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15 mpg highway, black soot from exhaust when cold, what to do?

Coolant temp sensor/ect sensor. CHANGE THE DAMN THING.

I've had it fail on two Volvos. Both times, it resulted in sooty blackness from the exhaust, crappy mileage, and a reluctance to start on cold mornings.

Just make sure you're replacing the SENSOR and not the SENDER.
 
Yup the ECT is on order. Should be here tomorrow...

Now that should be a pretty simple job, right? Its right below the intake manifold, correct?
 
Had very similar issues on my '89 240 a few weeks back.

Try this: Find the ECT and first start by checking the connection. Remove the connector and spray it out real well with a high-pressure air hose, as well as cleaning the connector end of the sensor. Reconnect and see if that cures it. If not, I definitely concur with the other contributors, which is to say "replace the ECT before doing anything else".

Good luck to you, btw - where in Maine are you? My wife is from South Thomaston (Midcoast). Sure love it up theyah. :)
 
The ECT is the rear most temperature sender in the head, located below intake runner 3. Start by removing the expansion tank cap, this will release the pressure in the cooling system. Then put the expansion tank cap back on, this will create a vacuum in the system when you remove the ECT sensor. By doing this you will not lose more than an ounce or two of coolant when you replace the sensor.

Edit: Test the new sensor before you install it.
 
The best way to test the temp sensor AND the wiring at the same time is at the ECU. Unplug the connector (or expose the back of the pins by taking off the cover) and test between pin and ground. I just OPENED A MANUAL and read the resistance values. I can also see what pin on the ECU I need to check. Lets take a look......32 deg F should be about 6000 ohms, 68 deg F should be about 2200 ohms, 176 deg F should be about 350 ohms.

www.brickboard.com -----700/900 FAQ. READ IT!
 
I replaced the ECT today with similar results. Runs a little better but still has the issue of black soot out of the exhaust while cold. Without the MBC in (will boost to 5 psi), it runs good, not great. If I put the MBC in, (8 psi), it will cut out. Rpm's drop, as well as boost. Whats weird is that it will build boost no problem, but the car doesn't go anywhere. Thinking it might be a faulty mbc, I swapped in one from my friends car and there was no difference. I have looked over all of the hoses and there doesn't appear to be any leaks. The only questionable hose is the intake hose between the AMM and compressor. Down by the compressor there is a bit of deterioration. The hose is soft but the cracks don't go all the way through... maybe a 1/4 of the way through.



pzs2k1- I'm up at school in Orono, ME right now.
 
why not thow in a set of STOCK greentop turbo injectors? instead ofd those nasty looking Ford injectors
maybe google the Ford partnumbers and see how much they flow (@3bar/min)
If it's anything higher then 305-315cc then this could be causing the rich running.
 
Janspeed said:
why not thow in a set of STOCK greentop turbo injectors? instead ofd those nasty looking Ford injectors
maybe google the Ford partnumbers and see how much they flow (@3bar/min)
If it's anything higher then 305-315cc then this could be causing the rich running.
Click to expand...

I'm beginning to think it is the injectors. After some research, it looks like these injectors are 380cc injectors. Makes sense why it would be running rich. Would this explain the issue of cutting out in boost though?

You think the stock greentop turbo injectors would be best for my setup?
 
I had the same issue- and putting "greentops" back in helped, since I didnt have a high enough flowing AMM to match the ford injectors (at a max of 11 lbs boost). Still, there is a little cut out issue under boost, but that could be for me due to a crank sensor issue which I may not have fully repaired, or because my spark plugs might be blowing out
 
Sleepy240 said:
I had the same issue- and putting "greentops" back in helped, since I didnt have a high enough flowing AMM to match the ford injectors (at a max of 11 lbs boost). Still, there is a little cut out issue under boost, but that could be for me due to a crank sensor issue which I may not have fully repaired, or because my spark plugs might be blowing out
Click to expand...

Okay sweet, I'm going to try and track down some greentops then.

What cars should I look for to find the injectors that I need?
 
Did you replace the coolant temperature sensor yet? What is the status? Did this solve the problem? I've been having the same issue on and off for a while now. It seems to occur mostly when the temperatures change, ie summer to winter and winter to spring, etc..., but all in all, I always have a rough idle or high idle, less than desirable fuel economy, and the whole car bucking under boost, esp in the higher gears. Doing better now that I have swapped AMM with a jy AMM, but still not perfect. I'm going to do my throttle position switch next. Let me know what you find.
 
Sorry for the lack of updates. I have replaced the following since my last post:

-Coolant temp sensor
-Turbo inlet hose
-Injectors

The coolant temp sensor didn't make a difference. The new inlet hose helped a with building boost and the idle. The injectors helped the most though. No more black soot out of the exhaust, overall it runs much better, and much better MPG's. I'm getting 22 mpg highway and 17 city. This is in the winter, so I would expect these numbers would increase in the summer.

Thanks for the help guys, and Sleepy240- Good luck! Have you had your injectors cleaned, or replaced?
 
I have not cleaned the injectors yet- I will do so, and hopefully find another spare set- I do not remember what car they need to come off of though- I will let you know when I find out. I replaced my spark plugs today, and found all the old ones have a white glaze, with the exception of the one closest to the firewall, which is black, with soot or oil, I'm not sure right now. I may have a missfire issue to top the original, seeing as how I'm also getting backfiring.
 
Sleepy240 said:
I have not cleaned the injectors yet- I will do so, and hopefully find another spare set- I do not remember what car they need to come off of though- I will let you know when I find out. I replaced my spark plugs today, and found all the old ones have a white glaze, with the exception of the one closest to the firewall, which is black, with soot or oil, I'm not sure right now. I may have a missfire issue to top the original, seeing as how I'm also getting backfiring.
Click to expand...

Mark I'll send you a text later, About the problems your having.

-Jack
 
Sleepy240 said:
I have not cleaned the injectors yet- I will do so, and hopefully find another spare set- I do not remember what car they need to come off of though- I will let you know when I find out. I replaced my spark plugs today, and found all the old ones have a white glaze, with the exception of the one closest to the firewall, which is black, with soot or oil, I'm not sure right now. I may have a missfire issue to top the original, seeing as how I'm also getting backfiring.
Click to expand...

Hmm that sounds like a misfire issue if you're plugs aren't all a consistent color. Have you replaced the cap and rotor? Or at least taken it off to inspect? Check that and also, how recent are your plug wires?
 
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