Help! Car Will Not Start! Running Out Of Ideas

[camer0nn]

I have a 1990 Toyota Celsior which was running fine apart from stalling when starting cold.

Currently the car will fire but wont run. It revs up and then dies.

So what I have done

1. Firstly I began by replacing the coolant temp sensor. It still ran after this but still stalled when cold.
2. Got given a replacement IAC valve (with a different part number but was assured it would be okay) so I installed it. The car would not start with the new IAC valve in and just clicked like a flat battery but I had loads if juice and even tried jump starting of another vehicle - no luck.
3. Replaced the IAC valve with the original one. Tried to start but still clicked like flat battery. I hooked it up to another car and managed to get it to jump start. Took it for a spin around the block, parked back home and then it wouldn't turn off. I removed the coil pack to kill it.
4. Since putting the coil pack back on it will not start. I bought a new IAC valve (with the correct part number) and installed it. Car will still not start.
5. I checked the codes and came back with a 51 - switch condition signal but don't really think this is the cause of the issue.

Where to now?

I thought perhaps that because I put the incorrect IAC valve in that I possibly have done something to the ECU? Can this happen

My next best guess is to replace the ECU but I would like to know if anyone has better suggestions to try first? Any help is greatly appreciated.

If it helps I can fire up the car and upload a video of it trying to start so you can hear and see for yourselves.

[curiousB]

1. Firstly I began by replacing the coolant temp sensor.

   It still ran after this but still stalled when cold.

2. Got given a replacement IAC valve (with a different part number but

   was assured it would be okay) so I installed it. The car would not start

   with the new IAC valve in and just clicked like a flat battery but I had

   loads if juice and even tried jump starting of another vehicle - no luck.>>>

   can you start it with a light foot on the gas pedal? The IAC just allows

   some air to pass throttle plate to idle the engine. You can simulate this

   with a light pressing of the pedal.<<<<

3. Replaced the IAC valve with the original one. Tried to

   start but still clicked like flat battery. >>>> you have

   either a dead or weak battery or loose/corroded connections to it. You

   need to fix this under any scenario. You shouldn’t need to jump start it.

   I would get this resolved and start knocking off issues rather than

   dealing with them all concurrently<<<<< I hooked it

   up to another car and managed to get it to jump start. Took it for a spin

   around the block, parked back home and then it wouldn't turn off. I

   removed the coil pack to kill it.>>>>>why did you do

   this?!?!?! Couldn’t you just turn the key off? Seems like you broke a

   connection doing this or have a loose/dirty wire/connection. I’d get some

   contact cleaner spray and clean up connections and retry. Back off on the MacGyver

   methods and get a little more organized<<<<<

4. Since putting the coil pack back on it will not start.

   I bought a new IAC valve (with the correct part number) and

   installed it. Car will still not start>>>>The IAC isn’t the

   reason you aren’t starting. That is a red herring. IAC modulated idle

   speed. Try the light pedal approach and get it running before you dive

   into the IAC issue<<<<<

5. I checked the codes and came back with a 51 - switch

   condition signal but don't really think this is the cause of the issue.

Where to now?

I thought perhaps that because I put

the incorrect IAC valve in that I possibly have done something

to the ECU? Can this happen >>>>>>>>>>>not

likely, I would park this theory to the side for

now<<<<<<<<<<<<

My next best guess is to replace the

ECU but I would like to know if anyone has better suggestions to try first? >>>>>>>>>>>bad

guess. Try the items above first. Fix battery, get engine running by sorting

out the coil pack problem, then go after IAC issue. ECU is expensive and you

haven’t done any diagnosis that suggests it’s a good candidate to change out.No

need to drop a lot of $$$ on a hunch. Be patient and methodical. Report back

once car cranking reliably and if engine starts or doesn’t with a light foot.

We can take it from there. My guess is you aren’t getting spark on at least 4

cylinders due to your coil unplugging mishap.<<<<<< Any help is greatly appreciated.

You may have a fuel problem too but you have to get it back to at least starting for a moment before jumping into that one.

[KeyKeeper]

If the car would not shut off with the key, I would suspect an ignition relay or a faulty ignition switch. I may be mistaken, but normally cars have higher voltage to the coil packs during starting. This is achieved with a dual relay approach. One relay is for higher voltage during starting, the other is for run condition. However, this may be off a bit.

[camer0nn]

Hey guy (@curiousB) thanks for your response - greatly appreciated.

1. The car was running with me applying a little gas. I was doing so to keep the revs up to stop the car stalling. Once it was warm it ran fine. This is why I thought to replace the IAC valve and coolant temp sensor (to stop the cold stalling).
2. I tested the volts, had 12.5v, cranked the terminals up tight still no go. I will try a different battery to eliminate the battery as an issue.
3. ^ Again will check with new battery and ensure terminals are well taken care of. As for the coil pack, when I got back home and turned the car off it was still running with key out of ignition and in hand. Will check contacts.
4. ^^^ Should be okay when it fires again.

