Smoke from engine bay

bbade · 07-19-2009, 09:53 AM

Yesterday after about a 45 minute drive with some spirited driving down the highway I pulled into the driveway and shut off the car. During the drive water temp did not go above 88 degC and air temp did not go above 40 degC. I went back to the car and decided to leave the keys on so the fans would come on after the car sat for a bit.

After the fans came on I noticed white smoke coming from the driver's side of the car, I opened the hood and noticed white smoke coming from what appeared to be the driver's side, back of the engine underneath the UIM. It took several minutes for the smoke to dissipate, but the car started up fine and ran perfectly long enough for me to move it into the garage. If hot had a smell I would describe the engine bay as smelling hot, I did not notice the sweet smell that coolant has.

The car is a 1993 with about 65,000 miles on it. It has a rebuilt motor and turbos with approximately 10,000 miles on them. It also has a koyo radiator, power fc, downpipe, and racing beat catback exhaust. The koyo radiator was installed about 2000 miles ago and the coolant was replaced during installation.

Any suggestions as to what might be the cause of this? Also, is their anymore relevant information that might help with diagnosis? Thank you all for your help!

David Jerome · 07-19-2009, 04:56 PM

I am assuming you still have all the stock coolant hoses(throttle body hoses, etc)? On that side of the engine it would be either one of those small hoses or could be the oil filter pedestal burning some oil off or the oil pressure sending unit. More details and we can help.

bbade · 07-19-2009, 07:40 PM

I replaced the coolant hoses to the radiator when I installed the Koyo, but other than that everything is original unless Dave replaced some when he did the rebuild. I will have my father check the receipt for the rebuild as it is back home in PA and the car is in IN with me.

I did remove the UIM and TB several times last summer while I was working on polishing the UIM. I was pretty rushed the last time I put everything back together so there is a good possibility I did not get one of the hoses on correctly.

I will get the hose info and try to take a look at the car early this week so I can get back with an update, hopefully it's just a loose hose!

bbade · 08-08-2009, 01:45 PM

Little update, when Dave did the rebuild the following hoses were replaced:

n3a1-13-681a (hose)
n3a1-13-691a (hose)
n3a1-13-692 (hose, water)
n3a1-13-536 (hose)
n3a1-13-54x (hose)
n3a1-15-186b (upper rad hose)
n3a1-15-185b (lower rad hose)

I am not sure what each of those hoses are though

.

Anyway I finished installing SuperPro bushings in the front of my car about a week ago. I took it for a short drive to test the bushings and see if I could get the white smoke to come back, no dice. I also started it up several days later took it for a short drive and no smoke again. I did not push the car on either drive so I'm thinking the smoke only appears after a hard drive.

When I finish installing the SuperPro bushings in the rear I will take it for a hard drive to see if I get any white smoke again. In the meantime any suggestions as to possible things to look for?

Thanks again!

rx4ur7 · 08-11-2009, 03:42 PM

Those are the ones that are supposed to be replaced.

Well you have all three fluids under there. Fuel, water and oil. Generally the top of the motor shouldn't get hot enough to vaporize oil or water and fuel would be pretty obvious. You would have definitely known that smell.
Was it thick smoke? Blue tint at all? Mazda spring clamps or American screw?

Oil would be coming from metering lines or turbo blow-by in the intake.
Fuel either fuel lines(non-mazda fuel lines or clamps), injectors or regulator.
Water, from that area would be the 90*(691A) hose, (non-mazda clamps)

The reason I mention clamps is because Mazda spring clamps change tension with temperature, they always maintain the same clamping pressure. Where screw type remain the same. The other problem with screw clamps is that people get frisky with over tightening and damaging the hoses causing leaks. Non-mazda, non-metric fuel lines or screw clamps are one of the biggest causes of engine fires. Out of all the engine fires I have had to repair only one was the result of a leaking injector.

With the fans on the source area could be somewhere else, not under the UIM. My guess is oil and or water hitting the turbos. I had one car that had me going for awhile, it had a smaller than pin hole leak in one of the welds of the turbo water line.

There is also the possibility of something electrical small but possible.

