That should help cold starts. I have done the same.toml said:
Let me think about the voltage.
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Can a CPS output be dependent on temperature?
- Thread starter toml
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Let me think about the voltage.
I had prepared an answer, but looked it up and had to reconsider. My 91 repair manual says .1 to 1.0 volts at 176 F, between THW and E2. Or right on the sensor.
So that appears to be correct.
THA says 1-3 volts at 68 F, so that isn't too much help, other than watching the THA and THW go up together. Something that is much easier with a Vetronix scan tool.
edit again: These input sensors are often a 5 volt refrence. The sensor alters the known voltage and interprets it. But it has been a while since I have dealt with it, and the repair manual says nothing about the refrence voltage.
So that appears to be correct.
THA says 1-3 volts at 68 F, so that isn't too much help, other than watching the THA and THW go up together. Something that is much easier with a Vetronix scan tool.
edit again: These input sensors are often a 5 volt refrence. The sensor alters the known voltage and interprets it. But it has been a while since I have dealt with it, and the repair manual says nothing about the refrence voltage.
Right, so as far as we can tell, the sensors seem to be operating normally and within range. I have no reason to doubt their operation...
Testing hot probably isn't what you want, since it is a cold drivability problem. Test that sensor stone cold and see if you still have the same voltage.
Yay for usIJ. said:Really interesting thread guys well done!
Nick: I did test the car last night when it was cold, but it's now morning and the car has been sitting all night so I'm about to go test them all again, just to make sure.
Well, stone cold readings:
Water temp: 1.9 V
Air temp: 2.0 V
They warmed up to an operating temperature at:
Water temp: 0.4 V
Air temp: 1.75 V
jetjock: Unfortunately, no, I didn't test the CSI when cranking. I tried, but I just couldn't find a way to test it whilst still attached to the car without spraying fuel everywhere!
Since my water temp sensor is working and my cold start time switch is within correct resistance specification, and I know the CSI by itself works fine - could the only other cause of the CSI not firing be the ECU?
Either way, I'm under the impression that even without the CSI in there, the car should start after a little extra cranking, where as mine does not.
Water temp: 1.9 V
Air temp: 2.0 V
They warmed up to an operating temperature at:
Water temp: 0.4 V
Air temp: 1.75 V
jetjock: Unfortunately, no, I didn't test the CSI when cranking. I tried, but I just couldn't find a way to test it whilst still attached to the car without spraying fuel everywhere!
Since my water temp sensor is working and my cold start time switch is within correct resistance specification, and I know the CSI by itself works fine - could the only other cause of the CSI not firing be the ECU?
Either way, I'm under the impression that even without the CSI in there, the car should start after a little extra cranking, where as mine does not.
jetjock, Yeah I tried it in a bottle but of course the bottle was still upside down so fuel would've leaked everywhere
I'll check that I get 12 V at the connector when cranking the engine.
I also tried the 'foot to the floor' flooded start mode today, but that didn't help.
Oh well, hopefully I'll get it fixed up soon. Thanks for the help.
I wish I had one of those TCCS checkers but I'm sure I could buy a new Supra for the amount of money I'd need to spend on one...
(would a local Toyota service centre have a TCCS checker I could hook my car up to?)
I'll check that I get 12 V at the connector when cranking the engine.
I also tried the 'foot to the floor' flooded start mode today, but that didn't help.
Oh well, hopefully I'll get it fixed up soon. Thanks for the help.
I wish I had one of those TCCS checkers but I'm sure I could buy a new Supra for the amount of money I'd need to spend on one...
(would a local Toyota service centre have a TCCS checker I could hook my car up to?)
Thanks jetjock. I'll have to get my hands on a timing disc (or whatever they're called) to check that the timing notches on my crank pully are correct. It's set to 10 deg BTDC but maybe the notches are incorrect after my rebuild.
I'm very certain that the CSI is now working as the last couple of times I've started it cold since I've cleaned the CSI, the car's started much easier - but still struggles on that first crank... it just cranks, cranks, cranks until it gets tired!
If I unplug the injector resistor pack, won't that deliver _no_ fuel to the engine?
I might call into the local Toyota dealership on the way home and at least find out whether they've got a TCCS checker they could plug into my car
I'm very certain that the CSI is now working as the last couple of times I've started it cold since I've cleaned the CSI, the car's started much easier - but still struggles on that first crank... it just cranks, cranks, cranks until it gets tired!
If I unplug the injector resistor pack, won't that deliver _no_ fuel to the engine?
I might call into the local Toyota dealership on the way home and at least find out whether they've got a TCCS checker they could plug into my car
Tom: Grab some vacc hose about 150mm long pull #1 plug and drop the hose in on top of the piston.
Turn the crank and watch the hose rise, it'll stop just before it heads back down this is true TDC now compare this with what the marks on the balancer say.
