Tripminder on HO ecu?

Topic: Tripminder on HO ecu? (Read 760 times) previous topic - next topic

Tripminder on HO ecu?

January 21, 2008, 04:05:54 AM

I just got back my car after having it be stuck in Seattle for a month due to many issues with installing the new motor. I was curious how accurate the tripminder's fuel readings are or if they're basing it on the 14lb injectors with the SO ecu. Insight?

I burned 4.6 gallons of gas total from Federal Way, giving me an average of 30.5mpg on the new motor - was at 33.5mpg through Olympia before the speed limit jumped to 70. Motor's built with an HO cam/computer with '93 cobra heads and intake, all with stock exhaust, so I'm not quite believing these economy numbers but won't know for sure until I put a couple tanks through it and see what the pump says.

Other than still having air bubbles in the cooling system causing the thermostat to open/close continously and me needing to top the tranny off, everything seems great, fluids all check out, it pulls above 2500rpm...although it doesn't take off as well as the SO when from a stop

Tripminder on HO ecu?

Reply #1 – January 21, 2008, 11:02:15 AM

What processor are you running? If the injectors are matched to the processor, the fuel consumption information sent to the cluster should be correct. I'm using a A9P which was calibrated for 19lb/hr injectors and my fuel economy numbers from my tripminder appear to be correct. I average 25mpg steady cruise at 70mph.
Check your fuel usage against your mileage driven manually. If your speed is off due to different gears or tires, this can give you a false fuel economy reading also.

Tripminder on HO ecu?

Reply #2 – January 21, 2008, 12:32:18 PM

This IS going off the fuel numbers and manually calculating the distance - my tripminder and speedometer read a little slow (TC rims and their stock tires compared to the factory 14" 8 holes...I meant to buy 55's because of this AND price, but forgot when I purchased them and got 60's). The ECU is from an 88 mustang so speed density system and it has 19 lb/hr fuel injectors form a '94 tbird.

If you read this vinnie, the ecu works great. Well, I think it does anyway. KOER codes never seem to finish - they get stuck after code 33-EGR and never give me a 10/11.

Tripminder on HO ecu?

Reply #3 – January 21, 2008, 02:21:55 PM

The ECU generates the DOL [Data Output Link - aka Fuel Flow Output - pin 34] output based on the injector scalar (lb/hr) set in the EEC. The tripminder just reads whatever comes in via the DOL and uses the VSS input to calculate mpg.

If you run injectors that didn't originally come with the EEC, you must modify the FI scalar to get an accurate DOL signal.

Tripminder on HO ecu?

Reply #4 – January 21, 2008, 03:41:16 PM

So 19lb = 19lb isn't necessary true? I'll have to check at the pumps then.

Tripminder on HO ecu?

Reply #5 – January 21, 2008, 06:27:00 PM

To clarify, I mean if you don't run the same (size) injectors, there will be a problem.

Tripminder on HO ecu?

Reply #6 – January 21, 2008, 08:36:49 PM

...please refer to http://foxtbirdcougarforums.com/showthread.php?p=199160#post199160

Car isn't running again after yesterday it went 160 miles great.

Tripminder on HO ecu?

Reply #7 – January 26, 2008, 04:05:29 PM

Whatever it was, the problem hasn't resurfaced since. I didn't change anything.....

On another note, either I had a ton of air in my heating system or there may be a tiny head gasket leak somewhere. Fluids are all still clean but after dumping another 1/2 gallon into the car, the thermostat is again working properly. I'm hoping its just air burping from the system but I'm not believing anything until the car gets more miles on it.

Tranny is at the full mark but still slipping when its cold. I don't think its liking the fresh fluid.