I finally got TunerPro RT to work with me after a few months. I decided to do a quick test.
On cold startup Tuner Pro says my idle is 1,000-1,025. But my tach reads 1500 or so.
My IAC also says Steps: 95 on cold start up.
I plan to run this on my way to work to get a good reading after everything is warmed up. Could someone direct me to what the values of everything should be with a good-running 2.8L?
Could be. I'm new to reading data off of a computer, Are Tunerpro's values straight from the ECM?
Should I abide by them, and do secondary tests to confirm Tunerpro's values?
My engine "seems" to idle faster on cold startup, it feels like it actually is 1500RPM, but when I saw TPRT, it was fine. Would my timing be off? (I don't have a timing light at the moment.)
Would TP allow me to determine if my timing is off? (By looking into other values?)
yes the values on the tuner pro are from the ecm, that is why I would guess tach is off. I have never used Tuner pro ,but It should tell you if timing is being advanced or retarded and by how many degrees from tdc. Someone that knows a lot more than I do will be along soon and hopefully answer your questions better, but as far as rpm the tuner pro is more accurate and would be what I went by over the tach.
------------------
87GTseries 1 3800sc (7.597 @88.53 1.579 60ft) (series II swap in progress) 85GT Northstar/ 4t80e 86GT 3800 n/a Northstar Rebuild
There is a resistor on the circuit board for the tach, that deteriorates over time and makes the tach read higher and higher. Lots of cars have this problem - probably any GM (with a tach) from the 70s or 80s. My Fiero tach read close to double the correct numbers. There is a fix posted on here somewhere for it; it involves replacing the suspect resistor with a variable resistor and tuning it to match the correct RPMs.
[This message has been edited by css9450 (edited 01-02-2014).]
No. I have a v6 tach It probably is going, who knows. If I had a spare I'd confirm it.
Does anyone else know how to properly read all the values of TP? I was reading 660 on my o2 sensor today?
Look at the Brightside! You could have paid THOUSANDS for a 4.9 swap only to have it shipped back to you reading 33% higher because changing that resistor was way more effort than what you paid for... [looks at his 4.9 fiero] sigh...
Once the O2 sensor is warmed up it should jump around quickly between ~100mV and 8-900mV. While it's cold, mine reads ~445 mV. YMMV.
The ideal BLM is 128, but you'll seldom see exactly 128. It will likely bounce around between 124 and 132, but should spend most of it's time right around 128. If it's consistently off to one direction, there is something else going on. If it sits constantly at 120 or 136, there is definitely something going on. (Too much or too little fuel being reported.)
My o2 sensor bounces back and forth (between 100-900mv.) My INT and BLM seems to stay in the 140's consistently. Sometimes 120, then to 139-140. My INT and BLM were between 128-144 (Jumped together at the same time from 120-142 a few times. Max 146 I think. (INT was 146 too.) Coolant temp never rose above 200.
Earlier this evening, five hours after I'd most recently driven my Fiero, it was a "balmy" 0oF outside. That represented an opportunity to check and record "cold-start" and "post-cold-start" RPMs for my Fiero.
87FieroSport, you'd mentioned...
quote
Originally posted by 87FieroSport: On cold startup...my tach reads 1500 or so.
Same here (at "cold-start" idle, and while in "Park").
Later, as my Fiero's engine began evidencing some warm-up while still at idle (via the temperature gauge needle starting to move rightward), engine tach RPMs gradually declined, essentially stepwise, in approximately 100-RPM increments.
And finally, when the engine reached normal operating temperature, engine tach RPMs at idle (while in Park) stabilized at around 950 to 1000.
You mentioned:
quote
Originally posted by 87FieroSport: My engine "seems" to idle faster on cold startup, it feels like it actually is 1500RPM....
My Fiero's engine does idle faster at cold-start (at around 1500 tach-indicated RPM) than it does after warming up (post-cold-start, tach-indicated RPMs decline to around 950 to 1000 RPM).
You'd asked:
quote
Originally posted by 87FieroSport: ...do secondary tests to confirm Tunerpro's values?
I think it would be prudent to record and compare four numbers: TunerPro-indicated RPMs first, and tach-indicated RPMs second --- under "cold-start" and then "post-cold-start" conditions.
