Toyoland: Toyota car and truck forums

Hello to all,
I have a 87 Camry 2.0 5 speed and have a problem with the idle dropping low when I start the car ONLY after it is extremely hot (been traveling far).  The weird thing is it only does it intermittently and it can easily be fixed by either giving the car a lot of gas (revving up the motor) or turn the car off (or let it conk out) then restart the engine.  Okay so I am giving up here the following is a list of what I have done to fix the problem.....
egr valve replaced & cleaned, egr valve solenoid/modulator inspected and tiny filter replaced, all vacuums lines inspected visually and by hand thoroughly, sensors i.e. tps and numerous others unplugged while the engine was running to test them and make sure they were working properly.  In addition throttle body cleaned thoroughly, pcv/hose/tube cleaned & replaced.   So again I am perplexed here as to what to check next or where to look?  Can someone please help/advise me here and what to look for next and what they thing it might be.  I am sure someone on these forums has had it happen to them or something similar look forward to hearing from you thanks.
Dave

Too low of an idle when hot - most likely EGR, TB, or vacuum issue - but it sounds like you hit them first.

Things to double check:

- vacuum leak (spray suspect hoses, unions, base of components with some very lightly soap water, soap acts as a surfactant, allowing hte water to caot the suspect part.  If the idle improves after you spray something, you found the leak source - could be a leak too small to be visually detected)
 
- fuel pressure regulator may be operating at too low a pressure (put a pressure gauge on the fuel log and see if the pressure stands up, could also indicate a dying pull pump)

- Idle speed set incorrectly (probably not much you can do about this, I believe that model year is fuel injected, so idle speed is set by the computer)

- ignition system problem (check cap, rotor, distributor, plug wires, sparkplugs, ignition coil - this generation had some \"hot\" coil problems)

- check compression to determine engine condition

- fuel injectors may be dirty or dying

- check the throttlebody idle air circuit, may not be functioning properly (turn on A/C, see if idle speed jumps - it should, if not, circuit could be clogged)

Thanks very much for all that info.  Okay the Distributor is new whole unit 1 year old.  Here is my thoughts please concur with me and give me your advise on this.  I have a 90 Honda accord that did this and it was the fuel main relay.  The solder joints were bad only when it got extremely hot outside.  So replacing the fuel main relay was the fix.  Do you think the Toyota might have the same problem or similar?  Do you know if the Toyota has a fuel main relay and if so where is its location?  Please advise me here thanks.

Oh btw I can\'t do the fuel pressure test as I don\'t have the equipment or know how to do that.  Can you advise me as to what the car would do if the fuel pressure regulator would go bad?  Why would the car\'s fuel system work fine when the car is cold and only not work properly when the car is hot?  Please advise me thanks.
Dave

For the fuel pressure regulator, same manner that the you had with the Honda - at higher temps, connections can be broken or shorted.  Either through the main wiring, connection, or the component itself.  

With intermittent issues, really tough to fix them unless you get lucky.  Toyota main relay is under the hood - should be a fuse panel on the driver\'s side fender.  There should be a silk-screen diagram under the cover of the fuse/relay box.  You also have an intergration relay inside the car - though if something is amiss with that - you\'d have other electrical problems.

I\'d start ruling possible culprits off the list - only good thing going for you is that the symptoms are related to idle after a hot-restart.

Hello thanks for the info tell me where the fuel pressure regulator is located on my car please if you know.  Do you think I should replace that or test it?  How likely do you think its that?
DAve

Not 100% sure on your car, but it would be either close to the fuel pump or on the fuel rail itself.  This car uses a return style fuel system circuit, so the regulator could be inline anywhere in the circuit.

I\'d test the regulator before you replace it - as there is a strong chance the regulator is perfectly fine.  

The apparent fuel starvation issue when restated hot could be from something as simple as vapor lock - or gasoine that is so hot, that it vaporized before it gets to the fuel rail.  Pretty common on older carburated engines.  Or from air being sucked into the fuel line from some point.  Car has no way of knowing how much fuel got injected - it only now how long to cycle the injectors and for how long - if fuel comes out or not, doesn\'t matter.

Interesting I did not think of that.  You are correct I will monitor the situation more and see if it does it again.  The good news is I took apart the entire throttle body, IAC, and TPS.  I ended up replacing the TPS, and since the IAC spring felt a bit stiff I replaced it with another IAC from salvage yard off a 89 Celica (same motor) with 109k that had a much more looser spring.  I am thinking that this spring opens up when the car is hot not sure exactly what it does or purpose.   At any rate with a STIFF spring that means 1 of 2 things its really new and stiff (my car has 170k so that is not option) or 2 something is causing the spring to be stiff.  So I went ahead and replaced it with the IAC with loose spring from celica.  Since that time the car has not acted up and done the starting problem however it has not been hot enough for me to test it either.  It must be hot at least 84f and I must really drive the car  alot.  So hopefully I fixed the problem by doing/replacing all those things.  I will let you know once I can test it when it gets hot enough.  Thanks for your help and if you can think of anything else let me know.
Dave

Okay now I am getting very PERPLEXED HERE.... I tried a lot of stuff still the same problem I am running out of places/things to check on this car. I completed the job of cleaning & replacing the IAC that is NOT THE PROBLEM. The car is still doing the same thing. Now before I do anything else I will be asking many ? \'s on here as I have done a lot of work for NOTHING..... Okay so here is my next suspect and question for you guys/girls. Would a dirty/clogged Fuel Filter cause/make the idle drop (only when car is hot) after starting the car when its hot? If a dirty fuel filter would not cause/make the problem with idle dropping then there is not point in checking/replacing it so please advise me on this question thanks. Next ? to all what do I check next I am running out of ideas on here guys PLEASE HELP.
Dave

Generally - a dirty fuel filter will choke the car at higher speeds (higher demand for fuel will show any restriction in fuel flow)

For something that happens only on a hot restart - that sounds more like a bad ignition coil or ignition system.  Vacuum leak seems to fit the description better - but hard to say without the car infront of me.  I think this generation also had a cold start injector - but I\'m not 100% sure.  That also seems to cause some idle quality issues.

Did you notice any slop in the throttle plate inside the throttle body?  Too much slop in the plate could leak extra air, that will shift your idle speed.  Happens all the time on my old carburetors - principle is the same for fuel injected systems.

Hello there,
Thanks for getting back to me.  No slop that part is okay i cleaned it and put it back together that is fine.  I concur about the fuel with you.  The coil and distrubitor is new and I justed checked them today with ohm meter they are fine.  Running out of ideas or places to look.  Cold injector should not effect the car on hot start.  Vaccum leak perhaps I already looked though everything looks fine.

You\'ve pretty much turned over every stone on this problem.  Not much else to check other than to double check the parts that you\'ve repalced.

I\'ve seen brand new EGR that are faulty out of the box. Same with ignition components - but it sounds like you rang those out pretty well.

Really does sound like a vacuum leak - might need to use the propane trick to verify.  Some shops run a propane torch (turn on the gas, not lit) around vacuum hoses and possible vacuum leaks while the engine is running.  If they run past a leak, the engine RPM will surge, due to the propane being pulled into the engine and combusted.  Not suggesting that you wave a propane torch at the engine, but shop might have someone that is familiar with that technique - highly combustible gas around a hot engine = potentially bad situation.

Interesting test thanks for your input and help.  I did double check the new distributor it is fine.  The only thing left in which it could be is vaccum leak, fuel pressure regulator, or fuel pump.  Not sure I will wait until the car does the problem again.