1987RX7guy

iTrader: (3)

Ok I have hesitations after 4k roughly at 47-4800 rpms and then on down the rpm range every other 500 or so rpms. I have the pill in the vac line to the boost sensor and it has a nice big extra ground on it.

What else can cause hesitations like this?

RoninAutoBoX

There is supposed to be a pill int he vacuum line to the boost sensor? Is this an S4 only thing, or both S4 and S5?

1987RX7guy

iTrader: (3)

pretty sure ita applicable for all FC's

RoninAutoBoX

The plot thickens at to the cause of my shitty performance. I don't even know why I am bothering. T2 conversion is less than 2 weeks away.

1987RX7guy

iTrader: (3)

anybody have an idea? : /

7th Deadly Sin

i actually had this problem w/my 86 na, around 2nd gear..and around that much RPMS...i blame it on my fuel pump/regulator, cuz i was having problems w/it and it wouldnt pump consistant, but i dont know about w/the T2s

1987RX7guy

iTrader: (3)

this problem is on an 87 N/a

7th Deadly Sin

well im not expert but check if your regulator is in good shape, thats what this shop told me when i brought it in

1987RX7guy

iTrader: (3)

Well I am going to check that out. I have a spare rail here so I will swap that over tommorow. If the problem is solved I know that was it.

7th Deadly Sin

hahah aights man, let me know too, because i bought the whole SX PUMP/FUEL FILTER/REGULATOR....soo i'll know that my problem will be solved when i put those in

White_FC

Check the connections on both of your secondary injectors aswell mate. Sometimes even if at first they appear ok on closer inspection might actually be totally rooted, case in point my old ones.

1987RX7guy

iTrader: (3)

Will do I will check on the connectors when I take them out.

7th Deadly Sin

aights i'll check mines too since we seem to have the same problem

1987RX7guy

iTrader: (3)

Since I can't find the damn thing in stock at MT what parts did you get? I may need to go aftermarket if my spare rail doesn't do the trick. :/

mazdaspeed7

Clean your injectors, clean your spark plugs, and replace your fuel filter.

1987RX7guy

iTrader: (3)

I hope somebody locally has a filter. I already have brand new plugs.(Got them for the dyno runs) and I have a set of 91 injectors that I am searching for the parts I need to swap while I have the low imp injectors cleaned and rebuilt. : / ahh the wallet is quiverring(sp?) in fear. Oh well. Thats the price for Dyno runs I guess. :/

Santiago

PS- If anyone has alternate causes for this problem let us know.

7th Deadly Sin

all i bought was the SX fuel filter/regulator/pump, i didnt buy any plugs/injectors, i will later, car is under project, the shop didnt say i needed to replace the fuel rail but it might b a good idea since im replacing everything else, but i dont know wher ei can get an aftermarket one

mazdaspeed7

The FPR is not causing your hesitations. The rarely fail, and when they do, it will cause a lot more than hesitations. It is most likely your injectors, ESPECIALLY if you have been running premix. Ive noticed since running premix(over 2 years), the fuel filters dont last nearly as long, and the injectors need to be cleaned regularly. I usually just dump a quart of MMO in a full tank of gas every couple of oil changes, and that takes care of the injectors.

Dont discount the little things. That should always be the first things to be checked, instead of the last.

1987RX7guy

iTrader: (3)

Huh I will see what happens. I am doing the filter if I can find it localy if not I have to wait for nopi or RP to ship. I am also taking some injector connectors and using them for my 91 Injectors and having my old ones cleaned. But I am still going to switch the rails and see if that does anything. Who knows I may get lucky.

1987RX7guy

iTrader: (3)

Problem solved. It was the Boost sensor.

I ran it for a little and it didn't have any more hesitations.


Santiago

Thank god for parts cars!

1987RX7guy

iTrader: (3)

OK problem is now back. I am buying a fuel filter this friday to see if that will do it. I am also going to swap with my spare fuel rail to see if its the FPR. If those two don't work I guess I will send of my injectors when I can cuz I still don't have a spare set that will fit. :/

White_FC

And your Suuuuuuuuuuuuuure its not your connectors? I don't mean to flog the dead horse over this but this is exactly what my car was doing..
would be there.. then not... then come back..

1987RX7guy

iTrader: (3)

Ok I am going out right now to check my secondary plug connectors. I will take some pics brb you guys.

Santiago

Sesshoumaru

iTrader: (1)

i would consider the fp (maybe not enough volts?).

I would check on that pill. My s4 TII isn't running one now atleast

i would also check timing also........and like suggested.....just make sure everything is up to snuff.

just throw'n ideas out

1987RX7guy

iTrader: (3)

ok I didn't take pics of all the injectors but hell is 11pm here and I am comming down with a cold Here is the injector connector and plug: