stumbling and choking after 5,000 rpm?
#43
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You can't imagine how much help and advice you have given, I can say on behalf of the members here and espeically me the great appreication for you contribution. Sorry if I put that in a bad manner. I am just very fustrated and tire thinking the possbilites of it going sour!
#46
Figured as much. You are probably dumping raw fuel out the tail pipe
When you changed to the walbro pump the problem got worse right, the stumbling came on earlier. Stronger pump builds pressure earlier, makes sense.
Using the 12:1 disc and the OEM pump you will max out pressure (85psi) at only 3psi of boost (in reality it is more like 70-80psi). As the boost climbs FP does not becasue the pump is flowing all it can. Now put in the Walbro and at 5psi you are getting 110psi of fuel. The 12:1 disc and the walbro are WAY WAY to much fuel, especially with the 1.8 injectors.
Why it did this with the OE fuel pump? Maybe you had a REALLY strong OEM pump and it was able to sustrain the higher pressure.
I bet if you could get a 6:1 disc you'd be in business providing the FPR you have now is working properly and is installed correctly.
Hope this helps.
When you changed to the walbro pump the problem got worse right, the stumbling came on earlier. Stronger pump builds pressure earlier, makes sense.
Using the 12:1 disc and the OEM pump you will max out pressure (85psi) at only 3psi of boost (in reality it is more like 70-80psi). As the boost climbs FP does not becasue the pump is flowing all it can. Now put in the Walbro and at 5psi you are getting 110psi of fuel. The 12:1 disc and the walbro are WAY WAY to much fuel, especially with the 1.8 injectors.
Why it did this with the OE fuel pump? Maybe you had a REALLY strong OEM pump and it was able to sustrain the higher pressure.
I bet if you could get a 6:1 disc you'd be in business providing the FPR you have now is working properly and is installed correctly.
Hope this helps.
#49
Just buy another turbo miata and swap parts. Seriously, my car stumbles bad at the middle rpms under boost at WOT, but goes great past 5K. I just figure there is too much fuel to get used until the upper rpms. Shows what I know!? It would probably be a good idea to diagnosis this while the setup is simpler, but I am basically doing the same thing, just switching to MS. Just don't have the car out of the garage yet to get tuned by a friend. The screwy idle does tend to lend itself to a vaccum leak. Spray something in the engine compartment and watch it get sucked into the leak. Just watch what you spray.
#51
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im still heading more towards vacuum leak and not fueling. Overfueling in boost will not cause his idle issues. and if anything stumbling/hestiating is more of a lean issue.
And I still want you to check for fuel leaks damnit....takes 2 mins tops, dont need a gauge; just a paper clip and a wrench.
And I still want you to check for fuel leaks damnit....takes 2 mins tops, dont need a gauge; just a paper clip and a wrench.
#53
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I've run a complete weekend on the track running 9:1 AFR and 170rwhp (I dynoed the day before)....no bogging/hesitation/choking, just less torque.
It might end up being a fuel issue, but I dont think overfueling is the answer. Cause now with 115psi and the same thing, not worse, then i'd rule it out.
other things id consider: coilpack, wires & plugs, afm.
It might end up being a fuel issue, but I dont think overfueling is the answer. Cause now with 115psi and the same thing, not worse, then i'd rule it out.
other things id consider: coilpack, wires & plugs, afm.
#55
I've run a complete weekend on the track running 9:1 AFR and 170rwhp (I dynoed the day before)....no bogging/hesitation/choking, just less torque.
It might end up being a fuel issue, but I dont think overfueling is the answer. Cause now with 115psi and the same thing, not worse, then i'd rule it out.
other things id consider: coilpack, wires & plugs, afm.
It might end up being a fuel issue, but I dont think overfueling is the answer. Cause now with 115psi and the same thing, not worse, then i'd rule it out.
other things id consider: coilpack, wires & plugs, afm.
If it was a coil pack why does he see the problem at WOT (building boost) and not at 1/2 throttle (no boost)? Same with plugs? Wires? Afm? Not talking about a large amount of boost.
It looks to be boost related, and the one thing that is directly refrencing boost is the Vortech unit. Now a vacuum leak might show up at higher boost levels for sure, but it sounds like he's having the problem right at cross over to positive manifold pressure. Just went the FPR starts to clamp down on the return.
Car was fine (I assume) NA. So what did he change? A turbo (duh) and a whack load of extra fuel.
I'm not being argumentitive, I just don't want to poor bastard to go and replace plugs/wires/coils only to find out the FPR is label backwards or some ****.
Start with the basics, confirm what you've changed.
#57
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Jayc, sorry... that was to answer Brainack.
Brainack, I just took out the AFM for a clean up and see if the brushes have good contacts.
I am still running with the linear AFPR, took out the vortech. I have not put in a fuel guage yet. might do it later today.
Let say I do not attach a vaccum line to the AFPR, will that disable its function?
Brainack, I just took out the AFM for a clean up and see if the brushes have good contacts.
I am still running with the linear AFPR, took out the vortech. I have not put in a fuel guage yet. might do it later today.
Let say I do not attach a vaccum line to the AFPR, will that disable its function?