dmcrx7

I set my TPS to 1 ohm and 1 volt.

Using the lights, this makes one light. Could this be the wrong light, other light comes on by itself at 0 v

Idle bounces up and down quickly until I adjust TPS to 0.070 V, then it is perfect.
Also, BAC controls idle at 0.07 v, but does nothing with tps set to 1 v.


At first I thought I had a vacuum leak, but then it should not hold idle regardless of TPS.

Could the ECU be bad?

WAYNE88N/A

Anything's possible, where are you getting this .070v? Out at the connector?

I didn't think it was possible to adjust the TPS down so low, if it's working right...And you're on the right wire...

Check the sucker at the ECU, adjust it to 1 volt (plus or minus .1v) at a 750 idle, hot engine, then if you're still having problems we can look elsewhere...

dmcrx7

I have the ecu feed going into an extra output on my SAFC. Found a broken wire on the BAC last night. Now I can get it to idle at 1V, but my lights don't act right,
I can find the range from 0 lights to 1 but not 1 light to 2.

I am going to try another ECU this week, then I'll have to send it off to RTEK to have the chip switched again if that's it.

Just to clarify, if I can get a good idle by adjusting my SAFC, then there are no major vacuum leaks, right?

Also, I am having a 5000-7000 rpm hesitation problem. Wondering if a coil could be weak. The car will idle off of either coil, but both read 0 ohms on an ohmmeter. How do you tell for sure if they are good? Is it worth over $300 to put a new leading coil in?

Also, could be fuel, secondaries are new, primaries are 7 yrs old and have been cleaned.
Could I have clogged a fual filter or inlet filter in only 3000 miles?

Mod's:
Rebuilt S4 motor with ceramic apex seals and almost all new parts, streetport
ARC TMIC
SAFC,
4x720's
New FD fuel pump
Majestic Turbo Upgrade TO4E - 46 wheel

dmcrx7

Also, could it be my knock box?
I have noticed the car occasionally stumble when checking timing at idle. Timing jumps, then returns to dead on.

WAYNE88N/A

Yeah, if you've got a nice fairly smooth idle, a majorr vac leak is out of the question...

Do you still have the switching solenoid & port air solenoids on the car? If not, the light test may not be working right. The ultimate TPS adjustment is at the ECU input wire anyway, IMO, so forget about the test light thingy. That was a test for the Mazda techs that knew nothing about electrical troubleshooting, lol...

Coils don't go "weak", per se...It's a loop of wiring- it either works, or it doesn't. If you're getting less than 1 ohm or so through the coil, you're good, as long as the coil is not breaking down due to heat, (creating an open in the wiring), which is easy enough to troublehoot (read it out when hot) ....

dmcrx7

Found a broken wire on the BAC valve.
Now to work on the stumble, I got most of it out by putting the vacuum restrictor back in. The old one got sucked into the motor when I put on a new vac line that was too dig ID.

My options are:

1)buy a brand new leading coil or used one from a trusted member, although it sounds like mine is fine

or 2) believe my EGT and greddy A/F meter... EGT stays solid at 700 till 5000 then rockets towards 800 from 6-7000 rpm. A/F hiccups towards lean at the same time. SAFC used to be tuned to -14 to -22 on 680's/720's with -12 at 7000, now set to -10 till 6000, -2 at 7000. This led me to injector, pressure reg, or fuel pump prob. New FD3s fuel pump and 3000 miles on fuel filter, 32psi at idle, 48 psi at 8 lbs boost. That should mean fpr, pump, and filter are good, right.

So, next steps are:
1) replace 5 yr old 720's and try again, can always switch if 1 yr old, 3000 mile 720's are bad.
2) Ignition amplifier like MSD or HKS to get more spark, since I am using RTEK chip, stock ECU and SAFC.

BTW, car is making 235-239 rwhp at 7-8 psi, shooting for a bit more at 11-12psi, may go to 4x750 from injector.com. The car has been dynoed twice with this setup and on track twice, just want to tune it smoother.

Thanks for all your help, wayne

dmcrx7

TPS is now adjusted to 1v, thanks to BAC wire fix.

Could 7's & 9's be too hot of spark plug for this setup?

