for those running lexus is 300 coils, input needed

spoolint78

Representing T.O
Mar 30, 2005
352
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T.O
Went to the dyno the other day for the first time. I just did 3 base pulls to see what the car would do.

The setup is a follows.
gt76 x trim dbb turbo (6.5-6.8psi)
4inch downpipe, 3inch catback, 3inch catalytic with a 4inch center section. The 3inch reducer on one end of the cat sits inside the 4inch dp flex (restrictive i know).
Stock fuel setup (dual feed rail, stock pump, fpr).
Built motor, ross pistons, eagles rods, mkiv ffim, intercooler pipes, hks racing bov, lexus is 300 coils.

When we did all our passes the graph started to spike really bad top end.
The guy said it could be bad coils, spark plugs, or something ignition related.
Sparkplugs are ngk 6097s with like 1000km on them.

Now I knew my cps was in ok shape, but when i tested the three ohm readings, it is suppose to be between 160-180, and 2 of them fell around 175 and one didn't even register.
I was wondering if that could have been the problem with the spiking on the dyno graph?
Sparkplugs were gapped to .30 but # 1 was at .28 (checked them after).

Anyone have idea idea why the graph would spike so much?

Also, my tach was off a little. When the shop reved the car they thought they stopped at 6500rpm, but fell short but at least 500rpm. THey didn't rev the car completely out as well due to the ignition breakup.

And does anyone know how to test the lexus is 300 coils to see if they are in good working order or not?

 
Last edited:

polobai

New Member
Apr 1, 2005
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Orlampa
only way to test is to swap coils with a working set. I know on mine I had no breakup at 20psi on a gt4082 setup. Also check the wires to ensure they are not arching...
 

spoolint78

Representing T.O
Mar 30, 2005
352
0
0
40
T.O
Ok, I think I may have narrowed down the problem. I changed the cam position sensor recently because after testing the older cps via TSRM
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=IG&Page=16

G1 and G- terminals don't even register anything on the older cps, but all the other terminals (G2, NE) show around 160ohms. The new cps is fine and falls within the limits, but when it gets hot and I test it, it reads around 185+. Is it normal to change when hot?
Lastly, could this be the reason why I have a slight miss and causing the dyno graph to spike in reference to the G1 and G- terminals not registering?
 

adampecush

Regular Supramaniac
May 11, 2006
2,118
3
38
Edmonton
resistance will increase when hot, this is a fundamental electronic property of materials. I have no idea what the G1/G signal does, but if it has a specified range as per the TSRM, I assume it is critical to the correct operation of the car.