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XR4Ti / Sierra / Sierra Cosworth Discussions - Questions, problem resolution, general talk, technical tips and modifications.
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Carlisle 2020
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Post by XR4 » Tue Dec 04, 2007 7:09 pm

Ok when i'm around my friends i feel like a genius but you guys know some stuff and i feel like a bum but most of the time either i don't have an answer for people's questions or it's already been answered but reading makes me just ask more questions.

Computer
Ok my car has always ran rich one reason is the adj fuel pressure regulator and 2nd is the ecu (PF2) has a super chip chip (trust me not my doings) does anyone have a stock chip or and idea to make it run better! Like a better ECU that they want to trade/sell?

FMU
Also i just got a new turbo (T3/4) so i also picked up an OBX FMU (12-1 i think? the one for stock turbo cars) and i was just wandering if i should keep it or just get rid of it?

Missfire
Also i changed my plugs in June that day i drove to the drag strip and blew the turbo on friday i got the car back on the road and it ran! i drove to get some food let it run with the turbo timer then when i came back started it up and it sounds like a subaru (definately a miss fire). I added some octane booster and some seafoam didn't help. Could it sitting foulded my plugs or is it more likely to be a clogged injector?

-Also i know that i can just change my plugs and see if it fixes it but with the Stinger Performace manifold i need to take the turbo off and i don't want to do that every 2 days.
T3/T4 turbo, Stinger Performance manifold, FMIC, Knock off Greedy type s bov, T-5 trans, Steeda Short shifter, Stage 1 clutch, OBX FMU, adj Fuel pressur regulator, MBC, external wastegate, and a few problems. But i still love it WHY?

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Post by mtnXRti » Tue Dec 04, 2007 7:36 pm

FMU :?:
'87 XR Street Ninja
'89 XJ Urban Krawler




Aaron
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Post by Texranger » Tue Dec 04, 2007 7:48 pm

mtnXRti wrote:FMU :?:
FMU = Fuel Management Unit (a.k.a Fuel Pressure Regulator)

Nick.

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Post by XR4 » Tue Dec 04, 2007 7:55 pm

Fuel pressure regulator that adj fuel pressure as boost increases not manually
T3/T4 turbo, Stinger Performance manifold, FMIC, Knock off Greedy type s bov, T-5 trans, Steeda Short shifter, Stage 1 clutch, OBX FMU, adj Fuel pressur regulator, MBC, external wastegate, and a few problems. But i still love it WHY?

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Post by DPDISXR4Ti » Tue Dec 04, 2007 8:08 pm

For starters, I'd just pull the J3 board with Superchip off the back of the PF2 and start with a stock setup.

Same deal on the FPR. Keep the stock one in place and get the thing running right. The more complex FMU's just give you more excuses to screw up. At best, I'd just go with a AFPR, but you don't even need that.

Do a basic tune-up - plugs, wires, rotor, cap. If your distributor is original and has over 100K miles, I'd suggest just getting a rebuilt distributor and you'll have a fresh PIP and TFI as part of the deal.
Brad

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Post by mtnXRti » Tue Dec 04, 2007 8:49 pm

Texranger wrote:
mtnXRti wrote:FMU :?:
FMU = Fuel Management Unit (a.k.a Fuel Pressure Regulator)

Nick.

Gotcha. I've heard of an FMU before. Just never switched the term for a FPR.
Thanks.
'87 XR Street Ninja
'89 XJ Urban Krawler




Aaron
Longmont, CO

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Post by Maurice S » Tue Dec 04, 2007 9:06 pm

I'd leave the chip on and set the FPR to stock which is 39~41Lbs at idle with the reference line diconnected??

The chips are made to work at stock FP's....it might run a little stronger at elevated boost levels...if not pull the chip off and go from there.
85 XR '" Lightly Street Massaged"

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Post by XR4 » Tue Dec 04, 2007 9:45 pm

DPDISXR4Ti wrote:For starters, I'd just pull the J3 board with Superchip off the back of the PF2 and start with a stock setup.

Same deal on the FPR. Keep the stock one in place and get the thing running right. The more complex FMU's just give you more excuses to screw up. At best, I'd just go with a AFPR, but you don't even need that.

Do a basic tune-up - plugs, wires, rotor, cap. If your distributor is original and has over 100K miles, I'd suggest just getting a rebuilt distributor and you'll have a fresh PIP and TFI as part of the deal.
Can i just pull out the super chip and will it run? I didn't put it in so i don't have a stock chip and i read somewhere how to test the FPR (factory not adj.) because i found one in the car but i don't know if it works or not?
T3/T4 turbo, Stinger Performance manifold, FMIC, Knock off Greedy type s bov, T-5 trans, Steeda Short shifter, Stage 1 clutch, OBX FMU, adj Fuel pressur regulator, MBC, external wastegate, and a few problems. But i still love it WHY?

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Post by merkurdriver » Wed Dec 05, 2007 6:47 pm

XR4 wrote:
DPDISXR4Ti wrote:Can i just pull out the super chip and will it run?
Its like an "override chip" it just overrides the factory settings. Pull it off and you'll be instantly back to the factory settings - you don't need to put a different chip on, just pull that one off and your computer is back to stock.

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Post by jkxr4ti » Wed Dec 05, 2007 11:14 pm

If your turbo went south recently you might want to consider replacing the o2 sensor. Plugs are a yearly maintenance item, and are dirt cheap so i would get a new set of those as well. You may want to run the codes as well, that could point you in the direction of whats causing the rich condition.

Also as was said above, get it running right in a stock configuration before throwing modifications in the mix, even if you have to take a couple bolt on items off for a bit. This from my experience will save you alot of headaches and broken parts.
Merkur....Its German for Mutt....Mustang, Saab, Volvo, Lincoln, Contour, Cummins... and the list goes on.

Jeremy Kemp

1988 XR4Ti Chestnut Brown/Spice Leather
MC2 Coilovers and Bushings, Contour Rims and Rotors, Ported Motorsport Head, Cosworth 4x4 Intercooler, Holset HY35 Turbo, 80LB Injectors, Megasquirt2 EFI

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Post by XR4 » Thu Dec 06, 2007 12:50 pm

thanks guys
T3/T4 turbo, Stinger Performance manifold, FMIC, Knock off Greedy type s bov, T-5 trans, Steeda Short shifter, Stage 1 clutch, OBX FMU, adj Fuel pressur regulator, MBC, external wastegate, and a few problems. But i still love it WHY?

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