Mazda comp has some 10.5's I could run all the way around.

dmcrx7

Ok, just finished another round.
Hooked up a pressure gauge after the fuel filter and got 32psi at idle, 45 psi at 8 psi boost.
So that should be good.
Also hooked up a duty cycle dmm to the primary injector signal and voila! the duty cyle drops abruptly from over 60% to less than 40% around 6000 rpm, when the car stutters.
SAFC still shows the right correction, so I assume it is an airflow meter problem, but that checks out too according to the fsm.
If the tach output feeding the SAFC was intermittant, the dash tach would show it too, right?
I am at a complete loss now. I took out the RTEK ecu and put in a spare box with an FCD and no change.
Pressure sensor shows 3.25v at the ecu, so it can't be fuel cut, right??
Could the water thermo sensor cause this quick of a reaction?
May need to plea to Hailers and some of the others on this one.

WAYNE88N/A

What are your secondaries doing when the primaries fall to 40%?

An intermittent water thermo sensor can drive you crazy too, but it's fairly random- it won't happen at exactly 6K rpm all the time if that's the problem...

dmcrx7

That's my next check, it has to be an input to the ecu somewhere, cause I've tried two ecu's
Also going to check rear rotor vs. front injectors and prim. vs. sec.

dmcrx7

I unplugged the water thermo sensor, just in case, saw a code on it when I unplugged the pressure sensor. Also swapped pressure sensors, no improvement.
The problem happens anywhere between 5000-7000 rpm any time its under boost. I found out last night that I can trigger it under moderate throttle and boost- hopefully better than test runs under full boost considering the lean cond.
I have checked just about everything in the fsm for fuel.
Presure sensor reads 2.2 volts atm, 1.8 at idle, and 3-3.25 under boost (FCD)
If not for the fact that I've already swapped ecu's, I would swear its fuel cut.

WAYNE88N/A

Hell, I'm fighting FPR problems, maybe you are too. Something in the air, maybe, lol...

dmcrx7

That is crazy, this morning it dawned on me that that could be it, before I read your post.

When I got off the dyno the other week, my fpr vac line blew off and the car did the exact same thing its doing now. The vac line has since been replaced and checked and checked and...

When I put a test gauge on, I got 32 psi at idle and 45 under boost, I figured that meant the fpr was ok but... when I pull the vac line off at idle, or let the hot start solenoid set it to atmospheric, I also get 44 psi, so where is my extra 8 psi for 8psi boost. So I am ignoring the duty cycle readings as inaccurate.

I am ordering an fpr and fuel filter from mazda comp today, sure hopes this works.

WAYNE88N/A

Mine would hit good pressures too, for a while, then on the freeway somehow would just stay cracked open a bit too much, and the fuel pressures in the rail would just keep falling, I would watch the O2 sensor, and it would go from a good stoich of .4 to .5v, then just start oscillating down, .3 to .4, .2 to .3, etc...She'd hit 0 to .1v, and then the "mini-hesitations" would start. When it got really bad, the O2 would just jump all over the place, mostly down (lean) on any bump in the road. Everything got much better when I pulled the sucker off of the car and cleaned it out and beat on it some, but it's taking so damn long to get another one, she's starting her **** again. Ordered the damn thing over 2 weeks ago from Mazdatrix, it's supposed to be here today. How long is it supposed to take Mazdacomp to get you yours?

dmcrx7

should be here tuesday, it's in stock. What kind of pressure should you see at WOT 8 psi boost?

HAILERS

B/T 45 and 50 psi at wide open throttle. Just put a fuel pressure gauge on your fuel inlet hose and turn the key to ON (with a jumper in the fuel check connector). Look at the pressure. It will be approx 37 to 39 psi. So that is atmospheric pressure or the boost gauge at zero. So just add a psi for every boost psi. As in eight plus 37 to 39psi. That's the scenario with a stock fuel pump, not some overblown aftermarket fuel pump.

dmcrx7

Installed a new fpr and redid my intercooler elbows.
Hesitation is worse. Now any time its under boost.
FPR reads 32 at idle, 48+ under boost.