I contacted an ECU specialist and he said he would take a look at it for free, so will do that anyway given the offer. Once I get it back I will work through your great suggestions and see how I go. Will also get a recording of it firing if no luck so you can see and hear for yourself

Thanks heaps for your help. Will keep posted

[fsuguy]

Hi,

As CuriousB says, check the battery thoroughly first - all other bets are off if your battery is going south, since the electronics and electrical circuitry are dependent upon the correct voltages.

[curiousB]

1. The car was running with me applying a little gas. I was doing so to keep the revs up to stop the car stalling. Once it was warm it ran fine. This is why I thought to replace the IAC valve and coolant temp sensor (to stop the cold stalling).

A damaged ECT sensor is typically open circuit or infinite resistance. The ECU will see that as cold engine and adjust fuel mix to richer to get it running and warming up. A warm sensor is more closer to a short circuit (100-300 Ohms reading).

So the symptom I would expect for you is that it starts easy when cold (since ECU thinks engine is cold when it is) but starts very poorly when warm (cold ECT reading makes ECU send too much fuel to warm engine and floods it). You have the opposite which is strange. Maybe by some fluke you have a shorted temp sensor although the typical failure mode is to blow like a fuse and go open circuit.

http://www.autozone.com/autozone/repairguides/Lexus-GS-SC-1998-06/Coolant-Temperature-Sensor/Testing/_/P-0996b43f80382b2a

A voltage reading on an unloaded battery doesn't mean too much. What is voltage under some load? Turn on headlamps with engine off. Does battery sag to very low voltage? That can mean weak cells and/or poor connections. Undo battery connections and clean up all mating surfaces with wire brush. Reconnect and ensure clamp bolts are good and tight. If you can wiggle the connector then they aren't tight enough. Starters draw a couple hundred amps, you won't pass that kind of current on a loose connection. If the connection cleaning doesn't help any it points to the battery. Anyway worth a few minutes effort to try the clean up connections before dropping $100+ on a battery.

No harm in an ECU test if it is free. I just wouldn't buy one yet given the preliminary state of diagnosis so far.

[camer0nn]

Okay, So I got the ECU back - no fault.

I have gone back to basics for a car to run, air, fuel and spark. I have air and spark but when I removed one of the banjo bolts on the fuel rail (key to turned to ignition position) no fuel came out. The fuel pump was not making any noise so I removed it and ran 12v across it. It worked. So somehow there is now power getting to the fuel pump when its in the car? I ran a multimeter over it while in the car and there was zero current passing across the terminals.

I have yet to test the fuel pump relay but not sure where it is. Also do these cars have immobilizers? I'm wondering if I have somehow activated it (I don't have the key with all the buttons on it) and now can't deactivate it.

Have had the battery out the car and it charges to 14v and holds about 11.85v under load

[fsuguy]

Hi,

The FP relay should be on the passenger side inside the engine bay on the right wheel cover, if the '90 is similar to the '92. It will be coverred by a black plastic cover that you can remove easily. You may have a test ODBC under the hood that will allow you to test the FP by jumping a couple of connections - look up the lexls site for how to do this. You may also have a FP resistor in the same place - check your connections for any loose ones.

A couple of things to check are the fuel filter - if it is blocked/clogged you may not be getting fuel; also, any loose connections to the Fuel system; I am guessing that since the car was running, but has since refused to run, your filter may be clogged, or a wire has come loose! Your battery is still suspect, unless you have a new one. I would eliminate the obvious problem areas first and for all components to function correctly you need a good battery.

Hope this helps.

[camer0nn]

Found it, have removed the relay but don't really have any way I can test it (or know of). Might take it into the local auto sparky.

I don't think that the fuel filter is the issue as the pump isn't going when wired into the car. I will check the connections related to the fuel system and see how I go.

Getting close to having to call out an auto sparky to fault properly.

[camer0nn]

Car has been to an auto sparky now. I got it back ($400 later!) They got the fuel pump going again but it would seem I'm not back to a couple of steps ago. The car will start, splutter and die. I can't get it to stay running. They also informed me that there is no issue with the battery.

They recommended that I take the car to a tuner. I don't know that that will help me get the car firing. I don't know where to from here at this point. Will have a look at other posts but I'm open to suggestions and when I get round to it will put a vid up of it starting and dying.

[fsuguy]

Hi,

Sorry I cannot be more specific with which thread it was, or when, but if you can, try to find a post by Landar - he has listed an excellent series of steps to eliminate various issues; basicaly divide the possibilities into fuel, and spark, then methodically eliminate each possibility one by one till you find the culprit/s.

Hope this helps.