1990 DX hatch with Si/MPFI conversion. So some time ago when I first finished this project I started a thread on here about it consuming oil and we could never figure out what was causing the issue. I looked in to or tried everything suggested and nothing made a difference. Car runs and drives fine otherwise, absolutely no problems or check engine lights.

Compression test results were good, vacuum test results were good, never did a leakdown test because I can't find my leakdown tester.

I replaced the valve cover gasket, spark plug tube gaskets, rocker assembly o-rings, valve stem seals, and pcv. No change.

Pulled the valve cover breather and replaced it with a mini filter like I always do. No change.

I unhooked and plugged the PCV lines thinking that was the issue. No change.

Just like before if I really get on it, or let the engine brake(i.e., going down a hill) and get back on the throttle it blows either blueish-white smoke or dark smoke.

The spark plugs and inside the exhaust are blackened. I blow soot out of the tail pipe and you can see little black specks all over the back of the car.

It does smell like it's running rich, and I can obviously smell the oil being burnt off. I didn't really ever acknowledge the fact it was running rich until today and that got me thinking...could the issues be related, one causing the other? Is it possible that the car running rich/washing out the cylinders has anything to do with the oil consumption?

I have also noticed a small misfire @ idle lately. I know it's about time to clean up or replace the plugs as they're probably all fouled up/black. I have pulled and wirebrushed them several times over the few years I've had the car. Fuel filter is due for a replacement as well.

I have not checked/ruled out the MAP sensor or anything else that might be causing it to run rich since I just now realized it. 99.9% sure it's got the correct ECU, gutted my '91 Si to build this DX and everything was swapped over.

Thoughts?

ETA: Someone at work asked about my MAP sensor and I honestly don't remember if I'm using the DX one or the Si one. It's the single solenoid setup. Here is how it's routed...

MAP > TB
Vacuum Solenoid Side Port > Vacuum Canister
Vacuum Solenoid Bottom Port > Back of Intake Manifold

ETA2: That little vacuum solenoid looking deal on the bottom right of the backside of the IM, closest to the brake master cylinder, is installed with a big vacuum hose running to the back of the IM but the plug for it is just hanging there. I remember noticing this when I did the swap/conversion but just left it unplugged since I had nothing to plug it in to. What is this and is it causing any harm by being installed and connected via vacuum hose to the IM but not connected to electrical?

ETA3: Dashpot was deleted during the swap and the port for it on the front of the IM was plugged. Shouldn't be related to the issues I'm having, but I figured I'd mention it anyway.

 

Bump?

 

What was your compression test results? And is your timing good?

 

I don't remember off the top of my head, but I do remember they were better than what the chilton's manual recommended.

Pulled the plugs last night and noticed some things...

-Plugs had oil on the threads and the washers. Plug ends were black with white buildup.
-Spark plug tube 1, 2, and 3 had oil on the ledges where the spark plugs sit.
-Piston 4 has carbon buildup and looks wet with oil.
-Piston 3 looks great.
-Pistons 2 and 1 look soaked in oil, it's almost pooling on top of them.

 

you need to change the sparkplug o-rings and then change the valve cover sparkplug tube seals. to change the o-rings you need to remove the valve cover and then the rocker arm assembly, at the same time u can change the sparkplug seals on the valve cover. go to autozone and get a valve cover gasket set should be 1 valve cover gasket and 4 sparkplug tube seals to get the 0-rings you have to go to Honda and buy them or you can order online ebay/any parts store that you can fidn that has them. after you fix those your oil burning issue should stop. if it continues its 1 of 3 things from there. 1 bad piston rings. 2 valve seals(slightly more difficult fix) 3 external oil leak i.e. oil pan gasket, oil filter. at autozone you will want this aprt number VS50073 victor reinze valve cover gasket. if u got time then order it on ebay its cheaper and the same. for the 0-ring seals you need these 2 part numbers 91302-PJ7-003 and 91301-PJ7-000. now e are normal 0-rings but 1 is a figure 8 style o-ring. you need 3 normal 0-rings and 1 figure 8 o-ring. this will stop the leaky oil into the combustion chamber. oh and replace the sparks with NGK new psarks ar ea must. quick tip put some anti sieze on the threads of the sparks to prevent rust and allow easy removal next time( just a pinch of antie sieze to cover the threads). now to address the excess fuel issue. 2 things O2 sensor and injectors. you can let the car idle and hold a long screw driver to each injeector 1 at a time put the rubber or plastic grip to your year and the tip of screwdriver on the injector you should hear a clicking sound. if no clicking then the injector may be stuck on and will need replacing. GL

