jjacks01

iTrader: (7)

Ok Guys,

I am sorry to bring this to the main forum, but i have been working this on the new member line and have not gotten this resolved. I have an 87 TII and i just installed a JDM engine. All of the electrical is hooked up with the exception of subzero start, EGR, secondary air. THe coolant temp(s), TPS, AIT, AFM, CAS, coolant fan swithc and coolant level, oil pressure, and IMP sensors are hooked up. The engine cranks and quickly fires every time only to die almost immediately. Here's what I have done:

-checked the AFM teminal resistances per FSM they check OK. Nonetheless I hooked up a second one ... same result
-jumped the fuel pump jumper ... same problem
- With the ign on, manually moved the afm vane and i hear the fuel pump and circulation in the rails.
- checked operation of the circuit opening relay and resistor regulator...the fuel is flowing.
- Checked and adjusted TPS to 1.0 volts
- chacked the AIT sensor resistance 32kOhms within spec.
- checked EVERY possible vaccum leak multiple times
- checked that the fuel lines were not backwards...

Again the car fires strong but cuts almost instantly. The strange part is that the car will actually run without the AFM hooked up.

Any other possible leads?

I understand the afm is not used in start mode. After stsart mode it relies on the switch in the AFM on the first two pins (E and Fc) Mine appears to work as the fuel flows when the vane moves a bit. Does the AFM have any other way of shutting it down?

Does the ECU shut the engine only by fuel or are there modes that kill spark only. It appears that the ecu does not acutally control spark, the CAS does it all...correct?

Help!!!!!

JOn

calpatriot

Is it possible that the AFM signal is not getting to the ECU, i.e. bad wiring between the AFM and the ECU?

misterstyx69

iTrader: (142)

Check the fuel lines at the engine.
the Ratsnest is slightly different and the Fuel lines are Backwards,compared to a US engine.make sure that the Rubber line From the car's fuel filter is Going to the Primary rail and the Return is coming of the Steel line/rubber line from the secondary rail.

jjacks01

iTrader: (7)

Thanks for the responses. Ireally think this is very atypical problem or I am just off my rocker....

Today I replaced the ECU with another known good ECU... same problem. I also rechecked the fuel lines for the umpteenth time. They were correct. Just to have all my bases covered I switched the fuel lines. She will not even fire. Put them back... she fires.
I also rechecked the pins on the fuel pump resistor relay and resistances are w/i FSM numbers. I pulled the green /red (ECU ground to reduce voltage to ~9) just to take it out of the equation. No effect. so my running current status is:


-checked the AFM teminal resistances per FSM they check OK. Nonetheless I hooked up a second one ... same result
-jumped the fuel pump jumper ... same problem
- With the ign on, manually moved the afm vane and i hear the fuel pump and circulation in the rails.
- checked operation of the circuit opening relay and resistor regulator...the fuel is flowing.
- Checked and adjusted TPS to 1.0 volts
- chacked the AIT sensor resistance 32kOhms within spec.
- checked EVERY possible vaccum leak multiple times
- checked that the fuel lines were not backwards...
- switched fuel lines to be sure... they are correct.
- repinned resistor relay...looks good.
- Removed ECU ground to resistor relay to keep it at 12v for simplicity

Again the car fires strong but cuts almost instantly. The strange part is that the car will actually run without the AFM hooked up. As soon as you kook up the AFM she dies.

Any other possible leads?

I understand the afm is not used in start mode. After start mode it relies on the switch in the AFM on the first two pins (E and Fc) Mine appears to work as the fuel flows when the vane moves a bit. Does the AFM have any other way of shutting it down?

Does the ECU shut the engine only by fuel or are there modes that kill spark only. It appears that the ecu does not acutally control spark, the CAS does it all...correct?

And can anyone tell me where i can get a GOOD wiring diagram for S4 fuel pump related item. THe ones online are cut in half that I found.

Thanks!!!!

JOn

jjacks01

iTrader: (7)

THought of one more thing that may be im portant. i also tried starting the car and holding in the start position after she fired as this would supposedly keep one of the fuel pump power ciscuits closed and at least keep the fuel pump running.... she still dies right away if i HOLD the key in START position....

JOn

jjacks01

iTrader: (7)

Moderator, please rename this thread "Save an FC from going into a lake"....ha ha

OK I am more perplexed than ever. I connected the fuel pump wire to battery to run the fuel pump continuously and get the circuit opening relay and resistor / relay our of the equation. I still have start and die!!! so we are not dealing with a problem with the afm, etc. What else can shut the engine down in the control system???

I also tried to pinch the return line to increase FP...no change.........

Another clue..sometimes she will start and during the spin down she has attempted to catch again once she gets down to 1000 or so rpm....


