mr2 fuel shut off while driving 91 jspec

[91ghosttuner]

I am new to posting on this forum, but have been reading it for awhile. You guys are extremely helpful, and hopefully will be able to help me as well.
I just purchased the car not to long ago, and during the trip home, it was over heating and running very rich, with black smoke coming out the exhaust occasionally. I figured this was a knock sensor and a thermostat. (maybe oxygen sensor or water pump as well). I was going to take the car to a dealer for a diagnostic just in case, but on the way there the car suddenly lost power. I was going about thirty five, and all of a sudden the rpm's dropped and the pedal wasn't responding.(not giving the car gas when I was pushing it) the pedal still has tension and the throttle cable is still tight. The car ultimately stalled out. It will start back up and I can rev it for about a half of a second, and then it will stutter and die. I am honestly clueless about what this may be. When I first started driving it I heard a clunk. I didn't thing anything of it, but it may be a symptom to think of. Any help about any of these problems would be greatly apreciated.

[Itech]

Originally Posted by 91ghosttuner

I am new to posting on this forum, but have been reading it for awhile. You guys are extremely helpful, and hopefully will be able to help me as well.
I just purchased the car not to long ago, and during the trip home, it was over heating and running very rich, with black smoke coming out the exhaust occasionally. I figured this was a knock sensor and a thermostat. (maybe oxygen sensor or water pump as well). I was going to take the car to a dealer for a diagnostic just in case, but on the way there the car suddenly lost power. I was going about thirty five, and all of a sudden the rpm's dropped and the pedal wasn't responding.(not giving the car gas when I was pushing it) the pedal still has tension and the throttle cable is still tight. The car ultimately stalled out. It will start back up and I can rev it for about a half of a second, and then it will stutter and die. I am honestly clueless about what this may be. When I first started driving it I heard a clunk. I didn't thing anything of it, but it may be a symptom to think of. Any help about any of these problems would be greatly apreciated.

something's wrong with your air flow sensor?

check your piping and wiring?

[91ghosttuner]

Thanks, Ill check that out. I also discovered a new symptom today. When you just bearly touch the throttle, the car immediately chokes, but if you push through it, you can hear the exhaust sputter but it doesn't choke. Im sorta thinking a head gasket as well now, as well as a sensor of some sort. Does this sound right?

[Zz_005_zZ]

Here are my theories. Air Flow sensor (meter), Water in gastank, head gasket. Hopefully not the last option :0)

[tHa kNiGHt FaLL]

no not head gasket...

i'm thinking TPS or Crank Sensor

[Zz_005_zZ]

Thinking back... I had the same problem with my motorcycle, check the sparkplugs... see if there is alot of carbon buildup on them.. this might give a good indication if u are running too rich upon startup... then u can start to fugure out why...Might be a great indicator of the air flow sensor, or something as simple as an 02 sensor

[91ghosttuner]

Ok, so I hooked up a compression test on the cylinders, and they were running between 125 and 135, but the car was cold. I know it is supposed to be warm, but I could hardly keep it on at this point. So I determined it wasn't the head gasket. Now here is the awesome part, I've only had the car about a week and a half and haven't really looked over the engine really thoroughly, and while I was back there, I discovered the kid who owned it before me disconnected the mass air flow sensor!! Needless to say that was a very stupid thing to do, and a stupid thing to miss on my part. But the car is still over heating, and the radiator looks a little beat up as well. Im thinking that might be the problem there. But I am really appreciative of you guys, you gave me some good ideas, and eventually directed me to the MAS. Hopefully this overheating thing will be resolved shortly enough. It seems to be loosing a substantial amount of coolant, and the car overheats after 8-10 minutes of driving. No visual leaks but I also noticed that the cooling fans look to be disconnected and I haven't ever heard them come on. Im going to check into this tomorrow. Let me know your opinions. Thanks Again!!

[tHa kNiGHt FaLL]

Mas Airflow might not be your problem. cars equipted w/ a MAF and MAP the MAP acts as the MAF if its ever disconnected. you can disconnect it not even notice the difference except it would throw a code.

whats the problem anyways... i see cooling system... MAF won't affect cooling... it effect, air/fuel and emissions

[91ghosttuner]

The air/fuel was an issue as well, but the mass air flow fixed that. The problem that remains is the cooling. The car overheats in about 10 minutes of driving. It seems like the coolant itself is boiling over, so Im thinking that it is not flowing properly through the radiator, or the cooling fans arent working properly. But it does it on the highway as well, where the cooling fans aren't as big of an issue. I'm lost and I don't want to dump money in a new radiator and end up being wrong. Anybody have any opinions on this?

[tHa kNiGHt FaLL]

over heats how? like shoots out the overflow?
check for bubbles in under the radiator cap
if yes,

compression test... if your low in two adjacent cylinders you have a bad head gasket.

if not... you have a flow issue like you think. if you get to this point post saying you did and i'll help along troubleshooting flow. but you need to eliminate the more serious of it all

[Zz_005_zZ]

you said the radiator looked pretty beat up, so replacement might be a good thing anyways, u can also buy a dual core radiator, and ensure good cooling.... make damn sure the fans are working no matter what... might be the wiring got caught in the fans... and secondly, an oil cooler aftermarket won't cost you too much money, and might be a great investment... not that you need it, but always a smart move.But I would really be concerned with the radiator, and the cooling fans, even if u are moving. Good Luck

[91ghosttuner]

I did hook up the compression test, but I did it with the engine cold so the results probably aren't dead on, but all of the cylinders were close to each other. 125-135. I know they are supposed to be higher, but with it being cold, I figured it was about right. When I took apart the water outlet there was coolant a plenty in there, but I just don't know if while it is running, what the flow is like. When the car overheats it seems like steam is coming solely from the overflow. (I don't give the engine time to get to hot, just when it starts to spike I pull over). Im trying to locate the thermostat, but it has evaded me so far. I think it is on the lower part of the engine on the passanger side right? An oil cooler is an intriguing idea... About how much does one cost? A little extra protection is always worth while! Im hoping it is not the radiator though. Those things are horribly expensive for an MR2. I found an PWR alluminum radiator for 450$. Im not sure how good of a brand that is or not. Does anybody know?
Thanks again guys!

[tHa kNiGHt FaLL]

drain the radiator... using water. pour it in the up radiator inlet and watch it come out the bottom. should come out the same rate it went it, and the same color. check the condenser in front of the radiator... if air doesn't flow thru the condensor it won't go thru the radiator. then check between the condenser and radiator... for say, dead animals... plastic bags... then check the side of condenser for the foam inserts that keep air infront of the radiator.
you have a fan shroud in place? fan shroud should go around the fan not in front of it.
then make sure your fans are working... does the car overheat at idle... if so let it ldle and see if the fan comes on at all before it over heats.

[91ghosttuner]

Alright I will give that a try. Im going to replace the thermostat too just for the heck of it. You never know right? But I will check the flow of the radiator while I am at it. If thats good, I will check the cooling fans. I haven't checked to see if they come on yet. The car is still new to me, and I haven't done a thorough look over yet.
thanks