Long story short, I'm not yet convinced that your tach-indicated RPMs at "cold-start" and then "post-cold-start" idle conditions are wrong, but your TunerPro-indicated RPMs are right: For example, a tach-indicated 1500 RPM at "cold-start" idle --- when the engine is still stone cold --- doesn't seem especially high to me.
[This message has been edited by project34 (edited 01-03-2014).]
Yes, Fiero V6's "stock" idle at 1500 until a certain temperature is reached. In my '7730 conversion, I actually programmed this down to 1250, I believe, with a warm idle of 800rpm.
I actually have to keep reminding myself that my tach is off because it cold starts to 1600 and idles around 1100 on the TACH but in actuality, it's where I programmed it to. Does anyone have a link to the thread about the resistor?
My o2 sensor bounces back and forth (between 100-900mv.) My INT and BLM seems to stay in the 140's consistently. Sometimes 120, then to 139-140. My INT and BLM were between 128-144 (Jumped together at the same time from 120-142 a few times. Max 146 I think. (INT was 146 too.) Coolant temp never rose above 200.
This is all under load between 35-50MPH.
With the INT and BLM that high, your ECM is adding more fuel than "normal". It thinks the engine is running lean.
That may be a function of the air temp. If the intake air temp is very cold, the ECM will tend add fuel to compensate. It would be worth rechecking when the ambient temp is warmer, to see if the BLM and INT drop closer to 128.
I have this issue in my Fiero, however I'm not sure in my case it's the tach because when I swapped out the tach with a supposedly working one from a member on here, it still read high by about 30% or so (same amount as before). Tach is pegged by about 4500 or so true rpm so it's hard to tell when I'm hitting 7k lol. The car has had this issue since I've owned it with a stock 2.8 then with a swap. Is there anywhere particular that the wiring might be causing this?
If I was able to play my logs this would be easier..
I'll do an overnight cold start, key on/engine off data acquisition starting. My engine does not warm up at all (only if I'm driving, it reaches only 180-200 and fluctuates. In park it can take up to 10-15mins) I'll get the blm/int from cold start and warm start
I have this issue in my Fiero, however I'm not sure in my case it's the tach because when I swapped out the tach with a supposedly working one from a member on here, it still read high by about 30% or so (same amount as before). Tach is pegged by about 4500 or so true rpm so it's hard to tell when I'm hitting 7k lol. The car has had this issue since I've owned it with a stock 2.8 then with a swap. Is there anywhere particular that the wiring might be causing this?
I had the same problem where my tachometer read off than I replaced it with a known good one and that one began to read off too.. Sometimes the known good one can also go bad leaving you with two bad tachometers.. Im sure many members as well as I have a few bad tachometers that were once known good replacements to bad ones.. as far as the wiring it seems to be more that that the tach A) has a bad resistor and is just reading off.. the link above can fix it. or B) does not have the right resistor to read the correct engine RPM for you swap motor due to the problems you say you have which leads more to the tach. could be wrong though
------------------ 1988 Pontiac Fiero Gt (fully optioned, factory leather, 5-speed, CJB T-Tops: Black w/ gray interior and blk wheels) 1992 GMC Typhoon #0203 1971Chevorlet Corvette 454cu/ LS5/ 4-speed/ convertible 1993 BMW 850 Ci 6-speed V-12
BLM 120 then hits 144 and drops to 120, then back to 144 a few times INT 120 then hits 144 and drops to 120, then back to 144 a few times
Closed loop occurrs after 4mins.
I'm not seeing much wrong.. Could there be another cause for my horrible mileage? If it was possible to let someone see my data, if they knew more that would help.
I had the same problem where my tachometer read off than I replaced it with a known good one and that one began to read off too.. Sometimes the known good one can also go bad leaving you with two bad tachometers.. Im sure many members as well as I have a few bad tachometers that were once known good replacements to bad ones.. as far as the wiring it seems to be more that that the tach A) has a bad resistor and is just reading off.. the link above can fix it. or B) does not have the right resistor to read the correct engine RPM for you swap motor due to the problems you say you have which leads more to the tach. could be wrong though
Yes it's possible that the new one has gone bad as well however I think it would be a strange coincidence that the tach reads off by exactly the same amount as with the old tach. I do have the correct tach as I have a V6 car, V6 tach, and V6 engine. Tach filter is not used with the engine swap so that's not an issue. And it's more than just being a few hundred rpm off as with lou's car. It more seems to be consistently off by a percentage not a set amount of rpm. With the ignition at run/engine off the tach sits at zero.