Carry a fire extinguisher, just in case. Until you can 100% rule out any fuel issue.
This just because I can not see or smell the car.
You didn't drive through any water did you?

bbade · 08-15-2009, 04:08 PM

I still have not had a chance to look at it, hopefully this week once i finish the suspension and get it off the jack stands.

The was definitely no fuel smell, but there was a fair amount of white smoke. I did not drive through any water, but there were some small sprinkles on the way home.

Thanks for your help, keep tuned as I'll post an update as soon as I get a chance to work on it.

Kinsan24 · 02-17-2010, 11:40 PM

The same thing happened to mine and what I found was the turbo to water pump housing hose had a cut under the bend going to the turbo where there is a protective covering. Undetectable unless you look really hard. I bought a new one from my local parts shop here in Japan for 8 bucks and I bought new OEM hose clips too. You have to remove the air pump to get access to this hose. You can also get it here. http://atkinsrotary.com/store/produc...cat=745&page=1 Hope this helps.

07-19-2009, 09:53 AM	#1
bbade Rotary Fanatic Join Date: Mar 2008 Location: Macungie, PA iTrader: (0) Posts: 163 Rep Power: 17	Smoke from engine bay Yesterday after about a 45 minute drive with some spirited driving down the highway I pulled into the driveway and shut off the car. During the drive water temp did not go above 88 degC and air temp did not go above 40 degC. I went back to the car and decided to leave the keys on so the fans would come on after the car sat for a bit. After the fans came on I noticed white smoke coming from the driver's side of the car, I opened the hood and noticed white smoke coming from what appeared to be the driver's side, back of the engine underneath the UIM. It took several minutes for the smoke to dissipate, but the car started up fine and ran perfectly long enough for me to move it into the garage. If hot had a smell I would describe the engine bay as smelling hot, I did not notice the sweet smell that coolant has. The car is a 1993 with about 65,000 miles on it. It has a rebuilt motor and turbos with approximately 10,000 miles on them. It also has a koyo radiator, power fc, downpipe, and racing beat catback exhaust. The koyo radiator was installed about 2000 miles ago and the coolant was replaced during installation. Any suggestions as to what might be the cause of this? Also, is their anymore relevant information that might help with diagnosis? Thank you all for your help! __________________ Proud owner of a base 1993 Montego Blue FD. PFC, RB single tip, Koyo Radiator, KDR rebuilt motor, polished OEM front strut bar, FEED replica sideskirts, OEM 99 spec rear spoiler, SuperPro Bushings Many thanks to Dave at KDR for sparking my rotor addiction.

07-19-2009, 04:56 PM	#2
David Jerome RCC Contributor Join Date: Jan 2008 iTrader: (10) Posts: 713 Rep Power: 17	I am assuming you still have all the stock coolant hoses(throttle body hoses, etc)? On that side of the engine it would be either one of those small hoses or could be the oil filter pedestal burning some oil off or the oil pressure sending unit. More details and we can help. __________________ David Jerome Broker for Speed For Sale LLC (David@SpeedForSale.com) (Pre-owned RX7/sports car sales & new parts sales/installs/tuning) PM me about low priced, high quality port work

07-19-2009, 07:40 PM	#3
bbade Rotary Fanatic Join Date: Mar 2008 Location: Macungie, PA iTrader: (0) Posts: 163 Rep Power: 17	I replaced the coolant hoses to the radiator when I installed the Koyo, but other than that everything is original unless Dave replaced some when he did the rebuild. I will have my father check the receipt for the rebuild as it is back home in PA and the car is in IN with me. I did remove the UIM and TB several times last summer while I was working on polishing the UIM. I was pretty rushed the last time I put everything back together so there is a good possibility I did not get one of the hoses on correctly. I will get the hose info and try to take a look at the car early this week so I can get back with an update, hopefully it's just a loose hose! __________________ Proud owner of a base 1993 Montego Blue FD. PFC, RB single tip, Koyo Radiator, KDR rebuilt motor, polished OEM front strut bar, FEED replica sideskirts, OEM 99 spec rear spoiler, SuperPro Bushings Many thanks to Dave at KDR for sparking my rotor addiction.

