When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Encountered this problem last night. Car sputters under load and struggles to get through rpm range. Changed all 4 plugs and made sure I was getting spark from each wire. AFRs seem normal around the 11s and 10s when I'm putting it under load. I thought it might be an electrical draw since I was driving with my headlights on, but it does it with them off as well. I don't see any vacuum leaks.
Only thing I did yesterday was put fuel in it and premix. I over premixed by 5 oz because my fuel gauge is 1/4 off and this was my very first fill up owning the car. I was shooting for 1oz per 1gal since my omp is removed. Check out the video below. Frame rate makes the gauges hard to read.
Tested a bunch of stuff just now. Seasoned all the fuel and or in 2 new gallons of 93 premixed at 0.75oz/gal. Did a compression test on both leading plugs. Got 60 psi at both. My compression tester I think is reading low. Tested the pressure with my air blower which the regulator was set at 160 psi and the compression tester read only 120. So if it's off by 40, then that means my engine compression test should have been 100 on all faces. Still getting the sputtering. Catch can was full so I thought the oil might be making its way back into the intake. Emptied that out and checked the forward turbo. Not a drop of oil on the turbine or inside the piping. Tested the wastegate actuator with air compressor and it moves freely. On my test run after getting new gas I noticed oil all over the engine bay. Somehow I'm building up enough crankcase pressure to blow the dipstick up and shoot oil out. The pcv system has been deleted. Line coming off of oil filter neck to in on catch can and it goes to nope on forward turbo inlet piping. I'm really stuck here. Also just to add this engine only had 1,100 miles on it. Rebuilt and street ported by IR Performance. I think next step is to plug in they laptop to the haltech and see if there is any usable days to help track this down.
Tested my lead coil pack this morning. Plug leads read 12.25 on resistance but the pins for power read 1.6 ohms which is above the spec. FSM says it needs to be below 1 ohm and if abov, replace. So I think that's what I'll do. Going to try an fc leading coil pack just to see if I can get it to clear up.
Ok I checked all of the coil packs and I was getting the same numbers on all 3, 1.5 ohms. So I can't imagine all 3 packs are bad at the same time. As mentioned before I am having crankcase pressure issues. So I took the oil filler cap off and zip tied a paper towel around it. Also disconnected the line coming off of the catch can going to the turbo inlet. Dipstick stayed in place that time. Oil pressure is reading pretty high under boost. I only have the stock gauge, so the mark directly before the 120.
Get another compression tester. Anything else is potentially wasted effort until you verify you have good compression. And remember that a piston tester will only give you compression on one rotor face with the most compression.
It will only give you compression on the highest face after you release the the button on the side of the tester. It bounces at the same psi on all faces. I verified that this tester is off by 40 psi.
There is no negative on the compression gauge, but when it was tested against 160 psi of air pressure it registered at 120 psi. I doubt the car would even run if all 3 faces on both rotors we're actually at 60.
I dont think the oil has anything to do with your coil pack. Grab the meter set it on Ohms, touch the leads to each other and see whats the resistance so you can subtract the lead resistance to your coil reading. Usualy the leads add .8 Ohms to the reading. Does the oil presure get high.?
Here is a list of everything that is done to the car. Still have the stock coils. Relocated to where the cruise control module would normally sit. Again, has new plugs (9s on all 4), new fuel filter, drained tank. Also here is a detailed list of everything that I have tried since last Thursday (mod list is after troubleshooting below):
Thursday morning 4/26: Drove car to work in the (30 miles). No problems got into boost maybe 2 times.
Thursday afternoon 4/26: Drove home from work (30 miles). No problems. Boosted very little. Stopped to get gas before getting to house. Put 14 oz of Idemitsu premix in the tank, but only 9 gallons of fuel went in (gauge reads 1/4 lower than what it should, maybe bent float on pump).
Thursday evening 4/26: Drove to movies (20 miles). Very little time spent in boost. No problems. Parked car for 3 hours.
Thursday night 4/26: Leaving movies. Started car. Exhaust smoked a little more than normal on cold start, didn't think much of it. Drove fine until under load and in boost. Started breaking up/misfiring throughout rpm range under boost. Thought I might have gotten bad fuel or I over premixed. stopped at gas station to add an additional 2.5 gallons to help even out the amount of premix. Still getting breaking up. Got home and parked car. Idle sounded "off" slightly. Shut car down and went in for the night.