It acts like someone just turns off the fuel, but the pressure is stilll 48+. I pulled both trailing plugs and they look nice and black, like they should, no sign of the lean condition, but my egt goes flying past the 700c it used to hold and a/f's are way lean on a greddy 5v a/f meter. Have tried swapping ecu's and pressure sensors, disconnecting water thermo sensor, still convinced its electronic. It was running so well in the rpms that it didnt hesitate in that I thought no way an injector was clogged. What about the cat tho. Could a clogged cat cause this? Could I have burned it up in 2 track events and 3000 miles?

dmcrx7

Installed a new fpr and redid my intercooler elbows.
Hesitation is worse. Now any time its under boost.
FPR reads 32 at idle, 48+ under boost.

It acts like someone just turns off the fuel, but the pressure is stilll 48+. I pulled both trailing plugs and they look nice and black, like they should, no sign of the lean condition, but my egt goes flying past the 700c it used to hold and a/f's are way lean on a greddy 5v a/f meter. Have tried swapping ecu's and pressure sensors, disconnecting water thermo sensor, still convinced its electronic. It was running so well in the rpms that it didnt hesitate in that I thought no way an injector was clogged. What about the cat tho. Could a clogged cat cause this? Could I have burned it up in 2 track events and 3000 miles?

dmcrx7

Installed a new fpr and redid my intercooler elbows.
Hesitation is worse. Now any time its under boost.
FPR reads 32 at idle, 48+ under boost.

It acts like someone just turns off the fuel, but the pressure is stilll 48+. I pulled both trailing plugs and they look nice and black, like they should, no sign of the lean condition, but my egt goes flying past the 700c it used to hold and a/f's are way lean on a greddy 5v a/f meter. Have tried swapping ecu's and pressure sensors, disconnecting water thermo sensor, still convinced its electronic. It was running so well in the rpms that it didnt hesitate in that I thought no way an injector was clogged. What about the cat tho. Could a clogged cat cause this? Could I have burned it up in 2 track events and 3000 miles?

dmcrx7

Car starts right up, no flooding/leaking injectors
Car idles fine and cruises fine, compression is three solid swoops all in the 100-110 psi range.

Only ecu pinouts that were out of spec at idle were int air temp sensor 0.9 (1-2 spec) and int air pipe temp sensor 2.94 (1-2 spec), variable resistor 4.95 volts (4-5 spec)
Will check fuel filters tommorow, but fuel pressure shows great. It just acts like fuel turns on and off at whim, but inputs to SAFC all look good. TPS looks solid, pressure sensor, which feed SAFC as TPS looks good, AFM looks good in volts and %. SAFC outputs are stable. Doublechecked all splices. Put new injector connectors on. Need to check injectors next.

RETed

What kinda spark plugs are you using?
Have you pulled the leading spark plugs?
Sometimes the trailings do not give a good indication, so always try and check the leadings if possible.

Man, are you serious???
Ceramic apex seals???


-Ted

dmcrx7

Update:
I check resistance this time on the injectors at the ecu and got 0.3 ohms on the rear secondary, 14.6 on the others - short.
Now I've got the intake manifold off and I am getting .497 k on all of them.
How do I get the main and circuit opening relays to trip so I can trace it down.
Can I just run a new 12v side wire straight back to the ecu to go around the short and cut the existing wire at the connector and ecu?

And yes, ceramic apex seals - my builder talked me into them and I swear they have helped save this motor with these fuel problems. Car dyno'd 239 at 8-9 psi, looking for a bit more at 11-12 with an ARC top mount. It is a blast on the road course (when its running right)

dmcrx7

Ok, Finally got it. Replaced the injector wire, which I think had the rear secondary running intermitttently all the time. No wonder it was hard to tune with a SAFC. I went ahead and replaced the secondaries incase the one got damaged by running 100% duty cycle.
Still had spiking A/F and EGT's, but it flet like it was rich. So I started leaning it out and it started running better and better. Fine tuned it on the dyno. Now I'm off to Carolina Motorsports Park to try it out.
Car dynoed 205 before and 230 after at 11 psi. on a Dynojet. Definately a more conservative dyno than the dynapack.

dmcrx7

EGT is now holding steady at 725c and A/F is between 11 and 12 (10.75 to 11.25 on dyno's wideband)