Cold Start and Warm Up Idle Questions

[JDMMA70]

Every morning when i go to start my car say to pop down the road for some milk or something, when i crank my car the first time it seems like its about to start but then dies right after. Then i crank it a second time and it starts fine, it did this before and after i did my head swap. Anytime after i get it to start it will start fine unless its been sitting for about four hours, then when i go to start it, the car will start but somewhat rough and somewhat struggle to bring itself up to idling speed in this case, 1100rpms and after the car warms up again it will drop to 650rpms. What can cause the car not to start on the first time, ive got no vacuum leaks, i was thinking maybe my fuel filter needs to be changed, but i wanted opinions first maybe there are other things i can check.

My next question deals along with the warm up idle speed, on all the Supras ive seen they seem to hold their warm up idle speed at 1500rpms, im wondering if its ok that mine starts at 1350 then drops to 1200 fifteen seconds later and then just drops to 900 after about a minuete and a half. I figured it was because where i live its so humid and hot but then that doesnt explain where my friends Supras all hold their speed steady.

Im uploading a video from when i starting my car 15min ago first time today.


Thanks
~JDMMA70

 

[Nick M]

You can check the cold start injector time switch. It closes when it is cold. The circuit does the same as a choke on a carbureted car. You only need it to make that first cold start.

Oh yeah, it should be open when hot, grounded when cold. Go to the manual.

 

[grimreaper]

depending on your climate as well, toyo has produced a new tts for the csi, it allows the use of the csi in a larger range of temps. stock wont activate with coolant above 70-80 degrees and the new one will activate up to 130 degrees of coolant temp. this is from jeff at champion in houston (think thats the right dealer) $80 for the new swtich and if you still want the orginal one, its over $100 for it new.

 

[tekdeus]

My car has the same problems starting after sitting overnight, after it has cooled off. It can be in a warm garage, but still it takes 10 seconds of cranking and pumping the pedal to get it started. Once started, it's fine, and restarts very easily when warm.

I've read that the cold start injector is inoperable above 70 degrees, and many don't even need it. Is this true? I've solved the Code-43 Starter signal code I was having, but I still have this problem. What else could it be?
Mods: Stock ECU, Lex AFM, 550's, SAFC. Runs great, just hard to start when not warm.

 

[Rennat]

My car has the same problems starting after sitting overnight, after it has cooled off. It can be in a warm garage, but still it takes 10 seconds of cranking and pumping the pedal to get it started. Once started, it's fine, and restarts very easily when warm.

I've read that the cold start injector is inoperable above 70 degrees, and many don't even need it. Is this true? I've solved the Code-43 Starter signal code I was having, but I still have this problem. What else could it be?
Mods: Stock ECU, Lex AFM, 550's, SAFC. Runs great, just hard to start when not warm.

didnt you also remove the VSV's from under the intake manifold?

my cold start rpm's are 1500 for a few seconds, then drop pretty quickly after. but i have my TB coolant and ISC coolant lines bypassed. so if yours are bypassed like mine, then that would explain it.

 

[johnathan1]

I had the same cold start problems for a LONG time...time switch was working properly, wiring to cold start time switch and cold start Injector was fine. I pulled the CSI out and cleaned it, didn't help. Finally I replaced my CSI with a good used one, and now my car starts flawlessly when cold.

I would remove your CSI, clean it up with brakleen (they get super sludgy and gunky due to the EGR system)...if that doesn't fix it, then it may need to be tested and/or replaced.

 

[johnathan1]

My car has the same problems starting after sitting overnight, after it has cooled off. It can be in a warm garage, but still it takes 10 seconds of cranking and pumping the pedal to get it started. Once started, it's fine, and restarts very easily when warm.

I've read that the cold start injector is inoperable above 70 degrees, and many don't even need it. Is this true? I've solved the Code-43 Starter signal code I was having, but I still have this problem. What else could it be?
Mods: Stock ECU, Lex AFM, 550's, SAFC. Runs great, just hard to start when not warm.

You probably have the same issue as the original poster...

Also, pumping the pedal while cranking will not help at all.

 

[tekdeus]

I had the same cold start problems for a LONG time...time switch was working properly, wiring to cold start time switch and cold start Injector was fine. I pulled the CSI out and cleaned it, didn't help. Finally I replaced my CSI with a good used one, and now my car starts flawlessly when cold.

I would remove your CSI, clean it up with brakleen (they get super sludgy and gunky due to the EGR system)...if that doesn't fix it, then it may need to be tested and/or replaced.

When you had the problem, was it still hard to start when the outside temperatures were 70-80 degrees? I'm just wondering if the CSI injects fuel at each non-hot start, or just when it's quite cold outside. Because even in the middle of summer, if my engine is not warmed up, it's very hard to start.

 

[jdub]

When you had the problem, was it still hard to start when the outside temperatures were 70-80 degrees? I'm just wondering if the CSI injects fuel at each non-hot start, or just when it's quite cold outside. Because even in the middle of summer, if my engine is not warmed up, it's very hard to start.

The system is based on coolant temp...OAT is as cold as it will get after a sit. Read post #3.