Friday evening 4/27: Pulled spark plugs. They were "dirty", but didn't look fouled. Changed plugs anyways, 9's on all 4. Checked spark by holding plug near ground on all wires. Had spark. Went for test drive. Still breaking up. AFR's were reading 10s-11s under boost. Engine temp was fine. Oil pressure was about 100 under full throttle. next I decided to drain the fuel tank. I thought, maybe it was bad fuel or I accidentally put in 87 just out of habit from the daily. Drained tank and put 2 gallons of new 93 fuel in with 0.75 oz/gal of premix. Took it for a drive. Still breaking up. Now I am building so much crankcase pressure that I blew the dipstick up and oil shot everywhere under the hood. Next I checked compression on both rotors only on the leading plugs. Compression gauge is cheap and doesn't read full pressure (tested against 160 psi of air pressure and it read 120 psi). Got even bumps on each face on both rotors at 60 psi (remember gauge reads low so should be 100 psi). If they indeed were at 60 psi, I doubt the car would even start or be able to stay running under its own power.
Saturday morning 4/28: Tested resistance of leading coil. FSM states plug pins should read below 1 ohm. I got 1.5 ohms. High tension leads should read between 9.6 and 16 ohms I got 12.25 ohms. I thought the coil was the problem, but then I tested the 2 trailing coils and got the same readings on the electrical connection of 1.5 ohms. I don't think that all 3 of my coils could be bad and have failed at the same time.
Sunday 4/29: Took oil cap off and disconnected out line from catch can going to turbo inlet. Zip tied a paper towel around both locations to help relieve pressure build up. Test drove. Still breaking up, but dip stick stayed in. Towels not covered in oil. Hooked laptop up to Haltech to try and see if there was any data that would scream at me. I really don't know much of what I was looking at, so not sure it did me any good. Went for a test run and did some data logging. Car is running super rough at this point (sounds like it's firing on one rotor). Sounds like it has a cam. Getting harder to start without giving it a little throttle. Will also die after running on its own power for several minutes. Decided to change the fuel filter. Test run, nothing changed except I blew oil all over my engine bay again (soaked throw the paper towel). I took the intake side off of the throttle body and saw no oil in the intercooler piping or intake. I did see oil behind the butterfly valves on the throttle body (engine side). No oil on the turbo side either. Turbo forward (still twin ran in parallel) had no play or oil on turbine. No oil on intercooler piping for hot side. Did another compression test and got same results as before. Last thing I checked was the brass filter on the catch can. Didn't see anything really clogging the filter or that screamed at me there was an issue. There are a few things that I didn't get a chance to test yet. The resistance of the plug wires and the igniter.
RX-7 Modifications
Electronics
Haltech Platinum Sprint RE ECU
Silicone-Wrapped Engine & Charge System Harnesses (Haltech Loom/OEM; New Connectors/Terminals/Relays)
So do you have non-sequential twins or a single turbo?
Do you have the stock PCV system at all? Do the line(s) from the oil fill neck go to a catch can?
Don't know if the Haltech has an easy way to look at the sensor inputs (I imagine it does). Worth making sure they are all reporting in at normal ranges especially the water temp, TPS, MAP sensor, intake air temp sensor.
The amount of oil and crankcase pressure is alarming. Any smoke from the tailpipe?
still twins (run in parallel)
No PCV system. Line ran from oil filler neck to in on catch can and out ran to nipple on forward turbo inlet pipe. I have since removed the out line to the turbo and placed a paper towel over the out bung.
I'll include a picture from a data log I did. Only has MAP, wideband and RPM overlaid. Other channels didn't seem to be out of the normal, but i don't really know much about tuning.
I am only getting oil smoke on cold starts, it dissipates after warming up. I had several people watch as I did a test run and they reported no smoke coming out of the exhaust at any throttle condition.
Well, if your datalogs are actually spot on (Which it's really hard to tell as the Y-axis only shows kPa), it looks like there are massive lean spikes as your RPM is increasing. Assuming your car is tuned for your mods and nothing changed between engines mechanically, I would still put money down on injectors being dirty and having poor spray patterns but that doesn't explain the amounts of crankcase pressure.
Lean spikes are from lean out on decel still being active. The car hasn't been tuned since the rebuild. Had no problems running on base tune until now.
04-27-18, 06:26 PM