08-08-2009, 01:45 PM	#4
bbade Rotary Fanatic Join Date: Mar 2008 Location: Macungie, PA iTrader: (0) Posts: 163 Rep Power: 17	Little update, when Dave did the rebuild the following hoses were replaced: n3a1-13-681a (hose) n3a1-13-691a (hose) n3a1-13-692 (hose, water) n3a1-13-536 (hose) n3a1-13-54x (hose) n3a1-15-186b (upper rad hose) n3a1-15-185b (lower rad hose) I am not sure what each of those hoses are though . Anyway I finished installing SuperPro bushings in the front of my car about a week ago. I took it for a short drive to test the bushings and see if I could get the white smoke to come back, no dice. I also started it up several days later took it for a short drive and no smoke again. I did not push the car on either drive so I'm thinking the smoke only appears after a hard drive. When I finish installing the SuperPro bushings in the rear I will take it for a hard drive to see if I get any white smoke again. In the meantime any suggestions as to possible things to look for? Thanks again! __________________ Proud owner of a base 1993 Montego Blue FD. PFC, RB single tip, Koyo Radiator, KDR rebuilt motor, polished OEM front strut bar, FEED replica sideskirts, OEM 99 spec rear spoiler, SuperPro Bushings Many thanks to Dave at KDR for sparking my rotor addiction.

08-15-2009, 04:08 PM	#6
bbade Rotary Fanatic Join Date: Mar 2008 Location: Macungie, PA iTrader: (0) Posts: 163 Rep Power: 17	I still have not had a chance to look at it, hopefully this week once i finish the suspension and get it off the jack stands. The was definitely no fuel smell, but there was a fair amount of white smoke. I did not drive through any water, but there were some small sprinkles on the way home. Thanks for your help, keep tuned as I'll post an update as soon as I get a chance to work on it. __________________ Proud owner of a base 1993 Montego Blue FD. PFC, RB single tip, Koyo Radiator, KDR rebuilt motor, polished OEM front strut bar, FEED replica sideskirts, OEM 99 spec rear spoiler, SuperPro Bushings Many thanks to Dave at KDR for sparking my rotor addiction.

08-11-2009, 03:42 PM	#5
rx4ur7 Rotary since 1972 Join Date: Nov 2008 Location: Tucson iTrader: (0) Posts: 231 Rep Power: 17	Those are the ones that are supposed to be replaced. Well you have all three fluids under there. Fuel, water and oil. Generally the top of the motor shouldn't get hot enough to vaporize oil or water and fuel would be pretty obvious. You would have definitely known that smell. Was it thick smoke? Blue tint at all? Mazda spring clamps or American screw? Oil would be coming from metering lines or turbo blow-by in the intake. Fuel either fuel lines(non-mazda fuel lines or clamps), injectors or regulator. Water, from that area would be the 90*(691A) hose, (non-mazda clamps) The reason I mention clamps is because Mazda spring clamps change tension with temperature, they always maintain the same clamping pressure. Where screw type remain the same. The other problem with screw clamps is that people get frisky with over tightening and damaging the hoses causing leaks. Non-mazda, non-metric fuel lines or screw clamps are one of the biggest causes of engine fires. Out of all the engine fires I have had to repair only one was the result of a leaking injector. With the fans on the source area could be somewhere else, not under the UIM. My guess is oil and or water hitting the turbos. I had one car that had me going for awhile, it had a smaller than pin hole leak in one of the welds of the turbo water line. There is also the possibility of something electrical small but possible. Carry a fire extinguisher, just in case. Until you can 100% rule out any fuel issue. This just because I can not see or smell the car. You didn't drive through any water did you?

02-17-2010, 11:40 PM	#7
Kinsan24 RX-7 in Tokyo Join Date: Feb 2010 Location: Ayase,Japan iTrader: (0) Posts: 1 Rep Power: 0	The same thing happened to mine and what I found was the turbo to water pump housing hose had a cut under the bend going to the turbo where there is a protective covering. Undetectable unless you look really hard. I bought a new one from my local parts shop here in Japan for 8 bucks and I bought new OEM hose clips too. You have to remove the air pump to get access to this hose. You can also get it here. http://atkinsrotary.com/store/produc...cat=745&page=1 Hope this helps.