Turn the crank and watch the hose rise, it'll stop just before it heads back down this is true TDC now compare this with what the marks on the balancer say.
Just checking a few other things... The voltage across Vf1 and E1 in my diag block is 3.4V - I believe it's meant to be 2.5V with no correction, and 3.4V is towards the lean side. I'm assuming I don't have enough fuel pressure or my injectors aren't injecting fuel cleanly..
Hmm.. if I had a boost leak (suspicion), would I be running rich or lean? I'd think rich, since the air that's escaping has already been measured by the AFM and entered into the ECUs calculations? In this case, am I able to presume that if i'm running slightly lean, then I do not have a boost leak?
Or am I thinking too much into this?
Hmm.. if I had a boost leak (suspicion), would I be running rich or lean? I'd think rich, since the air that's escaping has already been measured by the AFM and entered into the ECUs calculations? In this case, am I able to presume that if i'm running slightly lean, then I do not have a boost leak?
Or am I thinking too much into this?
Bumppp...
I have the EXACT same problem man... I cannot for the life of me figure it out! I checked the CPS, timming, CSI, Cold Start Timming Switch...
The only thing I haven't looked at was the fuel... If it was fuel not being delivered propely I would suspect that the stumbling would be caused by the lack of fuel coming into the combustion chamber causing a lean conidition... Or it could be the other way around, too much fuel going into the engine, causing a rich condition... I'm not sure myself..
I've had the same experiences ... I start the car, it cranks cranks cranks, but it never catches. 2nd time I crank for like 2/3 times and it fires up, stumbles a bit and the check engine light flashes. I even find that cranking even 1/2 times then stopping and then cranking 2/3 times it fires up, but stumbles again...
Did you end up fixing this problem? Any help would be greatly appreciated
Thanks
I have the EXACT same problem man... I cannot for the life of me figure it out! I checked the CPS, timming, CSI, Cold Start Timming Switch...
The only thing I haven't looked at was the fuel... If it was fuel not being delivered propely I would suspect that the stumbling would be caused by the lack of fuel coming into the combustion chamber causing a lean conidition... Or it could be the other way around, too much fuel going into the engine, causing a rich condition... I'm not sure myself..
I've had the same experiences ... I start the car, it cranks cranks cranks, but it never catches. 2nd time I crank for like 2/3 times and it fires up, stumbles a bit and the check engine light flashes. I even find that cranking even 1/2 times then stopping and then cranking 2/3 times it fires up, but stumbles again...
Did you end up fixing this problem? Any help would be greatly appreciated
Thanks
bigaaron said:
Strangly enough... I get no codes... arrr
I have tons of white smoke puffing away on start up... it never seems to go away until i drive it around the block... after that, the heavy white smoke dissapears... I've been hunting this smoking problem for sooooo long and have not found a solution yet. The white smoke billows out of the tail pipe and seems to linger in the air for a little while before evaporating... Also, when I took out my stock exhaust, the resonator was full of water that I could not get out!
I did a BHG Job over a year ago and only put ~25kms on the car since then. I doubt its valve stem seals b/c I replaced those with non-toyota ones.
I wonder if coolant/oil is getting into my combustion chamber and causing this awful rough start! When the car is dead cold, idling at around 1100-1200rpm, I would push the gas hard and it wanted to cut off on me. Finally after several times doing that, the car would rev normally with no stumbling. I have NO codes too!
This problem is very wierd and I'm almost certain that something is burning in my combustion chamber. Is there some sure way of smelling the emissions to tell if its oil or coolant? It smells bad, but then again it "seems" to smell sweet... I'm not sure if my mind is playing with me lol... I got very thick oil in the engine now (lucas + 20W50)... so I doubt its oil...
This problem is mind boggling. :cry:
It sounds very much like BHG. You put a stocker in itlast time? If so.....ya , go steel and arp's.
tookwik4u89 said:
I had the head lapped, and put in a toyota stocker HG with ARPs torqued to like 95ft-lb with engine oil (no special moly lube). I did check a compression check awhile ago and it was pretty good. 170-180 across. I'm guessing carbon build up when i was testing it with the timing off.
I've only put 25kms on this car and this shit happens... Awhile ago, I suspected that the head I bought was cracked and I kept on doubting that idea.. but the further I dig into this, checking various things, that is the only thing I can think of... Other things that may be cracked could be the Throttle body, turbo, ISC...but how often do you see a cracked TB? I've changed the turbo and it made no difference, so I highly doubt its a crack in that cast.
My next step will be to unplug each spark plug after the initial crank and look into the combustion chamber to see if there is any coolant/oil in it before a COLD start. I'll stick a piece of paper towel to the end of a stick and swirl it around to see if I can find anything.