A Hard Start Conundrum...

[Mattr165]

First, to get the technicalities out of the way, I just recently acquired an 87 (N/A) and I have:
- Replaced plugs (NGKs)
- Replaced wires (ditto)
- Replaced most of the smaller vac tubes
*I haven't replaced the cap and rotor yet...

Now the problem:
I'm having severe issues starting with a cold engine, as in several (sometimes as many as 5) minutes of crank, turnover but no catch, pause (cuss), repeat. Once she fires up, I have no idling problems, no hesitation, no smoke of any kind, and no problems starting on a warm engine. If it sits and cools, however, I have to repeat the process (above). I'm assuming it's most likely a fuel delivery issue as there's spark (obviously, since it runs), and if I spray some starter fluid in the intake, it'll fire right up...

Any help would be greatly appreciated!
I've done my homework and searched the forum, promise; can't seem to find anything/one with ONLY a cold start problem.

 

[jetjock]

Probably far out there but have you checked the cold start injection system? And codes? Like maybe a 43?

 

[Mattr165]

I've not done either of those things, but [I'm guessing] if it were the cold start injector, it'd have to be stuck closed? Given that I'm not running abnormally rich. I, unfortunately, don't have a code scanner, but I'm replacing the fuel pump, filter, and pressure regulator within a week, so if that doesn't clear it up... Out of curiosity, what would a 43 indicate?

 

[Dirgle]

Since you're fairly new to Supras here is something your going to refrence a lot with an older car.

Toyota Supra Repair Manual

And one of the first things you're going to learn about when diagnosing engine problems on the supra is to pull the codes. It's a complex motor and the codes will point us in a direction. You can find how to pull codes and what 43 means, here:
Engine Error Codes

P.S. The only thing you need to pull the codes is a paper clip and the ability to count like a certain vampire from Sesame Street.

 

[Mattr165]

I have the TSRM, but I appreciate the Error Code guide; I also forgot to mention that I've not had a CEL on at any time whatsoever, so I feel like an error read is unlikely? But, I'll definitely check that out once finals are over... Thanks!

I might have to watch some reruns of the Street just to make sure I can handle it :biglaugh:

 

[Dirgle]

That's a good start, a lot of people begin with a Chilton's or Haynes and create true chaos before they find the TSRM. Most of the codes get stored in memory and don't leave the CEL light on once the malfunction clears(such as 43), but you can still pull them to see whats going on.

Don't forget the "HA...HA...HA.." after each number.

 

[Mattr165]

First, thanks to all for all of the help so far. Jetjock, you might actually be a mad genius as I pulled the codes this evening and it was a 43! My only question--this car has an aftermarket starting system (the security system went out on it like many of the other older Supras) so it's a hardwired push-button start. Could that be the reason for a 43? Or could it be the ECU which is the other error area for a code 43? And a hearty thanks to Dirgle as the diagnostic guide was beyond helpful.

 

[D.J.T.]

First, thanks to all for all of the help so far. Jetjock, you might actually be a mad genius as I pulled the codes this evening and it was a 43! My only question--this car has an aftermarket starting system (the security system went out on it like many of the other older Supras) so it's a hardwired push-button start. Could that be the reason for a 43? Or could it be the ECU which is the other error area for a code 43? And a hearty thanks to Dirgle as the diagnostic guide was beyond helpful.

He IS a mad genius.

 

[jetjock]

Neither genius nor mad. I just understand how the car works. Fix the 43 (make sure terminal STA at the ECU gets 12 volts when cranking) and check the cold start injector and thermal time switch. Since it also gets power from the starter circuit odds are both problems are related. Fix that and the engine will get the cold start enrichment it needs from both sources. And yes, Dirgle is a class act. Smart, polite, and patient. Along with a few others we're lucky to have him.

edit: Nice of the OP to provide enough information to support a diagnosis. On the other hand omitting a "minor" detail like a severely hacked starting circuit was no bueno. 10 lashes...

 

[Mattr165]

JJ, will do. I appreciate everything once again, and I'll be sure to punish myself appropriately haha

 

[Dirgle]

Thanks for the complement JJ, it means alot. To the OP the ECU probably never gets an STA signal because you probably never push the key over to START while cranking. Considering how most people bypass the alarm/starter, you probably turn the key to run, and the push your button to turn the starter over. They probably ran a wire down to the starter and unplugged the original wire from the harness. The best place to start is by fixing this. Ditch the push button start, fix the reason it got installed inthe first place, and your code 43 and hard starts will follow.

 

[Mattr165]

Dirgle, that's exactly how I get the car to run, my only question: this car has been a push-button start for the last 5-7 years, and it's never had this problem before now--if it were related to the push-button start, why would the problems just crop up now?

 

[Nick M]

Dirgle, that's exactly how I get the car to run, my only question: this car has been a push-button start for the last 5-7 years, and it's never had this problem before now--if it were related to the push-button start, why would the problems just crop up now?

Because the aftermarket unit has fell to entropy.

 

[Dirgle]

Because the aftermarket unit has fell to entropy.

Indeed.

Dirgle, that's exactly how I get the car to run, my only question: this car has been a push-button start for the last 5-7 years, and it's never had this problem before now--if it were related to the push-button start, why would the problems just crop up now?

To answer this we would need to know more about the push button start. What make/model is the aftermarket unit. Was it professionally installed? How is it wired.

 

[jetjock]

this car has been a push-button start for the last 5-7 years, and it's never had this problem before now--if it were related to the push-button start, why would the problems just crop up now?

Because something broke. That's what working things do, they break. They don't get better with time. It's why I'm always amused by the "but it worked yesterday" crowd.

Maybe it's a CSI or TTS issue. Maybe it's unrelated to your pushbutton although everything points to it. Only by troubleshooting will you learn exactly what happened and all this hypothesizing can be dispensed with. Besides, what difference does it make? Quit "anal-yzing" and fix the car so it works. That's the desired result isn't it? Either put it back to stock or create the equivalent conditions. Stop making this more complex than it needs to be.

 

[7MAce]

I have been having a similar hard start problem the last week or so where I am having to crank the engine 4-5 times before it finally catches and fires, then it dies, I repeat the starting process and after 2 or 3 sputtered dying attempts it fires up, idles out, and runs just fine, same issue where it starts just fine when warm it is only when I leave it for more than 6~ish hours does it not want to start the right way. I just had a cel pop on this morning but I have not had time to run the Diag on my super monitor yet, when I get home from work I will run the codes and share my findings but just thought I would see if there is any input to the issue before getting those codes, I have also started to notice the rushing water noise coming from behind the dash this morning, first time I have experienced this as well, from my findings this morning I am seeing that this is likely caused by exhaust gasses building up in the coolant system? I did a recent tune up on the car, new plugs, wires, cap, rotor, valve cover gaskets, cold start injector and a few other small things. I do not have a push button start, just factory system, though since I have began to think about it the PO installed a Viper alarm system that included a remote start function as well as keyless entry, if that may have something to do with it. Hate to thread jack just looking for more information on a similar problem

 

[7MAce]

Got it worked out today, code was for temp sensor, sure enough the coolant sensor had deteriorated around the base and one wire broke when I touched the clip, replaced that and notice the clip on the EGR thermal time switch looked off, pulled it off and the innards of plastic crumbled to the floor, I have it secured in now and no long have the starting problem, but I have to locate a harness that has a good clip on it to cut off and use, or my other option is replacing the whole harness.

 

[jetjock]

That would be the CSI thermal time switch but yeah, those failures jive with your symptoms. Especially the coolant sensor. An open circuit there results in a default of about 180 F, hence no cold start enrichment...