM on good parts.
For now I'm going to keep driving it through another tank and see if I can pick up any other common elements before I replace anything else. I'm tempted to go ahead and replace the TPS, but with it testing out I'm wary that this is just doing PM on good parts.
I replaced every sensor and vacuum line on my old '93 Isuzu Trooper. This process made a huge difference in driveability, but the TPS was still causing problems. I replaced it again with a $40 part vice $20. Solved my troubles.
Just trying to relay my experiences.
Just trying to relay my experiences.
I'll have to give it more time - when this first arose for me, it ran perfectly except stall at sitting idle. So I can't say for sure yet what temps do or don't mean, but appreciate the idea and will take a quick peek.
I only bypassed the coolant through the ISC, still going through TB. The ISC has a motor and motors generally don't run all that well HOT even though the OHMs are correct cold on the bench. It was worth the 1' of fuel line and 2 extra clamps
well it kept developing a bad miss after the head job that got worse every day. drove it uphill for about 15 mi the other day and the head blew again about a mile from the driveway. I'm giving up on that 92 and do the sheet metal job on the 91 with a low mileage good engine. should have gone that way to start with. but now I know a lot more about these 3FEs. the 92 is now a $5K parts truck
- Thread starter
- #78
Sorry to hear that things went south on you.
Ouch. Sorry to hear it.
My story continues. Stall when cold, holding very low rough idle at 400 RPM when hot - around 175F. Drives perfectly normal under throttle. I am just going to take the TPS off the table.
To the readers here generally, Is the EFI temp sensor the same unit that will report engine water temp to the OBDII? I have a ScanGauge II and temp readings are perfectly normal. I'm not going to mess with that route at all if there isn't a separate sensor component that could be affecting the electronic control systems.
Edit: I just bought the temp sensor, too. Might as well go through all of this stuff at 22 years and 235K miles.
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