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To see if the injectors are getting pulse or to see if the cold/warm coolant sensor is working properly at the ECU?
I just meant to get a resistance measurement across those wires at the ECU. The injector pulse reference was my situation, and how they were telling me to check it.
What I'm getting at, is if you're getting a wildly different reading at the ECU than at the injector, you probably have a wire issue.
Ok I've been fighting a bad cold and on top of freezing temps here lately -2F last night(my garage heater can only do so much) I will try more diagnostics tonight.(with photos)
Ok I've been fighting a bad cold and on top of freezing temps here lately -2F last night(my garage heater can only do so much) I will try more diagnostics tonight.(with photos)
How can I check if the Coolant sensor for the ECU is functioning properly and giving the ECU the right signal(bottom circle). As in probe the ECU and see the difference both hot and cold? Hot water read out in a cup? already checked that.
This is the Sensor that is not hooked up to anything (top circle). But my gauge cluster in the dash is fried anyways so this should not have an effect on no hot start, although I will connect the blue wire for the 4WD and the Original(broken) wire for the gauge to it.
If there is a wire for it, go ahead connect it.
The temp sender for gage is hard to see/access, it is below the intake manifold and have been mentioned many times in forum. Please see THE OTHER hard warm start threads.
Thanks for the comprehensive photo, Rick!
Here it is below labeled:
Wired to THW on ECU (from RasaLibre's photos):
FSM ha procedure for checking THW at various temps.
Last edited by RAD4Runner; 02-07-2018 at 10:39 AM.
Ok so tonight I'm going to town with my multi-meter. those that have been following, especially you RAD4Runner,what piks of the readouts you are needing to help diagnose the issue or tips on what to look for. I plan on checking CSI time switch hot and cold and also ECU temp wires and the sensor itself. Also might drop the gas tank to see if the screen is clogged at the fuel pump. but I think that would affect fuel pressure and my pressure is fine.
Last edited by YotaRick27; 02-07-2018 at 10:45 AM.
Ok so tonight I'm going to town with my multi-meter. those that have been following, especially you RAD4Runner,what piks of the readouts you are needing to help diagnose the issue or tips on what to look for. I plan on checking CSI time switch hot and cold and also ECU temp wires and the sensor itself. Also might drop the gas tank to see if the screen is clogged at the fuel pump. but I think that would affect fuel pressure and my pressure is fine.
Sorry, I haven't had the chance to crawl down there to take measurement because my issue is very intermittent, and idle smooths out as soon as I leave my parking spot
Will take a photo of FSM page as soon as I can.
I Really doubt that you have fuel pressure issue. It would be nice to use an electrical sender to fuel pressure read-out on dash for that.
If there is a wire for it, go ahead connect it.
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This could be a temp switch(for AC), or a temp sender (for the dash). You do not want to mix them up, similar to putting the oil pressure switch on a oil pressure gauge(sr5 cluster swap), bad things happen..
TSW ( the temp switch ) to the tccs ecu has a different style plug and housing. It is central located and has a round body that encloses it.
Here are some kind of crappy photos, to the rear is TSW signal for tccs ECU, the front is the AC cut off switch.
ignore the grungy old engine here.. At the far bottom right is the AC temp switch wire. This runs between location 3&4 in the wiring diagram layout.. (,think that is in jnky's thread?)
Knew I had answered this somewhere in detail. Give me awhile and I can probably/maybe dig up what TSW signal actually does, it is kind of an important signal for the ECU and shouldn't be left loose..
Originally Posted by Co_94_PU
Here is the pictures from the wiring book.
Also the A/C one is not part of the EFI harness, the A/C cowl harness follows along side the EFI harness and goes under the throttle body near the THW sensor wire. The TSW is part of the EFI harness and exits the loom under the plenum near the aft injector wires and gauge temp sender.
It is part of the fuel pressure up vsv activation. It also uses THA (intake air temp) in the calculation (which explains why unplugging the vafm effects your start up).
So there might be light at the end of the tunnel! I will attach both 4wd sensor and the coolant temp sensor to the upper radiator inlet housing. And see if anything changes. (praying this is it) hopes are low due to all other failures...I'll have to pull the intake yet again to get that other wire out of the harness.
So there might be light at the end of the tunnel! I will attach both 4wd sensor and the coolant temp sensor to the upper radiator inlet housing. And see if anything changes. (praying this is it) hopes are low due to all other failures...I'll have to pull the intake yet again to get that other wire out of the harness.
pretty sure your TSW wire is AWOL, its the one that needs hooked up, but that's the wrong sensor for it.
(From memory, the AC switch closes when hot, the TSW temp switch closs when cold, again not sure off hand. Either way it won't be set for the correct temperature)
In one of these threads is the diagram from an 86 FSM (see I've done gone and forgot if this is an 88 or 86). You want to verify you have the fpu vsv, and what signal it received under which circumstances.
The redneck fix is to put a toggle switch. In the air sensor line, at the ECU for TSW, or for the fpu vsv..
A simple test would be temporarily bypass the vsv to trigger the higher vacuum in the regulator.
Yeah I know that feeling, I'm sure a floppy high pressure fuel line isn't a safety concern right?... You might recognize that lovely shade of Colorado mud everywhere, that's the motor the po installed as I was pulling it.
My truck is a 1986 but I do not see a 4WD temp sensor. Maybe an auto transmission one may have i
Only the temp sensor on top of tstat housing, and definitely does not affect dash gage, so more likely a sensor to do with AC. Maybe to shut AC down when engine's too hot?
My truck is a 1986 but I do not see a 4WD temp sensor. Maybe an auto transmission one may have i
Only the temp sensor on top of tstat housing, and definitely does not affect dash gage, so more likely a sensor to do with AC. Maybe to shut AC down when engine's too hot?
According to the 86 FSM and a continuity check on my 5Speed 87. The switch on top of the thermostat housing is TSW water temp switch, 4WD only.
My stab at it would be a bad ground at E2 (high resistance to ground at E2) when engine is heat soaked. Possibly bad connections similar to how your injector wiring was. E2 is tied into the AFM, TPS, and THW (ECU water temp sensor.)
02-07-2018, 08:51 AM
