I guess now its my turn to have a stupid problem I can't seem to pin down. Here is the problem with some history.

Replaced the fuel pump with an FD pump, changed strainer and filter at the same time. Took of UIM to fix an OMP line that had broke. New plugs were put in. Car was running stellar.

Went to Deals Gap Rotary Rally. Beat the snot out of it. No problems.

On the last leg of the drive home, I noticed there was a slight hesitation and the car felt like it was bogging at part throttle.

Got home, took off the TMIC and UIM, noticed a bunch of cracked vacuum caps. Decided to replace all of them. Also decided that at the same time I might as well throw in some BRAND NEW injectors (I get them CHEAP).

Today after work, I put in the new injectors, all new vacuum caps, new booster line.

Crank it, catches, dies, repeat.

Jumpered the fuel pump, flowing good, can hear it splash return into the tank.

Checked the plugs, a little wet. Replaced them.

Crank, catches, dies, repeat.

Took it all back apart and did it all over again. Same result.

WTF.

Help please.

 

Is your AFM plugged in or working correctly? I know once I forgot to plug that in and the car would do exactly what yours did.

Mike

 

AFM was NEVER unplugged.

But that was the first thing I checked.

I'm thinking I might have cracked the lower injector grommets when I reinstalled them. They were pretty dry and hardened.

But I don't know if that will cause this or not.

 

This may sound stupid but I am assuming by vacuum caps, you mean one way check valves... If that is the case, you may have one or more of them on backwards... Other than that there is probably one or more vacuum lines not connected or maybe they are old and cracked...

I suggest replacing all vacuum lines when you pull the UIM since you are already there... Dont use the cheap silicone ones from the local auto parts store... I did and I have had nothing but problems with them shrinking and coming off or even collapsing when I throttle up...

Also check the compression of course...

Do you have an aftermarket FPR? If so pulle the vacuum line off of it and watch it while you try to start it... See if gas is coming out of the vacuum port on the FPR...

I hope at least one of these suggestions help... Good luck...

 

I have no emissions on my car. So no 'check valves'. lol.

I only have three vacuum lines, they are new, and its impossible to screw them up.

Stock FPR, holds pressure.

 

Just ordered some upper and lower injector grommets from Mazdatrix.

I would still like some insight in cast this is not the problem.

 

I'm with bushy tea on this one. I accidentaly bumped my afm off one time and didnt notice(wasnt clamped). And the car would start catch and instantly die.

 

go back and check everything that you did....it wasnt dieing before you replaced some of these things so the best bet is that you might have a huge vac leak, or maybe a connector you forgot to plug back in.....double check everything

 

it sounds like you have a vaccum or intake leak.

 

Dumb question.. I know I have had issues with every car parts store known to man (ask me what happens when you get the wrong axles for a miata) is it possible they sent you the wrong impeedance injectors? I know your car is S5 but maybe they fuckared them up.... Or your injector ground isn't on tight....

 

No, I got them myself through work, they are the correct ones. Double checked all the part numbers, crossed them over, tested them (click open/closed) they are definetly NOT the problem.

I ordered the grommets, I will take it apart when I get them.

Here is all that needs to be removed from my car to do this job (in order):
-TMIC
-Throttle Cable
-Unplug TPS & AIT
-Disconnect brake booster vacuum line
-Disconnect OMP vacuum spider
-Disconnect boost sensor vacuum line
-5 bolts and the UIM is off and open

Trust me, its all together right. I am ALMOST sure its the injector grommets.

I would like a 'guru' to give some insight.

 

Sounds to me like you have a major vacuum leak. Possibly the uim gasket, or one of your tmic hose connections. I just fixed a buddies car with the exact symptoms you are having a couple of weeks ago by repairing a major vacuum leak.

 

Wouldn't a bad injector grommet(s) cause a major vacuum leak? It may not be a vacuum line, but it is still a vacuum that is not supposed to be there which would cause all other vacuum dependant functions (I think he said he only had two vacuum lines and a MAF) to be deprived...

 

What happens when you get the wrong axles for a miata?

 

^...you don't drive the aforementioned miata for another few days?

Sounds to me like a major vacuum leak (big fitting or hose left loose, etc.) or the bad or unplugged afm. The ecu has a default fuel delivery map for cranking, and only once it catches does it rely on the AFM for correction of fuel. So, your cranking map is starting the car, but the afm correction is not working.

Either the afm is stuck shut, showing the ecu no airflow, the ecu then leans out fuel and the engine stalls. Or the afm is unplugged, see above. OR the afm is working, but there's an air leak sufficiently large to let air in and keep the afm nearly closed, see above.

I might be tempted to throw the old primaries back into place just to see what happens, as that was the only relevant thing that was changed since the setup last ran.

Also the TPS must be plugged in for the ecu to let the engine run...be sure you have a good connection.

 

I've ran my car just fine without my TPS plugged in. My idle sucked... but it still drove fine.

 

Is your car s5 or s4? My s5 will not stay running without the TPS plugged in. Now my s4 would run all day.

One time a field mouse chewed through my AFM wiring when I let the car sit for a couple days... Why do they love the taste of wire??

 

I know I have no vacuum leaks at the UIM a or any of the hose connections.

It either has to be the Injector Grommets, AFM or TPS.

The TPS was unplugged, but the AFM never was, but I will still check.

Waiting on Mazdatrix.

 

s4 cars will *usually* run without the TPS. Hell, sometimes they run better without it.

s5 cars will NOT run without the TPS in any way, shape, or form. Most will not even start without it.

 

Yeah, should of clarified. I have an S4.

 

*UPDATE*

Well today I put took it apart again.
-new vacuum lines-every one
-new vacuum caps-every damn one
-new injector grommets
-NEW injectors

Still does the same friggin thing. Nothings changed.

Checked the AFM for connections and free movement of the cone. Its fine (no multimeter check, yet)

Checked the injector plugs for pin issues. Nothing all good.

I even put the stock BOV on incase the Apexi one was leaking. No change.

No check engine light.

No start.

I'm getting pissed.

 

Here is another question to maybe go along with this.

How long should the pintle caps be?

The new injectors have a longer pintle cap than the old ones, but otherwise the same. I would not assume that would make a difference. But who knows. I might put the old ones back in and see what happens.

 

.

 

Thanks Kev. LOL

 

I've got a 93 FD and seem to have the same problem! I can start it but it dies after about 2 seconds, New fuel pump, filter and I have no idea why it isn't running!