Your v6 Tach and v6 engine take a tach filter, period. Do get a tach filter and install it
Arn
I've never seen a car with DIS that uses a tach filter. Edit: 4 cyl Fieros with DIS don't use a tach filter either. My Fiero had one originally but when the DIS module was wired in it was deleted.
[This message has been edited by bcampbell (edited 01-04-2014).]
The ignition isn't feeding the tach. It is the pulses going to the sparks. That tach needs the filter. The ignition does not.
Arn
The tach signal is a 3x signal generated by the ICM. It is similar/the same as the signal sent to the ECM. It is my understanding that HEI distributors need a filter because the moving parts in the system cause interference. Since the only moving part in a DIS system is the crank trigger wheel itself, no external filter is required. Show me a car that came factory with GM DIS and a tach filter and then I may see a point in installing one.
It is also my understanding that a bad tach filter causes a jumpy tach vs. one which just reads high. This is not the case with my tach.
I know I need a tach filter now. Okay. But what about my poor mileage, any of the posted data resulting in that?
I'm not worried about my tach.
Your MAP sensor values sound reasonably normal to me, however the fact that the BLMs are jumping between 120 and 140 tell me that something is wrong. When the BLMs go to 140 the computer is adding fuel to compensate for it sensing a lean condition. Either there is a fuel system issue causing the engine to run lean or there is something wrong with the O2 sensor. When BLMs go to 120 it should actually be helping fuel economy as it's reducing fuel to compensate for what it senses as a rich condition. If you're running rich you could have a leaky injector or possibly other issues.
Filter was there to filter out RFI from the ignition system, doesn't make much of a difference nowadays... I run no filter in my '78 Malibu that originally had a filter, no issues. http://www.youtube.com/watc...J5wZSaWNqPym1V7D91Sg
I was working on the same problem but just decided to park it and take things apart and fix that and the other thing. Mine smells filthy rich, I changed my plugs and my gap .52 might be helping but it was pretty rich at .3 ( that's what they were).
You said it never warms up which mine did not either, that is to turn on the rad fan 195 (I think is the CTS I installed) and a 180 thermostat). Kinda cold that day and not driven.
Is your intake air sensor (IAT) and the ECM temperature sending unit indicating the proper temperature. Is your radiator fan or inside blower motor running? In TP they are shown in Celcuis at least when I have used it. My next step is to disconnect the cold start injector but I may run the TP first to see if anything shows up. I think I have to drive it and not just let it idle for good readings.
I have a CAI, with the IAT into it. My mileage was the same before and after the CAI was installed.
My temp gauge reads a little above 190 if not 190 on my cluster (Same as TP.)
My radiator switch is broken actually come to think of it. My car used to overheat (Doesn't anymore since I did a coupe bumper swap.) My CSI is deleted and plugged.
Does anyone know what the vacuum pressure of the Fiero is at idle? Maybe I have a leak? But my Idle in Park RPM shows 925 lowest, 1025 highest. on TunerPro
How would I be able to tell a leaky injector? Would timing affect my MPG? (I replaced my rear head, but never used a timing gun to achieve perfect 10degree timing. (it still idles fine.. it does feel a little hesitant at times, not very often.))
My TPS also reads 1.0v in Park. Is this allowable? I know the TPS can have different tolerances, but I've heard .55 is superb.
1v sounds high; you can try resetting it by turning key to on/engine off with the TPS unplugged, then plug it in and start the car. It won't be a permanent fix but it should at least temporarily reset the TPS to 0.
My formula 5 speed averages 26mpg of mostly highway. A 3 speed auto will be worse. I don't think that would affect your mileage much unless you spend a lot of time idling. The holes that hold the TPS in place should be slotted so adjusting the idle voltage is just a matter of twisting it and tightening it down.
Disconnect the TV cable and check your voltage with the key in the on position. That should tell you if it's tugging on it a little if you can't adjust the TPS anymore.
You adjust the cable as follows. Underneath the cable end (at the TB bracket )is a lever. You press the lever in and at the same time push the cable stub all the way in. You then rotate the throttle all the way open. The cable self adjusts.
[This message has been edited by lou_dias (edited 01-07-2014).]
)