If i cant get this thing resolved she's going for a swim!!!!

RXJIM

iTrader: (3)

Agreed. Have you checked wires from AFM back to the ECU yet? Pm HAILERS if your convinced it is a wiring problem. He-da-man!

http://foxed.ca/foxed/index.php?page=rx7manual

This is the site I use for FSM and parts catalogs. Page 50-25 has the wiring for the AFM

Banzai-Racing

iTrader: (11)

Sounds like you have checked everything in the fuel system but not the ignition system. Verify that you have 12V at the coils with the key in the run/on position. This would be the black/yellow wire, it is also the 12V power for your fuel injectors.

jjacks01

iTrader: (7)

I will plan on tracing the afm wires and the ignition leads this evening. I was assuming that I have ignition as we can make her run. Are there distinct ignition modes or circuits for start vs running as there is in the fuel system?

One problem is that the FSM is not real clear to me exactly which afm pin goes to which cavity on the ecu....but from a search i found a post that had the color of the wires on the afm plug and they appear correct....

Thanks again everyone.....!!!!

JOn

jjacks01

iTrader: (7)

OK, an update, I pinned everything last night and the wiring appears to be correct. I made sure every contact was clean. Upon reassembly I can now get the car to stay running if i keep my foot on the throttle or bounce the throttle beyond a certain point. Seems like vacuum leak to me, but I will have to go over the system in its entirety. Any conjecture or suggestions to check.

I also installed the checker LEDs and I get a code 7 - boost sensor. checked Vref and signal at ECM and they look good. i understand this would not affect my idle... could I be wrong?

JOn

RXJIM

iTrader: (3)

Did you rebuild the engine? I had a friend that had to do a little dance on the gas pedal to keep it running after a rebuild.

cone_crushr

iTrader: (18)

When you say EVERY possible vaccum leak, do you include the fuel injector air bleed o-rings? I had identical symptoms and traced the problem to them.

ajmacke

I second that Cone... the o-rings on the green plastic parts that includes the fuel atomizers that the injectors seat into are what he is talking about, if you aren't familiar. I think mazda trix called them air bleeds, mazda motorsports called them injector sockets. O-rings should part number 9954-10-1252 from mazda, iirc. Might be able to test by getting it to run, maybe with the afm disconnected and spray something like carb cleaner around the base of the injectors.

gavinmosher

My car was doing the same thing earlier today come to find out i forgot to hook the hose on the underneath of the intercooler on the driver side once i hooked it up it stayed running now i just have the problem that it wants to die under boost

jjacks01

iTrader: (7)

I will give this a try shortly... I am open to any ideas on vacuum leaks as I would have though I hadve most areas covered. I looked closely at the rubber bushings around the injectors...but may have missed an opportunity here. She definitely runs now in the upper rpms and is responsive, but the symptoms really seem like vacuum leak.....just not an easy one to spot!

Thanks for the ideas !!!

JOn

HAILERS

http://www.teamfc3s.org/info/articles/idle.html

Air line from the BAC to turbo outlet duct off???

Checkvalve installed in the aft side of the TID?

BOV (I think it's called air bypass valve in Mazdaspeak) plugged into the aft side of the TID?

Brake booster vacuum feed line left wide open? I'm not sure where this is on your JDM engine. ON a USA series four car it's on the backside of the upper intake manifold,. ON a JDM I think it's on the lower intake manifold.

TID cracked AT where it attaches to the turbo?

Fuel lines on a JDM are different than on a USA turbo engine. But you seem to have fuel so I guess that in't a problem now.

cone_crushr

iTrader: (18)

You should be using something like carb cleaner spray to trace out the vaccum leak as aj mentioned. I prefer starting fluid, although, use at your own risk.

jjacks01

iTrader: (7)

All, Thank you for your suggestion and pointers.... I wanted to give some closure to this thread so it can be beneficial to future searchers. I removed the upper intake today and the fuel rails and as per these suggestions checked the injector air bleeds. I noticed one of the middle sockets ( spacer with O ring) had a crack in it and replaced it from one off the original motor. I also cleaned up my injector grommets and reinstalled. during the process I noted that one of the injector connectors was in pretty poor shape. The crimped metal end was not staying in the plastic connector. I redid the the connection and shrink wrapped it. TO make a long story short i am almost there... she starts, stays running although she wont do base idle speed. I assume at this point its just tuning....Thanks a bunch. i will put a wanted add in the appropriate section for low impedance center notch connectors to replace mine shortly!!!!!

This did bring up a question. I performed the emissions removal per the rotary resurrection instructions. In that they instruct to cap the vacuum port for the primary injector bleed. (vacuum nipple between the two secondary oil nozzles on LIM) This seems to serve a purpose...is this wise?????