1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Fuel pressure question ( TII swap )

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Old Jul 6, 2006 | 02:09 AM
  #1  
rotary emotions's Avatar
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From: Elsenborn, Belgian Eifel
Fuel pressure question ( TII swap )

I finally got my car running again. Took ages, mainly cause I was so dissapointed with it not running, that I couldn't bother working on it...
Anyway, these are the specs: S2 body (1982) with Mariah mode one kit.
S5 TII engine, J-spec (no cats, otherwise like US ones I think), running on a Wolf 3D V3.1. Removed all emission stuff, BAC etc.
I'm using an SX fuel pump (18201 model), but still have the stock fuel pressure regulator. According to what I asked on the forum this should be ok.
Right now the engine starts quite easy, and idles at around 950-1000rpm. It runs rather smooth, but not as smooth as I would like. But it's running VERY RICH.
Since I have mappings that are coming from another S5, it shouldn't be running that rich. I can't ad any accelerator enrichment, cause then it'll drop dead.
If I don't ad enrichement in any way (accelerator, cold start, post start) it'll start, run and pick up speed (and make boost).
So suspect the FPR being wrong, and the pressure being too high. I can't check the exact pressure right now, since I don't have the gauges etc, and can't drive the car to a shop (not allowed to be on the streets overhere: no licence plate, yet).
But it looks like the pressure is the problem, so I thought I'd ask here first.
Where do you guys take the vacuum line from that goes to the FPR? As said I removed all emission controls etc. Does it need "boost" or "VAC" to work? Depending on which connection I use, I get either. I reckoned it needed boost.
Maybe one of the TII guys can help me here.
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Old Jul 6, 2006 | 08:48 AM
  #2  
REVHED's Avatar
Hunting Skylines
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From: Brisbane, Queensland, Australia.
How do you know the mapping is correct?

The regulator should read both boost and vacuum.
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Old Jul 6, 2006 | 09:29 AM
  #3  
rotary emotions's Avatar
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From: Elsenborn, Belgian Eifel
I don't know if it's correct, but it comes from a S5 TII that did run fine on it. Obviously, every engine will need it's own fine tuning, but I can't believe mappings from a dyno tested engine would end up running so rich on another engine in the same configuration (stock except emission removal and larger exhaust). I see you have a TII in your car too, so where did you take the signal line for the FPR from? I'm trying to read and understand the drawings in my Haynes manual (I have a degree as a car mecanic, so even if I don't do this for a living I can work myself through these drawings ), but the differences between S4 and S5 manifolds/plenums don't match my engine??? So either the manual is wrong, or my engine is different???
As for the Malpassi you have (just read your signature) which model is this? I'm thinking about switching to a better (adjustable ) FPR too, but I'm not sure which would suit my needs best.
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Old Jul 6, 2006 | 07:00 PM
  #4  
REVHED's Avatar
Hunting Skylines
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From: Brisbane, Queensland, Australia.
To be honest, the Malpassi's have a reputation for being inconsistent. I'd recommend something like a Sard or Turbosmart.

I took my vac/boost reading for the FPR and map sensor from the lowest port on the front side of the UIM as it reads from all four runners. This gives a more consistent signal as there is less pulsing.

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Old Jul 7, 2006 | 06:20 AM
  #5  
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From: Elsenborn, Belgian Eifel
I tried this port (read the Hitman site about Haltech installations) but I got vacuum readngs here. when the throttle was opened the engine didn't built up boost, but vacuum increased (and so did misfiring, so I quit very soon). The only port that seems to work well for me is one of the ports at the rear. I believe it's the lower one I used there. This gives boost readings when engine rpm increases. So I'd guess the FPR should see the same signal, since I spliced the line to the MAP sensor in the Wolf and the FPR.
I'm wodering if my O2 sensor is working correctly. Any way I could test this?
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Old Jul 7, 2006 | 09:04 AM
  #6  
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What?
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From: CT
Ask the 2nd gen guys.
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Old Jul 7, 2006 | 09:13 AM
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From: Elsenborn, Belgian Eifel
Most of them will have basicly stock cars, very few have all the emissions removed. I must also say there seems to be more knowledge overhere. I think we are more likely to WORK on our cars instead of bolting on some cool rims and a shopping cart wing.
Because a few guys overhere did basicly the same as I did (TII into a first gen and using an aftermarket ECU) some should have run into the same problems, I'd guess.
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Old Jul 7, 2006 | 11:51 PM
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From: 3OH5
You've answered your own questions. Connect a FP gauge, and see.
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