 

[JDMMA70]

I got a video for you folks to see

10am this morning 36'F, so i guess we can say its my CSI

 

[jetjock]

Looks like a cold start enrichment problem alright. Either the CSI isn't working or the starting coil in the Circuit Opening Relay isn't coming on. Try jumpering B+ and FP (with the key on) for 10 seconds prior to a cold start. If the problem goes away check the STA circuit and COR. If the problem remains check the entire CSI system.

 

[JDMMA70]

Looks like a cold start enrichment problem alright. Either the CSI isn't working or the starting coil in the Circuit Opening Relay isn't coming on. Try jumpering B+ and FP (with the key on) for 10 seconds prior to a cold start. If the problem goes away check the STA circuit and COR. If the problem remains check the entire CSI system.

Just went outside and did this its now 30'F and lightly snowing, i stuck the pin in with my shivering hands, and waited 15 seconds and attempted. Same problem as before. So when you say check the entire CSI system, that included the CSI itself as well correct? If so im going to see if i can get another and try it out to see if that solves the problem.


Thanks
~JDMMA70

 

[jetjock]

30F? Come on, it's Houston....

Yeah, that includes the CSI itself. You could get another one but it'd be better to pull out the one you have and see if it sprays. Or put a test light on the thermo time switch (TTS) connector or the CSI connector itself. If there's voltage there during cranking odds are the CSI is plugged or the coil is open. You can check the coil with an ohmmeter. If there's no voltage you'll have to look at the TTS or the cranking circuit that powers the entire setup. Have you tried enriching it yourself to see if that helps? Shoot some starting fluid or carb cleaner into the brake booster fitting. Could be the coolant sensor too....

 

[JDMMA70]

30F? Come on, it's Houston....

Yeah, that includes the CSI itself. You could get another one but it'd be better to pull out the one you have and see if it sprays. Or put a test light on the thermo time switch (TTS) connector or the CSI connector itself. If there's voltage there during cranking odds are the CSI is plugged or the coil is open. You can check the coil with an ohmmeter. If there's no voltage you'll have to look at the TTS or the cranking circuit that powers the entire setup. Have you tried enriching it yourself to see if that helps? Shoot some starting fluid or carb cleaner into the brake booster fitting. Could be the coolant sensor too....

Its cold enough for me when youre wearing sweatpants and a tank top. When i pulled my head i took the CSI out and it was dirty, i didnt do the spray test then i shouldve. As for the Coolant Sensor its brand new, i guess i could try another. My CSI Time Switch clip is pretty much broken and falling apart, im thinking it would be wise to get one of those too. I havent tried enriching it myself yet i think ill do that tommorow morning before i head of to a friends house. The brake booster line fitting as for that, where exactly is it? Im thinking its on the intake manifold on the rear?

Thanks
~JDMMA70

 

[Nick M]

I have used old fashioned, highly flammable, carb and choke cleaner on Toyota cold start injecotors before.

 

[jetjock]

^ Me too. Works well on the outside but a real cleaning involves flowing solvent through it or using ultrasonics, which is what I do.

OP: Now that I read your first post again I doubt it's the coolant sensor because cold idle is high. I'm a bit curious as to why the ECU doesn't seem to be asynchronously firing the injectors but that's not important right now because if the problem turns out to be a lack of STA all the problems will go away when you fix it.

The booster port is on the rear of the manifold. If manual enrichment helps your best bet is go through the CSI system. That connector would be a good place to start.

 

[3p141592654]

I had my CSI cleaned by RC engineering along with the main injectors. Probably a waste of money living in So Cal!

 

[tekdeus]

I solved my problem today! It was the code-43 problem after all (ECU is not getting a signal that you are trying to start the engine). I got this code a while ago, so I made sure that the original starter circuit was getting a signal (it was cut at the steering column to install a hot start relay). The code never came back after I reset the ECU, but I still had the problem, so I figured it was something else.

But I decided to find out for sure by checking the STA wire at the ECU for 12v when I turn the key to start. I found it was not getting a signal, and traced the circuit to find the problem, which in my case, was the clutch pedal switch.

JDMMA70, I suggest you check your codes to see if code 43 comes up. Even if it does not, connect a voltmeter to the STA terminal of your ECU and see if it is getting voltage when you turn your key. If it does not, then that is your problem. My car had the exact same symptoms as yours. I beleive it has nothing to do with the cold start injector at all.

Cheers - Brad

 

[JDMMA70]

I solved my problem today! It was the code-43 problem after all (ECU is not getting a signal that you are trying to start the engine). I got this code a while ago, so I made sure that the original starter circuit was getting a signal (it was cut at the steering column to install a hot start relay). The code never came back after I reset the ECU, but I still had the problem, so I figured it was something else.

But I decided to find out for sure by checking the STA wire at the ECU for 12v when I turn the key to start. I found it was not getting a signal, and traced the circuit to find the problem, which in my case, was the clutch pedal switch.

JDMMA70, I suggest you check your codes to see if code 43 comes up. Even if it does not, connect a voltmeter to the STA terminal of your ECU and see if it is getting voltage when you turn your key. If it does not, then that is your problem. My car had the exact same symptoms as yours. I beleive it has nothing to do with the cold start injector at all.

Cheers - Brad

Forgive me if this sounds like a dumb question but where is the STA terminal? Im assuming thats the TTS on the Thermostat Housing? http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=112 Also my car is auto if that makes a difference.


Thanks
~Derek

 

[tekdeus]

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=D&P=5

Cheers