 

Already changed the valve cover gasket, spark plug tube gaskets, and rocker assembly o-rings. Did the valve stem seals at the same time. Listed those in the first post. I replaced all that trying to get the oil consumption to stop and it didn't help at all.

I am 100% sure it is not an external oil leak. This engine is sealed up tight.

 

Compression test it. Sound then yhat you have bad rings, also check ur injectors to see if their stuck on. You do this by using a mechanics stethoscope or a long screw driver place the metal tip to the injectors and the handle to your ear. You csn hear the clicking. It should be a constant clcking its it pauses or doesn't click eiyher stuck opp en or closed. But for sure u got bad rings if u did all that already. If I got a blown gasket oil would mix with coolant before it gets to the combustion chamber since all the oil ports are outside the water jacket. I would expect wster burning before oil on a headgasket. The smoke from exhaust is blue?

 

Fyi if you are burning excess oil fast then you can create a false reading on compression. Where you leak so much oil you do almost a leakdown test.

 

I'll try to compression test it again today if I get the time.

It blows blueish-white smoke, sometimes black.

It doesn't go through oil super fast, but it does require topping off weekly or bi-weekly.

 

do the compression test cold. dont warm the car up. and only after it has sitten for a night.
this way any one left in the chamber would have had a chance to leak back down past the pistons.
just in case here is how to do a compression test.

1. disconnect distributor
2. open throttle (i use a flat head screw driver to hold it completely open)
3. remove all spark plugs
4. insert your compression tester in chamber 1 to 4 (chamber 1 is closest to the timing best)
5. press clutch (if aplicable) and Gas Pedal Completely down.
6. crank and watch the gauge on the tester. count the jumps of the neadle it will bounce up 5x then stop. check the gauge reading and write it down repeat on each cylinder.
FYI if you go past the 5 jumps its fine if it has bad compression it wont go very high up and will level out at the max of the compression
for a D series engine(well most engines in general) compression at 185 is considered excellent if it is bellow 120 you are in trouble. i say anything bellow 135 is a big red flag anything lower your looking at a rebuild or replace situtation. wish you luck. FYI toping off weekly is alot of oil. im assuming taht what a 1/4-1/2 a quart a week/2weeks thats alot of oil. anything over a half a quart a month is excessive.

IF i have made any mistakes in my guide on compression test please someone correct me. thank you in advance.

 

I'm having the same issue.
Did you ever figure this out?

 

Nope, sold the car like 9 years ago. I did all new top end gaskets/seals/etc, even the valve stem seals. The only things left that would have caused oil consumption/burning oil would have been the head gasket or whooped piston rings.

 

I did a Si Mpfi swap
and manual swap on my 91 dx and my car was running perfect before the swap and the second i got the car started after finishing the swap it smokes, runs rich and burns oil but the parts car i got the swap out of ran perfect and my car ran perfect before.
Do you know any parts i may have forgotten to replace or what might have made it start with mpfi
Haven't been able go find anything about an issue similar

 

If the swap didn't have this issue in the original car but does in your DX, could be some sort of weird issue with crankcase pressure/vacuum system? Beyond that, I have no idea. Sold that car, used the money to build a '98 EK sedan with MiniMe swap, then switched to LS powered cars and never looked back.