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Discussion Starter · #1 ·
Diagnosing a persistent problem on a friends 87T. The car has a bad miss and smells of fuel badly, but only after car has warmed up. This happens while under light load or idol, and is worst around 2500rpm. On Directscan recording, the miss turns out to be many of the values (LV8, fuel injectors,etc...) temporarily goto WOT readings. For just a fraction of a second, the readings goto LV8=255 , Fuel inj PW=Static, and other variables do the same. Every time the car misses, this is recorded. Remember the TPS never moved from 1.4mv or so. Just idoling or creeping along, basically for an instant, the car goes and sets everything to WOT, then back to normal. This is when it sputters and smells of fuel (from the injectors going full on) So, whats causing the car to think its going to WOT for a fraction of a second, and causing these problems? Only when hot does the car do this. Thanks!!
-Bob

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Direct Scan cable seated properly?

Try a different chip?

Check main ground that goes to the bottom bolt in the passenger head?

Just some places to start.

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Current Combo: Stock Turbo, V4, MSD50's, TH DP, JayJackson 62mm TB, 16position MaxEffort Chip.
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Discussion Starter · #3 ·
Thanks for the suggestions; It's happening with 2 ecm's , one w and one w/o DS... I'll kep you posted.

-Bob
 

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In my non-expert opinion, i'd say try out a known good maf sensor. Had a friend with similar running rich all the time type problems and it turned out to be his maf, which by the way was able to pass the "tap" test and was also still a fairly new "rebuilt" unit.
 

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In my very non-expert opinion, doesn't the O2 sensor determine rich and lean? A somewhat quick swap-out might be prudent to at least rule it out.

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87 GN
Stock, basic mods, etc.
 

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Discussion Starter · #7 ·
Thanks for the suggestions. He's checking the MAF Today.

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UNplug the TPS and let it use its backup value, then see if the problem persists. Might have a short in the TPS.

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Jim Testa
1986 Regal T-Type
Stock block, Turbomotion ported heads, PTE 210 roller cam, GNT ported intake, PTE Plenum, 70mm TB, PTE FM IC, MSD 50's, TE61, TPS-TEC, JT Chip, JT 200R4, Vigilante 2800 LU convertor, JT Boxed lower arms, working on girlde....
 

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Discussion Starter · #9 ·
Problem Solved!! His ground wires were caught between the trans dipstick and the heads. He recently did a torque converter swap, and mistakenly the wires ended up there. They chafed enough to spark as soon as he went and looked underneath and touched them to see if they were tight on ground. Thanks for all your input!

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Working to be an 11-second 1/4 mile, Autocrossing GN.
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