GooRoo

iTrader: (4)

Do you mean like 178? or like 165-170?

If it's 178 I'd say yeah, gauge is probably just a bit off. But at that temp the ECU shouldn't be 'protecting' the motor (by adding fuel). Could just be that the ignition system is a little weak for whatever reason and just getting into an area with a bit to much fuel.

If you mean 165-170 then there has to be something wrong with the cooling system. It may be slight right now, and get worse, or just a slightly off thermostat or whatever. In addition to what I said before, it could also be bad temp sensor, but given the rest of the behavior it seems like that wouldn't be the case.

I ran my car at the thermostat opening temp on a night where the ambient was about 35ish and went full boost (15-16psi at the time) and had no issue. Car was super strong (I just had had it dyno tuned by Steve K) and the Air intake and water temps never moved after 3 runs to 8000. A/F was exactly where I wanted it. Of course this is with PFC, etc, etc etc. My point is there isn't really any specific reason that the car should protect itself in cool ambient temps once it is up to operating temp. It has the built in corrections. The only thing you might have to watch for is outflowing your wastegate if it's stock/borderline too small and make sure you have the tuning done right if it's non-stock.

Just remembered one other thing. There's also an Injector vs Air Temp map (on the PFC, probably M2/Stock as well?) that will also add fuel if the temp is cold. Could be another 5-10% in that as well, so maybe that is also part/all of the issue.

My mistake:

WHAT R JOO DOING crazy fool? Your CAR is totoallly broken!!11

adam c

iTrader: (2)

My estimate of the coolant temp is probably 175-178. The gauge doesn't have enough markings for me to determine the exact temperature.

http://www.egauges.com/vdo_mult.asp?...Vision&Units=E

I'm sure that your PFC lacks many of the quirks of the stock ecu. However, I have what I have, and I don't plan on changing anytime soon. About a year ago, I was going to race a friend of mine in his modded 01 Cobra. It was also a cool night. I kept boosting the engine on the way to the race in an attempt to get the engine temps higher (to avoid the hesitation). I was successful, and I beat him (again). Then he hooked up his 125 shot, and beat me pretty good .

Trout2

iTrader: (5)

If you still have the secondary butterflies in your upper intake manifold, they may be causing the problem. These will not fully open until the engine is warmed up thus restricting airflow.

I'd say test the thermostat or even replace it (less than $15 with o-ring). My PFC will read low 80's-C in colder weather (30-40's-F) like this while my SPA gauge with sender in the stock location (rear plate) will be in the mid 170's-F.

Jack

adam c

iTrader: (2)

Jack,

I broke a nipple on the double throttle solenoid a few years ago, so I disabled it. The butterflies are always fully open. I was never great with the conversions from C-F. What's the temp (F) difference between your two gauges?

Trout2

iTrader: (5)

Here's a helpful link: http://www.sciencemadesimple.com/conversions.html

Make a cheat sheet and after using it a dozen times you start to remember the conversions.
165 -F is about 74-C
170 = 77-C
175 = 79
180 = 82
185 = 85
190 = 88
195 = 91

Cruising 80mph in cold weather, I never see below 81-C on the PFC commander but my SPA gauge will get down to the high 160's F. In traffic, I think the stock sender heat soaks (similar to the air temp sensor) because my SPA will vary 175-185 F as the fans turn off and on while the PFC varies 89-92-C (settings programmed in datalogit).

Some things I would look into:
1. Thermostat opening too soon, I lost my original motor at 52K mi due to a half opening thermostat. Stock gauge never moved past the middle and I had no aftermarket gauge at the time.
2. Green sensor in back of the water pump housing. The ECU references this one for fuel adjustments (the black sensor controls the fans). On the PFC, 80-C corresponds to no fuel enrichment. If your green sensor is original it might be flaking. A new one is reasonably priced from Malloy.
3. Wiring harness if original could be a culprit.
I'd guess the sensor or wiring harness would cause problems in warmer weather also, which you don't describe as a problem.

Jack

adam c

iTrader: (2)

Thanks for your input Jack. I will consider replacing the green sensor.

adam c

iTrader: (2)

I did the test today. Coolant temps at 180. 3rd gear pull. Boost steady all the way, and does not drop off when hesitation hits at 7k. I did the test 3 times with the same results, and then took an off ramp. I sat at the stoplight for a minute. Then did a 2nd gear pull with coolant temps about 190. No hesitation all the way to 8K.

DamonB

No way. The tip of the sender is where the reading of the temperature takes place and that's completely immersed in coolant.

Besides, the mass of the sender compared to the mass of the coolant flowing across it is going to insist that the temp of the coolant is absolutely dominant over any environment that may be around the outside of the sender.

DamonB

Any failure in the double throttle system will cause the butterflies to stay open. The butterflies are spring loaded in the open position and the dt solenoid supplies vacuum to them to hold them shut. If you have a vacuum or solenoid failure in the dt system the secondary butterflies will remain open at all times.

WaLieN

Man, I really miss the 101 at night. I should be heading out to SLO sometime, once my car gets out of the shop.

guywiththesti

Adam,

What's going on Adam. It's the guy in the sti that you raced that night, Phung. My friend that I told you about with the single turbo FD show me this thread.

What can else I say but good race. You had me from the gun and can't really do anything if you're faster. I really underestimated your rx7 and not going to from now on or any other Rx7 (Jun).

It's hard to find races around here in SLO, so whenever you're down for races hit me up. I can always use practice and I do need them. Anyways, good to run into you on the forums. Take the turns slowly unlike my friend Jun with the single turbo FD.

Phung

Montego

iTrader: (1)

Welcome. Why hasn't your friend chimed in? We would be very interested on his set up and what numbers he is kicking out.

adam c

iTrader: (2)

Hi Phung. That was a fun race the other night Next time I will try to get my car warmed up better!!! I look forward to seeing you again.

I'm thinking that Jun's car has stock turbo's. Better check on that.

From the West section:

TK1999

lol lol phongie... it's called stock twin and of course we agreed your the first in line...
I'm wanting to see what the out come is very much...

Lynn Bordes

I had this miss also. More in coldweather, worse in 3rd and 4th. Finally broke an apex seal. Installed a HKS Twin Power..... Case Closed!
Barry