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.
I am currently wrapping up my M2 medium intercooler and intake install for which I had been gathering/fabricating parts for several months. The original plan was to retain the stock air pump which is the reason for running the bent tubing on the hot side of the IC. I thought I could outsmart that whirling chunk of steel with a few bends, but it got the best of me and I put on a pineapple idler pulley (thanks, Jim!).
I am running a PFC. The O2 feedback is OFF and always has been. I had idle tune roughed, though it has always been quite rich and stinky any time I unplugged the airpump to tune. AFR is around 12 at idle IIRC. Can't remember if that was always the case and I don't have any old idle logs.
My understanding of the air pump/acv/split air is that it puts air into the exhaust ports and cat... so, capping the two hard lines above the turbo is the same as blocking off the ACV correct?
I plan to remove/block off the ACV down the road, especially if I yank the UIM to put in bigger secondaries.
The reason I ask is that after the engine fully warmed up it surged between 500-750 rpms. It knocks it off immediately with any throttle input. It was always a rock-solid idle before this work. I haven't idled it that long and haven't even driven it yet with the new setup.
Here is a list of what I changed:
-Remove air pump, cap two hard lines above turbos
-Greddy elbow with no AWS nipple, cap hard line leading to AWS valve
-Re-plumb catch can (oil neck -> catch can -> primary turbo elbow nipple) was previously just vented with a breather
Should I play around with idle tune a bit more to see if that helps? Did I not delete the air pump correctly? Do I need to re-learn idle with the PFC? Advice appreciated.
The ACV has 3 external inputs/outputs - the air line coming from the air pump, the relief line that goes back to the stock airbox (to be silenced), and the air line going to the main cat.
Internally behind the ACV is a check valve that is for air going into the exhaust manifold.
If the ACV is still plugged in with its solenoids and the vacuum rack solenoids are still plumbed in it could do some weird stuff since it's not receiving any air pressure at this point.
Removing the ACV and blocking it off isn't too bad. Get some 1/4" drive tools and a 10mm socket that has a universal joint built into the socket and decent length and you can get to all 3 nuts that hold the ACV on. Trying it with 3/8" drive tools there's no way you can fit in there. If memory serves you can do this without removing anything but the UIM, you may have to remove the coil packs but that's easy.
This should take about an hour in total to do, I'd go ahead and do it before trying to figure anything else out.
Ok I plan to do that when I get the plates from Banzai and get a free evening.
Any harm in driving it in the mean time? I have been itching to since we've had a few warm days recently. Almost drove it this morning, but the lemons car blocking the driveway wouldn't start
Not that I can think of. You may have some odd noises, I was working on a car once with air pump and ACV removed and the port for the split air pipe to the cat was unplugged. That port made some odd noises for whatever reason. Once it got a block off plate it was fine.
Blocked off everything that was removed using the Banzai kit. Capped off unused solenoids and hardlines/nipples. Relocated the upper turbo control solenoid to the old crossover pipe bracket.
Car idles great again. This intake and IC kick ***. Looking forward to playing around with the duct inlet and seeing what kind of IATs I am getting now at 13 psi during autocross.
Tuned idle to around 13 AFR. It was at 12 and would make your eyes water!
AFR would go higher, but I heard that could push EGT's too high. Confirmed my suspicions that it would be stinky without the air pump. 13+ AFR no pump smells way worse than 12 AFR with the pump on. Oh well... I kinda like the smell!
Thanks for the info about the smell without the airpump. I hate the smell. I'm in the process of converting my CYM to sequential and was tempted to remove ACV and air pump but decided to keep it.
Me too! I was missed the car and have been ripping around in it the past few nights after hours.
Yeah, it stunk up the garage a bit when I pulled in last night and let it idle for a few seconds. Not enough to really bother me, but worse than before without a doubt.
I toyed around with the idea of a GM electric air pump or making the old one work somehow, but ultimately I just wanted the car back on the road.
Do you have a cat on the car or a mid pipe? I have an SMB high flow cat with no air pump and there is some smell but nowhere near as bad.
Johnny you can do a "smell test" on my car at DGRR to see what you think .
