I've recently gotten my rebuild up and running. The build is in my signature. I'm having trouble understanding why my trailing time is off. Leading is set with RPMs below 1k, engine warmed up. But I go to check trailing and the pointer is about 1/3 of the way between leading and trailing marks.

Possibly related, but I don't think TPS sets timing, my TPS is not seeming to pass voltage test. It passes resistance test and continuity test. But I set TPS to 1v and start moving throttle and the TPS ranges up to about 3.8v and then goes into OL. This happens very quickly, before I reach 1/3 of WOT throttle.

Later today I'll be putting a different TPS on. The replacement also passes resistance and continuity, but I cannot test voltage until it's on the engine.

 

the TPS has an effect on the trailing split, so fix that and timing should be right

 

This is encouraging news, hopefully kill two birds with one stone

 

TPS voltage at WOT should be between 4.5 amd 5.0, but it will reach this level at about half throttle, so don't worry about that, its normal.

 

^ Throttle probably doesn't even get to 1/4 WOT before it his around 3.something and goes into OL and stays there for remaining throttle movement up to WOT.

Also when I set TPS to 1v and then check resistance on the TPS the narrow range closed is sitting at 1.4ohms rather than the .8-1.2ohms per FSM.

 

your DMM may not be on auto adjust, which means it is "over limit". set it higher and try it again. it depends on the meter as to what it means but if all other tests pass i assume it is just not automatically bumping the range up to the next level.

 

My DMM defaults to autoranging when I turn it on. I have to take it off autorange for it not to be on.

That being said, I swapped a different used TPS. I made a patch with male and female ends for my turbo TPS harness to reach my N/A harness. On my previous TPS I simply soldered in longer wires and extended the harness. This one does test differently. It reaches 4.75v by about 1/3 WOT and holds. My DMM does show one blip just after high 3v where it goes into OL, shows like 7-8v and then goes back to 4.75 and holds. I've been advised autoranging DMM will show OL while it is seeking ranges....because of that for resistance testing TPS set DMM to continuity rather than resistance. With that in mind, I wanted a second opinion so I tested my fathers N/A TPS with voltage. It shows the identically oddity at exactly the same readings. So I think my TPS is good.

BUT my timing is still off on trailing side. I was wrong about it being 1/3 between leading and trailing marks. It is in fact 1/2 way between the two. IIRC that means my trailing timing is advanced too far.

I thought I had struck gold when I first fired up the engine after swapping TPS. Engine idled just about perfect. It sounded much smoother and sounded like timing was on. When I started mucking around to test voltage, timing, etc. It instantly reverted back to how it was idling with the old TPS.

Could my TPS wiring be picking up magnetic fields from the alternator? TPS wiring runs directly behind the alternator and the harnesses meet right around where OMP lines are. I don't have any shielding on my harness patch I created, but neither does the engine harness for TPS. My solder for each wire are solid, I triple checked each wire to make sure I didn't cross any wiring while making the patch. Everything is very clean, with shrink tubing over each solder point and that cheap plastic conduit running the length of the patch. Hell I even did my best to stage each soldered wire at differing lengths so that I didn't have one big "knot" on the harness.

Could I have a problem with my engine harness, battery/alternator wiring

Could my trailing coil be going out?

I haven't had a chance to look through FSM for what to test next, but any ideas would be greatly appreciated

 

that's why i prefer voltage to test, because resistance isn't always accurate on a loaded circuit.

i don't see why the trailing would be off though, unless something else is preventing it from going into idle mode. the TPS won't be thrown off by interference, only very sensitive wiring will be like a knock sensor or O2 sensor would be susceptible to electrical noise.

it could also be something with the Rtek chip, i honestly never checked timing on a car that had a chipped ECU. you could call them and ask if they remapped the split to affect idle.

 

I looked over my literature that came with the Rtek, the only thing it lists about timing is retarding timing for boost over OEM. But contacting them might be the next step while I figure out what to test next.

 

Had a thought. I haven't gotten restrictor pill for my vacuum hose. Is it possible that not having one in my pressure/MAP sensor hose is causing my idle problem?

For the record, no local parts stores has the pill or can order them, Mazda doesn't have them listed either. One of the veteran parts guys at my dealership said he thinks those pills are part of a vacuum and harness assembly and that's the only way to get them via Mazda. They are sold on eBay for Subaru turbos.

 

the oriface has its own page in the catalog, 8931-13-986 worst case you need a piece of something that is 3.5mm OD and .5mm ID...

 

i had heard that the orifice was closer to .7mm id

 

Thanks for the heads up. I thought about making my own, but I don't have any materials to put one together. I've got some JB Weld but I don't have a drill bit small enough. By the time I buy the stuff to make one I can order one for cheaper and easier

 

Do S5 NA's have these restrictor pills?

I put on new vac lines a year ago and I never even checked. Right now, i have no restrictor pill.

 

yes, they did.

 

I haven't had any issues that I know of....****...

How do i source one?

 

you can find them in the help section at some auto parts stores. otherwise you can make one with a small drill and a round billet of aluminum that fits inside the vacuum line. .5mm is probably a little on the small side, .7mm is a little more reasonable.

you probably won't notice the absence of it but your timing is going to be a little on the erratic side due to the bouncy pressure sensor signal. we're probably talking in the range of a max 5whp difference due to timing fluctuations under WOT.

 

What problems can it cause on an NA motor if it isn't there? I am just curious for information sake.

Edit: just spilled beer all over my keyboard, thank god it still works.

 

go to any Mazda dealership and order 8931-13-986. or take something that is 3.5mm OD and drill a .5mm ID hole in it.

 

edited my post with the answer above.

 

Thanks Karack!

Now i must fix my car with a restrictor pill and cold spilled beer crotch.

 

^The woman who brought you the faulty beer should clean your crotch.....just saying

 

without using her hands

 

I need to go to Lowes today anyway, so I'm going to see what I can find to make one. I doubt this is going to have much of an effect on idle timing but I still should have one regardless.

 

Well, I just got a big clue on my problems. I believe I have faulty wiring on one of my engine harnesses. I pulled CELs and found a laundry list that includes most all of the major sensors.

11 - Air intake thermosensor
12 - TPS full range
13 - Pressure sensor
18 - TPS narrow range
30 - Split Air Bypass solenoid
38 - AWS

There also might have been, (don't have my notes in front of me)

33 - Port Air Bypass solenoid

One other extremely strange thing. While disconnecting my battery terminal (-) my aftermarket alarms siren starts going off, but very very low. What makes this incredibly strange is that I do not have aftermarket constant (+) even connected.

I disconnected battery to see if resetting the ECU would clear those codes. When I reconnected the battery negatives my aftermarket alarm siren starts going off full volume. I had to get under my dash and pull the main harness off the alarm CPU.

I'm going to start going through all of my wiring, I installed all my gauges, alarm and stereo several years ago so I do not remember specifics of how I wired it in. I created some common grounds for the gauges as well as alarm.

Also now seems like a good time to do the ECU grounding mod/upgrade. Though I need to read up on that. IIRC you simply splice into the 4 engine harness grounds at the ECU. Create a common ground for all 4 and ground it right at the ECU bolts.

I imagine all my codes are related to improper grounding, cause I find it hard to believe that all those sensors are all faulty. I've got the OEM ground on top of the keg triple grounded. I've got the OEM ground and then I added two 4ga grounds. IIRC I have 2 separate grounds on top of the keg. OEM and one 4ga on one housing bolt and the other 4ga on a different housing bolt. All three ground to the same bolt on the firewall..which maybe where my problem is.