Possible HESITATION issue

[MX5RACER]

I have done much searching and I cannot find a decent discription for the dreaded hesitation (Pre-flash). What I am experiencing is this:

When the car is cool, as in first thing in the morning, the car pulls really hard. As the car comes up to operating temp, I have an issue that pops up. Between 4,000 and 5,000 the car will stop accelerating at the same rate. Then as soon as it passes the 5,000 mark it pulls hard again. South Florida area, so the air temp. is in the 80's or so, and it seems to get worse as the car gets hotter. This is my first experience with a turbo car, so it could just be heat-soak.

Some info. on the car. Brand new ATP wastegate actuator, new plugs and new coils. I also replaced the vac. lines from the intake manifold to the wastegate actuator including the BPV. Stock everything else. Boost level seems pretty consistent btwn 6-8, peaking to 8 then leveling out at 7, til 4,000 then goes to 6, til 5,000 then back to 7. Vac. at idle is btwn 20-22 inMg.

I also cannot find any sticker in regards to the re-flash on the car, and I don't want to pay $80 to a dealer. Any suggestions would be greatly appreciated. I am going to replace the BPV with another stock unit that I have from my brother's car and see if the problem continues. Thanks.

[mikeski]

hesitation is normal for our cars, the reason i believe is because of the crappy tuning. the reflash will help that. it gets worse when the car warms because of the tiny intercooler heatsoaking, the way to fix that is to get an aftermarket intercooler. if you dont want the reflash you could consider getting some kind of ems to help smooth out the rich fuel conditions, but this would cost more than the reflash. welcome to the MSP.

[MX5RACER]

Thanks, so this seems to be the dreaded hesitation issue then, not something else?

[mikeski]

yea thats what it sounds like to me.

[vangj01]

This is my setup:

Perrin FMIC
HKS SSQV BOV w/dual setup
SS AFC V2
Injen CAI
PG 2.5" Midepipe+Cat

I still seem to have some hesitation issues. Usually if I WOT it then it's fine, but at times when I just want to drive normal the car seems to hesitate and jerk. My AFC is set to the stock MSP tune. It doesn't have a lag like how it did when it was stock (like MX5Racer's issue), but it just more jerks at lower rpm driving normal; and it doesn't happen all the time.

Maybe this is just how they still drive even with the AFC. Anything that I can do that might help? Maybe I just need to get the AFC tuned?

[MX5RACER]

I did some more digging and it appears that my issue might also be the BPV. If I short-shift from first into second and mash the gas the car starts to build speed and boost. Then about 3,800 the car starts to slow down, sometimes it will sort of buck a tad. If you do the same thing in third, fourth and fifth the buck becomes more pronounced. A friend of mine with an Audi was describing exactly my symptoms, but his story ended with it being the BPV. It would leak and cause the boost to be diverted back to the compressor.

It is a really good thing that the MSP BPV don't leak right

I have gotten a hold of a slightly used stock BPV and put it on, but the S. FL rain made it impossible to test after lunch. Which is when I swapped out the valves. I will test it out again on the way home and will report back with the results.

My issue is probably two, not just the hesitation. I will probably still have the hesitation issue, but I think the BPV leaking could have caused the hesitation to become even worse... OH NO!

[MX5RACER]

OK, good news. The newer BPV made a big improvement in the car. Now there is only a slight pause at 4,000 (Hesitation, most likely), but the car recovers from that much quicker now. Instead of just falling off and then pulling after 5,000 it pulls from 4,250 or so. So the hesitation is lessened to liveable levels.

I am still trying to have the reflash done as well, because I have no plans to modify this car at all.

[mikeski]

let me know how the reflash helps,.

[ogsp5]

The re-flash will help, but I would invest in the SS afc. Since I have had installed no hesitation at all. If you have a wide band that also helps. Do some data logging (for daily driving) and then dyno tune ( for power).

[Warlock2X]

I have done much searching and I cannot find a decent discription for the dreaded hesitation (Pre-flash). What I am experiencing is this:

When the car is cool, as in first thing in the morning, the car pulls really hard. As the car comes up to operating temp, I have an issue that pops up. Between 4,000 and 5,000 the car will stop accelerating at the same rate. Then as soon as it passes the 5,000 mark it pulls hard again. South Florida area, so the air temp. is in the 80's or so, and it seems to get worse as the car gets hotter. This is my first experience with a turbo car, so it could just be heat-soak.

Some info. on the car. Brand new ATP wastegate actuator, new plugs and new coils. I also replaced the vac. lines from the intake manifold to the wastegate actuator including the BPV. Stock everything else. Boost level seems pretty consistent btwn 6-8, peaking to 8 then leveling out at 7, til 4,000 then goes to 6, til 5,000 then back to 7. Vac. at idle is btwn 20-22 inMg.

I also cannot find any sticker in regards to the re-flash on the car, and I don't want to pay $80 to a dealer. Any suggestions would be greatly appreciated. I am going to replace the BPV with another stock unit that I have from my brother's car and see if the problem continues. Thanks.

thats exactly whats happening to me. i was wondering what it was. on a cold motor it pull just fine but gets to operating temp and it doesnt hit full boost till about 5k. im hooked up to a spearco FMIC and hard pipes and it still does it. what should i do to fix this? also my BOV isnt BOVing, this started when i hooked up a slowboy racing MBC i dont know if its coinsidence or if the MBC is the problem. its a greddy type s im jrunning just a BOV and i relocated my MAF closer to the throttle body

[juancarloszx9]

Hello guys, I just wanted to say (I don't know if you are experts) but the flash, is irreversible, if you ... later on want to put a boost controller on it, the flash has been proven to not be exactly best friend with it

[Stormtrooper77]

Hello guys, I just wanted to say (I don't know if you are experts) but the flash, is irreversible, if you ... later on want to put a boost controller on it, the flash has been proven to not be exactly best friend with it

I put a boost controller on mine post reflash and everything works fine. There are numerous threads regarding the flash and boost (how much you can run, etc.). Just don't be stupid with it and you should be fine.

[MSP2k3]

My MSP is flashed and I am running 8psi with SS AFC and no problems. The car runs great. I will mention that I had a problem with hesitation and bucking when i first got the car almost to the point where it wasn't drivable. I took it in and my fuel pump assembly was going bad. It would lose fuel pressure at about 3k rpms. Replaced the pump and assembly and the car has ran great ever since.

[HondaNoMore]

easy way to test the fuel pump? i get a stutter around 3k

[MSP2k3]

If you have a fuel pressure gauge you can watch to see if it holds pressure throughout the rpm range.. i had to take mine to a shop and they hooked it up to a fuel pressure gauge and tested it out. Other than that i do not know