Miss firing when first running

[suprapunkd]

I got a free supra when i was working for this dealership... i sat for like 5 yrs. Its the targa top none turbo.... it had no interior except the dash and front seat and the gauge cluster (which btw only the fuel gauge and the speedo work.... anyone know what would cause the other guages not to work?

Well sometimes when i would start it it would miss a little like once or twice then no problems thru the winter.... i didnt drive it for about 2 months and decided that i wanted to sell my eclipse and just drive this. I cleaned out the intake properly taking it apart and soaking it over night to get all the carbon out (btw only has 93000miles)
after i did that it missed the first day then never again til last week.... that was about 3 months ago. well i decided to change the fluids... since it sat for so long and i changed oil again and flushed radiator.... which was clogged with nasty rusty water.
well it ran fine that day and the next. Then i had 2 days off and went to drive to work and it heavily missed like a cylinder or two were out... so when i got to work i checked the cap and rotor and wires.... all good and giving spark... (btw by the time i got to work it stopped... live less than 5 min from work)
well i changed the plugs thinking that was it and now it only does it when i first start it up til it warms up..... does anyone have a clue as to wat it could be?
any suggestions would help thanks!

 

[suprapunkd]

I read through google and thru my haynes manuals and data information systems from the dealership i used to work at... do you think the bvsv could cause this? I know it controls the on off of the egr but wouldnt it cause a miss fire all the time? not just part of the time?

 

[metaphysico]

First the bvsv is the bimetalic vacuum switching valve for the evap, then one vsv is for fuel up (ie runs to fuel pressure regulator), the other vsv runs the egr, but even then it only when its on it only causes the system to start and its regulated by the dpfe( not sure what toyota calls it).

Anyways, you may be in the start to what all supra owners have gone through and have a head gasket going out, look around here you will see its the most common problem on supras. As for the miss when you just start it could be the cold start injector. ( under the intake.) or you are using the wrong type of spark plug, supras are pretty picky and I have seen bosch and autolites fail within a few miles.

 

[91Supra313]

Mine is missing a bit also. What are the recommended plugs for our cars. Mine is modded pretty well, and I have no clue on this subject. It's sad that I know how to rebuild this motor damn near blindfolded but don't know what plugs to use...lmao

 

[metaphysico]

Go with ngk, the laser platinum is the oe plug, the iridium is the closest to the laser platinum, a lot of people like the coppers, but they always foul on me in a few thousand miles and its such a pita to replace them I just go with iridium and change them every 100k, also you can change the heat index, but on a ge there really wont be any need.

Now from your sig 91supra313 im guessing you have a gte (this is the ge section thats why I was saying about ge). So you would probably want to go with ngk copper one heat range cooler, which on ngk for some reason is going to a higher number, so if you have the (from memory) 6 heat index go with a 7. That will give you a cooler plug. Maybe someone can cue in here and give the exact numbers

 

[AJ'S 88NA]

Have you checked for oil down in the plug wells?

 

[suprapunkd]

ok so today i spent most of the day trying to track this problem down. As far as i can tell there is no oil in the water and there is no water in the oil.... my friend did a compression test and said its within reason for a car this age with mileage. But he did find out that i have alot of oil in the valley where the spark plugs go. He couldnt confirm that this is the problem but i blew most of the oil out with compressed air and it seemed to have gotten better. But we also noticed that the wires have little cracks in the bottom where they seal to the spark plug. He told me to start there. But one thing he couldnt answer was this
The charcoal canister has one huge wire going into it and a little nipple for another but no vaccuum line .... there is also on the power steering pump two little nipples for what look to be vacuum lines but for the life of me i could not find that bimetallic valve!!! lol
Cold start injector.... is that the one that sits on the intake between the two prerunners where the connect to the upper portion of the manifold?
Also any ideas on why my gauges arent working? only the fuel and the speedo... all fuses and relays are good. Like i said tho this car sat for a good portion of 5 years in a field/ impound lot.
thanks for any suggestions!!!!

 

[metaphysico]

Didnt think about the oil in the galley that is a common problem, but I usually figure pulling the plug wires and checking for oil or whatnot is a given so take it for granted.

The canister should have a vac line on top that routes from there across to a metal pipe on the afm, then from there to the bvsv, which is the blue plastic thing on top of the thermostat housing. The lower larger lines on the canister- one is for vent one goes to a metal line that goes under the car to the gas tank.

The power steering idle up valve has 2 nipples on it, one should have a hose going to the accordion hose on the bottom (you will see a nipple sticking out of the bottom of the accordion hose), and the other will have a short rubber hose that goes towards the front of the engine which connects to a metal line that wraps around the front of the engine to the driver side, where it will join a bunch of other hoses at the union coming off the intake.

The cold start injector/ cold start valve is under the intake between the runners, if this goes out it will take a little longer to get the car to start up after sitting and you can get some random miss fires right after startup which will clear up within a few seconds.

As for the gauges I think they mostly get power and/or ground from a common source, then the other side will go to the sensor or electronic component. May have some bad parts or sensor. To check the oil gauge you take the wire off the sensor and ground the wire the gauge should max out when you do that. Anyways did u check the fuses under the dash and the ones in engine bay because the under dash ones will control those. Also there are two fuse panels under the dash to check.

 

[suprapunkd]

thanks for the quick reply. I am bout to go replace the valve cover gaskets. Now when i got this car one of the guys that worked at the dealership with me told me that he was going to take this supra and he did a little research.... said that it was possible a jdm engine.... idk if thats true( he didnt take it because no turbo lol) but i dont have the blue nipple thing coming out of the water inlet pipe. I tried looking for pics on here but only thing i have seen is a few others that dont have it but they seem to be 90-92 supras....
i checked both fuse panels but doesnt seem like anything is blown now i dont have the cover to tell me which fuse is to what but everything in the car works great! is there a way to rebuild the gauges? or sending units?
Btw the volt meter, fuel and warning light, and speedo work. just not oil pressure gauge, tach, temp.... idk i have always had honda so this is my first toyotas sorry for all the questions in advanced!

 

[suprapunkd]

Thanks for the help guys... i took apart the top end of the motor and actually found that it had a new head on there and someone had just not tighten down the screws that held the valve covers. I also saw that there were alot of bolts and even a fuel injector that was very loose. I appreciate all the help! I maybe selling this car tho... my roomie has a 1991 turbo one that he wants to sell.... so if anyone wants to buy thats in or around dallas let me know!