Also I think the electric air pumps are a pipe dream. They are typically designed for occasional use (I know the RX-8 pump only runs for like 10-30 seconds on cold starts). The RX-7 is designed to run the air pump constantly. An electric air pump would likely burn up in short order from being run constantly. Also, they are bulky and it's a plumbing mess. I know a number of people have talked about doing it but no one I know of has ever done it.
When I went single turbo back in 2004, I had to remove the the ACV in order for my 1600 injector rail to fit.
I kept the air pump which was modified to clear the singles air filter. The air went from the pump directly through a modified tube to the MP which had an
air inlet pipe. Thus up to 3000 rpm, the air pump was always forcing air into the MP or CAT for yearly inspection.
It did its job and made the exhaust smell better.
Do you have a cat on the car or a mid pipe? I have an SMB high flow cat with no air pump and there is some smell but nowhere near as bad.
Johnny you can do a "smell test" on my car at DGRR to see what you think .
Also I think the electric air pumps are a pipe dream. They are typically designed for occasional use (I know the RX-8 pump only runs for like 10-30 seconds on cold starts). The RX-7 is designed to run the air pump constantly. An electric air pump would likely burn up in short order from being run constantly. Also, they are bulky and it's a plumbing mess. I know a number of people have talked about doing it but no one I know of has ever done it.
Dale
I have a Bonez cat. Don't worry, these days I don't have the time/stubbornness to attempt something like an electric airpump.
I have been playing around with idle AFR via PFC commander INJ correction table and it's gotten much better. I might need to do a proper log instead of just guessing at how much fuel to take out and where.
With a stock ECU, if you just leave the solenoids in the rack it will be fine code-wise. Removing the ACV will log a code since it does have 2 or 3 wires going to it, that can be addressed with resistors.
You SHOULD be able to pass emissions but only an emissions test will show for sure.
If you are running a PowerFC it won't care if you remove the solenoids. You can also wire up the Check Engine light to the PFC so it blinks when you have knock, etc. I think in doing that it will come on then go off when you start the car.
My post is not about the posted problem but how to solve problems.
You first have to understand how the air pump/ACV/ works with the ECU and how it functions.
Then what effects happen when removing parts of it and how to compensate or make it work again.
You sometimes have to be imaginative and think outside the box for solutions.
Currently there are many facts/data/information about our 27 year old cars and how to modify them.
Unlike back in the 90s when people were removing air pumps and wondering why the idle got so screwed up:
why the ISC system went weird when the ACV was removed: why the idle went weird when the DATALOGIC INJ map was RECALC into the base map, etc.
Whenever air or fuel flow is changed, re-tuning is often involved.
The problem is formulating the correct search function to find fixes on this site. I prefer to USE GOOGLE ADVANCE against a sub-forum URL then using the sits feeble search.
So the car has been running great with the exception of a tough to tune idle AFR.
Most of the time it has a good solid idle and decent AFR from stone cold to fully warmed. Somewhere in the 12.5-13.5 range.
Where I run into problems is warm starts like if it just sat for an hour. Idle is lean around 15 lambda and surges. It's fine when it fully warms up again.
Based on the PFC tuning notes... Am I correct that I should use the PFC water temp correction table to try and alleviate this?
I had a similar problem with a restart after the car was already warmed up after my last rebuild. I too had a lean AFR immediately after restart. If you still use the fast idle on the throttlebody like I do, this is already disengaged on warm restart and therefore does not help keep the idle higher on the restart. I found the problem was I did not have enough fuel in the basemap right below my idle area. The typical vacuum while cranking is less or right below your idle vacuum cell on the basemap. Add some fuel, 5% of so, in the cell or two right below idle at 800 rpm. This should not affect your idle AFR since you are in the cells right below.
Mike
Thanks. I'll give that a try. My throttle body is completely stock, so it has the thermowax and fast idle cam.
You are saying that on hot start the typical idle cells weren't being used?
On my engine the idle cell is not used. I would just crank your car and see the boost readout on the commander and correlate it to the correct cell or use the cell display function on the commander and see what cell is being used while cranking. I would add fuel to this cell and maybe a little to the above and below cells as long as it isn't your idle cell. I also match the fuel in the 400 rpm cell to the 800 rpm cranking cell since when you first crank the lower rpm cell will also be used.
02-14-19, 08:58 AM
.
