1997 850 T5 No Run/No Start, have tried the basics

sschlage · Post by **sschlage** » 27 Jul 2018, 07:13

I have had some significant problems with my 1997 850 T5 since January. There is only about 150k on the car and I really don't want to get rid of it. Here is a timeline of events

January - Very cold weather start in January. Idle seemed normal, put the car in gear to find low power. Open hood found white (oil or fuel smelling, cant remember) smoke from exhaust side of turbo and noticed exhaust more smoky than normal (tough to distinguish in Jan when the exhaust is already very white). Turned off the car to find oil and coolant mixed (brown coolant in reservoir, milky oil), coolant level dropped. I let the car sit for half a week then drained the coolant and oil. The fluids were indeed mixed. I drained and filled both fluids started the car again to find the same symptoms, but not as bad as the first time. I drained and filled the fluids again; there was still some mixing of the fluids but not as bad. Let the car sit. It was a cold winter which made it tough to work in an unheated garage.

Late January - Had to move 1 mile across town to a new rental house. I drove the car the one mile and it smoked the whole way. It had low power. I didn't have the time or I was lazy and the car sat.

July - Time to get the car to run. I wanted to see if the car would run. The car had clean and full oil and coolant. After charging the battery I attempted to start it. The starter was cranking the engine, but it would not fire. After a few start attempts the engine would come to an abrupt stop when cranking. I removed the spark plugs to find cylinder 4 FULL of fuel (passenger to driver cyl 1 to cyl 5). Injector 4 was mechanically stuck open. It was dumping about 2 oz of fuel into the cylinder with every charge of the fuel system, while the injector was unplugged. I removed all 5 injectors, cleaned them by submerging them for ~24 hours in a generic fuel sys cleaner. I tested the functionality of the clean injectors. They were good to go and I gave them new o rings. The injectors all read ~11 ohms and the harness ~12 volts. Have not tested fuel pressure, but there is pressure there, enough that I think it should run. With the "rebuilt" injectors on the car still does not start/run. (it did idle for a minute, but i had to hold the throttle open the whole time) The cylinders did sound dry (if that is a thing). It also does not dump fuel into the cylinders so that is good. This might have been a stupid idea, but just to rule out injectors and fuel pump relay all together i swapped the rail+injectors from my 98 V70 and the fuel pump relay onto the 850. The car started and idled, once, the exhaust was fuel smelling and white. The car hasn't started again. I don't think its a fuel issue.Tested cylinder compression next. Test results: 1) 125, 2) 125, 3) 140, 4) 125 all psi. Not sure if these are good results or not. Did not do a leakdown test. Compression seems to be ok, so probably not a blown head gasket. I check spark at one point, but I will verify all 5 have spark tonight.

So I'm pretty stuck at this point..what do I try next? Has something gone wrong in the intake system? Is some part of the turbo potentially clogged? Is there potentially a bad turbo coolant/oil barrier OR bad radiator coolant/oil barrier? Is the intercooler potentially clogged? Can I try a start directly into the engine, bypassing the turbo system? Is it something electrical, possibly crank position sensor? Any other common electrical issues related to no start? The grounds look ok and fuses are all intact. I haven't checked relays other that the fuel pump relay. There is not a CEL or any other warning lights. Should I reset the ecu?

Any ideas? Please help.

Thanks!
Shawn

Post by **erikv11** » 27 Jul 2018, 07:59

The last two times the car idled, was that for like a full minute of real idle each time or more like a few seconds of rough and chuggy idle, like it's trying to get going but never really does> Especially the last time. If so, it could be dry cylinder walls - give each one a teaspoon of oil then crank it with the throttle wide open (disables fuel pump) until it chugs, when it does chug keep cranking just a bit more until you can get idle. That may be the reason it won't run.

Swapping in the fuel rail from your V70 was totally fine, a smart move. The red injectors will eventually throw a fuel trim code (your 97 T5 has orange injectors, they flow a little more. Fuel relays are exactly the same part.

The head gasket can be leaking only one way between only two compartments, coolant into the oil for example, and not show a cylinder breach when you test compression. I'm not saying that's your problem, just letting you know to keep it in mind. You can have one-way or two-way leaks between any of the three compartments (oil, cylinder/combustion, coolant).

Coolant and oil mixing is most commonly the radiator on a T5. Basically never the turbo. Can you pressure test the cooling system?

sschlage · Post by **sschlage** » 27 Jul 2018, 08:50

The starts/idles were chuggy, I had to have the throttle way open to keep it idling. I agree the walls could be dry. I'll try the oil trick if the coolant sys holds pressure. Any easy way to determine if it is the radiator that has the breach? A bad radiator would be an easy one to fix.

Post by **erikv11** » 27 Jul 2018, 14:58

If the coolant system doesn't hold pressure, that points toward a bad radiator. Maybe you can isolate the radiator and pressure test it separately, I've never done that.

sschlage · Post by **sschlage** » 29 Jul 2018, 07:56

The coolant system held pressure. I oiled the cylinders and it fired right up. However, the exhaust was still smoky and smelled like fuel. I'd say I am back to the status the car was at in January. I checked that the injectors were mechanically working again. They were. So now I am thinking that it could be the injector electronics or ignition electronics. There definitely seems to be unburned fuel in the exhaust.

Post by **Ozark Lee** » 29 Jul 2018, 11:31

How far have you driven it? After being parked that long and the problems you found I would expect it to smoke badly for the first 20 miles or so.

Did you ever isolate the problem with the oil and coolant mixing? If you never definitively found it I would put a breach in the oil cooler in the radiator at the top of most likely suspects list.

...Lee